tag:blogger.com,1999:blog-66354799515045211662024-03-26T23:37:22.563-07:00KR7W's Ham Radio BlogHam Radio and Electronic Experimenting...kr7whttp://www.blogger.com/profile/12925283975807120485noreply@blogger.comBlogger16125tag:blogger.com,1999:blog-6635479951504521166.post-43025879884010623922023-07-30T17:17:00.032-07:002023-11-08T12:02:13.055-08:00Building a Low Power RF Attenuator and Some Nano VNA Fun<p><span style="font-family: verdana;"><span style="font-size: medium;">This Project's main goal</span> is to build a RF ATTN (attenuator) to lower the RF Output level of my Baofeng UVR-5 Handy Talky that will be used as a Hidden Transmitter Hunt Fox Transmitter.</span></p><p><span style="font-family: verdana;">The secondary goal is to get to know and use my newly acquired <b>Nano</b> <b>V</b>ector <b>N</b>etwork <b>A</b>nalyzer to test the attenuator.</span></p><p><span style="font-family: verdana;">The Baofeng TX outputs 1.2 watts on Low power. Ideally, I want to transmit approx. 200mW to the Fox Antenna. General License Test math says: If I place a 6dB </span><span style="font-family: verdana;">(Divide</span><span style="font-family: verdana;"> by 4) </span><span style="font-family: verdana;">ATTN between the TX output and the antenna feedline- the resultant RF Level should be approx. 300mW. </span><span style="font-family: verdana;">Since</span><span style="font-family: verdana;"> I used to work for the Government... that's close enough.</span></p><p><span style="font-family: verdana;">Regarding how to build the ATTN, this particular Youtube video inspired me the most:<br /></span><a href="https://www.youtube.com/watch?v=A5gGeV7CiQ0"><span style="font-family: arial; font-size: x-small;">#91: Basic RF Attenuators - Design, Construction, Testing - PI and T style - A Tutorial - YouTube</span></a></p><p><span style="font-family: verdana;">But instead of doing lots of math in my Spiral Notebook... An online App was discovered to provide the schematic and calculate the resistor values. <br />Check it out: </span><a href="https://www.everythingrf.com/rf-calculators/pi-attenuator-calculator"><span style="font-family: arial; font-size: x-small;">Pi Attenuator Calculator - everything RF</span></a></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj8VtnZ5MoJ_iWOuRsPj-Pyg4c_wXL2fVr_ZeH5w24PZtNTCnxAfZzt6C5l_Rfvl2q7em2cHGxYFfQ-Zb-37vUUOypChXTj67xuQoVCrp845CVEmTEljYR36qXZ4aJzdPemJEnywt_aiWB4msb4kc046VUzN7mfp7pMdYYZPDrwtmv8JHI8JDty8QEtFeaf/s848/Resistor%20Value%20Calculator.jpg" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="806" data-original-width="848" height="379" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj8VtnZ5MoJ_iWOuRsPj-Pyg4c_wXL2fVr_ZeH5w24PZtNTCnxAfZzt6C5l_Rfvl2q7em2cHGxYFfQ-Zb-37vUUOypChXTj67xuQoVCrp845CVEmTEljYR36qXZ4aJzdPemJEnywt_aiWB4msb4kc046VUzN7mfp7pMdYYZPDrwtmv8JHI8JDty8QEtFeaf/w399-h379/Resistor%20Value%20Calculator.jpg" width="399" /></a></div><p><span style="font-family: verdana;">Values of R1 and R2 are rounded off.</span></p><p><span style="font-family: verdana;">In my collection of 1-watt resistors- I didn't have the exact values. So put resistors in parallel until the approx. desired value was obtained.</span></p><p><span style="font-family: verdana;">Then blob soldered two SMA-F chassis connectors to a piece of blank <b>P</b>rinted <b>C</b>ircuit <b>B</b>oard.</span></p><p><span style="font-family: verdana;">Lastly, blob soldered the resistor combinations to the PCB, accidently in a neat fashion.</span></p><p><span style="font-family: verdana;"><br /></span></p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgxUrj11G9HaCOemX8qNKLMWIxnE4rESDc13vQHPyzWS2wCdRzCZ1ChpQ9-toWyjNsJOB-F4-zWYjzR6LA2tMKyVKpoD0qMSYTbDCXFe-l_RNYNK0Ka_FMxeDufxYfNLx962b2EzJmc8A4fegmjdvNJEEhTMx-lAdfaawRJ8lvKz7LGCsF7po5qiBLTjs1D/s1400/CloseUp%20of%20ATTN.jpg" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="641" data-original-width="1400" height="246" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgxUrj11G9HaCOemX8qNKLMWIxnE4rESDc13vQHPyzWS2wCdRzCZ1ChpQ9-toWyjNsJOB-F4-zWYjzR6LA2tMKyVKpoD0qMSYTbDCXFe-l_RNYNK0Ka_FMxeDufxYfNLx962b2EzJmc8A4fegmjdvNJEEhTMx-lAdfaawRJ8lvKz7LGCsF7po5qiBLTjs1D/w534-h246/CloseUp%20of%20ATTN.jpg" width="534" /></a></div><p><br /></p><p><br /></p><p><br /></p><p><br /></p><p><br /></p><p><br /></p><p><br /></p><p><br /></p><p><span style="font-family: verdana;">How did I do? Is the Attenuation close enough? Is the SWR on each side of the ATTN = 50 ohms? Enter the Mini Vector Network Analyzer...</span></p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgHDo8HfmJNB_tiB-0S2ZMxT6xed-juBJrGj5toRs60IjosasK4Yl4e5fh7ADonuyetmjzwe5RxRiq4JS33xv00xKU6ElD30ST-k2PB_eyXLyfxjRB5aCgvwpraYMXVNfjXP73vUmNVh4cHw-IwByjaGkSSZizVCnO1l4DwFcpuBGpsUBmyQSwlOVMwmWGL/s1600/ATTN%20es%20VNA.jpg" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="1166" data-original-width="1600" height="359" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgHDo8HfmJNB_tiB-0S2ZMxT6xed-juBJrGj5toRs60IjosasK4Yl4e5fh7ADonuyetmjzwe5RxRiq4JS33xv00xKU6ElD30ST-k2PB_eyXLyfxjRB5aCgvwpraYMXVNfjXP73vUmNVh4cHw-IwByjaGkSSZizVCnO1l4DwFcpuBGpsUBmyQSwlOVMwmWGL/w493-h359/ATTN%20es%20VNA.jpg" width="493" /></a></div><span style="font-family: verdana;"><p><span style="font-family: verdana;">Important Note: This my second time using the VNA to make a semi precision measurement. I had to start over many times until I was satisfied that I was doing the testing correctly.</span></p><p><span style="font-family: verdana;"><br /></span></p>The VNA was set up and calibrated to measure a 2-port device via Port 1 to Port 2. And SWR measured on Port 1 only. </span><p></p><p><span style="font-family: verdana;">The SWR and Log Magnitude (signal level) displays selected. </span></p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEggKWa7VBWAyAp9hahLMlGPtT0RfR2r1bcE8fT37vIxrkUZjBttYSChr1pfTeHvnjY7QP3k5VGgsCGZoP3bZ3aWVeTewS9cW9WRYjGrIcY53nKBrB1lrH9V_5m7VkJIgCoVqZB7v-gYwAr4ZN1g2k_hx1pu8b53yBvv1gaF5co4hB_Rrv8KezdOZh45J8Ye/s1200/VNA%20Screen.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="640" data-original-width="1200" height="303" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEggKWa7VBWAyAp9hahLMlGPtT0RfR2r1bcE8fT37vIxrkUZjBttYSChr1pfTeHvnjY7QP3k5VGgsCGZoP3bZ3aWVeTewS9cW9WRYjGrIcY53nKBrB1lrH9V_5m7VkJIgCoVqZB7v-gYwAr4ZN1g2k_hx1pu8b53yBvv1gaF5co4hB_Rrv8KezdOZh45J8Ye/w567-h303/VNA%20Screen.jpg" width="567" /></a></div><br /><span style="font-family: verdana;">VNA frequency span is set: 10MHz to 200MHz- as seen at the bottom of the screen. The Green trace is the amount of attenuation measured across the frequency spread. There is a marker (little box with 1 inside of it) at 141.1 MHz on the <b><span style="color: #6aa84f;">Green</span></b> trace that indicates 5.71 dB loss, Port 1 to Port 2.</span><p></p><p><span style="font-family: verdana;">Also, another marker that indicates the same frequency on the <b><span style="color: #2b00fe;">Blue</span></b> SWR trace at the bottom of the display- which reveals it is 1 to 1 across the frequency span. When removing the test cable from Port 2 of the VNA, which unterminated the ATTN of its 50-ohm load... the resultant SWR at Port 1 was 1.5 to 1. </span></p><p><span style="font-family: verdana;">Another concern is: Will the 1.2W of RF Power melt down the ATTN's resistors? After testing the Baofeng HT for 5 hours with the ATTN in series with the antenna- the resistors get noticeably hot to the touch.</span></p><p><span style="font-family: verdana;">As mentioned above, the Baofeng's Power Out measures as 1.2W. At the output of the ATTN, the Power Out measures approx. 320mW. Almost as calculated. Much too close for Government work.</span></p><p><span style="font-family: verdana;">If the Nano VNA sparks any interest for you, gentle readers... I received my inspiration and information from this Youtube Ham Radio enthusiast: </span><a href="https://www.youtube.com/results?search_query=smoking+ape+nanovna+"><span style="font-family: arial;">smoking ape nanovna - YouTube</span></a> -<span style="font-family: verdana;"> a Smart easy to listen to presenter. There are many Mini VNAs to choose from. I chose this particular model because the Port 1 to Port 2 dynamic range was listed as 70dB versus 50 or 60 dB in others. </span></p><p><span style="font-family: verdana;">End of Blog. As usual- THX for reading this far. 30, 73 - Ricky KR7W.</span></p><p><span style="font-family: verdana;"><br /></span></p><p><span style="font-family: verdana;"><br /></span></p><p><span style="font-family: verdana;"><br /></span></p><p><span style="font-family: verdana;"><br /></span></p><p><span style="font-family: verdana;"><br /></span></p><p><span style="font-family: verdana;"><br /></span></p><span style="font-family: verdana;"><br /></span><p></p>kr7whttp://www.blogger.com/profile/12925283975807120485noreply@blogger.com0tag:blogger.com,1999:blog-6635479951504521166.post-7736183167532659322023-07-25T09:17:00.000-07:002023-07-25T09:19:56.397-07:00Hidden Transmitter Hunting - Fox or Bunny Transmitter Controller<p><span style="font-family: verdana;"> <span style="font-size: 11pt;">The KR7W Hutch
of Hidden Transmitter Hunt Bunnies are becoming aged. The old timer bunnies are made from Icom
handy talkies from </span><span style="font-size: 14.6667px;">approx.</span><span style="font-size: 11pt;"> 1982, use a </span><span style="font-size: 14.6667px;">Ham Gadgets</span><span style="font-size: 11pt;"> Repeater controller circa 2005, and contain a </span><span style="font-size: 14.6667px;">5-pound</span><span style="font-size: 11pt;"> Sealed Lead Acid battery. The battery seems to double in weight for each year I grow older. Enter some fairly new technology – that’s not
just for newly licensed hams.</span></span></p><p></p><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhcRRPntDBxBz9tH2HZMsORisiOOc6dNpiWG462Cjry9fzVyG2REClDoZyAR0ARZprAZS122PHDMZ5vJoCTxcxY-q_YfJl1mSQcCtdl3vmflYn8Dk920VWr3KCZFuGpD0l0SbTmFRRDUxtz0cIDmDHEhqrjvBNAZ7lxfHWEaJc66-u67ZRIoJHAkPhz7OM-/s861/Title%20Photo%20UV5R%20es%20Controller.jpg" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="861" data-original-width="800" height="392" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhcRRPntDBxBz9tH2HZMsORisiOOc6dNpiWG462Cjry9fzVyG2REClDoZyAR0ARZprAZS122PHDMZ5vJoCTxcxY-q_YfJl1mSQcCtdl3vmflYn8Dk920VWr3KCZFuGpD0l0SbTmFRRDUxtz0cIDmDHEhqrjvBNAZ7lxfHWEaJc66-u67ZRIoJHAkPhz7OM-/w364-h392/Title%20Photo%20UV5R%20es%20Controller.jpg" width="364" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;"><span style="font-family: arial;">Since College Days- KR7W's workshop has been<br />dubbed "Acme" after the many projects built. Where some projects<br />worked as well as Roadrunner catching gizmos that the Coyote<br />used to entertain us with.</span></td></tr></tbody></table><p class="MsoNormal" style="mso-pagination: none;"><span style="font-family: verdana;"><span style="font-size: 11pt;">At Amazon.com, </span><span style="font-size: 14.6667px;"><b>Baofeng</b></span><span style="font-size: 11pt;"><b> UV5R</b> handy talkies are currently priced at approx $20 and their Extra Strength <b>3800 m/A batteries</b> are the same price.</span></span><span style="font-family: verdana; font-size: 11pt;"> </span><span style="font-family: verdana;"><span style="font-size: 11pt;">For about $40 (plus ancillary parts) a </span><span style="font-size: 14.6667px;">long-lasting</span><span style="font-size: 11pt;"> hidden
transmitter can be built.</span></span><span style="font-family: verdana; font-size: 11pt;"> </span><span style="font-family: verdana; font-size: 11pt;">But, how to
control it?</span><span style="font-family: verdana; font-size: 11pt;"> Or...</span><span style="font-family: verdana; font-size: 11pt;"> how to key the FM signal
plus the station ID for a certain time, then shut down for a certain time, and then start
back up, over and over again? </span><span style="font-family: verdana; font-size: 11pt;"> </span><span style="font-family: verdana; font-size: 11pt;"><b>Arduino Nano </b>(3 for $20 at
Amazon), plus inexpensive miscellaneous parts to the rescue.</span></p>
<p class="MsoNormal" style="mso-pagination: none;"><span style="font-size: 11pt;"><span style="font-family: verdana;"> </span></span><span style="font-family: verdana; font-size: 11pt;">This blog article hopefully reveals my so far successful creation of a reliable, powerful, Hidden Transmitter or Fox or Bunny that will run for the duration of the hunt.</span></p>
<p class="MsoNormal" style="mso-pagination: none;"><span style="font-size: 11pt;"><span style="font-family: verdana;"> </span></span><span style="font-family: verdana;"><span style="font-size: 11pt;">The </span><span style="font-size: 14.6667px;">Baofeng</span><span style="font-size: 11pt;"> part is easy– insert the
charged 3800 a/H battery, set the frequency, set Low Power, let the LOCK.</span></span><span style="font-family: verdana; font-size: 11pt;"> </span><span style="font-family: verdana; font-size: 11pt;">The Arduino </span><span style="font-family: verdana;"><span style="font-size: 14.6667px;">controller was</span><span style="font-size: 11pt;"> challenging.</span></span><span style="font-family: verdana; font-size: 11pt;"> </span><span style="font-family: verdana; font-size: 11pt;">I do not know the C++ Programming language to
create a program of my own.</span><span style="font-family: verdana; font-size: 11pt;"> </span><span style="font-family: verdana;"><span style="font-size: 11pt;">Persistent Google searches found a <b><a href="https://projecthub.arduino.cc/nfarrier/auto-keyer-for-radio-fox-hunting-693269" target="_blank">Fox Controller Project</a></b> that uses an Arduino Nano that has simple wiring and a </span><span style="font-size: 14.6667px;">well-documented</span><span style="font-size: 11pt;"> <b>sketch</b> (the program file) that helped me to figure out what to
change to fit my Fox Hunt needs.</span></span><span style="font-family: verdana; font-size: 11pt;"> </span></p><p class="MsoNormal" style="mso-pagination: none;"><br /></p><div class="separator" style="clear: both; text-align: center;"><span><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh4jVu-Meq5E5NwMLfSsj6hfc-8hhfhrv3sZO1cjF-uztBDkg81cO5Zy3KR7jyP0kt-hMYGZcF5rkhdoh9sTT0nzui5CB5ivU3VdBKOTMUkqfkRvtHwRxiRMEmdhMii1u90htuBgeiDz_m4qLW_EAb11DYCw7IbSNWkxKRN-tKOc1Jh6fmmRIyPX4DTD6Ps/s1383/Schematic%20Fig%201.jpg" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="1079" data-original-width="1383" height="517" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh4jVu-Meq5E5NwMLfSsj6hfc-8hhfhrv3sZO1cjF-uztBDkg81cO5Zy3KR7jyP0kt-hMYGZcF5rkhdoh9sTT0nzui5CB5ivU3VdBKOTMUkqfkRvtHwRxiRMEmdhMii1u90htuBgeiDz_m4qLW_EAb11DYCw7IbSNWkxKRN-tKOc1Jh6fmmRIyPX4DTD6Ps/w662-h517/Schematic%20Fig%201.jpg" width="662" /></a></span></div><span style="font-family: verdana;"><br /><o:p></o:p></span><p></p>
<p class="MsoNormal" style="mso-pagination: none;"><span style="font-family: verdana;"><span style="font-size: 11pt;">The Block Diagram - Schematic basically explained:</span><span style="font-size: 11pt;"> The Arduino is programmed to
operate </span><b style="font-size: 11pt;">P</b><span style="font-size: 11pt;">ush </span><b style="font-size: 11pt;">T</b><span style="font-size: 11pt;">o </span><b style="font-size: 11pt;">T</b><span style="font-size: 11pt;">alk and play a user defined Morse Code
sequence for 33 seconds.</span><span style="font-size: 11pt;"> Pin D12 outputs
+5V when this happens.</span><span style="font-size: 11pt;"> +5V is divided by
R1 and R2 to place </span><span style="font-size: 14.6667px;">approx.</span><span style="font-size: 11pt;"> 2.5V on the </span><b style="font-size: 11pt;">G </b><span style="font-size: 11pt;">of the 2N7000 transistor.</span><span style="font-size: 11pt;"> A </span><b style="font-size: 11pt;">GND </b><span style="font-size: 11pt;">then appears on the </span><b style="font-size: 11pt;">D</b><span style="font-size: 11pt;">
lead– which is </span><b style="font-size: 11pt;">PTT</b><span style="font-size: 11pt;"> toward the </span><span style="font-size: 14.6667px;">Baofeng</span><span style="font-size: 11pt;">. </span><b style="font-size: 11pt;">PTT</b><span style="font-size: 11pt;"> is
wired to the 3.5mm plug </span><b style="font-size: 11pt;">Sl</b><span style="font-size: 11pt;">eeve lead.<o:p></o:p></span></span></p>
<p class="MsoNormal" style="mso-pagination: none;"><span style="font-size: 11pt;"><span style="font-family: verdana;"> </span></span><span style="font-family: verdana; font-size: 11pt;">The Morse Audio appears at Pin </span><b style="font-family: verdana; font-size: 11pt;">D13</b><span style="font-family: verdana; font-size: 11pt;">.</span><span style="font-family: verdana; font-size: 11pt;"> </span><span style="font-family: verdana;"><span style="font-size: 11pt;">The Audio Level is a 5V square wave that is
divided (attenuated) by R3 and R4 to emulate the level of a </span><span style="font-size: 14.6667px;">Baofeng</span><span style="font-size: 11pt;"> Speaker
Mic.</span></span><span style="font-family: verdana; font-size: 11pt;"> </span><span style="font-family: verdana; font-size: 11pt;">Capacitor </span><b style="font-family: verdana; font-size: 11pt;">C1</b><span style="font-family: verdana;"><span style="font-size: 11pt;"> blocks the DC
voltage from the </span><span style="font-size: 14.6667px;">Baofeng mic lead</span><span style="font-size: 11pt;">.</span></span><span style="font-family: verdana; font-size: 11pt;"> </span><span style="font-family: verdana; font-size: 11pt;">Transmit
audio is applied to the </span><b style="font-family: verdana; font-size: 11pt;">R</b><span style="font-family: verdana; font-size: 11pt;">ing lead of the 3.5mm Plug. Note: Pin D13 has a board mounted LED connected across it. When the Morse Message is playing- the LED flashes along. </span></p><p class="MsoNormal" style="mso-pagination: none;"><span style="font-family: verdana; font-size: 11pt;">9V from the battery passes through
a small toggle switch that turns the Arduino controller ON-OFF.</span><span style="font-family: verdana; font-size: 11pt;"> </span><span style="font-family: verdana; font-size: 11pt;">The 9V source connects to the Arduino at the
<b>V-in</b> pin.</span><span style="font-family: verdana; font-size: 11pt;"> </span><b style="font-family: verdana; font-size: 11pt;">GND </b><span style="font-family: verdana;"><span style="font-size: 11pt;">for the </span><span style="font-size: 14.6667px;">Baofeng’s</span><span style="font-size: 11pt;"> PTT and Mic Audio In is delivered via the <b>sleeve</b> of the 2.5mm Plug.</span></span></p>
<p class="MsoNormal" style="mso-pagination: none;"><span style="font-family: verdana; font-size: 11pt;">Many people have told me that the hardest part of
programming Arduinos is ‘Getting the Sketch into the Arduino’. I encourage you to watch some Youtube videos like: </span><span style="font-family: verdana;"><span style="font-size: 11pt;"> </span><a href="https://www.youtube.com/watch?v=a7_qy4L4ukc">Arduino Nano how to load a Sketch - YouTube</a>...</span><span style="font-family: verdana; font-size: 11pt;"> </span></p><p class="MsoNormal" style="mso-pagination: none;"><span style="font-family: verdana; font-size: 11pt;">Or read about it at: </span><a href="https://www.arduino.cc/en/Guide" style="font-family: verdana;">Getting
Started with Arduino products | Arduino</a><span style="font-family: verdana;"> </span><span style="font-family: verdana; font-size: 11pt;">Ask around at
your Radio Club. </span><span style="font-family: verdana; font-size: 11pt;">The sketch I
used is here: </span><span style="font-family: arial;"><span style="font-size: 11pt;"> </span><a href="https://projecthub.arduino.cc/nfarrier/auto-keyer-for-radio-fox-hunting-693269">Auto-Keyer for Radio "Fox Hunting" | Arduino Project Hub</a><span style="font-size: 11pt;"> </span><span> </span></span></p>
<p class="MsoNormal" style="mso-pagination: none;"><span style="font-size: 11pt;"><span style="font-family: verdana;">I’d like to tell you that customizing
the Arduino to meet your Fox/Bunny Hunt needs is EASY– but, nah.<span style="mso-spacerun: yes;"> </span>However, it’s not too difficult if the notes in
the sketch are carefully read.</span></span></p>
<p class="MsoNormal" style="mso-pagination: none;"><span style="font-family: verdana;"><span style="font-size: 11pt;">An example is </span><span style="background-color: #fcff01; font-size: 11pt;"><u>Changing the Morse
Message</u>.<span style="mso-spacerun: yes;"> </span></span><span style="font-size: 11pt;">Note:</span><span style="font-size: 11pt;"> If the line of programming in the sketch is preceded by a double
slash </span><span style="font-size: large;">//</span><span style="font-size: 11pt;"> – what follows is the explanation the programmer left for you. Also known as 'comments' or 'commented out'- which has no effect on the Adruino Programing. <o:p></o:p></span></span></p>
<p class="MsoNormal" style="mso-pagination: none;"><span style="font-size: 11pt;"><span style="font-family: verdana;"> </span></span><span style="background-color: #fcff01; font-family: arial;">//
</span><span style="font-family: arial;">the loop routine runs over and over again forever:</span></p>
<p class="MsoNormal" style="mso-pagination: none;"><span style="font-family: arial;">void
loop() {<o:p></o:p></span></p>
<p class="MsoNormal" style="mso-pagination: none;"><span style="font-family: arial;"> digitalWrite(relay, HIGH); <span style="background-color: #fcff01;"> </span><span style="background-color: #fcff01;">// </span>turn the relay on (HIGH is the voltage
level)<o:p></o:p></span></p>
<p class="MsoNormal" style="mso-pagination: none;"><span style="font-family: arial;"> delay(1000); <span style="background-color: #fcff01;"> </span><span style="background-color: #fcff01;">//</span> wait for a second, 1000mS<o:p></o:p></span></p>
<p class="MsoNormal" style="mso-pagination: none;"><span style="font-family: arial;"><span style="mso-spacerun: yes;"> </span> SendText("A A A A A A A A A A A DE
KR7W"); </span></p>
<p class="MsoNormal" style="mso-pagination: none;"><span style="font-family: arial;"> delay(1000); <span style="background-color: #fcff01;">// </span>wait for one second</span></p>
<p class="MsoNormal" style="mso-pagination: none;"><span style="font-family: arial;"> </span><span style="font-family: arial;"> <span style="background-color: #fcff01;"> </span></span><span style="font-family: arial;"><span style="background-color: #fcff01;">//</span>SendText("KR7W FOX HUNT");//
alternate text to use</span></p>
<p class="MsoNormal" style="mso-pagination: none;"><span style="font-family: arial;"> </span><span style="font-family: arial;"> </span><span style="font-family: arial;"><span style="background-color: #fcff01;">//</span>tone(TonePin, frequency);</span><span style="font-family: arial;"> </span><span style="font-family: arial;"><span style="background-color: #fcff01;">//</span> send 7 sec tone</span></p>
<p class="MsoNormal" style="mso-pagination: none;"><span style="font-family: arial;"><span style="mso-spacerun: yes;"> </span><span style="background-color: #fcff01;">//</span>delay(7000);<o:p></o:p></span></p>
<p class="MsoNormal" style="mso-pagination: none;"><span style="font-family: arial;"><span> <span style="background-color: #fcff01;"> //</span>noTone(TonePin);</span><span><o:p></o:p></span></span></p>
<p class="MsoNormal" style="mso-pagination: none;"><span style="font-family: arial;"><span style="mso-spacerun: yes;"> </span></span><span style="font-family: arial; mso-spacerun: yes;"> </span><span style="background-color: #fcff01; font-family: arial;">//</span><span style="font-family: arial;">delay(1000);</span><span style="font-family: arial; mso-spacerun: yes;"> </span><span style="background-color: #fcff01; font-family: arial;">//</span><span style="font-family: arial;"> 1 seconds transmit w/o tone</span></p>
<p class="MsoNormal" style="mso-pagination: none;"><span style="font-size: 11pt;"><span style="font-family: verdana;"> <o:p></o:p></span></span></p>
<p class="MsoNormal" style="mso-pagination: none;"><span style="font-size: 11pt;"><span style="font-family: verdana;">Find the line that begins with: <b>SendText(</b> The text between the
quote marks is what will be sent in Morse Code.<span style="mso-spacerun: yes;">
</span>The amount of text, between the quote marks, determines the amount of time <b>P</b>ush <b>T</b>o <b>T</b>alk will be operated.<span style="mso-spacerun: yes;"> </span>I added this amount of <b>A</b>s to make
the PTT stay operated for 33 seconds.<span style="mso-spacerun: yes;">
</span>Experiment to meet your needs. <span style="mso-spacerun: yes;"> </span>Change the sketch then reload it into the
Arduino.<o:p></o:p></span></span></p>
<p class="MsoNormal" style="mso-pagination: none;"><span style="font-size: 11pt;"><span style="font-family: verdana;"> </span></span><span style="font-family: verdana; font-size: 11pt;">Here,</span><span style="font-family: verdana; font-size: 11pt; mso-spacerun: yes;">
</span><span style="font-family: verdana; font-size: 11pt;"><b>digitalWrite(relay, LOW); </b> turns OFF Push to Talk.</span><span style="font-family: verdana; font-size: 11pt; mso-spacerun: yes;"> </span><span style="font-family: verdana; font-size: 11pt;">Then delay(cycleDelay); makes the Arduino wait
for 15 seconds (defined elsewhere).</span><span style="font-family: verdana; font-size: 11pt; mso-spacerun: yes;"> </span><span style="font-family: verdana; font-size: 11pt;">It
performs this command twice for a wait time, with PTT <b>non</b>-operated, for 30 seconds.</span></p>
<p class="MsoNormal" style="mso-pagination: none;"><span style="font-size: 11pt;"><span style="font-family: verdana;"> </span></span><span style="font-family: arial;">digitalWrite(relay,
LOW);<span style="mso-spacerun: yes;"> </span>// turn the relay off by making
the voltage LOW</span></p>
<p class="MsoNormal" style="mso-pagination: none;"><span style="font-family: arial;"><span> </span><span style="mso-spacerun: yes;"> </span>delay(cycleDelay);<span style="mso-spacerun: yes;"> </span>// wait for cycle time (because the
largest value is 16383)</span></p>
<p class="MsoNormal" style="mso-pagination: none;"><span><span style="font-family: arial;"><span style="mso-spacerun: yes;"> </span>delay(cycleDelay);<span style="mso-spacerun: yes;"> </span>// wait for cycle time<span style="mso-spacerun: yes;"> </span></span></span></p><p class="MsoNormal" style="mso-pagination: none;"><span style="font-family: verdana; font-size: 11pt;"> </span></p>
<p class="MsoNormal" style="mso-pagination: none;"><span style="font-size: 11pt;"><span style="font-family: verdana;">The following photos show how I went
about creating a Fox / Bunny Controller that works for me and just might provide some ideas for your project.<o:p></o:p></span></span></p>
<p class="MsoNormal" style="mso-pagination: none;"><span style="font-size: 11pt;"><span style="font-family: verdana;"> </span></span><span style="font-family: verdana; font-size: 11pt;">Electronic parts are shown on the
schematic-block diagram, Fig 1, above.</span></p>
<p class="MsoNormal" style="mso-pagination: none;"><span style="font-size: 11pt;"><span style="font-family: verdana;"> </span></span><span style="font-family: verdana; font-size: 11pt;">A Mint Tin ended up being the perfect
size for the Arduino and the 9V battery.</span><span style="font-family: verdana; font-size: 11pt; mso-spacerun: yes;">
</span><span style="font-family: verdana; font-size: 11pt;">My </span><u style="font-family: verdana; font-size: 11pt;">non odorous </u><span style="font-family: verdana; font-size: 11pt;">mint tins, as well as the Arduino, battery
connector, small toggle switch, 2N7000 transistor, Audio Plugs, hook up wire,
solder, soldering tips, resistors and capacitors conveniently came from
Astronaut Bezo’s Amazon dot com.</span></p><p class="MsoNormal" style="mso-pagination: none;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhJgpEjwolID1_KLH-C-sQBdKMAyzYjyynhHtnnjsf-bLxkpkSC475H6buuR0KQntzeLDvVkOq5kEaTxHK_tBAGX2drPUQlU4JN8NHrQxkGJ5H1yFgn_JQOl4WiBeBTqB0N78LzoMZYSEcJrK7m88fqdVIP3ZQ3KRj79RgctAUH6W8yE2rdHu9xadCjtTmK/s800/Controller%20door%20open%20Fig%202.jpg" imageanchor="1" style="clear: left; display: inline !important; font-family: verdana; margin-bottom: 1em; margin-right: 1em; text-align: center;"><img border="0" data-original-height="646" data-original-width="800" height="332" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhJgpEjwolID1_KLH-C-sQBdKMAyzYjyynhHtnnjsf-bLxkpkSC475H6buuR0KQntzeLDvVkOq5kEaTxHK_tBAGX2drPUQlU4JN8NHrQxkGJ5H1yFgn_JQOl4WiBeBTqB0N78LzoMZYSEcJrK7m88fqdVIP3ZQ3KRj79RgctAUH6W8yE2rdHu9xadCjtTmK/w412-h332/Controller%20door%20open%20Fig%202.jpg" width="412" /></a></p>
<p class="MsoNormal" style="mso-pagination: none;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgZ6ynua-M1Id99ZzgEaxOiq9jlzxbyxsjoReI8ypf9NEzFA6Goq8a6qXuo1riizy25McyKbVgQSzD8sBhr1ZhOa86PDlVe0Viml55ORsj3ZaJ5EJU9S6q-8fT1HsHf4lnTy_SUqoOJDAfEaP_y96O0NMxnaHAkQb8rPIH1Y1pksxo8TwcaWz3pszZmI1bE/s1008/PCB%20Chassis%20Fig%20A.jpg" imageanchor="1" style="clear: left; display: inline !important; float: left; margin-bottom: 1em; margin-right: 1em; text-align: center;"><img border="0" data-original-height="1008" data-original-width="788" height="208" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgZ6ynua-M1Id99ZzgEaxOiq9jlzxbyxsjoReI8ypf9NEzFA6Goq8a6qXuo1riizy25McyKbVgQSzD8sBhr1ZhOa86PDlVe0Viml55ORsj3ZaJ5EJU9S6q-8fT1HsHf4lnTy_SUqoOJDAfEaP_y96O0NMxnaHAkQb8rPIH1Y1pksxo8TwcaWz3pszZmI1bE/w162-h208/PCB%20Chassis%20Fig%20A.jpg" width="162" /></a><span style="font-size: 11pt;"><span style="font-family: verdana;"> </span></span></p><p class="MsoNormal" style="mso-pagination: none;"><span style="font-family: verdana; font-size: 11pt;"><b>(</b></span><b style="font-family: verdana; font-size: 11pt;">Fig. A) </b><span style="font-family: verdana; font-size: 11pt;">A piece of Printed Circuit Board</span><b style="font-family: verdana; font-size: 11pt;"> </b><span style="font-family: verdana;"><span style="font-size: 11pt;">with </span><span style="font-size: 14.6667px;">Dremel</span><span style="font-size: 11pt;"> cuts creates Manhattan style solder pads for wires to attach– as well as a ground plane to easily GND a component or wire connection.</span></span><span style="font-family: verdana; font-size: 11pt; mso-spacerun: yes;"> </span></p><p class="MsoNormal" style="mso-pagination: none;"><br /></p><p class="MsoNormal" style="mso-pagination: none;"><span style="font-family: verdana; font-size: 11pt;"><br /></span></p><p class="MsoNormal" style="mso-pagination: none;"><span style="font-family: verdana; font-size: 11pt;"><br /></span></p><p class="MsoNormal" style="mso-pagination: none;"><span style="font-family: verdana; font-size: 11pt;"><br /></span></p><p class="MsoNormal" style="mso-pagination: none;"><span style="font-family: verdana; font-size: 11pt;"></span></p><p class="MsoNormal" style="mso-pagination: none;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjKQlb3Nsvr3-vGSsfWJ-EyRLQ2X4B00EqAO_gSL_ZKTB9ffoI5jiFrKyHoSfVvEry7cVlkkd15UbK5EQN0qxgzXPPVW7kFe6LJkr8MzxtlxZ1aLlEmEludczfVkbG64iYGNpQRV05DKscFxAZYyGZ4dxQ5wFF_UuJReDqo2R3Dc-k6ugD21vzNhX7xjsIP/s749/Wood%20Mount%20Fig%20B.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="749" data-original-width="600" height="200" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjKQlb3Nsvr3-vGSsfWJ-EyRLQ2X4B00EqAO_gSL_ZKTB9ffoI5jiFrKyHoSfVvEry7cVlkkd15UbK5EQN0qxgzXPPVW7kFe6LJkr8MzxtlxZ1aLlEmEludczfVkbG64iYGNpQRV05DKscFxAZYyGZ4dxQ5wFF_UuJReDqo2R3Dc-k6ugD21vzNhX7xjsIP/w160-h200/Wood%20Mount%20Fig%20B.jpg" width="160" /></a></p><b style="font-family: verdana; font-size: 11pt;">(Fig. B) </b><span style="font-family: verdana; font-size: 11pt;">A piece of 5mm scrap </span><span style="font-family: verdana;"><span style="font-size: 14.6667px;">plywood was</span><span style="font-size: 11pt;"> cut into 2 pieces and glued together to become the 'platform'. The smaller plywood piece became the
divider to hold the battery in place.</span></span><span style="font-family: verdana; font-size: 11pt; mso-spacerun: yes;">
</span><span style="font-family: verdana; font-size: 11pt;">The Arduino is glued to the platform with E6000 hobby cement.</span><p></p><p class="MsoNormal" style="mso-pagination: none;"><span style="font-family: verdana; font-size: 11pt;">Hot Glue would work just as well.</span></p><p class="MsoNormal" style="mso-pagination: none;"><span style="font-family: verdana; font-size: 11pt;">The wire shown- passes through small holes drilled through the plywood and printed circuit board. The wire ends are soldered to the PCB Ground Plane. The intent is to Bond the PCB GND Plane to the Mint Tin. This may not be needed- but did it, as it was easy.</span></p><p class="MsoNormal" style="mso-pagination: none;"><span style="font-family: verdana;"><span style="font-size: 14.6667px;"><br /></span></span></p><p class="MsoNormal" style="mso-pagination: none;"><br /></p><p class="MsoNormal" style="mso-pagination: none;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjFzWzbmiguRwLLFegzdXlsGRC-kH8BkEezcEwVjlnJBQsd9LHWQBkl-yK9c0XjNN7o74BwHGasluOjpu0a009Xs9kMqlq2ctgx4g42s1IfrwtyAVA2auWe1btRg8kQH8ZVaBEsJA6rfwiZND_DKJ4DOKPZVGLrEr9bPShcrik6Wq_adDiiMqrK8HOmVpV1/s800/Wood%20Mount%20w_PCB_Arduino%20Fig%20C.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="800" data-original-width="636" height="209" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjFzWzbmiguRwLLFegzdXlsGRC-kH8BkEezcEwVjlnJBQsd9LHWQBkl-yK9c0XjNN7o74BwHGasluOjpu0a009Xs9kMqlq2ctgx4g42s1IfrwtyAVA2auWe1btRg8kQH8ZVaBEsJA6rfwiZND_DKJ4DOKPZVGLrEr9bPShcrik6Wq_adDiiMqrK8HOmVpV1/w166-h209/Wood%20Mount%20w_PCB_Arduino%20Fig%20C.jpg" width="166" /></a></div><span style="font-family: verdana;"><span style="font-size: 14.6667px;"><br /></span></span><p></p><p class="MsoNormal" style="mso-pagination: none;"><span style="font-family: verdana;"><span style="font-size: 14.6667px;"><b>(Fig. C)</b> The notch Dremel carved into the plywood platform holds it in place under the switch.</span></span><span style="font-family: verdana; font-size: 14.6667px; mso-spacerun: yes;"> At some point the platform will need to be removed for Arduino reprogramming. Accidental Engineering provides the platform to easily slide out toward the bottom of the tin without removing the battery for access to the USB port.</span></p><p class="MsoNormal" style="mso-pagination: none;"><span style="font-size: 11pt;"><span style="font-family: verdana;"> </span></span></p><div><br /><span style="font-family: verdana; font-size: 11pt; mso-spacerun: yes;"><br /></span></div><div><span style="font-size: 11pt;"><span style="font-family: verdana;">Got Questions?<span style="mso-spacerun: yes;"> </span>Email me.<span style="mso-spacerun: yes;"> </span></span></span><span style="font-family: verdana; font-size: 14.6667px;"> </span><span style="font-family: verdana; font-size: 14.6667px;"> </span><span style="font-family: verdana; font-size: 14.6667px;"> </span><span style="font-family: verdana; font-size: 14.6667px;"> </span><span style="font-family: verdana; font-size: 14.6667px;"> </span><span style="font-family: verdana; font-size: 14.6667px;"> </span><span style="font-family: verdana; font-size: 14.6667px;"> </span><span style="font-family: verdana; font-size: 14.6667px;"> </span><span style="font-family: verdana; font-size: 14.6667px;"> </span><span style="font-family: verdana; font-size: 14.6667px;"> </span><span style="font-family: verdana; font-size: 14.6667px;"> </span><span style="font-family: verdana; font-size: 14.6667px;"> </span><div class="separator" style="clear: both; text-align: center;"></div><span style="font-family: verdana;"><br /> </span><span style="font-family: verdana; font-size: 11pt;">As Always– thanks for reading this
far.</span><span style="font-family: verdana; font-size: 11pt; mso-spacerun: yes;"> </span><span style="font-family: verdana; font-size: 11pt;">30, 73, Happy Trails, KR7W</span><p class="MsoNormal" style="mso-pagination: none;"><span style="font-family: verdana;"> </span></p>
<p class="MsoNormal"><o:p><span style="font-family: verdana;"> </span></o:p></p></div>kr7whttp://www.blogger.com/profile/12925283975807120485noreply@blogger.com0tag:blogger.com,1999:blog-6635479951504521166.post-91365794900687808932023-07-24T16:09:00.002-07:002023-07-24T16:09:42.921-07:00Hallicrafters R46 Speaker - Perhaps a Useful Hack<p> </p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj9SbvtufipEOw7EXgLfYFe81e68ahZtWs75l9zELrAIhY_NnEJUiG-SZP7WUoTsSRanAeJ0cBesYU--oWiNFU9pXj37wh7HtHi27yfCfuu_hk6WDyxxqxqrUm9ZxuQZolXR10cV_b-YraPOpS7ZGS8tYadXzBmlRKMe57lX1dzawAdZg0b1YMmuuz0gA/s858/R46%20es%20SX101.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="858" data-original-width="720" height="639" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj9SbvtufipEOw7EXgLfYFe81e68ahZtWs75l9zELrAIhY_NnEJUiG-SZP7WUoTsSRanAeJ0cBesYU--oWiNFU9pXj37wh7HtHi27yfCfuu_hk6WDyxxqxqrUm9ZxuQZolXR10cV_b-YraPOpS7ZGS8tYadXzBmlRKMe57lX1dzawAdZg0b1YMmuuz0gA/w537-h639/R46%20es%20SX101.jpg" width="537" /></a></div><div class="separator" style="clear: both; text-align: center;"><br /></div><div class="separator" style="clear: both; text-align: left;"><span style="font-family: verdana;">The Classic little <span style="font-size: medium;">h</span> R46 speaker nicely matches up with the SX-71 or SX-101 Mk 3.</span></div><div class="separator" style="clear: both; text-align: left;"><span style="font-family: verdana;"><br /></span></div><div class="separator" style="clear: both; text-align: left;"><span style="font-family: verdana;">This R46 came with a 10-inch speaker which in my opinion was intended for listening to 3875 AM, Shortwave Listening AM broadcasts which included music, and the Phono Input where the record player delivered music to the receiver's 6V6 audio amplifier.</span></div><div class="separator" style="clear: both; text-align: left;"><span style="font-family: verdana;"><br /></span></div><div class="separator" style="clear: both; text-align: left;"><span style="font-family: verdana;">Whilst listening to SSB or CW from either receiver- the 10-in speaker cuts the high frequencies too much. It's my opinion that the cutting of the high audio frequencies reduces the intelligibility of SSB and CW signals. </span></div><div class="separator" style="clear: both; text-align: left;"><span style="font-family: verdana;"><br /></span></div><div class="separator" style="clear: both; text-align: left;"><span style="font-family: verdana;">For me- the best speaker to listen to modern day ham radio communications is with an older Mobile Radio Speaker- like GE MASTRII or Motorola equivalent. In addition, a tuned port CW speaker is beneficial to use with older receivers that do not have modern DSP noise reduction or sharp selectivity. </span></div><div class="separator" style="clear: both; text-align: left;"><a href="https://qsl.net/wa3mej/Articles/Misc/Ressonant%20Speaker%20for%20CW.pdf">Ressonant Speaker for CW.pdf (qsl.net)</a></div><div class="separator" style="clear: both; text-align: left;"><a href="https://k4lxycw.wixsite.com/blog/post/a-tuned-speaker-for-cw">A tuned speaker for CW (k4lxycw.wixsite.com)</a></div><div class="separator" style="clear: both; text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: left;"><span style="font-family: verdana;"><br /></span></div><div class="separator" style="clear: both; text-align: left;"><span style="font-family: verdana;">In this modification, the goal is to improve the audio intelligibility from my two little <span style="font-size: medium;">h</span> boat anchor receivers. Specific measurements and how to assemble will not be provided- but photos will hopefully give enough info if you choose to modify your Hallicrafters R46 or another classic boat anchor speaker. </span></div><div class="separator" style="clear: both; text-align: left;"><span style="font-family: verdana;"><br /></span></div><div class="separator" style="clear: both; text-align: left;"><span style="font-family: verdana;">The original R46 10-in speaker was removed and stowed away for safe keeping. The mask between the speaker and the cabinet was used as a <u>pattern</u> to create an interior front panel between the<span style="font-size: large;"> h </span>cabinet and the new speakers. 3/16" hardboard / Masonite material was used. 5mm or 1/4" plywood would work just as well.</span></div><div class="separator" style="clear: both; text-align: left;"><span style="font-family: verdana;"><br /></span></div><div class="separator" style="clear: both; text-align: left;"><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiXbY03m9BDtULmHCaLN9QxTkSlcBtlHA0HW3BoY4A2WrG1ayEfJ-N0XW2BMx0vb0fmB2D9JoFxNDL5UOoyW0Mf86T0IItzKGfysPEi6PoT3UgfPXGW1AqIuzKTYNALkk3U5Hrj3aWAev3DpaGkB9hKzWuNTvK109mMA9CPcQjZSqnafyFz5N1R1scXaQ/s792/New%20Interior%20Front%20Panel.jpg" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="481" data-original-width="792" height="307" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiXbY03m9BDtULmHCaLN9QxTkSlcBtlHA0HW3BoY4A2WrG1ayEfJ-N0XW2BMx0vb0fmB2D9JoFxNDL5UOoyW0Mf86T0IItzKGfysPEi6PoT3UgfPXGW1AqIuzKTYNALkk3U5Hrj3aWAev3DpaGkB9hKzWuNTvK109mMA9CPcQjZSqnafyFz5N1R1scXaQ/w506-h307/New%20Interior%20Front%20Panel.jpg" width="506" /></a></div><br /><span style="font-family: verdana;"><br /></span></div><div class="separator" style="clear: both; text-align: left;"><span style="font-family: verdana;">Arrow points to the original internal mask between the speaker and metal grille.</span></div><div class="separator" style="clear: both; text-align: left;"><span style="font-family: verdana;"><br /></span></div><div class="separator" style="clear: both; text-align: left;"><span style="font-family: verdana;">Next, a platform / deck was built to match the needed elevation of the Comm and CW speakers. Plywood would work best, OSB was used- as it was on hand.</span></div><div class="separator" style="clear: both; text-align: left;"><span style="font-family: verdana;"><br /></span></div><div class="separator" style="clear: both; text-align: left;"><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgUx7S4DDFcT6dflrfPcezRjpHMPt-_lmw0D0J-uiwAkaUvV5NpxYiZ6s0q3YExC1nKWwcL5YwUW1qxWOCmzY1eQmvHWDA0gpbGAcTSUR7fyKD0_782aiI9_040wb1meeNjEf_BDfXU1ANHu70DrddW2M-xG9oq9fwyDPc1JJy98UBK-809ke9-gUVde5YN/s1000/Rear%20View%20of%20SPKR%20Assy%20Ver%202.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="817" data-original-width="1000" height="410" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgUx7S4DDFcT6dflrfPcezRjpHMPt-_lmw0D0J-uiwAkaUvV5NpxYiZ6s0q3YExC1nKWwcL5YwUW1qxWOCmzY1eQmvHWDA0gpbGAcTSUR7fyKD0_782aiI9_040wb1meeNjEf_BDfXU1ANHu70DrddW2M-xG9oq9fwyDPc1JJy98UBK-809ke9-gUVde5YN/w503-h410/Rear%20View%20of%20SPKR%20Assy%20Ver%202.jpg" width="503" /></a></div><br /><span style="font-family: verdana;"><br /></span></div><div class="separator" style="clear: both; text-align: left;"><span style="font-family: verdana;">Height of platform that the speaker(s) sit on depends on the size of the speaker(s) being used. The opening space where sound it emitted from is sharpie penned on the hardboard front panel.</span></div><div class="separator" style="clear: both; text-align: left;"><span style="font-family: verdana;"><br /></span></div><div class="separator" style="clear: both; text-align: left;"><span style="font-family: verdana;">The vertical 'stick' provides support for the DPDT switch that switches between CW or SSB speakers. The switch is elevated to a convenient height for easy access from the front of the speaker. </span></div><div class="separator" style="clear: both; text-align: left;"><span style="font-family: verdana;"><br /></span></div><div class="separator" style="clear: both; text-align: left;"><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjmE31RENIaUOK__gmFNsxyyNyvQLO5iN-5EFTWlU7HjDUIEuI4YDr3SgH6yiavuzbXIqqPJ_yfSthPpXseWVuRYDpDk_0Dqu_DiUUBIu7Z3PFAncgmz_-Q-gzAv1j9vt6KZSysX_yxecSAA9Lz3uB09NkRhe9euhUwNa-D7sm8D3s7R4XEtLvOlr_nwIjN/s2067/SPKR%20DPDT%20Switch.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="832" data-original-width="2067" height="216" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjmE31RENIaUOK__gmFNsxyyNyvQLO5iN-5EFTWlU7HjDUIEuI4YDr3SgH6yiavuzbXIqqPJ_yfSthPpXseWVuRYDpDk_0Dqu_DiUUBIu7Z3PFAncgmz_-Q-gzAv1j9vt6KZSysX_yxecSAA9Lz3uB09NkRhe9euhUwNa-D7sm8D3s7R4XEtLvOlr_nwIjN/w538-h216/SPKR%20DPDT%20Switch.jpg" width="538" /></a></div><br /><span style="font-family: verdana;"><br /></span></div><div class="separator" style="clear: both; text-align: left;"><span style="font-family: verdana;">PCB material was my choice to support the slide switch that connects to the support stick. Masonite or 5mm plywood would also work well.</span></div><div class="separator" style="clear: both; text-align: left;"><span style="font-family: verdana;"><br /></span></div><div class="separator" style="clear: both; text-align: left;"><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi-xcG5bz6657fMftCkOuai93Nmjp3OdqFWQY1EMdoEFSxN7ugunZr8WvVG9l7tcj6cm0ChNu5V13HEODVUs4KNNzw_uJka8DN3ASLLsU7zEfsNA4geWxFjbwkrDh9Z95bBb4FqJ08G9Jxlp5838diRK4HfYV_pcfz35feWiQ11T-CFW77eb3qBcOh3P-HA/s1000/SPKR%20Assy%20installed_%20Rear%20View.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="750" data-original-width="1000" height="371" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi-xcG5bz6657fMftCkOuai93Nmjp3OdqFWQY1EMdoEFSxN7ugunZr8WvVG9l7tcj6cm0ChNu5V13HEODVUs4KNNzw_uJka8DN3ASLLsU7zEfsNA4geWxFjbwkrDh9Z95bBb4FqJ08G9Jxlp5838diRK4HfYV_pcfz35feWiQ11T-CFW77eb3qBcOh3P-HA/w495-h371/SPKR%20Assy%20installed_%20Rear%20View.jpg" width="495" /></a></div><br /><span style="font-family: verdana;"><br /></span></div><div class="separator" style="clear: both; text-align: left;"><span style="font-family: verdana;">Arrows point to the R46's original speaker baffle attachment points.</span></div><div class="separator" style="clear: both; text-align: left;"><span style="font-family: verdana;"><br /></span></div><div class="separator" style="clear: both; text-align: left;"><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiU58dK0woL6H8btmBDaQkY9luvsjpc5TcK5F6ip4GSQJYt14LCMc9hdZDfhUhCZbPSlSyPNNJe7h6WJuY88hhky9KDG5Lf_Ic86nT7aq3hrFo2bp63UHzjwLBk5Vs5wdENu8wMp58u4gHjWFQxEmAF6XlXWtXf17k7XpMZ9Gl2YgmU-5FJY6Rn2QKQXW8Z/s720/R46%20Front%20View.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="540" data-original-width="720" height="375" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiU58dK0woL6H8btmBDaQkY9luvsjpc5TcK5F6ip4GSQJYt14LCMc9hdZDfhUhCZbPSlSyPNNJe7h6WJuY88hhky9KDG5Lf_Ic86nT7aq3hrFo2bp63UHzjwLBk5Vs5wdENu8wMp58u4gHjWFQxEmAF6XlXWtXf17k7XpMZ9Gl2YgmU-5FJY6Rn2QKQXW8Z/w501-h375/R46%20Front%20View.jpg" width="501" /></a></div><br /><span style="font-family: verdana;"><br /></span></div><div class="separator" style="clear: both; text-align: left;"><span style="font-family: verdana;">Squint just right and kinda see the two speakers behind the <span style="font-size: large;">h </span>grille cloth.</span></div><div class="separator" style="clear: both; text-align: left;"><span style="font-family: verdana;"><br /></span></div><div class="separator" style="clear: both; text-align: left;"><span style="font-family: verdana;">Note: No holes were drilled in this R46 Speaker enclosure. This modified R46 can easily be returned to Hallicrafters collector status. </span></div><div class="separator" style="clear: both; text-align: left;"><span style="font-family: verdana;"><br /></span></div><div class="separator" style="clear: both; text-align: left;"><span style="font-family: verdana;">End of <span style="font-size: large;">h</span> R46 modification report. Best Regards, Ricky KR7W</span></div><div class="separator" style="clear: both; text-align: center;"><br /></div><br /><p></p>kr7whttp://www.blogger.com/profile/12925283975807120485noreply@blogger.com0tag:blogger.com,1999:blog-6635479951504521166.post-77853942489532950322022-10-31T10:08:00.000-07:002022-10-31T10:09:27.187-07:00Adventures in the 2022 Fall Classic Exchange<p><span style="font-family: helvetica;"> </span><b style="text-align: center;"><span style="font-family: helvetica;">2022 Winter Classic Exchange, AKA 'CX' – CW Portion</span></b></p><p>
</p><p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span style="color: black;"><o:p><span style="font-family: helvetica;"> </span></o:p></span><span style="font-family: helvetica;">This is my first CX operating under my own call
sign. Previously I’ve operated many CXs at W7OS- the <a href="https://w7dk.org/index.php?option=com_content&view=article&id=54&Itemid=205">Doc Spike Antique Radio Museum</a> in Tacoma, WA- before moving to Idaho. </span><span style="font-family: helvetica;"> </span></p><p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span style="font-family: helvetica;">CX Info: </span><a href="http://classicexchange.org/"><span style="font-family: helvetica;">Classic Exchange CX</span></a></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span style="color: black;"><span style="font-family: helvetica;">The following radios emerged from moving boxes, were
briefly tested, and took turns on the modest sized op table:<span style="mso-spacerun: yes;"> </span><span style="mso-spacerun: yes;"> </span>Hallicrafters SX-101 and SX-71, Drake 2B, Heathkit
HW7 QRP, Homebrew WW2 Paraset Replica. They shared tabletop space with a
WRL Globe Chief 90 and a Heathkit VF-1 VFO transmitter- which outputs 50-60
Watts.</span></span><span style="font-family: helvetica;"> </span></p><p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgr69IgzqvSIOuWRh2o8y-tvGs8VitZ-S54IH5Y7KJWmecnTfVCI5BZEaNNfF1f06g_7trWD0kjnUqprIj22xsAFPbOGSyXlVHbG8H28ibKZrdUZn_zP5zhuXqlkXYz38PsBn2TE5BziFQ9UM5yRbEvjnQyPzog5A2uXxk_SwCUMMbiwEKTX1NR0LbgKw/s2000/CX%202022%20SX71%20SX101%20Globe%20KR7W.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="826" data-original-width="2000" height="269" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgr69IgzqvSIOuWRh2o8y-tvGs8VitZ-S54IH5Y7KJWmecnTfVCI5BZEaNNfF1f06g_7trWD0kjnUqprIj22xsAFPbOGSyXlVHbG8H28ibKZrdUZn_zP5zhuXqlkXYz38PsBn2TE5BziFQ9UM5yRbEvjnQyPzog5A2uXxk_SwCUMMbiwEKTX1NR0LbgKw/w653-h269/CX%202022%20SX71%20SX101%20Globe%20KR7W.jpg" width="653" /></a></div><span style="font-family: helvetica;">Hallicrafters SX-71, SX-101, Heathkit VF1 VFO connected to the WRL Globe Chief. A MC Jones Micro-Match power meter sits atop the VF1.</span><p></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span style="color: black;"><span style="font-family: helvetica;">The Antenna here is a HOA stealth 20M-40M fan dipole
in the attic, about 25 ft above ground and surrounded by 1000+ roofing
nails. There’s a bit of manmade noise on 40M.<span style="mso-spacerun: yes;"> </span>I am amazed that it works as well as it does. </span></span><span style="font-family: helvetica;"> </span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span style="color: black;"><span style="font-family: helvetica;">Starting on Sunday- the SX-101 and Globe Chief TX
combination worked well. After pairing the Drake 2B to the Globe Chief
TX, it was discovered that 2B did not receive 40M. The required 3
Qualifying QSOs were made on 20M and then the 2B was swapped for the
SX-71. Casual operating on Sunday netted a surprising 20 QSOs.</span></span><span style="font-family: helvetica;"> </span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span style="color: black;"><span style="font-family: helvetica;">Tuesday's game plan was to qualify a Homebrew WW2
Paraset replica and a HW7 QRP transceiver. </span></span><span style="font-family: helvetica;"> </span></p><p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgXlm4Nu8AL4T4pNZ-hjO-5ka_RCIC8KQ0j2b42zGinzUdltziPZpiwWgUgOFVpT9iDMx2Oc-bPNAYz26sEnBp37ypFtYwdReif1Y9P-dPYXFkxsth--mQKb1vwHhMqps6vnJbktLmQiz0XM3SvFrTZ_coggUZYPrkxWNtDEeGR3kQCNqlRmXFzrLBSdw/s3414/CX%20Paraset%20KR7W.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2956" data-original-width="3414" height="530" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgXlm4Nu8AL4T4pNZ-hjO-5ka_RCIC8KQ0j2b42zGinzUdltziPZpiwWgUgOFVpT9iDMx2Oc-bPNAYz26sEnBp37ypFtYwdReif1Y9P-dPYXFkxsth--mQKb1vwHhMqps6vnJbktLmQiz0XM3SvFrTZ_coggUZYPrkxWNtDEeGR3kQCNqlRmXFzrLBSdw/w612-h530/CX%20Paraset%20KR7W.jpg" width="612" /></a></div><span style="font-family: helvetica;"><b>Paraset in wooden box</b>. Russian Cold War tank radio set straight key plugs into Aux Key Jack of the Paraset. Under the modern speaker is the Paraset's 300V Power Supply.</span><p></p><p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span style="font-family: helvetica;">The Paraset only operates on 40M. The TX is a
XTAL controlled 6V6 oscillator and outputs 3.5W. The RX is a one tube
Regenerative Detector with a second tube audio amp. It runs on a separate
HV Power supply. </span><span style="font-family: helvetica;"> </span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span style="font-family: helvetica;">Transmitting with the Paraset the involves connecting the antenna, choosing the desired
crystal, then key down to peak the Tank and Ariel tuning caps for maximum
brightness of the two RF Power indicator lamps.<span style="color: black;">
</span>RX involves setting the Tuning cap to match the desired freq as noted on
a calibration chart or the RX frequency can be determined by listening on a
separate receiver to hear the small signal from the Regenerative Detector.<span style="color: black;"> </span>The RX tuning cap in conjunction with the
Reaction control adjusts the RX frequency and the sensitivity.<span style="color: black;"> </span>Each control affects the other.<span style="color: black;"> </span>The Receiver is quite sensitive and somewhat selective, but the op must listen closely as there is a high frequency audio
hiss present.<span style="color: black;"> </span>The RX is easily
overloaded by nearby higher-level signals. I was lucky to make 6 QSOs before a loud
digital signal started up 5 KCs away. <span style="color: black;"> </span></span><span style="font-family: helvetica;"> </span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span style="font-family: helvetica;"><span style="color: black;">For a small taste of Paraset info, see:<span style="mso-spacerun: yes;"> </span></span><a href="https://www.youtube.com/watch?v=JwMc53nE9kQ"><span style="mso-bidi-font-family: "Times New Roman"; mso-bidi-theme-font: minor-bidi;">#5 Valve QRP - Building a
Paraset - YouTube</span></a><span style="color: black;"><o:p></o:p></span></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span style="color: black;"><o:p><span style="font-family: helvetica;"> </span></o:p></span></p><div class="separator" style="clear: both; text-align: center;"><span style="font-family: helvetica;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgyXPUacyT8uNUL4wr4-Af4UyPI9X3E2qdw14CA83iNtVaTvurZuZZ4WwtKYKEymYBuGg0q6TWVkefkMgjaB_FT0cyCUE3aprpQFJdrktYY95fLG1JWsMWusJu9rLuEwE3pR3epY7T60mlrrtg98C9OVJ_ntDOSb5HaWNLthvTFkgJw4QbmZH8gfJJC8w/s2000/CX%20HW7%20Rig%20KR7W.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1710" data-original-width="2000" height="479" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgyXPUacyT8uNUL4wr4-Af4UyPI9X3E2qdw14CA83iNtVaTvurZuZZ4WwtKYKEymYBuGg0q6TWVkefkMgjaB_FT0cyCUE3aprpQFJdrktYY95fLG1JWsMWusJu9rLuEwE3pR3epY7T60mlrrtg98C9OVJ_ntDOSb5HaWNLthvTFkgJw4QbmZH8gfJJC8w/w559-h479/CX%20HW7%20Rig%20KR7W.jpg" width="559" /></a></span></div><p></p><p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><o:p><span style="font-family: helvetica;"><b>HW7 </b>sits on top of its modern 14V LiFe battery. Russian straight key and speaker.</span></o:p></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span style="color: black;"><span style="font-family: helvetica;">Heathkit’s second worse ham radio product, the HW7
replaced the Paraset and 1 QSO was made before the 40M band died. Then 3 QSOs
were made on 20M after the band woke up. . The HW7’s TX outputs
1.8W.<span style="mso-spacerun: yes;"> </span>The RX is direct conversion- which
produces an upper and lower sideband signal.<span style="mso-spacerun: yes;">
</span>On 20M the VFO tuning is doubled, so a very small movement of the tune
knob changes the frequency many KCs so it’s hard to precisely tune in a
station.</span></span><span style="font-family: helvetica;"> </span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span style="color: black;"><span style="font-family: helvetica;">It was very enjoyable to be able to make 34 Qs using
no more than 60 Watts attached to a crappy antenna with ham radio sets 65+
years older than an IC-7300.<span style="mso-spacerun: yes;"> </span>Could ‘<b style="mso-bidi-font-weight: normal;">IC</b>’ be the abbreviation for <b style="mso-bidi-font-weight: normal;">I</b>ce <b style="mso-bidi-font-weight: normal;">C</b>old? As compared to the warmth and glow produced by vacuum tube
radios?<span style="mso-spacerun: yes;"> </span>I think so, but YMMV.</span></span><span style="font-family: helvetica;"> </span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span style="color: black;"><span style="font-family: helvetica;">The best CW signal I heard came from The Doc Spike Antique
Radio Museum <b style="mso-bidi-font-weight: normal;">W7OS</b>'s XTAL Controlled
Globe Scout 65. It possessed a distinctive chirp but was easy to copy VS other
signals with too much chirp.<span style="mso-spacerun: yes;"> </span>An ARC-5
comes to mind.<span style="mso-spacerun: yes;"> </span>In this CX, I hit the
Jackpot- to copy Jim W8KGI's many rigs all in a row. This year on 20M Jim
offered up 6 combos. Also it’s interesting looking at the QRZ pages of participating
CX ops to see some photos of the unusual or interesting equipment they reported
using. </span></span><span style="font-family: helvetica;"> </span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span style="color: black;"><span style="font-family: helvetica;">For my next CW CX event I’d like to have a second 50W
transmitter- hopefully a homebrew. Thanks to all who
participated.<span style="mso-spacerun: yes;"> </span></span></span></p><p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span style="color: black;"><span style="font-family: helvetica;">Ricky KR7W<o:p></o:p></span></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span style="color: black;"><o:p><span style="font-family: helvetica;"> </span></o:p></span></p>
<p class="MsoNormal"><span style="mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="font-family: helvetica;"><span style="mso-spacerun: yes;"> </span><o:p></o:p></span></span></p><br /><p></p>kr7whttp://www.blogger.com/profile/12925283975807120485noreply@blogger.com0tag:blogger.com,1999:blog-6635479951504521166.post-29210543039435270682022-01-16T21:12:00.028-08:002022-10-31T14:53:11.082-07:002 Meter Coaxial Dipole for APRS or 2 Way Comms<p> <span style="font-family: verdana;">This article was originally written in 2013. For an unknown reason- Google's Blogspot had denied access. Now, The New and Improved Ver 2 has been edited to remove the 'fluff' for clarity and easier to access. </span></p><p><span style="font-family: verdana;">My intended purpose for this higher efficiency, <u>more gain that a 14-inch rubber duckie</u> 2 Meter portable </span><span style="font-family: verdana;">antenna was to slip it into an outside pocket of my hiking pack to transmit my APRS Position whilst enroute to Summits On The Air Peaks. Once I reached the peak- then the antenna would be used for 146.52 FM contacts. </span></p><span><span style="font-family: verdana;"><br /></span><span face="Verdana, sans-serif"><span style="font-family: verdana;">Before I retired- I worked as a 2Way Radio Technician. One of the common base station antennas I encountered was the <u>Coaxial Dipole</u>... sometimes known as a <u>Sleeve Dipole</u>... where a metal sleeve on the lower side of the antenna acted as the counterpoise. The coax cable feed line below the sleeve didn't affect the tuning or performance. Motorola spec sheets say the sleeve dipole is the same gain and performance as a J-pole, a Roll-up Slim Jim- but without the extra length of the 19-inch tuning stub. </span></span></span><div><span style="font-family: verdana;"><br /></span><div><br /><div class="separator" style="clear: both; text-align: center;"><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhgVYti8Z5T6goGr8qdsTCoplgPSSmq8OjZa-goEkPN8TjB3Z7llsdGUJe2rH2mTrZ4byYBHAbOm74mKlDXTQDJvSlGwOn9JaI_BOnF4ctZpAQrDhI_vC0k_4pj1paZ5rYO4m56iA2i-gcd/" style="margin-left: 1em; margin-right: 1em;"><img alt="" data-original-height="689" data-original-width="648" height="437" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhgVYti8Z5T6goGr8qdsTCoplgPSSmq8OjZa-goEkPN8TjB3Z7llsdGUJe2rH2mTrZ4byYBHAbOm74mKlDXTQDJvSlGwOn9JaI_BOnF4ctZpAQrDhI_vC0k_4pj1paZ5rYO4m56iA2i-gcd/w412-h437/image.png" width="412" /></a></div><br /></div><span face="Verdana, sans-serif"><span style="font-family: verdana;">This DIY project is to create an antenna that emulates the Coaxial Dipole.</span></span></div><div><span face="Verdana, sans-serif"><span style="font-family: verdana;"><br /></span><span style="font-family: verdana;">Above drawing: The location where the coax shield ends, and the top radiator (the whip) begins is the dipole's <u>FEED POINT</u>, the center of the dipole. One of the 1/4 Wavelength poles is the top section whip. The opposite pole is the coax's shield from the feed point to the beginning of the 7-8 turns of coax. The coil or turns of coax act as a Radio Frequency Choke. The purpose of the RF Choke is to stop RF from traveling any further down the coax feed line to the radio. The RF energy stops 18 in from the feed point- which is the correct length for 1/4 Wavelength 2 Meter radiator. <br /><br />The main support or handle of this antenna is 3/4" PVC Irrigation pipe which houses the coax cable lower pole. Sked 20 or 40 will work. A mobile whip antenna was added as the top pole- so to survive an occasional tree branch collision when hiking with the antenna in my pack.</span></span></div><div><span style="font-family: verdana;"><span><span face="Verdana, sans-serif"><br /></span><span face="Verdana, sans-serif">Finished antenna shown below: </span></span><br /><span face="Verdana, sans-serif"><br /></span><br /></span><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg8n8VOBD7NCrRdSLPgr2aMj7HowHJQkI6rVtUYl4NLhnnousSbBUT1Sd9CN1sfcQ02-fnaRMoC77U2-dPFByq0vW1svbzoSk3kMx471-QoigI0VTnMSyQkf_2qNL1mRbeq0ZKU2JvddmZm/s1600/coax+dipole+illustration+5.jpg" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><span style="font-family: verdana;"><img border="0" height="640" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg8n8VOBD7NCrRdSLPgr2aMj7HowHJQkI6rVtUYl4NLhnnousSbBUT1Sd9CN1sfcQ02-fnaRMoC77U2-dPFByq0vW1svbzoSk3kMx471-QoigI0VTnMSyQkf_2qNL1mRbeq0ZKU2JvddmZm/s1600/coax+dipole+illustration+5.jpg" width="257" /></span></a></div><div style="text-align: left;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj_2FSiAaY4afSB73aPw3rzfo1akFM0MEar_Ur28gES4Fg5g2Rko4sla8U_UitEIdwAF0B2Zs89ks4cdjAaBDinYh3ToV6Ef_aL41cWErc1Xbkf0JAPVb7FM8hCYQzOlRqAL3D273uY0nQc/s1600/coax+dipole+illustration+0.jpg" style="clear: left; margin-bottom: 1em;"><span style="font-family: verdana;"><img border="0" height="445" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj_2FSiAaY4afSB73aPw3rzfo1akFM0MEar_Ur28gES4Fg5g2Rko4sla8U_UitEIdwAF0B2Zs89ks4cdjAaBDinYh3ToV6Ef_aL41cWErc1Xbkf0JAPVb7FM8hCYQzOlRqAL3D273uY0nQc/w573-h445/coax+dipole+illustration+0.jpg" width="573" /></span></a></div><div style="text-align: left;"><br /></div><div style="text-align: left;"><span style="font-family: verdana; text-align: center;">NMOQ (quarter wave) has no loading coil inside.</span></div><div style="text-align: left;"><span style="font-family: verdana; text-align: center;"><br /></span></div><div style="text-align: left;"><span style="font-family: verdana; text-align: center;"><br /></span></div><div style="text-align: left;"><a href="http://4.bp.blogspot.com/-U_EKuYXfI0k/UggVv9nl75I/AAAAAAAAAf4/o4eVwo0QMHE/s1600/coax+dipole+illustration+1.jpg" style="clear: left; margin-bottom: 1em;"><span style="font-family: verdana;"><img border="0" height="532" src="http://4.bp.blogspot.com/-U_EKuYXfI0k/UggVv9nl75I/AAAAAAAAAf4/o4eVwo0QMHE/w665-h532/coax+dipole+illustration+1.jpg" width="665" /></span></a></div><span style="font-family: verdana;"><span face="Verdana, sans-serif"><div><span style="font-family: verdana;"><span face="Verdana, sans-serif"><br /></span></span></div><div><span style="font-family: verdana;"><span face="Verdana, sans-serif">After cutting the cap it should look something like above.</span></span></div><div><span style="font-family: verdana;"><span face="Verdana, sans-serif"><br /></span></span></div>I used RG-174 coax as the feedline- harvested from an Amazon purchased jumper (info below).<br /><br />When I place the antenna in a pocket of my pack- the whip extends about 18" above my head.<br /><br />I sometimes use another 18" piece of PVC pipe with a coupler as an extension for this antenna to elevate it higher when I think I am in a Sketchy APRS area. The extension makes it easy to jam into cracks or a rock pile on a summit. It also makes it easier to get bonked off the trail by hitting that low hanging branch. I have used electrical tape to secure it to my trekking pole handle stabbed into the dirt.</span><br /><br /></span><br /><div style="text-align: center;"><a href="http://3.bp.blogspot.com/-L3NNVgwO_60/UggVxkHawAI/AAAAAAAAAgM/pF5jiAhIFm0/s1600/coax+dipole+illustration+2.jpg"><span style="font-family: verdana;"><img border="0" height="465" src="http://3.bp.blogspot.com/-L3NNVgwO_60/UggVxkHawAI/AAAAAAAAAgM/pF5jiAhIFm0/s1600/coax+dipole+illustration+2.jpg" width="640" /></span></a></div><div style="text-align: center;"><br /></div><div style="text-align: justify;"><span style="font-family: verdana; text-align: left;">The piece of Perf Board supports the coax inside of the PVC pipe and makes the connection to the hacked NMO cap. Plywood, Plexiglass, or other non-conductive material can sub for Perf Board. </span></div><div style="text-align: center;"><span style="font-family: verdana; text-align: left;"><br /></span></div><div style="text-align: center;"><span style="font-family: verdana; text-align: left;"><br /></span></div><div style="text-align: left;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhPtvKWNKJ2s_i8Mji-0G0pMHqjlhDDpZQ2t3HewRh4U67blAusrN6dXw9GoWhT3VbgUhQ0NZfpIYahUNcknUd78PnBVmbi_PiznpgFerlp7H7vB7pZ4xOMdol48aqkhXZO9s9dpRwfxPRP/s1600/coax+dipole+illustration+3.jpg"><span style="font-family: verdana;"><img border="0" height="569" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhPtvKWNKJ2s_i8Mji-0G0pMHqjlhDDpZQ2t3HewRh4U67blAusrN6dXw9GoWhT3VbgUhQ0NZfpIYahUNcknUd78PnBVmbi_PiznpgFerlp7H7vB7pZ4xOMdol48aqkhXZO9s9dpRwfxPRP/s1600/coax+dipole+illustration+3.jpg" width="640" /></span></a></div><div style="text-align: left;"><br /></div><div style="text-align: left;"><span style="font-family: verdana;">A= Heat shrink tubing is placed over the coax center insulation because when soldering the center conductor wire to the larger copper wire... the heat will melt the coax insulation. The heat shrink keeps it from melting out of place.</span><br style="font-family: verdana;" /><br style="font-family: verdana;" /><span style="font-family: verdana;">B= Solder the coax center conductor to the NMO connection. Once soldered- use wet paper towel to absorb excess heat.</span><br style="font-family: verdana;" /><br style="font-family: verdana;" /><span style="font-family: verdana;">C= Epoxy or hot glue could be added at this joint for rigidity.</span></div><div style="text-align: left;"><span style="font-family: verdana;"><br /></span></div><div style="text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhCHoVUzBXWb2mP7UDDIhBXidt4jWJVc3MH2HIe4nazHWTskOW-qWsTZEErC2Iw3x3dmgMKCt_29sqhokZKeTbZXGytAOCinibT5to75BRV3hcpcSr41jQLRfarBmXLs8CYS65aMrG8ctDV/" style="margin-left: 1em; margin-right: 1em;"><img alt="" data-original-height="832" data-original-width="1200" height="373" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhCHoVUzBXWb2mP7UDDIhBXidt4jWJVc3MH2HIe4nazHWTskOW-qWsTZEErC2Iw3x3dmgMKCt_29sqhokZKeTbZXGytAOCinibT5to75BRV3hcpcSr41jQLRfarBmXLs8CYS65aMrG8ctDV/w538-h373/image.png" width="538" /></a></div><span style="font-family: verdana;"><span face="Verdana, sans-serif"><div><span style="font-family: verdana;"><span face="Verdana, sans-serif"><br /></span></span></div>Slide the Perf board with attached modified NMO cap down into the PVC coupler. The coax cable needs to be inserted first. Apply epoxy glue to the board and the top of the coupler for the NMO. A too much epoxy mess will not hurt- as epoxy is nonconductive. <br /><br /><br /> <div style="text-align: center;"><a href="http://1.bp.blogspot.com/-4HjhSMQjx3k/UggVz7LnANI/AAAAAAAAAgs/I6OTj_JF04k/s1600/coax+dipole+illustration+7.jpg"><img border="0" height="480" src="http://1.bp.blogspot.com/-4HjhSMQjx3k/UggVz7LnANI/AAAAAAAAAgs/I6OTj_JF04k/s1600/coax+dipole+illustration+7.jpg" width="640" /></a></div></span><br /><span face="Verdana, sans-serif">The 3-inch slot cut into the PVC pipe provides adjustment of the location of where the beginning of the coax RF Choke coil starts. If the antenna needs to be longer then move the coil further down- this makes the length of coax inside of the pipe longer. </span></span></div><div><span style="font-family: verdana;"><span face="Verdana, sans-serif"><br /></span></span></div><div><span style="font-family: verdana;"><span face="Verdana, sans-serif">The RF Choke coil can be temporarily secured in place with electrical tape while SWR testing takes place. Once the coax coil position is found- a couple of wraps with quality electric tape will hold it in place for years to come. <br /></span><span face="Verdana, sans-serif"><br /></span><br /></span><div style="text-align: left;"><a href="http://3.bp.blogspot.com/-6Ww9pPD0BxU/UggV0D78b1I/AAAAAAAAAgw/5v4XOQ4R_9Q/s1600/coax+dipole+illustration+6.jpg"><span style="font-family: verdana;"><img border="0" height="489" src="http://3.bp.blogspot.com/-6Ww9pPD0BxU/UggV0D78b1I/AAAAAAAAAgw/5v4XOQ4R_9Q/w652-h489/coax+dipole+illustration+6.jpg" width="652" /></span></a></div><span style="font-family: verdana;"><span face="Verdana, sans-serif"><br /></span><span face="Verdana, sans-serif">A standard 1/4 VHF quarter wave mobile whip antenna is used as the upper pole of the dipole. </span></span></div><div><br /></div><div><span style="font-family: verdana; font-size: medium;">ADDITIONAL INFO Section...</span></div><div><span style="font-family: verdana;"><br /></span></div><div><span style="font-family: verdana;"><span face="Verdana, sans-serif">I built another version of this antenna called the Lazy Pole- which uses a 3/4-inch wooden dowel for the support. The article for it is at:</span></span></div><div><a href="https://w7dk.org/images/rct_bark/bark_2020_04.pdf">bark_2020_04.pdf (w7dk.org)</a></div><div><span style="font-family: verdana;"><span face="Verdana, sans-serif">Page 24</span></span></div><div><span style="font-family: verdana;"><span face="Verdana, sans-serif">[ www.w7dk.org / Newsletters / April 2020 / Page 24</span></span></div><div><span style="font-family: verdana;"><span face="Verdana, sans-serif"><br /></span></span></div><div><span style="font-family: verdana;"><span face="Verdana, sans-serif">A 15 ft long RG-174 coax jumper with SMA (for Japanese handy talkies) and a Reverse SMA (for most Chinese handy talkies) coax connectors on each end can be purchased here:</span></span></div><div><span style="font-family: verdana;"><span face="Verdana, sans-serif"><br /></span></span></div><span style="font-family: verdana;"> </span><a href="https://www.amazon.com/Superbat-coaxial-Bulkhead-Adapter-Equipment/dp/B07FC8PVZS/ref=sr_1_1_sspa?crid=2RNBKJOD2CKIM&keywords=sma%2Brg-174%2Bcable&qid=1642376937&sprefix=sma%2Brg-174%2Bcable%2Caps%2C169&sr=8-1-spons&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyRzFFQkU0RkFLSDQwJmVuY3J5cHRlZElkPUEwNjM5MDQ4MTFRTVNXOVdQNUNKSCZlbmNyeXB0ZWRBZElkPUEwMTU4MzU4MkZUVE9ZOFhOVjFYWiZ3aWRnZXROYW1lPXNwX2F0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU&th=1" style="font-family: verdana;">Amazon.com: </a></div><div><br /></div><div><a href="https://www.amazon.com/Superbat-coaxial-Bulkhead-Adapter-Equipment/dp/B07FC8PVZS/ref=sr_1_1_sspa?crid=2RNBKJOD2CKIM&keywords=sma%2Brg-174%2Bcable&qid=1642376937&sprefix=sma%2Brg-174%2Bcable%2Caps%2C169&sr=8-1-spons&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyRzFFQkU0RkFLSDQwJmVuY3J5cHRlZElkPUEwNjM5MDQ4MTFRTVNXOVdQNUNKSCZlbmNyeXB0ZWRBZElkPUEwMTU4MzU4MkZUVE9ZOFhOVjFYWiZ3aWRnZXROYW1lPXNwX2F0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU&th=1" style="font-family: verdana;" target="_blank">Superbat RF coaxial SMA Male to SMA Female Bulkhead RG174 15ft Cable + 3pcs RF Coax SMA Adapter Kit for SDR Equipment Antenna Ham Radio,3G 4G LTE Antenna,ADS-B,GPS and etc : Electronics</a><br style="font-family: verdana;" /><div><span style="font-family: verdana;"><span face="Verdana, sans-serif"> </span></span></div><div><span style="font-family: verdana;"><span face="Verdana, sans-serif">Note: if the link does not work- please cut n paste it into your search engine.</span></span></div><div><span style="font-family: verdana;"><span face="Verdana, sans-serif"><br /></span></span></div><div><span style="font-family: verdana;"><span face="Verdana, sans-serif">Simply cut off the coax connector that does not match your radio.</span></span></div><div><span style="font-family: verdana;"><span face="Verdana, sans-serif"><br /></span></span></div><div><span style="font-family: verdana;"><span face="Verdana, sans-serif">Above I mention 'Quality Electrical Tape' my fav is Scotch 33, found at Home Depot.</span></span></div><div><span style="font-family: verdana;"><span face="Verdana, sans-serif"><br />The <u>Flowerpot antenna</u> is another version of the Coax Dipole Antena:</span></span></div><div><span style="font-family: verdana;"><span face="Verdana, sans-serif"><br /></span></span></div><div><span style="font-family: verdana;"><a href="https://vk2zoi.com/articles/half-wave-flower-pot/" target="_blank">Half-Wave Flower Pot Antenna – VK2ZOI</a></span></div><div><span style="font-family: verdana;"><br /></span></div><div><span style="font-family: verdana;">Again, if the link does not work- cut n paste it into your search engine.</span></div><div><span style="font-family: verdana;"><br /></span></div><div><span style="font-family: verdana;">You'll need a metric to Imperial length converter. There's an app for that.</span></div><div><span style="font-family: verdana;"><span><span face="Verdana, sans-serif"><br /></span></span></span></div><div><span style="font-family: verdana;"><span><span face="Verdana, sans-serif">The effectiveness of the Coaxial Dipole (named "The Home Brew Dipole") was tested as compared to other antennas typically used on a Handy Talkie. See:</span></span></span></div><div><span style="font-family: verdana;"><span><span face="Verdana, sans-serif"><br /></span></span></span></div><div><span style="font-family: verdana;"><span><span face="Verdana, sans-serif"><a href="https://w7dk.org/images/rct_bark/bark_2018_10.pdf" target="_blank">bark_2018_10.pdf (w7dk.org)</a> Cut n Paste if necessary.</span></span></span></div><div><span style="font-family: verdana;"><span><span face="Verdana, sans-serif">Scroll to Page 6 </span></span></span></div><div><span style="font-family: verdana;"><span><span face="Verdana, sans-serif">[ w7dk.org / Newsletters / Oct 2018 / Page 6 ]</span></span></span></div><div><span style="font-family: verdana;"><span><span face="Verdana, sans-serif"><br /></span></span></span></div><div><span style="font-family: verdana;"><span><span face="Verdana, sans-serif">End of this blog entry. Best Regards, Rich KR7W </span></span></span></div><div><span style="font-family: verdana;"><span><span face="Verdana, sans-serif"><br /></span></span></span></div><div><span style="font-family: verdana;"><span><span face="Verdana, sans-serif">Email me if you have questions. QRZ lookup will find me.</span></span></span></div><div><span style="font-family: verdana;"><span><span face="Verdana, sans-serif"><br /></span></span></span></div><div><span style="font-family: verdana;">Photo Below: Summits On The Air expedition. Coaxial Dipole is being held up by the brush. KR7W has QSO with a ham approx. 50 miles away- line of sight- 5 watts Kenwood Handy Talkie. </span></div><div><span style="font-family: verdana;"><br /></span></div><div><span style="font-family: verdana;"><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgQPSWZ0HHamwUWHWj70T1r0thFlPHhYBkzcgumJ8QdAa7A2tZ_SS7XkhjLgSPSR6zZkSg4RI9RpEkFzfHKbCOBE0lLP7RLRoUM_mN-qY2hKh_OCw4NTcPwfOHS1RjuDsEN4lHLN4Dt46RU/" style="margin-left: 1em; margin-right: 1em;"><img alt="" data-original-height="671" data-original-width="434" height="509" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgQPSWZ0HHamwUWHWj70T1r0thFlPHhYBkzcgumJ8QdAa7A2tZ_SS7XkhjLgSPSR6zZkSg4RI9RpEkFzfHKbCOBE0lLP7RLRoUM_mN-qY2hKh_OCw4NTcPwfOHS1RjuDsEN4lHLN4Dt46RU/w328-h509/image.png" width="328" /></a></div><br /><br /><span face="Verdana, sans-serif"><br /></span><span face="Verdana, sans-serif"><br /></span><span face="Verdana, sans-serif"><br /></span><span face="Verdana, sans-serif"><br /></span><span face="Verdana, sans-serif"><br /></span><span face="Verdana, sans-serif"><br /></span><span face="Verdana, sans-serif"><br /></span><span face="Verdana, sans-serif"><br /></span><span face="Verdana, sans-serif"><br /></span><span face="Verdana, sans-serif"><br /></span><span face="Verdana, sans-serif"><br /></span><span face="Verdana, sans-serif"><br /></span><span face="Verdana, sans-serif"><br /></span><br /></span><div class="separator" style="clear: both; text-align: center;"></div><div class="separator" style="clear: both; text-align: center;"></div><div></div><span face="Verdana, sans-serif" style="font-size: x-small;"><br /><br /><br /><br /><br /><br /><br /></span></div></div>kr7whttp://www.blogger.com/profile/12925283975807120485noreply@blogger.com0tag:blogger.com,1999:blog-6635479951504521166.post-48956809908486190212020-05-30T11:11:00.008-07:002020-05-30T12:57:29.348-07:00Rainy Day Monday - Old Radio Restoration - Philco 52-940<font face="verdana" size="2">Memorial Day, 2020 -'Twas dark, rainy and dreary as compared with the last 10 days of nice weather. A good day to retreat to the Covid-19 Proof Shelter in Place Bunker / Workshop for a "Now for something entirely different" project. This old entertainment radio was picked off the shelf for restoration:</font><div><font face="verdana" size="2"><br /></font></div><div><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj0X9LWQ6BzlJHWkE0yYG2Xpmqw-psRGTJPJmwnXiNCxafoz8hFOjlgqg49Jpq7p05bA11GtcxtCknPM5BmFdk2HXrcD2QTT5PrM9eTl5zgMOBNyTzuPwkuGq3G94_zLXBSOYhYbUon7x0/" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="524" data-original-width="800" height="263" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj0X9LWQ6BzlJHWkE0yYG2Xpmqw-psRGTJPJmwnXiNCxafoz8hFOjlgqg49Jpq7p05bA11GtcxtCknPM5BmFdk2HXrcD2QTT5PrM9eTl5zgMOBNyTzuPwkuGq3G94_zLXBSOYhYbUon7x0/w400-h263/Philco+52_940-1.jpg" width="400" /></a></td></tr><tr><td class="tr-caption" style="text-align: left;"><br /></td></tr></tbody></table><br /><br /><br /><font face="verdana" size="2"><br /><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><br /></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2">Philco 52-940 acquired at the Seaside Hamfest more than 10 years ago.</font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2">Blog Ver 2 Edit Note: The 52-940 radio is a newer version of the "Hippo" radio from Philco:</font></div><div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj7DXTe_JhUdb1hlof21H2jHfJXjGKmS9lQ6DvWT_8hUSA0q9Bb-4WfLaON6IGBRM5egOmz_tlfXB92HNua8tIFAWtoCL8eN4Yn5XhmQr85VmaRUfgwK8qe4iHQSjH1kHD4poPsl2Kt7KE/" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="450" data-original-width="640" height="281" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj7DXTe_JhUdb1hlof21H2jHfJXjGKmS9lQ6DvWT_8hUSA0q9Bb-4WfLaON6IGBRM5egOmz_tlfXB92HNua8tIFAWtoCL8eN4Yn5XhmQr85VmaRUfgwK8qe4iHQSjH1kHD4poPsl2Kt7KE/w400-h281/Philco+Hippo.jpg" width="400" /></a></div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><span style="font-family: verdana; font-size: small;">Above: Philco Hippo radio from 1948 (photo from Ebay)</span></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2">The rainy day restoration radio- was missing its back which contains the loop antenna. On initial power-up, using Isolation Transformer and Variac, revealed FULL AUDIO level AC hum noise from the speaker. The volume control had no effect. This was hopeful news that told me the series string tubes are not burned out, the rectifier and audio output tubes are working.</font></div><div><font face="verdana" size="2"><br /></font></div><div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh1O20wXwDlf0EqZbKQYcDY5yPqqc7Hsa5MHm35BcKtQfy3HGif6_O57El6diHhmod-JEO7FF2KMCksKN1b1bPufSt0K7W09b3kCUUD3EvdXchW-5XH_fnKouXXISSylO0AJu9Bt5c3olI/" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="497" data-original-width="800" height="249" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh1O20wXwDlf0EqZbKQYcDY5yPqqc7Hsa5MHm35BcKtQfy3HGif6_O57El6diHhmod-JEO7FF2KMCksKN1b1bPufSt0K7W09b3kCUUD3EvdXchW-5XH_fnKouXXISSylO0AJu9Bt5c3olI/w400-h249/Philco+52_940-2.jpg" width="400" /></a></div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><span style="font-family: verdana; font-size: small;">A sacrificial scrap wood 'cradle' was fabricated in the Acme Woodworks shop to protect the vulnerable components on top of the chassis. Did the uncontrollably extremely loud hum cause the speaker to shatter apart? or was the radio attacked by Speaker Bugs? Under the chassis- the first organ removed for transplant was the DC power supply Filter Capacitor- shown under speaker above.</span></div><div><br /></div><div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh3f9NLRMGc-PkqYz9uIWxeLes6OpOzxNGo398KDlbwb-mo0X65wDMdf-5HRfYkC_a0gd29F-Y0zYtki7QiZbcvn1IK5_YpaLblXCZvfaEJff2wVFz65msNBPqQsGt9jl2sBGQoabm4GYM/" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="343" data-original-width="800" height="171" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh3f9NLRMGc-PkqYz9uIWxeLes6OpOzxNGo398KDlbwb-mo0X65wDMdf-5HRfYkC_a0gd29F-Y0zYtki7QiZbcvn1IK5_YpaLblXCZvfaEJff2wVFz65msNBPqQsGt9jl2sBGQoabm4GYM/w400-h171/Philco+52_940-6.jpg" width="400" /></a></div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><div class="separator" style="clear: both; text-align: center;"><a href="https://1.bp.blogspot.com/-FLgtaycd9d0/XtKJIeQbwVI/AAAAAAAACV4/cnMWbmayh2YBuUwVuMA0ze-tuM3xj51YgCK4BGAsYHg/Philco%2B52_940-6.jpg" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><br /></a></div></div><div><span style="font-family: verdana; font-size: small;">Under the chassis the usual paper+wax capacitors were replaced with Yellow Polystyrene caps. Red arrow points to 3 electrolytic caps, taped together, sitting in a bed of silastic silicone compound which secures and isolates them from the chassis. The original filter cap wires were reused to connect to the new caps.</span></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2">Looking closely at the IF cans- their base is made from clear plastic- which means that they contain mica wafers separating silver plates that create the capacitors in the IF can's 455 KC tuned circuit. Almost always- these caps develop Silver Mica disease which causes scratchy sounding pops in the radios audio. Since this radio plays without noise- the IF cans did not undergo the SM Cure procedure. </font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2">At first I thought this radio was in the "Hot Chassis" category- where one side of the AC Line Cord attaches to the metal chassis- which was popular back then. Analyzing and experimenting reveals that the NEG power supply has a separate GND path- not connected to the chassis. Some items like the speaker common wire and tuning capacitor are GND'd to the chassis. It was confusing where to connect the polarized AC line cord NEUT wire- which, BTW connects to the AC ON/OFF switch (backwards in my thinking). The radio had a wax paper .047 mfd cap across the AC line to bypass noise from getting into the RF sections of this radio. Two .022 mfd X safety caps were transplanted that now perform this function. Note: experimenting has demonstrated the necessity of AC line bypass caps. Man made noise is drastically reduced in most cases.</font></div><div><font face="verdana" size="2"><br /></font></div><div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiENYaUr19H4xGxjrY9CVtdsvOnf59fYn3MSgT4lWjj4fV2i0lyWbbxRxtfFZkTHZB-b77lJiwwQfXUEAs4UpoXWcxmHtiI0bG1Jupk7JlFA1g1QP209kyRo_oaMHFmOn3AC3-u8nYQosU/" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="988" data-original-width="774" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiENYaUr19H4xGxjrY9CVtdsvOnf59fYn3MSgT4lWjj4fV2i0lyWbbxRxtfFZkTHZB-b77lJiwwQfXUEAs4UpoXWcxmHtiI0bG1Jupk7JlFA1g1QP209kyRo_oaMHFmOn3AC3-u8nYQosU/w314-h400/Philco+52_940-3.jpg" width="314" /></a></div><font face="verdana" size="2"><br /></font></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2">In the foreground is the new radio back panel and loop antenna. A piece of 2.3 mm plywood was carved, little by little on the table saw to fit into the rear of the radios case. 1.125" holes were hole-sawed. The loop antenna organs- the dowel-bobbins and the 40 ft of cloth covered wire- were harvested from an old battery powered set from the RCT Free table. </font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2">A same sized speaker was not found in the workshops acres of junk spare parts. The best sounding speaker that fit is from a Motorola Golden Voice radio- which sounds pretty well. Experiments were conducted with 'tone control' capacitors- from the Audio Output Tube Plate to the Negative supply- to make sure the selected speaker didn't sound too treble-y or too bass-y.</font></div><div><font face="verdana" size="2"><br /></font></div><div><div class="separator" style="clear: both; text-align: center;"><a href="https://1.bp.blogspot.com/-xJd0WV72riI/XtKR3pCVFII/AAAAAAAACX4/foFXx6dqx5Ill_M5jfZVcM1elBzoXwKigCK4BGAsYHg/Philco%2B52_940-5.jpg" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="515" data-original-width="800" height="258" src="https://1.bp.blogspot.com/-xJd0WV72riI/XtKR3pCVFII/AAAAAAAACX4/foFXx6dqx5Ill_M5jfZVcM1elBzoXwKigCK4BGAsYHg/w400-h258/Philco%2B52_940-5.jpg" width="400" /></a></div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2">The original crappy speaker was screwed to the radio chassis- which made it more difficult to replace. The Motorola Golden Voice speaker is mounted to a plywood adapter plate- in</font><span style="font-family: verdana; font-size: small;"> the same place as a cardboard gasket resided to isolate the original speaker from the bakelite radio case. The speaker was moved 3 times on the plywood- to get it to fit just right with the chassis placed inside of the cabinet. The front of the plywood adapter plate is painted black to hide this modification from outside view.</span></div><div><font face="verdana" size="2"><br /></font></div><div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjKEa-pAo40Gl0qc_F8fpCxo4Wz-varm_FOeBYeyMLxqvhfx5K8UkIvZHm_353IRRC6fqfyqBf9WCgUr4DI1MJiT6-3STS6fg_Dc5KjZjt4ZIi27sNvmEKxLKXID4zqJydyEUm1y4Y-vwA/" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="446" data-original-width="800" height="223" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjKEa-pAo40Gl0qc_F8fpCxo4Wz-varm_FOeBYeyMLxqvhfx5K8UkIvZHm_353IRRC6fqfyqBf9WCgUr4DI1MJiT6-3STS6fg_Dc5KjZjt4ZIi27sNvmEKxLKXID4zqJydyEUm1y4Y-vwA/w400-h223/Philco+52_940-4.jpg" width="400" /></a></div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2">The rear cover in place. More vent holes were later drilled after it was noticed that the power supply side of the radio seemed extra hot. </font></div><div><font face="verdana" size="2"><br /></font></div><div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEix-ATfgGsKZ9stp7l-Rbls8NKYSGNQ-daXBN1AeWukM9IFw4UmXxwj79-kEIYMzEinzlaHsJdUj0yiKS87qVDr_4qYttI74w-AekAd6Lh8fVqdpRFNo-WvqzNWkDW70k4d7ZheeeeV_g0/" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="499" data-original-width="800" height="250" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEix-ATfgGsKZ9stp7l-Rbls8NKYSGNQ-daXBN1AeWukM9IFw4UmXxwj79-kEIYMzEinzlaHsJdUj0yiKS87qVDr_4qYttI74w-AekAd6Lh8fVqdpRFNo-WvqzNWkDW70k4d7ZheeeeV_g0/w400-h250/Philco+52_940-7.jpg" width="400" /></a></div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2">Here the radio is on it's shelf in the Bunker Workshop- not being a Shelf Queen- but playing KIXI, KOMO, KVI on a regular basis. </font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2">The bakelite case received a bath in Dawn Dishwashing suds, then polished with automotive plastic headlight cleaner. The brass trim got an overnight soak in vinegar then precision polished with Brasso.</font></div><div><font face="verdana" size="2"><br /></font></div><div><span style="font-family: verdana; font-size: small;">After careful alignment the radio plays well, especially the Hispanic Music stations at the top of the AM band.</span></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2">End of Blog Report. KR7W</font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div><div><font face="verdana" size="2"><br /></font></div>kr7whttp://www.blogger.com/profile/12925283975807120485noreply@blogger.com0tag:blogger.com,1999:blog-6635479951504521166.post-36459835030464086262016-12-08T08:04:00.000-08:002016-12-08T09:40:19.592-08:00WW2 Paraset Spy Radio... Part 2<span style="font-family: "verdana" , sans-serif; font-size: x-small;">Construction of the radio has begun. The front panel- made from a layer of .040" PCB material sandwiched with a layer of .040 aluminum- left over from the small camping trailer I built. These materials were chosen because they were on hand... as well as- I didn't think the trailer aluminium was thick enough to be sturdy enough by itself- and the copper PCB allows for dead-bug and/or Manhattan component installation. Holes were drilled per one of the many scale drawings found on the web. </span><br />
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<tr><td class="tr-caption" style="text-align: left;"><span style="font-family: "arial" , "helvetica" , sans-serif; font-size: x-small;">Sandwich of PCB, Aluminum sheeting and drilling guide. The front panel is cut to be 1/4" wider on each side to provide a lip for the chassis to fit in its wooden box.</span></td></tr>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgiHAuR89JH-NvePQZfUjGxqcSoOBRLT8qOMS1IdIN-azHbNIGX9UndXEi9csvgaeuZe95YCn1KAUKe1gx9TsIGQqL4xskzUxmPwZDWKCMxt6h4NJ2D5na-_R37K7sqoc_VnCVqh55bPBY/s1600/Part+2+Chassis+Front.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="466" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgiHAuR89JH-NvePQZfUjGxqcSoOBRLT8qOMS1IdIN-azHbNIGX9UndXEi9csvgaeuZe95YCn1KAUKe1gx9TsIGQqL4xskzUxmPwZDWKCMxt6h4NJ2D5na-_R37K7sqoc_VnCVqh55bPBY/s640/Part+2+Chassis+Front.jpg" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: left;"><span style="font-family: "arial" , "helvetica" , sans-serif; font-size: x-small;">Aluminum front with many components installed. [</span><span style="font-family: "arial" , "helvetica" , sans-serif; font-size: xx-small;">The annotation is 'photo-shopped'- not actually stenciled on the panel. </span><span style="font-family: "arial" , "helvetica" , sans-serif; font-size: xx-small;">Note error: RX Band switch should read 'TX' Band switch. </span><span style="font-family: "arial" , "helvetica" , sans-serif; font-size: x-small;">]</span><span style="font-family: "arial" , "helvetica" , sans-serif; font-size: xx-small;"> </span></td></tr>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjJ20CPw9UFQl8sD7SpMtrcPeOv7UiVbvYgLcTsr1CrCzFGDlUOCNbQM_GTbhHL0zBeiY-8mSzfGiKa8xVYcFfE9ee-R3KCs4w6fujfKbwTy4w0HyoM1_wkjAS6H1UCtiR2OZhHdaFXi8Q/s1600/Part+2+Chassis+Inside+view.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="544" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjJ20CPw9UFQl8sD7SpMtrcPeOv7UiVbvYgLcTsr1CrCzFGDlUOCNbQM_GTbhHL0zBeiY-8mSzfGiKa8xVYcFfE9ee-R3KCs4w6fujfKbwTy4w0HyoM1_wkjAS6H1UCtiR2OZhHdaFXi8Q/s640/Part+2+Chassis+Inside+view.jpg" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: left;"><span style="font-family: "arial" , "helvetica" , sans-serif; font-size: x-small;">Some components shown from the back. </span></td></tr>
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<span style="font-family: "verdana" , sans-serif; font-size: x-small;">All holes drilled with .013" drill bit for #4 screws. Holes for capacitors and other devices with a shaft were enlarged with a step bit. The tube socket holes were drilled with a 1-1/8" hole saw. </span><br />
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<span style="font-family: "verdana" , sans-serif; font-size: x-small;">The two major challenges for me to create the Paraset replica like I have in mind are: </span><br />
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<span style="font-family: "verdana" , sans-serif; font-size: x-small;">1. The National model 10009 Tuning Dial with 'pinch wheel' gear reduction tuning for the receiver. Some builders don't bother with the pinch wheel mechanism- instead they install a small variable tuning capacitor in place of the pinch wheel shaft. The large tuning knob is course tuning; the small knob provides vernier tuning. This method is a good disguise and probably functions quite well. </span><br />
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<span style="font-family: "verdana" , sans-serif; font-size: x-small;">2. The built in Telegraph Key. </span><br />
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<tr><td style="text-align: center;"><a href="https://3.bp.blogspot.com/-Z-9PcOZOq6g/WEjnQ4AV3cI/AAAAAAAABmI/7NHaI7KtBRcYoQplo67poVowTxaRFS5OgCEw/s1600/Part%2B2%2BPinch%2BWheel%2BAnno.jpg" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="282" src="https://3.bp.blogspot.com/-Z-9PcOZOq6g/WEjnQ4AV3cI/AAAAAAAABmI/7NHaI7KtBRcYoQplo67poVowTxaRFS5OgCEw/s400/Part%2B2%2BPinch%2BWheel%2BAnno.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: left;"><span style="font-family: "arial" , "helvetica" , sans-serif; font-size: x-small;">A very nice replica shows the tuning dial I desire to have on my set. Underneath of the large tuning knob is a brass wheel almost the same size as the knob skirt. The small tuning knobs pinch wheel mates with the large wheel which creates an approx 3.33 to 1 ratio.</span></td></tr>
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<span style="font-family: "verdana" , sans-serif; font-size: x-small;">1. No pinch wheel dials were found scouring the web and radio club builders didn't have exactly what I was hoping for. I found that some builders had built their own dials. So I set out to do same- with some help. .026" brass sheet (for hobby use) was obtained from Amazon. pQRPer- PJ N7PXY generously offered to fabricate the brass wheels for the tuning dial in his metal working shop.</span><br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiDJHmU-2SW7D3jc0DKcyWSnf-QBbvP5vsTdz-TdKTkr8nMWSwQn1HoI8bwuJPmJ-LXgeDEOMeHNA3aptyBLxy3dEZOJnG8oA-VzrsezD6Hfh2gvUxRg9QhxH7DdDHajaKgl0YfExVWVt0/s1600/Part+2+PJs+Lathe.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="632" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiDJHmU-2SW7D3jc0DKcyWSnf-QBbvP5vsTdz-TdKTkr8nMWSwQn1HoI8bwuJPmJ-LXgeDEOMeHNA3aptyBLxy3dEZOJnG8oA-VzrsezD6Hfh2gvUxRg9QhxH7DdDHajaKgl0YfExVWVt0/s640/Part+2+PJs+Lathe.jpg" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: left;"><span style="font-family: "arial" , "helvetica" , sans-serif; font-size: x-small;"><span style="font-size: xx-small;">Here we are in PJs shop. The brass disk was cut using a 3" hole saw. The mandrel in the chuck is a 1/4" bolt. The disk was cut down to 2.5" to fit behind the 2.75" tuning knob skirt.</span> </span></td></tr>
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<span style="font-family: "verdana" , sans-serif; font-size: x-small;">The drawing called for .75" wheels with .15" center hole. The small wheels were cut using a smaller hole saw and sanded smooth. The end result size was .79". Close enough.</span><br />
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<span style="font-family: "verdana" , sans-serif; font-size: x-small;">Back in my workshop... the large brass wheel was drilled to attach to the large tuning knob skirt- using the same screws that hold it to the bakelite knob. The small pinch wheels were assembled to their shaft and inserted into its bushing through the chassis. </span><br />
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<span style="font-family: "verdana" , sans-serif; font-size: x-small;"><b><i>Curses!!</i></b> It did not work. Somehow the bushing or capacitor hole is in the wrong place by 1/8". The pinch wheels were just touching the large wheel- but not over lapping it. Recovery was accomplished by making new pinch wheels using the next larger hole saw size. It's a good thing that the pinch wheels do not need to be precisely round- as there's no metal lathe here.</span><br />
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<tr><td class="tr-caption" style="text-align: left;"><span style="font-size: x-small;"><span style="font-family: "arial" , "helvetica" , sans-serif;">The larger sized pinch wheels [ .97" dia and no spacer between them] hug the larger brass wheel with about 1/16 inch of meshing surface. The pinch wheel shaft is 1/4" diameter aluminium stand-off material with 6-32 threads. The shaft bushing is from an old junk box bakelite bodied 5 watt potentiometer that was easy to harvest with a few hammer blows. </span> </span></td></tr>
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<span style="font-family: "verdana" , sans-serif; font-size: x-small;"> 2. The Telegraph Key- As a CW straight key user... I am hoping for a key with a firm feel- not flimsy that feels like it is about to fall apart or a key that goes click-clack when the knob is pushed down. It's noted that some builders have adapted industrial electrical switches and others used PCB material to create their key. </span><br />
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<span style="font-family: "verdana" , sans-serif; font-size: x-small;">On line info reveals that there were two styles of keys used in the original sets-</span><br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjYE9GGOBZ44zYxYu8n7BmWKu0u-OUM1ubqXuxfaN3g81k0KCTiIEDaBLnUjEyxwsJeBSjiIfvNPDRtr6sSkm6r-m3MPKbgiYNdkxr1GFwWQMkTd3nGLB5OlaToGQHBIDIJ8ykgQjiCsJ4/s1600/Part+2+Orginal+Keys.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="222" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjYE9GGOBZ44zYxYu8n7BmWKu0u-OUM1ubqXuxfaN3g81k0KCTiIEDaBLnUjEyxwsJeBSjiIfvNPDRtr6sSkm6r-m3MPKbgiYNdkxr1GFwWQMkTd3nGLB5OlaToGQHBIDIJ8ykgQjiCsJ4/s640/Part+2+Orginal+Keys.jpg" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: left;"><span style="font-size: x-small;">Paxolin version key was included in the wooden box radio sets- which were built first. The metal "Cash Box" sets had the plastic body key. </span></td></tr>
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<span style="font-family: "verdana" , sans-serif; font-size: x-small;"><br /></span><span style="font-family: "verdana" , sans-serif; font-size: x-small;">The plastic key was attempted- but using hard maple in lieu of lexan or plexiglass. But the key body parts couldn't be cut precisely enough without putting my fingers in danger. A cutting jig assembly needs to be built. The Paxolin version was attempted. [Paxolin is an electrical insulating material with sandwiches of plastic and paper molded into sheets- sorta like PCB but no copper face]. Since the diagram came with a scale in MM- the drawing was imported into a CAD app, enlarged to scale, and printed to be a cutting guide. The keys parts were cut from PCB material with a diamond wheel in a Dremmel tool. </span><br />
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<tr><td style="text-align: center;"><a href="https://4.bp.blogspot.com/-S11JpbhbAbw/WEjnQO0ghLI/AAAAAAAABmI/7iM9ZTym8lIoVungAaIjAWuoG0NLI2CEgCEw/s1600/Part%2B2%2BKey%2BPrototype%2BA.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="402" src="https://4.bp.blogspot.com/-S11JpbhbAbw/WEjnQO0ghLI/AAAAAAAABmI/7iM9ZTym8lIoVungAaIjAWuoG0NLI2CEgCEw/s640/Part%2B2%2BKey%2BPrototype%2BA.jpg" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: left;"><span style="font-family: "arial" , "helvetica" , sans-serif; font-size: x-small;">Ver 1 prototype of Paxolin design PCB key. The spring/lever is .040" thick and .5" wide. It feels sorta flimsey. I am toying around with using a metal lever- but harvested from what? Hacksaw blade with brass screw contacts? </span></td></tr>
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<tr><td style="text-align: center;"><a href="https://4.bp.blogspot.com/-tKYs1ei4vNI/WEl5PGfY36I/AAAAAAAABm0/QwhPG-xiolAcASWd2DdgyOG1EKuslQ9zgCLcB/s1600/Part%2B2%2BKey%2BBat%2BSwitch.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="157" src="https://4.bp.blogspot.com/-tKYs1ei4vNI/WEl5PGfY36I/AAAAAAAABm0/QwhPG-xiolAcASWd2DdgyOG1EKuslQ9zgCLcB/s400/Part%2B2%2BKey%2BBat%2BSwitch.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: left;"><span style="font-size: x-small;"><br /><span style="font-family: "arial" , "helvetica" , sans-serif;">Whilst looking for a toggle switch... This switch was discovered. Perhaps the lever with contacts can be harvested and melded into the PCB Paxolin key.</span></span></td></tr>
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<span style="font-family: "verdana" , sans-serif; font-size: x-small;">Some useful Paraset links that are inspiring to me:</span><br />
<span style="font-family: "verdana" , sans-serif; font-size: x-small;"><a href="http://www.paraset.nl/">http://www.paraset.nl/</a></span><br />
<span style="font-family: "verdana" , sans-serif; font-size: x-small;"><a href="http://www.sm7ucz.se/Paraset/Paraset_e.htm">http://www.sm7ucz.se/Paraset/Paraset_e.htm</a></span><br />
<span style="font-family: "verdana" , sans-serif; font-size: x-small;"><a href="http://www.sm7eql.se/paraset/index.htm">http://www.sm7eql.se/paraset/index.htm</a></span><br />
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<span style="font-family: "verdana" , sans-serif; font-size: x-small;">End of Part 2. Thanks for reading this far. For Blog entry Part 3- I hope to have either the RX or TX working. QHH es 73 DE KR7W CL</span><br />
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<span style="font-family: "verdana" , sans-serif; font-size: x-small;"><br /></span>kr7whttp://www.blogger.com/profile/12925283975807120485noreply@blogger.com0tag:blogger.com,1999:blog-6635479951504521166.post-59673392405128102722016-11-27T12:02:00.001-08:002016-12-08T09:05:56.101-08:00November QRP-Tech Challenge Build - WW2 Paraset Spy Radio - Part 1<div class="separator" style="clear: both; text-align: center;">
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjkRkeT_M4av9sjlyvpbyindccO7d6gYIE8nf3LrK7wcs-rIVRJbjVlqDAE5UMKFg2AVEyIrMZB3z-ABuQq3cIXITq6Lc_sZYFYDqXj27rN19eKxRRCiTKcaaXV7Apbkx38s6Zltp7PWrg/s1600/Part+1+Paraset+W7OIL.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="352" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjkRkeT_M4av9sjlyvpbyindccO7d6gYIE8nf3LrK7wcs-rIVRJbjVlqDAE5UMKFg2AVEyIrMZB3z-ABuQq3cIXITq6Lc_sZYFYDqXj27rN19eKxRRCiTKcaaXV7Apbkx38s6Zltp7PWrg/s400/Part+1+Paraset+W7OIL.jpg" width="400" /></a></td></tr>
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<span style="font-family: Arial, Helvetica, sans-serif; font-size: x-small;">This nice Paraset replica built by Dan W7OIL. Check out Dan's Website here:</span></div>
<a href="http://www.w7oil.com/amateur.htm" style="text-align: left;"><span style="font-family: Arial, Helvetica, sans-serif; font-size: x-small;">http://www.w7oil.com/amateur.htm</span></a></td></tr>
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<span style="font-family: "verdana" , sans-serif;">Chuck K7QO, the spark plug of the </span><span style="font-family: "verdana" , sans-serif;">QRP-Tech Yahoo Group challenged the members to build some kind of QRP project during the month of November. This challenge became the stimulation to get my Paraset build started. My goal is to have my Paraset working and presentable for the Radio Club of Tacoma's Straight Key Night Celebration (Dec 31, 2016) and hopefully make QSOs with it. </span><br />
<span style="font-family: "verdana" , sans-serif;"><span style="font-family: "verdana" , sans-serif;"><br /></span>To build and operate a Paraset has been on/in my bucket list for about 5 years now. At the 2015 pQRP's Salmoncon... member Steve WG0AT brought his Paraset that he was gifted from Paul W0RW. Looking and touching Steve's little radio motivated me to start collecting parts for my someday build. </span><br />
<span style="font-family: "verdana" , sans-serif;"><br />A BOLO to fellow Radio Club of Tacoma members who are home builder hams (one who has previously built his own Paraset)... was initiated to obtain the parts I was missing. Hat tips to Jack's Corner Parts Store and Bob's Surplus... Still missing is the National 10009 friction drive receiver tuning dial mechanism... Construction has begun anyway. </span><br />
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<span style="font-family: "verdana" , sans-serif;">The first order of business is to build the<b> AC Mains Power Supply</b>. Years ago I obtained from the "Free Table" at the radio club- a defunct CB power supply which is about the same size as the original Paraset AC Mains supply. This power supply was loosely engineered and built to fit inside of this metal box.</span><br />
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<span style="font-family: "verdana" , sans-serif;">Reading the blogs of other Paraset builders reveals that their PS HV (also called HT in old documents) output ranged from 300 to 370 DC volts. Found in my box of 'heavy iron' was a suitable (to the voltage requirement and to the enclosure) HV power transformer. No volts will be wasted using a vacuum tube rectifier and there will be way less heat inside of the PS enclosure with a full wave solid state rectifier using 1N4007 diodes. </span><br />
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<span style="font-family: "verdana" , sans-serif;">The next PS puzzler was HV filtration. Choke Input? Capacitor Input? Minimum HV voltage swing in the XMT mode when the key is up vs key down is the goal. Too big of swing creates a a poor sounding chirpy note from the Paraset's 6V6 transmitter. [note 1: some distinguishing chirp is OK in my book. Note 2: 4 to 5 watts output is expected; bordering on the upper edge of QRP].</span><br />
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<tr><td class="tr-caption" style="text-align: left;"><span style="font-family: Arial, Helvetica, sans-serif; font-size: x-small;">Ha! What a mess. Prototyping the HV PS. I did shock myself by picking up a charged up Electrolytic cap by the leads. </span></td></tr>
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<i style="font-family: verdana, sans-serif;">Goldilocks and 3 Bears</i><span style="font-family: verdana, sans-serif;"> method of PS testing: Using Capacitor Input HV filtering resulted in too high output voltage (over 420V). Choke input lowered the voltage down to 330V. Both methods resulted in a 80 to 95 output volts swing from Key Up DC load of 15mA vs Key Down load of 60mA.</span><br />
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<span style="font-family: "verdana" , sans-serif;">Many Pre WW2 entertainment radios that I've restored placed the power supply filter choke (the speaker magnet field coil) in series with the transformers secondary (HV) center tap winding. This method is rarely mentioned in old ARRL or Jones radio handbooks and provided no techy pros or cons for doing this. Experimenting proved this method to be best for key up vs key down voltage regulation. Now KU vs KD swing is around 20 volts but the output voltage is 300 V instead of the 350 V originally hoped for. Now XMTR output watts will be more QRP. Baby Bear again wins. </span><br />
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<tr><td class="tr-caption" style="text-align: center;"><span style="font-family: Arial, Helvetica, sans-serif; font-size: x-small;">Cocktail Napkin Final PS Design</span></td></tr>
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<span style="font-family: "verdana" , sans-serif;">The RCVR in the Paraset is a "2 Tube Blooper" regenerative receiver. (more on this down in a future blog entry). To prevent</span><span style="background-color: white; font-family: verdana, sans-serif;"> 'tunable hum' in the Regen receiver- the filaments are powered by DC volts. The 5 V and 6 V filament transformer windings are connected in series to a bridge rectifier then fed to a switching buck-boost Voltage Regulator module: Measured VR watts IN vs watts OUT reveals 80% efficiency using a 5.6 ohm resistor = 1 amp load to emulate the Parset's 3 tubes. Also no noticeable heat present. 5 of these VRs came from Amazon for $9. See spec: </span><a data-saferedirecturl="https://www.google.com/url?hl=en&q=https://www.amazon.com/Qunqi-MP1584EN-Step-Down-Adjustable-Converter/dp/B014Y3OT6Y/ref%3Dsr_1_1?ie%3DUTF8%26qid%3D1477888078%26sr%3D8-1%26keywords%3Darduino%2Bvoltage%2Bregulator&source=gmail&ust=1480356497769000&usg=AFQjCNHXl80RRpoTj3Hv1UljpFOAvZMGBQ" href="https://www.amazon.com/Qunqi-MP1584EN-Step-Down-Adjustable-Converter/dp/B014Y3OT6Y/ref=sr_1_1?ie=UTF8&qid=1477888078&sr=8-1&keywords=arduino+voltage+regulator" style="background-color: white; color: #1155cc; font-family: verdana, sans-serif;" target="_blank">https://www.amazon.com/Qunqi-<wbr></wbr>MP1584EN-Step-Down-Adjustable-<wbr></wbr>Converter/dp/B014Y3OT6Y/ref=<wbr></wbr>sr_1_1?ie=UTF8&qid=1477888078&<wbr></wbr>sr=8-1&keywords=arduino+<wbr></wbr>voltage+regulator</a><span style="background-color: white; font-family: verdana, sans-serif;"> The VR module cleaned up the output voltage measurable AC ripple voltage to 2 mV.</span><br />
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<span style="font-family: Arial, Helvetica, sans-serif;"><span style="font-size: x-small;">For the more Geeky: Inside of PS... Copper clad Printed Ckt Board is used as a ground plane substrate. There's some Manhattan and Dead Bug this build.</span></span></div>
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<span style="font-family: Arial, Helvetica, sans-serif;"><span style="font-size: x-small;">Upper L white gizmo is a 6V incandescent light to indicate the DC filament voltage is available. Round blue gizmos are SAFETY CAPS from AC line to GND. [I recently learned that these are useful to bypass RFI to GND that might be generated within the PS circuitry. Also to bypass unwanted interference the AC power cord might be receiving plugged into house wiring.]</span></span></div>
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<span style="font-family: Arial, Helvetica, sans-serif; font-size: x-small;">Upper R KOOLOHM device is the HV Bleeder Resistor- which consumes 11mA @ 300 VDC to somewhat stabilize key up vs key down voltage swing.</span></div>
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<span style="font-family: Arial, Helvetica, sans-serif; font-size: x-small;"> Front panel view:</span></div>
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<span style="text-align: center;"><span style="font-family: Arial, Helvetica, sans-serif; font-size: x-small;">The NE-2 bulb indicates High Volts above 80V or so. </span></span></div>
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<span style="text-align: center;"><span style="font-family: Arial, Helvetica, sans-serif; font-size: x-small;">Thanks for reading this far. </span></span></div>
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<span style="text-align: center;"><span style="font-family: Arial, Helvetica, sans-serif; font-size: x-small;">End of Part 1 of Paraset Spy Radio Build. 73 DE KR7W CL</span></span></div>
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<span style="background-color: white;"><span style="font-family: "verdana" , sans-serif;">I began prototyping the Paraset two tube Blooper Regen Receiver per the schematics found on line... and it didn't work very well- which has been my experience with other vacuum tube regens I have attempted to build. I consulted with the ham club member who has built many regen receivers and I walked away thinking that I do not know what to look for to know if the RCVR is working or not. Further investigating was needed.</span></span><br />
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<span style="background-color: white;"><span style="font-family: "verdana" , sans-serif;">Googling took me to an in depth article about the Design of Regen Receivers from Nov/Dec 1998 QEX magazine by Charles Kitchin N1TEV. Since the Paraset uses the same tuning caps and coils as the receivers showcased in Mr Kitchin's article and I had the solid state parts on hand... I'm in progress to build a receiver that I could be more successful getting to work. When I am satisfied that 'I get it'... then I'll substitute the 6SK7 vac tubes + 300 VDC for 6 volt 2N2222s and J310 FETs. </span></span><br />
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<span style="background-color: white;"><span style="font-family: "verdana" , sans-serif;">Regards, </span></span><br />
<span style="background-color: white;"><span style="font-family: "verdana" , sans-serif;">Rich KR7W</span></span><br />
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kr7whttp://www.blogger.com/profile/12925283975807120485noreply@blogger.comtag:blogger.com,1999:blog-6635479951504521166.post-55147442123612399412016-01-16T12:14:00.112-08:002020-07-15T11:08:50.323-07:002 Meter ARDF Attenuator Project- project build notes<span><font face="verdana"><b>Prologue: </b> When I was a 12 YO kid, just getting into ham radio- the old guy hams who smoked cigars would take me along in their sedans to turn the broom handle with the semi-directional loop antenna atop it- outside the car window. The loop antenna was connected to a Heath Twoer, a 2 meter AM transmitter/receiver on the front seat of the car. <br /><br />The Hidden Transmitter or Bunny or Fox- another Twoer or 2 Meter transmitter was located in another sedan parked in an alley or driveway within a designated area or neighborhood. </font></span><div><span><font face="verdana"><br /></font></span></div><div><span><font face="verdana">The Fox or Bunny ham would transmit for a while to taunt the hunters to find him- then the hunters would rotate their broomstick loops to determine a direction to drive towards. I have fond memories of tagging along with the old guys to find the elusive Bunny in the '49 Chevy in the alley behind the Jones' house. Now I am that old ham- but no cigars. </font></span><br />
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<tr><td class="tr-caption" style="text-align: center;"><span style="font-family: arial, helvetica, sans-serif; font-size: x-small;"><b>Heathkit Twoer- AKA "Benton Harbor Lunchbox" 2M AM Transmitter-Receiver. Circa 1960. </b></span></td></tr>
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<font face="verdana"><span>Now-a-days, it's 2 Meter FM Hidden transmitter hunting, AKA Hidden T Hunting or Fox Hunting or Bunny Hunting. </span></font><div><font face="verdana"><span><br /></span></font></div><div><font face="verdana">For effective hunting- an attenuator is needed between the Directional Antenna and the Hunters receiver. Beginners as well as advanced hunters use a <a href="https://www.jpole-antenna.com/2017/02/07/build-it-2-meter-tape-measure-yagi-beam-antenna/#:~:text=1%20Cut%20three%20pieces%20of%20PVC%20tubing.%20One,director%20and%20reflector%20elements.%20...%20More%20items...%20"><b>T</b>ape <b>M</b>easure <b>Y</b>agi Antenna</a>, and an Attenuator that is connected to a <b>H</b>andy <b>T</b>alkie receiver. <br />
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<tr><td class="tr-caption" style="text-align: center;"><span><b><font face="verdana">Simplified schematic of ARDF Attenuator.</font></b></span></td></tr>
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<span><font face="verdana"><b><i>Factoid:</i></b> S meters on most HTs operate at full scale while receiving a very low level. When looking for 2M hidden transmitters- the HT can not see any difference in receive signal level when rotating the Yagi- unless the transmitter is really far away. In rare cases the direction can be discerned by listening to the receive audio. The direction of the most noise free audio is probably the direction to head. </font><br /></span></div><div><span><font face="verdana"><br /></font></span></div>
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<font face="verdana"><span>Two popular attenuators are <u>Resistive</u> with switches to switch in various levels of loss and the <u>Active Attenuator</u> which contains electronics. This blog addresses the <b>A</b>ctive <b>A</b>ttenuator.</span><br /></font>
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<tr><td class="tr-caption" style="text-align: left;"><span style="font-family: arial, helvetica, sans-serif;">Resistive Step Attenuator. Switch in dB increments of loss between the antenna and receiver.</span></td></tr>
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<font face="verdana"><span>The AA reduces the received level of the hidden transmitters signal so the S-Meter on the hunter's HT will show a High as well as a Low reading when rotating the Yagi. It does this (see schematic below) by controlling the amount of level that passes from the ANT to the RCVR via the diode mixer by varying the level of the MPF102 XTAL Oscillator signal into the mixer via the 1K pot. </span><span style="font-size: x-small;"> </span></font></div>
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<span><span><span>A huge benefit of the AA is that the hunter can quickly and easily reduce the signal level being receiving with a <u>simple level control</u>- sort of like a volume control- before the Hidden Transmitter times out and goes QUIET for its programmed interval. </span></span></span></font></span></div><div><span><span><span><span><font face="verdana"><br /></font></span></span></span></span></div><div><span><span><span><font face="verdana"><span>Caveats: The Active Attenuator offsets the receive frequency by plus or minus the Local Oscillator frequency. The AAs that I build and use... have a 4.0 MHz Oscillator which </span><span>sometimes can be a problem if the hunter does not remember to offset their input frequency + or - 4 MHz of the Bunny / Fox's output frequency.</span><span> </span></font></span></span></span></div><div><span><span><span><font face="verdana"><span><br /></span></font></span></span></span></div><div><span><span><span><font face="verdana"><span>Example: If the hunter is receiving 147.570, then the HT must be set at 143.570 or 151.570.</span></font></span></span></span></div><div><span style="font-size: x-small;"><span style="font-size: medium;"><span><span><font face="verdana"><br /></font></span></span></span></span></div><div><span><span><font face="verdana"><span><span>Another caveat is- the AA unit does not have Zero loss when set to minimum attenuation. It will always have an inherent</span></span><span><span> or minimum loss of about 30 dB. Normally the added loss is not a problem, unless the Bunny / Fox signal level is quite low.</span></span></font></span></span></div><div><span style="font-size: x-small;"><span style="font-size: medium;"><span style="font-family: verdana, sans-serif;"><span style="font-family: verdana, sans-serif;"><br /></span></span></span></span></div>
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<span style="font-family: verdana, sans-serif;">The AA I build comes from this website:<br /><a href="http://theleggios.net/wb2hol/projects/rdf/rdf.htm">http://theleggios.net/wb2hol/projects/rdf/rdf.htm</a></span></div><span style="font-size: x-small;">
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<tr><td class="tr-caption" style="text-align: left;"><span><font face="verdana"><span><b>DIY BUILD NOTES: </b> The enclosure fabricated from Copper Clad PCB Material cut with a Dremmel tool and soldered together. </span><span>This view shows the AA upside down. The cover- to the left- is the units bottom. </span><span> The interior depth dimension is 3/4" which makes the finished product 1" thick. A commercially made project box could also be used.<br /><br /></span></font></span></td></tr>
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<span><font face="verdana"><span>I will not go into a lot of detail of how I DIY'd this- but I do use dead-bug blob solder electronic construction. Measure and cut out the printed circuit material enclosure to fit a the battery holder. It turns out that the oscillator circuit wouldn't oscillate using 3 VDC battery- but will oscillate at 4.5V. A 9V battery fits well in the battery chamber. The current draw is very small. </span><span>The 1K ohm Local Oscillator level control is equipped with an ON/OFF switch wired to the red battery wire.</span></font></span></div>
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<span><font face="verdana">Note that the Mixer has its own shielded compartment. Past experimenting revealed with no shielding- the JFET oscillator running full blast would bleed into the diode mixer area and wipe out the Output Level Controls sensitivity- especially with the control set to provide close to maximum attenuation- when the hunter is very close to the transmitter. </font></span></div>
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<span><font face="verdana">Finished product. The enclosure corners are rounded over with sand paper to remove sharp areas. The antique instrument 'big knob' gives a little bling to an otherwise boring electronics device. Stick on Velcro is applied to the bottom of the OA- so it will adhere to the pad on my TM Yagi (blue plastic w/ black strips in photo below). </font></span><span style="font-family: verdana, sans-serif; font-size: x-small;"> </span></div><div style="clear: both; text-align: left;"><span style="font-family: verdana, sans-serif; font-size: x-small;"><br /></span></div>
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<span style="font-family: verdana, sans-serif; font-size: x-small;"><a href="http://4.bp.blogspot.com/-S321ZY8MtTk/Vpg9tGOiUJI/AAAAAAAABTw/qvPaB_XSAlY/s1600/TM%2BYagi%2BVer%2BX.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="395" src="https://4.bp.blogspot.com/-S321ZY8MtTk/Vpg9tGOiUJI/AAAAAAAABTw/qvPaB_XSAlY/s640/TM%2BYagi%2BVer%2BX.jpg" width="640" /></a></span></div>
<span><span><span><font face="verdana"> <a href="https://www.jpole-antenna.com/2017/02/07/build-it-2-meter-tape-measure-yagi-beam-antenna/#:~:text=1%20Cut%20three%20pieces%20of%20PVC%20tubing.%20One,director%20and%20reflector%20elements.%20...%20More%20items...%20">Build Instructions</a></font></span><br /></span></span><div style="clear: both; text-align: left;"><br /></div><div style="clear: both; text-align: left;"><span><font face="verdana">73 Rich KR7W</font></span></div>
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</div></div>kr7whttp://www.blogger.com/profile/12925283975807120485noreply@blogger.com0tag:blogger.com,1999:blog-6635479951504521166.post-2976920973062378712014-03-10T16:08:00.000-07:002014-03-10T17:04:23.748-07:00QRP Fun... Heathkit HW7 - Chapter 2 - RIT and CW Offset<div class="separator" style="clear: both; text-align: center;">
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<span style="font-family: Verdana, sans-serif; font-size: large;"><i><b>Prologue: </b></i> </span><span style="font-family: Verdana, sans-serif; font-size: large;">Today is 3/10/2014. I added this mod back in Dec 2013. I am looking at my work to come up with a description of what I've done... and I am having a hard time remembering what some of my initial thinking was. With that said, I will attempt to be clear to describe what I've done.</span><br />
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<span style="font-family: Verdana, sans-serif; font-size: large;">As mentioned in Chapter 1, Googling found me an article for RIT. The article was sritten by John Grebenkemper, WA6BVA, and appeared in the July 1975 QST, simply titled <a href="https://www.dropbox.com/s/czazoje0bpxpo8w/QST%20RIT%20for%20HW7.pdf" target="_blank">RIT for the HW-7</a>.</span><br />
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<span style="font-family: Verdana, sans-serif; font-size: large;">Here's how I think RIT is created in John's HW7: The battery supply feeding the VFO is stabilized using a Zener diode to bias a NPN switching transistor to be a voltage regulator. Now that the VFOs FET is stable then the FETs Biasing can be altered to predictably change the frequency. Resistors in series with the cold side of RFC-1 (Q2 Source to GND) alter the bias to change the frequency. On 40 meters additional biasing is needed so an extra resistor is added between the Drain and cold side of RFC-1 (via extra contacts in the 40M bandswitch)...Please read the article for more in depth info and to check my accuracy.</span><br />
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<span style="font-family: Verdana, sans-serif; font-size: large;">I did the mod as John's QST article prescribed. It worked very well... but I didn't like the fact that the range of the RIT adj pot increased as the frequency increased. Example: On 40M a 1.4 KHz shift occurs, On 20M there's a 2.4 KHz shift, and 15M results in a 3.4 KHz shift. It works and the VFO is amazingly almost drift free...but there's too much RIT range for my liking. Using the RIT Pot for fine tuning was </span><span style="font-family: Verdana, sans-serif; font-size: large;"><i>not all that fine</i> especially on 20M and 15M. Tic marks on the front panel for each band are needed.</span><br />
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<span style="font-family: Verdana, sans-serif; font-size: large;">Here's how I think RIT is created in kr7w's HW7: Since transistors Q103 and Q102 switch in/out the RIT adj pot while on receive... and on 40 meters a spare set of contacts from the band switch are used to add the additional 3.9K biasing resistor... I axed myself, "Can I use additional contacts in the 20 and 15M bandswitch to operate transistors to add the appropriate resistance for preset RIT of 700 Hz for CW offset as well as a RIT adj pot?" After some pondering... that's what I ended up doing. </span><br />
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<span style="font-family: Verdana, sans-serif; font-size: large;">But first, do this for me: If you are interested in modifying your HW7 like I did or want to use the concept for another project... then please read <a href="https://www.dropbox.com/s/czazoje0bpxpo8w/QST%20RIT%20for%20HW7.pdf" target="_blank">John's QST article</a> and get a more techy description of what he did.</span><br />
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<tr><td class="tr-caption" style="text-align: left;"><span style="font-family: Arial, Helvetica, sans-serif; font-size: small;">Comments below refer to this schematic from the QST Article. </span></td></tr>
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<span style="font-family: Verdana, sans-serif; font-size: large;">VFO Voltage Reguator: The Q104 voltage regulator BJT takes the place of the original R23- 100 ohm resistor. Using the holes in the PCB from R23 and a couple of additional drilled holes- I added Q104,the 11V Zener diode, and 4.7K. I didn't have the exact Zener, so I soldered two 5 volt Zeners in series. [Sidenote: according to my super Geeky engineer ham radio friend, Bob... this type of voltage regulation is far superior to Linear regulators and/or Zener diodes by themselves]. The regulator output is the Zener value minus .7 volts from the voltage drop across the transistor, BTW.</span><br />
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<span style="font-size: large;"><span style="font-family: Verdana, sans-serif;">I added transistor Q101 and R101 next to original RF Choke RFC1. I drilled holes in the PCB... but the VFO tuning capacitor must be removed to do this. </span><i><span style="font-family: Arial, Helvetica, sans-serif;">(I will have, "If I was to do this differently- this is how I'd do it" thoughts at the end of this blog entry)</span></i><span style="font-family: Verdana, sans-serif;">. A wire was run to the 12V Key Line (+12 volts applied when key is down) and to the RIT pot. C101 bypass cap was installed under the PCB in the area of RFC1. </span></span><br />
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<span style="font-family: Verdana, sans-serif; font-size: large;">The QST article shows a 3.9K ohm resistor-R104 being switched in when on 40M only. For an unknown reason to me now, I soldered this resistor in permanently. All 700 Hz offset resistor values were determined with the R104 in the circuit on each band.</span><br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgDhaAIbY1DWkCXYqEDh9__LyXuCm4gaipzwNyGUhgrSxRQCHAYZMaV_drzJ4OvCTPcFcdIx6R1G2NlCt9c16_JfsCdgqhNvc4wj5drFfQxoLWQ3R4dy3En74LOE_hxvckYOMCw05c1u24/s1600/HW7+RIT+schematic+VER2.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgDhaAIbY1DWkCXYqEDh9__LyXuCm4gaipzwNyGUhgrSxRQCHAYZMaV_drzJ4OvCTPcFcdIx6R1G2NlCt9c16_JfsCdgqhNvc4wj5drFfQxoLWQ3R4dy3En74LOE_hxvckYOMCw05c1u24/s1600/HW7+RIT+schematic+VER2.jpg" height="618" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: left;"><span style="font-family: Arial, Helvetica, sans-serif; font-size: small;">This is my rendition (first hand drawn then annotated with Photoshop) of the RIT modification to my HW7. Circuit description follows... Note: Just like there are no A, B, or C ionospheric propogation layers... there is no Q102A- there used to be... but it was removed to lessen the complexity.</span></td></tr>
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<b><span style="font-family: Verdana, sans-serif; font-size: large;">Example of Operation: 40M RCV- </span></b><span style="font-size: large;"><span style="font-family: Verdana, sans-serif;">When RIT pot is set in the center (~50 ohms) the bandswitch applies +12V (thru 10K) to the B of Q102B. This transistor conducts and GND appears on the Collector. This completes the path of 220 ohms in series with the RIT Pot which causes the VFO to shift its frequency ~700 Hz from the Transmit Frequency. Note: The 220 ohms was determined by trial and error using my Icom transceiver with my Fluke VOM. The procedure is described below. </span></span><br />
<span style="font-size: large;"><span style="font-family: Verdana, sans-serif;"><br /></span><span style="font-family: Verdana, sans-serif;"><b>40M XMiT: </b>When the Key is down, Q103 conducts and grounds out the Vcc on the Collector. This causes Q102B to not conduct which opens up the RIT 100 ohm pot path. Also, with Key Down... Q101 conducts and GNDS its Collector which places the 120 Ohm resistor in place of the RIT pot resistance path which determines the XMIT frequency. <br /></span></span><br />
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<tr><td style="text-align: center;"><a href="http://2.bp.blogspot.com/-HVX8hJZ68iM/Ux4mkWk6PHI/AAAAAAAAA2E/bxzPgT9_rUI/s1600/HW7+RIT+PCB+JPEG.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="http://2.bp.blogspot.com/-HVX8hJZ68iM/Ux4mkWk6PHI/AAAAAAAAA2E/bxzPgT9_rUI/s1600/HW7+RIT+PCB+JPEG.jpg" height="450" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: left;"><span style="font-family: Arial, Helvetica, sans-serif; font-size: small;">This is the circuit board I fabricated to contain Qs102B-D and Q103. Construction is in the Manhattan and dead bug style. A hand held Dremmel tool with a conical shaped dentists grinding stone was used to route out some islands for wires and BJTs to be blobbed soldered to. Looks messy- but it works. Wires to/from the board route along the vertical sides of the chassis. No X-country wires. All transistors are BJT MPS2N2222 acting as switches.</span></td></tr>
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<span style="font-family: Verdana, sans-serif; font-size: large;">Regarding the RIT pot I installed... I lucked out and found an old junked out Cushman CE-3 service monitor at my radio club. I harvested a very nice 100 ohm pot with a long enough shaft to fit through of the two front panels of the HW7. </span><br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjRtkAD4XruaJKJpkv1xGxCbevTI5AcSOPidvSZrTuEvgfh6mTmZRO3wt7GDFYYOTUIs6oIKFfMObcOelzE3rkZHf3fbQYO5yd7CdQYbZSc6KFwXS28ocOEwGJTN7Dvc_0mP-IxyVhh238/s1600/Chassis_Ckt+Board+RIT+pot+es+Band+SW+view.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjRtkAD4XruaJKJpkv1xGxCbevTI5AcSOPidvSZrTuEvgfh6mTmZRO3wt7GDFYYOTUIs6oIKFfMObcOelzE3rkZHf3fbQYO5yd7CdQYbZSc6KFwXS28ocOEwGJTN7Dvc_0mP-IxyVhh238/s1600/Chassis_Ckt+Board+RIT+pot+es+Band+SW+view.jpg" height="322" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: left;"><span style="font-family: Arial, Helvetica, sans-serif; font-size: small;">Here's a foto of the location of my RIT pot. Also seen is the bandswitch where I picked up spare contacts for the RIT/offset circuitry.</span></td></tr>
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<tr><td style="text-align: center;"><a href="http://4.bp.blogspot.com/-pS8-3y3TZ7k/Ux42c4i2qgI/AAAAAAAAA2Y/z3TPpv4GlZg/s1600/HW7+Front+Chassis+Panel.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="http://4.bp.blogspot.com/-pS8-3y3TZ7k/Ux42c4i2qgI/AAAAAAAAA2Y/z3TPpv4GlZg/s1600/HW7+Front+Chassis+Panel.jpg" height="250" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: left;"><span style="font-family: Arial, Helvetica, sans-serif; font-size: small;">Here's a foto of my HW7s inner front panel. Hole 1, 2, and the RIT pot hole were already drilled in the inner panel (but not the front panel) before I rescued this radio. The once pristine green front panel has been defaced with holes for the RIT control... and most recently holes 1 and 2 have been drilled in the front panel for push-button switches for the upcoming Freq-Mite and PK-4 Keyer controls. </span></td></tr>
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<span style="font-family: Verdana, sans-serif; font-size: large;"><b><i>If I were to do this again:</i> </b><br />>Even though Q101s functional position is where I put it- next to RFC1, under the VFO tuning capacitor... I would put it on the homebrew PCB. My reasoning is that since all wires are DC control (no RF signals) then having Q101 on the PCB would ease in trouble shooting and would lessen a couple of wires running along the chassis walls. </span><br />
<span style="font-family: Verdana, sans-serif; font-size: large;"><br /></span><span style="font-family: Verdana, sans-serif; font-size: large;">>I will order some small 500 ohm Ten Turn pots to adjust the offset resistor value for each band. The pots should be easy enough to solder to the PCB with the transistors. </span><br />
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<span style="font-family: Verdana, sans-serif; font-size: large;"><b>700 Hz Offset test procedure:</b><br />Note: When the HW7 is transmitting the RIT Pot has no affect on the output frequency. </span><br />
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<span style="font-family: Verdana, sans-serif; font-size: large;">Pick a band and transmit a carrier with the HW7 into a dummy load. Tune in the HW7 with a good HFT (HF transceiver). Zero beat the HW7s signal in the HFT or make sure it is tuned in properly for a 700 Hz offset. <u>Do not touch the HW7s VFO dial from this point on.</u><br /><br />Connect the HFT to a dummy load and transmit a CW carrier on the exact same frequency that the HW7 was received. On the HW7, make sure the RIT Pot is in the middle of its range. </span><u style="font-family: Verdana, sans-serif;"><span style="font-size: large;">Do not touch the HW7s VFO dial to tune in the HFTs signal.</span></u><span style="font-family: Verdana, sans-serif; font-size: large;"> <br /><br />Measure the beat tone from the HW7s Audio out with an audio frequency meter- Fluke VOM or equivilent device. This is the HW7s offset frequency. It should be 700 Hz or the frequency you like to listen to CW with. Adjust the resistor value in series with the RIT pot for the band you are operating on... until 700 Hz is obtained. </span><br />
<span style="font-family: Verdana, sans-serif; font-size: large;">End of procedure.</span><br />
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<span style="font-family: Verdana, sans-serif; font-size: large;">I was working on adding the Freq-Mite and PK-4 keyer to the HW7... and in the process of not treating sensitive semiconductors properly... I somehow blew out the PIC chip in my PK-4 keyer. I ordered two new chips plus a complete unit with circuit board to install in my HW8 someday. <br /><br />Still to come:</span><br />
<span style="font-family: Verdana, sans-serif; font-size: large;">> Progress on the 'new ears-best it can be SA602A Mixer direct conversion receiver.<br />> PK-4 Keyer for paddles + SK + sidetone.<br />> Freq-Mite frequency Morse Code output frequency counter + its sidetone.</span><br />
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<span style="font-family: Verdana, sans-serif; font-size: large;">Sidetone is a big deal to me. I do not like to listen to my Morse sending via square wave audio tones, like the HW7, RockMite, PFR-3, NE555 Astable oscillator and PIC based audio generators. I've been experimenting on how to filter out the squares in square waves for more pleasant CW listening. </span><br />
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<span style="font-family: Verdana, sans-serif; font-size: large;">End of this Blogger Entry. Please email me for info or if you have some ideas to share regarding this project. 71r5, Rich KR7W... -30-</span><br />
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kr7whttp://www.blogger.com/profile/12925283975807120485noreply@blogger.com0tag:blogger.com,1999:blog-6635479951504521166.post-61642993619229979832014-03-09T09:57:00.001-07:002014-03-09T09:57:26.306-07:00QRP Fun... Heathkit HW7 - Chapter 1 - New Ears<span style="font-family: Verdana, sans-serif; font-size: large;"><b><i>Prologue:</i></b> I have a complete Heathkit HW9 Station- the transceiver, antenna tuner, SWR meter, and the matching rare speaker. My HW9 is a Work In Progress and am currently performing mods on the transmitter to make it more stable<br /><br />For a long time I've wanted to add a HW8 QRP transceiver to my collection of unique radios that I take off the shelf, operate from the shack table, or set up on a picnic table in the park, or out back packing to make some QRP Morse QSOs. Hamfest and Ebay HW8 prices were way too high for my liking. One day I was surfing Ebay and found the HW8's older brother- an orphaned HW7. The seller advertised as "<i>Guaranteed Not To Work</i> (instead of UNTESTED) <i>Buy it Now!</i></span><span style="font-family: Verdana, sans-serif; font-size: large;">"</span><span style="font-family: Verdana, sans-serif; font-size: large;">. The 'not to work' grabbed my attention- just like the street person with the sign that says, "I need money for beer".<br /></span><br />
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<tr><td style="text-align: center;"><a href="http://3.bp.blogspot.com/-jdjc8nxHnTA/Uvm-vHzlhHI/AAAAAAAAA0o/4Ei513gdVdo/s1600/HW7+front+panel.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="http://3.bp.blogspot.com/-jdjc8nxHnTA/Uvm-vHzlhHI/AAAAAAAAA0o/4Ei513gdVdo/s1600/HW7+front+panel.jpg" height="337" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: left;"><span style="font-size: small;"><span style="font-family: Arial, Helvetica, sans-serif;">Here's someone else's HW7, circa 1972-75, that is better looking than mine. After reading about the disappointing receiver performance and lack of 700 Hz offset and RIT, this has got to be the second worse Amateur Radio product that Heathkit produced- <i>Note: this is</i></span><i><span style="font-family: Trebuchet MS, sans-serif;"> my humble opinion.</span><span style="font-family: Arial, Helvetica, sans-serif;"> </span></i></span></td></tr>
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<span style="font-family: Verdana, sans-serif; font-size: large;"><br />CHAPTER 1.</span><br />
<span style="font-family: Verdana, sans-serif; font-size: large;"><br />Sure enough, the HW7 did not work. Armed with the schematic, VOM, and O'scope I found two burnt traces on the PCB and the RF Choke in the output PA burned out. I thought that maybe lightning was the cause- but no solid state devices were damaged. </span><span style="font-family: Verdana, sans-serif; font-size: large;"> I soldered jumper wires around the burnt traces and rewound the RF Choke. This brought the radio back from the dead- </span><span style="font-family: Verdana, sans-serif; font-size: large;">Abracadabra!</span><br />
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<span style="font-family: Verdana, sans-serif; font-size: large;">I had great fun troubleshooting the radio and making some QSOs on 20 and 40 meters. The stations I had QSOs with were hard to copy because they were 'Zero Beat' in the receiver. If I adjusted the VFO to copy better then my XMIT frequency changed and the far end Op couldn't copy me some times.</span><br />
<span style="font-family: Verdana, sans-serif; font-size: large;"><br />Other issues I encountered:<br />>I was being QRMed by couple of nearby 50KW AM BC and strong SW stations like Radio Habana and WWV- received along with CW signals. </span><span style="font-family: Verdana, sans-serif; font-size: large;"><br />>AC hum in the audio (when on AC supply).<br />>Selectivity seems about 2 KHz wide.</span><br />
<span style="font-family: Verdana, sans-serif; font-size: large;">>Microphonics in the audio.</span><br />
<span style="font-family: Verdana, sans-serif; font-size: large;"><br /></span><span style="font-family: Verdana, sans-serif; font-size: large;">!! </span><span style="font-family: Verdana, sans-serif; font-size: large;">But not is all is crappy- the 2.5 watt transmitter part of the radio seemed to work pretty well. </span><span style="font-family: Verdana, sans-serif; font-size: large;">I became determined to improve the HW7s receiver. </span><br />
<span style="font-family: Verdana, sans-serif; font-size: large;"><br /></span><span style="font-family: Verdana, sans-serif; font-size: large;">While having those QSOs... I discovered that the HW7 has no means to offset the transmit vs receive frequencies.<br /></span><br />
<span style="font-family: Verdana, sans-serif; font-size: large;">I could live with the BC + SW QRM but not the lack of 700 Hz CW offset, wide bandwidth, nor the microphonics. I didn't find a lot of published modifications for this radio on the web or in my <i>HW8 Handbook</i>- which covers mods for the HW7, HW8, and HW9. Then it dawned on me- maybe there just wasn't enough time for geeky hams to come up with a lot of mods- as Heathkit came out the HW8, only four years later in 1976.<br /><br />Googling deeper, I found a mod from a 1975 QST that added a RIT pot for the user to offset the receive frequency separate from the transmit frequency but it did not produce a predictable 700 Hz offset like the RockMite, HW9, or modern transceivers. </span><br />
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<span style="font-family: Verdana, sans-serif; font-size: large;">Producing a 700 Hz offset on each band seemed difficult due to the design of the VFO. The 40M VFO operates on 3.5 MHz and is doubled. On 20M, the VFO also operates on 7 Mhz and is doubled. 15M is 3 x 7 Mhz. RIT on 15M is 4X as effective as on 40M. Using the principle of the original RIT mod, I came up with a more elaborate method of obtaining a 700 Hz offset for each band <i>and</i> a plus/minus 100 Hz RIT pot for fine tuning. This mod will be described in a future blog entry.</span><br />
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<span style="font-family: Verdana, sans-serif; font-size: large;">Regarding the AM+SW QRM in the detector... I read that balanced and doubly balanced Mixers are the solution to eliminating unwanted QRM. I found two more promising modifications. One used a CA3028A balanced mixer IC (remember when ICs were round?) and a mod that added a SBL-1 passive mixer chip. I harvested both mixers from junk found at my radio club. I wasn't able to get the SBL-1 to work for me. Then it dawned on me... the popular RockMite and other simple QRP radios have a Direct Conversion receiver like the HW7. I had two RockMites and made lots of QSOs... and the receivers worked pretty well aside from the BCI (broadcast interference). </span><br />
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<span style="font-family: Verdana, sans-serif; font-size: large;">I began to pursue a receiver design that uses a SA602A Gilbert Cell mixer IC that includes an on board RF input amplifier. I've noticed that the Elecraft KX1 and K1 radios also use the SA602A mixer IC </span><i><span style="font-family: Arial, Helvetica, sans-serif; font-size: large;">(these radios are not Direct Conversion- they have an IF)</span></i><span style="font-size: large;"><i><span style="font-family: Arial, Helvetica, sans-serif;">.</span></i><span style="font-family: Verdana, sans-serif;"> Now I have the wheel without reinventing it very much.</span></span><br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEihxJN0_l8uAHcDc0HR0ayt3RFeeRIDjCf5JGEWq6RViBloHM5L9mz02kDfheMYUAr4rffjbiNKCKHEaROpVaTt-vCOKtbeMoQrocHAh4yJCeB7bQanUPlCSMWm_D5LtF6SvXSCXLmMqcU/s1600/Chassis_Ckt+Board+View-1.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEihxJN0_l8uAHcDc0HR0ayt3RFeeRIDjCf5JGEWq6RViBloHM5L9mz02kDfheMYUAr4rffjbiNKCKHEaROpVaTt-vCOKtbeMoQrocHAh4yJCeB7bQanUPlCSMWm_D5LtF6SvXSCXLmMqcU/s1600/Chassis_Ckt+Board+View-1.jpg" height="542" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: left;"><span style="font-family: Arial, Helvetica, sans-serif; font-size: small;">On the left is the 700 Hz offset / RIT control circuitry. I added a pot on the front panel for + / - </span><span style="font-family: Arial, Helvetica, sans-serif; font-size: small;">RIT- which works quite well as a Fine Tuning control. The lightened area on the right side of the PCB is where approx 70 components were removed from the receiver and audio circuitry. On the right rear panel is the </span><b style="font-family: Arial, Helvetica, sans-serif; font-size: medium;"><a href="http://www.4sqrp.com/HiPerMite.php" target="_blank">HI-Per-Mite</a></b><span style="font-family: Arial, Helvetica, sans-serif; font-size: small;"> 50 dB gain audio amp / 700 Hz audio filter. I purchased this kit from the </span><b style="font-family: Arial, Helvetica, sans-serif; font-size: medium;"><a href="http://www.4sqrp.com/index.php" target="_blank">Four State QRP club. </a></b><span style="font-family: Arial, Helvetica, sans-serif; font-size: small;"> It works exceptionally well, BTW.</span></td></tr>
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<span style="font-family: Verdana, sans-serif; font-size: large;">Before I began the SA602A receiver prototype... I removed all of the receiver components</span><span style="font-family: Verdana, sans-serif; font-size: large;"> from the HW7s PCB to see how much real estate I have to work with. My goal is to build the new Direct Conversion receiver on a piece of PCB using Manhattan and/or Dead Bug style construction and mount it on top of the HW7s PCB. </span><br />
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<tr><td style="text-align: center;"><a href="http://3.bp.blogspot.com/-Vm5NBdROFEI/UvmCu09XJ-I/AAAAAAAAAz8/tAWof3NgM00/s1600/RCVR+SA602A+Prototype+1.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="http://3.bp.blogspot.com/-Vm5NBdROFEI/UvmCu09XJ-I/AAAAAAAAAz8/tAWof3NgM00/s1600/RCVR+SA602A+Prototype+1.jpg" height="360" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: left;"><span style="font-family: Arial, Helvetica, sans-serif; font-size: small;">Here's RCVR Prototype # 1. A PC Board like this will fit in the open space where the receiver components used to reside. The Pre-selector tuning cap will still reside on the front panel. </span></td></tr>
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<span style="font-family: Verdana, sans-serif; font-size: large;"><br /></span><span style="font-family: Verdana, sans-serif; font-size: large;">I've plagiarized a composite receiver design from web sources that use a pre-selector parallel tuned circuit (much like the original HW7 receiver) that doubles as a Z matching transformer to provide balanced input to the SA602A at approx 3K ohm Z. T50-6 toroids and the <a href="http://kitsandparts.com/toroids.php" target="_blank">www.kitsandparts.com toroid app</a> were used to calculate the # of turns and tuning capacitor size for 7-21 Mhz. </span><br />
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<tr><td class="tr-caption" style="text-align: left;"><span style="font-family: Arial, Helvetica, sans-serif; font-size: small;">I'm not sure that the Z match between the Preselector and the SA602A mixer is the best it can be. Further experimentation is needed.</span></td></tr>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjPmkke63UI_nWZnMV6Cb1qgteLPTGrdxL77_1etuwCsVddrZcRf22CQIWoTCGz63lshoh3WRYiBv7mXKLX2Q1onCaZgI4QAjH32Bw4Mxx2LwOC0jI7qxfJi4WBm7UIzE0xfYb-03NBjoU/s1600/SA600A+es+Hypermite+sketch.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjPmkke63UI_nWZnMV6Cb1qgteLPTGrdxL77_1etuwCsVddrZcRf22CQIWoTCGz63lshoh3WRYiBv7mXKLX2Q1onCaZgI4QAjH32Bw4Mxx2LwOC0jI7qxfJi4WBm7UIzE0xfYb-03NBjoU/s1600/SA600A+es+Hypermite+sketch.jpg" height="362" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: left;"><span style="font-family: Arial, Helvetica, sans-serif; font-size: small;">This sketch shows the mixer output and the Hy Per Mite Audio Filter/Amp. Pin 6 is the external signal input from the HW7s VFO. </span></td></tr>
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<span style="font-family: Verdana, sans-serif; font-size: large;">I wanted good audio filtering at ~700 Hz. So, I've added a <a href="http://www.4sqrp.com/HiPerMite.php" target="_blank">4 States QRp Club's Hi-Per-Mite</a> active audio filter with 50 dB audio amplifier was obtained and installed.</span><br />
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<span style="font-family: Verdana, sans-serif; font-size: large;">Side note: Working along side Geeks in my professional life.. I've noticed that they have a tendency to "Gold Plate" a project. Something tells me that I will be going down that path here.</span><br />
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<span style="font-family: Verdana, sans-serif; font-size: large;">At this point in my experimentation- these issues do not make my HW7 not ready for prime time:<br />>RF Pre-selector not sensitive enough of 40 and 15 M vs 20M.<br />>Lack of audio gain.<br />>Loud BC and SW stations still being detected when propagation is good.</span><br />
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<span style="font-family: Verdana, sans-serif; font-size: large;">Future blog 'Chapter #' entries planned:<br />>Techy info on the 700 Hz offset and RIT.<br />>Addition of <a href="http://wb9kzy.com/ham.htm" target="_blank">PK-4 Keyer </a>for Iambic + Straight Key + side tone.<br />>Addition of <a href="http://www.4sqrp.com/freq-mite.php" target="_blank">Freq-Mite frequency meter</a>. <br />>Making the 'best it can be' Direct Conversion Receiver' for this rig... or knowing when to stop. <br /><br />End of this Blogger entry. Please email me for info or if you have ideas for my project. 71r5, Rich KR7W... -30-<br /></span><br />
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<span style="font-family: Verdana, sans-serif; font-size: large;"> </span>kr7whttp://www.blogger.com/profile/12925283975807120485noreply@blogger.com1tag:blogger.com,1999:blog-6635479951504521166.post-3316577911755836612014-03-06T18:24:00.001-08:002022-10-31T09:36:28.244-07:00The Lectrokit Spider Page... <div class="separator" style="clear: both; text-align: center;">
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<span face="Helvetica Neue, Arial, Helvetica, sans-serif" style="font-family: helvetica;">Dah dit dit dit dah... Looky Here! It's the Lectrokit Spider QRP Rig.</span></div>
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<span face="Helvetica Neue, Arial, Helvetica, sans-serif" style="font-family: helvetica;">Info: The content in this blog entry was originally authored on Sept 8, 2012 and posted on the old kr7w.org ham radio hobby website. Slowly I am transferring old web pages into blogger entries. Please read on...</span></div>
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<a href="http://4.bp.blogspot.com/-aeNHqsGBPvE/Uxkod7LXrGI/AAAAAAAAA1A/ho-G5NHGeuk/s1600/SP_1_1.jpg" style="margin-left: 1em; margin-right: 1em;"><span face="Helvetica Neue, Arial, Helvetica, sans-serif" style="font-family: helvetica;"><img border="0" height="400" src="http://4.bp.blogspot.com/-aeNHqsGBPvE/Uxkod7LXrGI/AAAAAAAAA1A/ho-G5NHGeuk/s1600/SP_1_1.jpg" width="352" /></span></a></div>
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<span face="Helvetica Neue, Arial, Helvetica, sans-serif" style="font-family: helvetica;">I've had my Lectro-Kit Spider SP-1 for about 10 years. Someone from my radio club gave it to me cuz I am one of those 'QRP Hams'. I couldn't figure out what make and model it was so I've never tried to get it on the air. Recently I stumbled across a photo of it on the world wide web... which led me to the newly archived 73 Magazines on the web where I found the SP-1 lurking in the January 1993 issue.</span></div>
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<span face="Helvetica Neue, Arial, Helvetica, sans-serif" style="font-family: helvetica;">The SP-1s came in three flavors: 80, 40, and 20 Meters. I can tell from the number of turns on toroids that my unit is a 40 meter model. The 73 article says it outputs 1 watt. There's a RIT control that changes the voltage on a varactor diode to pull the crystal oscillators output frequency in the receive mode. The receiver appears to be a direct conversion design. It is sort of like a RockMite without a controller IC chip. The complete kit back in 1993 cost $39 postpaid.</span></div>
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<span face="Helvetica Neue, Arial, Helvetica, sans-serif" style="font-family: helvetica;">I spent some time with my SP-1 and know that it does not work... and I bet it never worked. A lot kits that are given to me by radio club members have been built incorrectly and it seems like the builder didn't delve into resolving the problems. In this kit... At first glance... it looks to me like the crystal oscillator has the wrong transistor installed. I am sure that I can find a 2N2222 around here someplace.</span></div>
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<span face="Helvetica Neue, Arial, Helvetica, sans-serif" style="font-family: helvetica;">So for now- back to the shelf it goes... as I am currently frying up other fish from the Retirement Things to Do List. I hope to get back to the SP-1 after the cold rainy season begins here in the Pacific Northwest.</span></div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiEfAGt2nJ69BwlIhGQkgkNxWm5lMjKZVt739YUS4zsuGbc2Ciba7oR1hEd8UJNQ6IbFfwtLrJtmRtBp4BEaYoztxGuTaDg5ewzehSR10GvBUlBEeLYtL61nSwKZbEiEwenMui0gSXGBXc/s1600/SP_1_2.jpg" style="margin-left: 1em; margin-right: 1em;"><span face="Helvetica Neue, Arial, Helvetica, sans-serif" style="font-family: helvetica;"><img border="0" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiEfAGt2nJ69BwlIhGQkgkNxWm5lMjKZVt739YUS4zsuGbc2Ciba7oR1hEd8UJNQ6IbFfwtLrJtmRtBp4BEaYoztxGuTaDg5ewzehSR10GvBUlBEeLYtL61nSwKZbEiEwenMui0gSXGBXc/s1600/SP_1_2.jpg" width="308" /></span></a></div>
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<span face="Helvetica Neue, Arial, Helvetica, sans-serif" style="font-family: helvetica;"> I am especially fond of the 'Built In Hand Key' (a piece of brass strip with a rubber foot as the key knob) on the SP-1. But if you don't like the feel of the built in key... you can plug your own key into the 1/8" aux. key jack. Also there's an earphone jack for receive audio from the LM386 IC audio amp (like Rockmite, Heathkit HW-9, KX-1, and others). It's too bad that this SP-1 has been hacked with the addition of the RCA jacks (Antenna and +12 V) just below the brown bakelite terminal strip.</span></div>
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<span face="Helvetica Neue, Arial, Helvetica, sans-serif" style="font-family: helvetica;">This little XTAL Controlled QRP radio reminds me of the WW2 resistance fighter Paraset Spy Radios equipped with One Tube 6V6 XTAL controlled XMTR and one tube Regen detector with a one tube audio amplifier. <a href="http://www.qsl.net/ik0moz/paraset_eng.htm">Here is One Ham's Paraset Page</a> <a href="http://search.yahoo.com/search?p=paraset+ww2+radio&fr=chr-tyc8">Use Google for others</a>.</span></div>
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<span face="Helvetica Neue, Arial, Helvetica, sans-serif" style="font-family: helvetica;">One day you will hear me calling CQ SOTA from a 6,000+ ft peak in my SOTA neighborhood with the SP-1. </span></div>
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<span face="Helvetica Neue, Arial, Helvetica, sans-serif" style="font-family: helvetica;">Thanks for reading this far. 71's, Rich KR7W</span></div>
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<br />kr7whttp://www.blogger.com/profile/12925283975807120485noreply@blogger.com0tag:blogger.com,1999:blog-6635479951504521166.post-78084334843721420762014-01-29T08:05:00.006-08:002022-11-01T05:05:49.984-07:00W7EAT Winter Bunny Hunt... Nov 19, 2011<div class="separator" style="clear: both; text-align: center;">
<span style="clear: left; float: left; font-family: arial; font-size: x-small; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="54" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjz42-yjC3hlAEU6Ksklp89B5Ch_N9AQ6D2b7ub04yxbGg2RJPWlSLdKDv2-Lsv2w0-monPIt4CzcDMzzsU9IitF3bTnM7axTs4G9GjqpWJHI07dHnYKPxtyNJcJRJZeugX4aHk0G3hKnM/w623-h54/masthead+JPG.jpg" width="623" /></span></div>
<span style="font-family: arial;"><br /><span face="Trebuchet MS, sans-serif"><br /></span></span><div><span style="font-family: arial;"><span face="Trebuchet MS, sans-serif"><br /></span></span></div><div><span style="font-family: arial;"><span face="Trebuchet MS, sans-serif"><br /></span></span></div><div><span style="font-family: arial;"><span face="Trebuchet MS, sans-serif">This blog is a re-post the photos of the ARDF Hidden Transmitter Bunny hunt that was held near Eatonville, WA on Nov 19, 2011. The photos were originally shown at www.kr7w.org - which no longer exists. </span><br />
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<tr><td class="tr-caption" style="text-align: center;"><span style="font-family: arial; font-size: x-small;">Al, N7OMS on the hunt.</span></td></tr>
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<span style="font-family: arial; font-size: x-small;"><span face="Trebuchet MS, sans-serif">After the monthly W7EAT South Pierce County Amateur Radio Club meeting breakfast gathering in Downtown Eatonville, we headed out to the hills above Alder Lake. We were greeted with almost three ft of snow to find the 4 and sometimes 5 transmitters that "Huntmaster Bob", K7MXE, had hidden before the pasture area became a winter wonderland. [Note: the 'sometimes 5th' transmitter was the one that didn't transmit on a regular basis. Cold temp? Low battery? Dunno].</span><br />
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<tr><td class="tr-caption" style="text-align: left;"><span style="font-family: arial; font-size: x-small;">Rich KR7W (on the right) observes Chuck AC7QN trying to figure out what Huntmaster Bob has planted for us to find. Note: We are wearing our ORANGE (and safety green) cuz it's deer hunting season in these hills.</span></td></tr>
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<span face="Arial, Helvetica, sans-serif"><span style="font-family: arial; font-size: x-small;">At this point... is when I figured out that the rules of the hunt had changed again.<br />"Wait a minute Bob, that's not what you said before".</span></span></div>
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<tr><td class="tr-caption" style="text-align: left;"><span style="font-family: arial; font-size: x-small;">Back at the Tailgates to socialize, some non-participants came out to cheer us hunters on. Lorraine K7LJN, Stan K7DKK. Hunters- Rich KR7W (back to camera again), Alan N7OMS. 1/2 of Huntmaster Bob K7MXE is seen on the right.</span></td></tr>
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<span style="font-family: arial; font-size: x-small;"><span face="Trebuchet MS, sans-serif">After a break... the hunt continued on. Huntmaster Bob included a bit of 'trickery' in this hunt. He hid a dummy antenna close enough to the radiating antenna to fool some of the hunters. This resulted in a conflict where two hunters were disqualified. </span><br />
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<tr><td class="tr-caption" style="text-align: left;"><span style="font-family: arial; font-size: x-small;">Ousted from the game for breaking a rule that hadn't existed until this last minute. Just like working for a large corporation that practices TEGWAR... aka The Exciting Game Without Any Rules. Corporate America in the snowy bucolic hills above Alder Lake. Who wudda thought?</span></td></tr>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi3S82e8fGRWQLNph_Sj7waqpSK_Ce6oZyh-TDQLHcowkMXRSa_nnDfAODioF78GWreGBRCie37YKxd31IynJT_U0N4QsQUic_qFo3jD0Lk678d4lxVNQTxDholQPEDOWXkhEI1NSXGaGg/s1600/EATPIE_12.jpg" style="margin-left: auto; margin-right: auto;"><span style="font-family: arial; font-size: x-small;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi3S82e8fGRWQLNph_Sj7waqpSK_Ce6oZyh-TDQLHcowkMXRSa_nnDfAODioF78GWreGBRCie37YKxd31IynJT_U0N4QsQUic_qFo3jD0Lk678d4lxVNQTxDholQPEDOWXkhEI1NSXGaGg/s1600/EATPIE_12.jpg" /></span></a></td></tr>
<tr><td class="tr-caption" style="text-align: left;"><span style="font-family: arial; font-size: x-small;">A late comer hunter to the party, Casey WW7CH (left) chats with Chuck AC7QN in the Tailgate area. Hot coffee was a welcoming break.</span></td></tr>
</tbody></table>
<span style="font-family: arial; font-size: x-small;"><span face="Trebuchet MS, sans-serif">It turns out that somehow Casey WW7CH was the grand prize winner of this hunt. The mystery of how he found all of the transmitters in such a short time still lingers. <br /><br />This Hidden T - Bunny hunt was the most fun of all the hunts I've participated in. I think it was the nice people and unique hunting environment made it a great outing for me. So, Bob, when the heck is the second annual W7EAT Winter Bunny hunt?</span><br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEirUm7r0uHbSUwr1_cWUricuBOaLkxuPu7p31CyUae_ej6VyQdURIzHi5T1iTmG4b5DWggmF5kxLshni0VBANH7NBgaL-ENPqn-NMaACktZFU0LlSxyo2s0XPC0KH6Olo-iSeDR9XqmKII/s1600/EATPIE_6.jpg" style="margin-left: auto; margin-right: auto;"><span style="font-family: arial; font-size: x-small;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEirUm7r0uHbSUwr1_cWUricuBOaLkxuPu7p31CyUae_ej6VyQdURIzHi5T1iTmG4b5DWggmF5kxLshni0VBANH7NBgaL-ENPqn-NMaACktZFU0LlSxyo2s0XPC0KH6Olo-iSeDR9XqmKII/s1600/EATPIE_6.jpg" /></span></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-family: arial; font-size: x-small;">He is still snickering about this hunt...</span></td></tr>
</tbody></table>
<span style="font-family: arial; font-size: x-small;"><span face="Trebuchet MS, sans-serif"><br /></span>
<span face="Trebuchet MS, sans-serif">Also, it was fun to dig out these photos and re-post them for all to see. Us Old folks love to reminisce</span><span face="Trebuchet MS, sans-serif">, don't we? </span><br />
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</span><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhJ4dsnlUqqqqEDcqn-WGBAAzMWNOAzSNbb_UHytNr5Ep6vsXuQNS9MIqwWYnH33a4PtkUtTBKhvlzCRe5oBtfLkg0B_x9Hudz5fS_FYkharOExjursnfpfbvrkKeF9O_FmcsBxXwK3aHg/s1600/EATPIE_11.jpg" style="margin-left: auto; margin-right: auto;"><span style="font-family: arial; font-size: x-small;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhJ4dsnlUqqqqEDcqn-WGBAAzMWNOAzSNbb_UHytNr5Ep6vsXuQNS9MIqwWYnH33a4PtkUtTBKhvlzCRe5oBtfLkg0B_x9Hudz5fS_FYkharOExjursnfpfbvrkKeF9O_FmcsBxXwK3aHg/s1600/EATPIE_11.jpg" /></span></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-family: arial; font-size: x-small;">It really was a pristine winter wonderland.</span></td></tr>
</tbody></table>
<span style="font-family: arial; font-size: x-small;"><span face="Trebuchet MS, sans-serif"><br /></span></span></div><div><span style="font-family: arial; font-size: x-small;"><span face="Trebuchet MS, sans-serif">End of this blog entry. Best Regards,</span><br />
<span face="Trebuchet MS, sans-serif"><br /></span></span></div><div><span style="font-family: arial; font-size: x-small;"><span face="Trebuchet MS, sans-serif">Rich kr7w</span><br />
<span face="Trebuchet MS, sans-serif"><br /></span></span>
<span face="Trebuchet MS, sans-serif" style="font-size: large;"><br /></span></div>kr7whttp://www.blogger.com/profile/12925283975807120485noreply@blogger.com0tag:blogger.com,1999:blog-6635479951504521166.post-77364505196729245332014-01-28T21:54:00.001-08:002022-10-31T09:33:10.479-07:00Collins R-388 Receiver Explorations<div class="MsoNormal" style="text-align: justify;">
<div class="separator" style="clear: both; text-align: center;">
<a href="http://3.bp.blogspot.com/-iivUlKi_xeg/UukVBAj7opI/AAAAAAAAAx8/4x8jrcYZ-kk/s1600/masthead+JPG.jpg" style="margin-left: 1em; margin-right: 1em;"><span style="font-family: helvetica;"><img border="0" src="http://3.bp.blogspot.com/-iivUlKi_xeg/UukVBAj7opI/AAAAAAAAAx8/4x8jrcYZ-kk/s1600/masthead+JPG.jpg" /></span></a></div>
<span style="font-family: helvetica;"><span face="Trebuchet MS, sans-serif" style="font-size: large;"><br /></span>
<span face="'Trebuchet MS', sans-serif" style="font-size: large;">I like to restore old radios. So far of the 100 or so radios I've restored
only a couple of those have been communications receivers. Enter the Collins R-388.</span></span></div>
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<span face="Trebuchet MS, sans-serif" style="font-family: helvetica; font-size: large;">A couple of months ago, the W7OS Museum at the Radio Club of
Tacoma (which I am involved with) received as a donation an old R-388, circa
1950. </span></div>
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<span face="Trebuchet MS, sans-serif" style="font-family: helvetica; font-size: large;">At first glance the radio seemed to play well but had 60 Hz
hum in the audio. It was easy to replace
the power supply filter capacitors which did not help. Listening closer I noticed that when there
was no signal being received then there was no hum. This 60 Hz hum was riding on the B+ rail and
measured at 1.0 VAC RMS. In addition to
the hum- the S-Meter did not work very well- no matter what receive level was
received- the meter never rose more than 20 percent of its travel. Investigation revealed a possible AGC
(Automatic Gain Control) issue. More on
that issue later.</span></div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiFSdtkLDAOw7QTXB827thJTENqz6FqdafdVJ2lwAC6qPkUvVqDKW3faKUOrcGQO-WEC1SEGhX85xpx0PacAH6HeHPGGkfdNd39HFM78KP-urBQfYBtPwXQOD31orfaGDQUDPovfasg8Vg/s1600/Photo+R388+Front+Panel+Large+x12.jpg" style="margin-left: 1em; margin-right: 1em;"><span style="font-family: helvetica; font-size: large;"><img border="0" height="480" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiFSdtkLDAOw7QTXB827thJTENqz6FqdafdVJ2lwAC6qPkUvVqDKW3faKUOrcGQO-WEC1SEGhX85xpx0PacAH6HeHPGGkfdNd39HFM78KP-urBQfYBtPwXQOD31orfaGDQUDPovfasg8Vg/s1600/Photo+R388+Front+Panel+Large+x12.jpg" width="640" /></span></a></div>
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<span style="font-family: helvetica; font-size: large;"><span face="'Trebuchet MS', sans-serif">History Lesson:</span><span face="'Trebuchet MS', sans-serif"> </span><span face="'Trebuchet MS', sans-serif">In
1949 Collins began building the 51J which was intended for military or commercial
users who required a drift free and very stable receiver with extremely
accurate frequency readout.</span><span face="'Trebuchet MS', sans-serif"> </span><span face="'Trebuchet MS', sans-serif">The 51J was
to be used for RTTY reception but could also provide good AM listening.</span><span face="'Trebuchet MS', sans-serif"> </span><span face="'Trebuchet MS', sans-serif">The cost of this receiver was $900.</span><span face="'Trebuchet MS', sans-serif"> </span><span face="'Trebuchet MS', sans-serif">The military bought the 51J and improved
51J-2 which evolved into the R-388.</span><span face="'Trebuchet MS', sans-serif"> </span><span face="'Trebuchet MS', sans-serif">This
receiver has a 500 KCs IF output jack that provided a signal for additional
equipment for decoding RTTY.</span></span></div>
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<span face="Trebuchet MS, sans-serif" style="font-family: helvetica; font-size: large;">The World Wide Web has a couple of good R-388 sites with
enough valuable information to get me started on the Museum receivers
repair. Note that this is a work in
process… with progress being made. The
websites will be listed below. I joined a Yahoo Group for Collins 51J, R-388, and R390 receiver aficionados to gather more information. I think it is interesting that the rules of
the Yahoo group state that a new member must post an introduction of them self and
the (implied) purpose of joining.</span></div>
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<span face="Trebuchet MS, sans-serif" style="font-family: helvetica; font-size: large;">I posted my introduction to the Yahoo group. Some helpful members provided information on
the most popular components to replace that might fix the Museums
receiver. C204 and C136 were the
culprits.</span></div>
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<span face="Trebuchet MS, sans-serif" style="font-family: helvetica; font-size: large;"> Geek talk follows: C204 provides a signal from the last IF
amplifier to the AGC detector and AGC amplifier which manages the gain of three
IF amplifiers and the front end RF amplifier.
If C204 is open then no signal would be detected and the receiver would
be at full gain. C136 was reputed to become
leaky and apply plate voltage from the Crystal Calibrator Oscillator tube to
one of the input grids of the first mixer.
That would make a mess of the mixers amplification which would severely
distort the received signal. It was hard
to find C136 as well as replace it… but perseverance prevailed. Note to self:
Get some longer needle nose pliers.
After the cap swap-outs, the receiver was connected to an antenna and
viola! No more 60 Hz modulated audio. High power AM broadcast stations sounded much
better than before- much more intelligible audio. But something was still wrong.</span></div>
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<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh9X0lvIrtTsgfs4ERcr6jokYdYCxWpm3GDFwcbkOIknnviIxbcUldAsr74FqpDoC0rLuFdRY5NEnfY6g8v6IFr138rTGlFjgJ04BfBNElIxXdCWBhzsinREpvnhali6JCy1EIOrmyKbNg/s1600/Photo+R388+Bottom+Access+x12.jpg" style="margin-left: auto; margin-right: auto;"><span style="font-family: helvetica; font-size: large;"><img border="0" height="480" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh9X0lvIrtTsgfs4ERcr6jokYdYCxWpm3GDFwcbkOIknnviIxbcUldAsr74FqpDoC0rLuFdRY5NEnfY6g8v6IFr138rTGlFjgJ04BfBNElIxXdCWBhzsinREpvnhali6JCy1EIOrmyKbNg/s1600/Photo+R388+Bottom+Access+x12.jpg" width="640" /></span></a></td></tr>
<tr><td class="tr-caption" style="text-align: left;"><span face="Arial, Helvetica, sans-serif" style="font-family: helvetica; font-size: large;">C136 and C204 are in there somewhere. New terminal strip in lower left is the AGC mod mentioned later in this blog entry. The cylendrical gizmo in the top-center is the PTO, which Collins is famous for. The PTO is part of the VFO that provides a super linear and accurate tuning dial.</span></td></tr>
</tbody></table>
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<span style="font-family: helvetica; font-size: large;"><span face="'Trebuchet MS', sans-serif">The receiver sounded weak, with more noise than signal.</span><span face="'Trebuchet MS', sans-serif"> </span><span face="'Trebuchet MS', sans-serif">The AGC was working but not on CW and SSB
with the RF Gain turned all the way up.</span><span face="'Trebuchet MS', sans-serif"> </span><span face="'Trebuchet MS', sans-serif">On
AM, the AGC worked pretty well but the audio sounded better with the RF gain
turned down a bit.</span><span face="'Trebuchet MS', sans-serif"> </span><span face="'Trebuchet MS', sans-serif">The S-Meter still
did not indicate a high reading on loud signals- like the 50KW AM station 6
miles away.</span></span></div>
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<span face="Trebuchet MS, sans-serif" style="font-family: helvetica; font-size: large;"><br /></span></div>
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<span face="Trebuchet MS, sans-serif" style="font-family: helvetica; font-size: large;">The Army TM854-25 instruction manual is a very good document
that explains in detail the operation of each of the radios stages. There's even a section on how to destroy the radio so it will not fall into the hands of the enemy. But some
internet enthusiasts have posted that "The manual has errors. Trust the schematic inside the radios cover”,
they say. I did find an error, BTW.</span></div>
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<span face="Trebuchet MS, sans-serif" style="font-family: helvetica; font-size: large;"><br /></span></div>
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<span face="Trebuchet MS, sans-serif" style="font-family: helvetica; font-size: large;"> The TM has a section
on the S-Meter that reveals the higher the amplification of the IF stages then
the higher the meter reading- which means that the S-Meter works with the AGC
OFF if the RF Gain is all the way up.
Also, low IF amplification could be caused by defective AGC circuitry. Armed with the Tech Manuals tube voltage
chart, simplified schematics, and my Fluke VOM… I set out to measure the front
end RF amplifier and the three IF amplifiers (all gain controlled by the AGC)
tube voltages looking for discrepancies.
</span></div>
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<span face="Trebuchet MS, sans-serif" style="font-family: helvetica; font-size: large;"><br /></span></div>
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<span face="Trebuchet MS, sans-serif" style="font-family: helvetica; font-size: large;">Tubes V101, V107, V108, and V107 pins measured pretty close
to the chart, EXCEPT pin 6 of V107, which is the screen grid of the first IF
Amplifier. I measured +3 V instead of
the required +47 V. </span></div>
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<span face="Trebuchet MS, sans-serif" style="font-family: helvetica; font-size: large;">Remembering my Dark Ages vacuum tube electronics training…
I knew that the tube will not conduct (and therefore not amplify) without a
large value positive voltage present on the SG.
It turned out that R126, a 27K ohm resistor, in between the B+ and the SG, had changed value to many
meg-ohms. I calculated the voltage drop
across this resistor to determine the wattage needed I substituted 3 various
values in parallel to come up with 27K at .7 watt. Knowing Ohms Law has benefits, me thinks. I'm excited... let’s take it for a drive. </span></div>
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<span face="Trebuchet MS, sans-serif" style="font-family: helvetica; font-size: large;">The R388 now connected to an antenna works hundreds of times
better. Stations were loud, proud, and
the noise was lower. And the S-meter
worked as it should. With the RF Gain
all the way up still caused SSB and CW signals to distort. It seemed like the AGC wasn’t fast enough to
deal with the quickly changing signal level of these modes. Whilst listening to AM Broadcast… the
receiver sounded pretty good and the S-Meter tracked the more solid signal
pretty well. Again, R388 aficionado’s websites mention that
the R388 AGC is lacking. The search is
on for AGC Mods.</span></div>
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<span face="Trebuchet MS, sans-serif" style="font-family: helvetica; font-size: large;"><br /></span></div>
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<span face="Trebuchet MS, sans-serif" style="font-family: helvetica; font-size: large;">I knew a small bit about AGC from restoring many 30s, 40s,
and 50s entertainment radios… but after reading the 388s Tech Manual I was a
bit puzzled over attack and decay times and how it happened. I found a nicely
written article by the modern day Flex Radio folks that was enlightening. Also, the website <a href="http://www.neidlinger.us/R388.htm">www.neidlinger.us/R388.htm</a> reveals there
are four different AGC mods to consider. </span></div>
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<span style="font-family: helvetica;"><br /></span></div>
<div class="MsoNormal" style="text-align: justify;">
<span style="font-family: helvetica;"><span face="Trebuchet MS, sans-serif" style="font-size: large;">The AGC Modification I settled on was written by Dallas
Lankford in an obscure publication called HSN (Hollow State News) Summer 1990
edition. My friend Google found HSN #26
which contains info on the R388s Band 1 sensitivity, the PTO, and the AGC
Mod. Mr Lankford’s modification is dependent
on the AGC <u>no signal</u> voltage being -1.60 to -1.80 volts. The Army Tech Manual says this voltage should
be -1.40 volts. Other AGC articles want
the voltage to be 1.40. Mr Lankford’s
article reasonably states that if the AGC voltage is too positive then the dynamic
range of the receiver will suffer. The R388’s AGC voltage is derived from R149,
R148 Pot, R147, and R146. I replaced
R147 because its value had changed 40 percent.
This resulted in idle AGC voltage of 1.7 volts. </span><br />
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<br />
</span><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://4.bp.blogspot.com/-Nv38h8Un2Jw/UuiWoIqO2NI/AAAAAAAAAxs/ANAQOo7N0bk/s1600/Photo+Landford+AGC+Mod+Term+Strip+es+parts+image.jpg" style="margin-left: auto; margin-right: auto;"><span style="font-family: helvetica;"><img border="0" height="528" src="http://4.bp.blogspot.com/-Nv38h8Un2Jw/UuiWoIqO2NI/AAAAAAAAAxs/ANAQOo7N0bk/s1600/Photo+Landford+AGC+Mod+Term+Strip+es+parts+image.jpg" width="640" /></span></a></td></tr>
<tr><td class="tr-caption" style="text-align: left;"><span face="Arial, Helvetica, sans-serif" style="font-family: helvetica; font-size: large;">Photo shows the terminal strip I added to add the AGC mod components to the AGC amp circuitry. With this set up I can easily reverse the modification. More info in the Dropbox folder listed below.</span></td></tr>
</tbody></table>
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<span style="font-family: helvetica;"><span face="'Trebuchet MS', sans-serif" style="font-size: large;">I performed the Lankford AGC mod with low expectations and was
greatly surprised with the results. Now
the R388 copies CW and SSB quite well with the RF Gain all the way up. AM Broadcast works quite well also. Of course with a really loud CW or SSB signal
it is prudent to turn the RF Gain down for more comfy listening. The AGC attack time is quite rapid and decay
is slow in comparison. I suspect that
this AGC would not work well for QSK CW when listening to my own transmit
signal in the receiver as it would take a while for the amplification to ramp
back up in order to quickly hear the far station.
I have been using the R388 with my circa 1950s Globe Chief transmitter with
manual T-R Dow Key type non-QSK operation.
Slow decay AGC is not a problem with my station. </span><br />
<span face="Trebuchet MS, sans-serif" style="font-size: large; text-align: left;"><br /></span>
<span face="Trebuchet MS, sans-serif" style="font-size: large; text-align: left;">AGC Movie:</span><br />
<span face="Trebuchet MS, sans-serif" style="font-size: large; text-align: left;"><a href="https://www.dropbox.com/s/9xhqd29u3hrxuxa/R388%20AVC%20Demo-Lankford%20Mod%20Movie.wmv">https://www.dropbox.com/s/9xhqd29u3hrxuxa/R388%20AVC%20Demo-Lankford%20Mod%20Movie.wmv</a></span><br />
<span face="Trebuchet MS, sans-serif" style="font-size: large;"><br /></span></span></div>
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<span face="'Trebuchet MS', sans-serif" style="font-family: helvetica; font-size: large;">The next step is to figure out if I want to do the product
detector mod. The suggested mod on the neidlinger website seems pretty easy, but it involves removing the
front panel. On this radio I’d have to
swap the AGC SPSP switch with the Noise Limiter DPDT switch to make the product
detector work. Before I do this I will
be seeking opinions and personal testimonies.</span></div>
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<span style="font-family: helvetica;"><a href="https://www.dropbox.com/sh/6i5za0ozryys290/LbEc5w97Vn" style="font-size: x-large;">https://www.dropbox.com/sh/6i5za0ozryys290/LbEc5w97Vn</a><br />
<br />
<span face="Trebuchet MS, sans-serif" style="font-size: large;">This dropbox link is to a folder that contains the documentation that I acquired during this receiver repair. I found most all of it on the web... so it's not new news. But it is all in one place. </span><br />
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<span face="Trebuchet MS, sans-serif" style="font-size: large;">What's in the folder...<br />+ Photos of my attempt of the AGC mod<br />+ A movie of the AGC in action<br />+ The Army Technical Manual (two parts)<br />+ Annotated schematic<br />+ PDF files that contain the content of the web pages I found useful.<br />+ An article on AGC that I found useful<br />+ The Hollow State News collections in PDF (the entire set of HSNs are worth reading if you are a boat anchor kind of hobbiest)</span><br />
<span face="Trebuchet MS, sans-serif" style="font-size: large;">+ Something I am forgetting to mention</span><br />
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<span face="Trebuchet MS, sans-serif" style="font-size: large;">But wait, there's more... in another blog entry.<br />That's all for now. Regards, KR7W</span><br />
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kr7whttp://www.blogger.com/profile/12925283975807120485noreply@blogger.com0tag:blogger.com,1999:blog-6635479951504521166.post-38085096518600943692013-09-24T17:59:00.001-07:002022-10-31T08:32:57.800-07:00The 10-4 QRM Slicer KX-3 Microphone<div class="separator" style="clear: both; text-align: center;">
<a href="http://2.bp.blogspot.com/-eCc7EyxGQeA/UkIhGYAl9mI/AAAAAAAAAsU/JihvlZD56Ic/s1600/masthead+JPG.jpg" style="margin-left: 1em; margin-right: 1em;"><span style="font-size: x-small;"><img border="0" height="56" src="http://2.bp.blogspot.com/-eCc7EyxGQeA/UkIhGYAl9mI/AAAAAAAAAsU/JihvlZD56Ic/s1600/masthead+JPG.jpg" width="640" /></span></a></div>
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<i style="font-family: Verdana, sans-serif;"><span>Note: This article was written on Oct 3, 2012 and was posted on the old kr7w.org website- which went QRT. Recently a fellow QRP enthusiast asked me where I got the 10-4 QRM Slicer Mic shown in some of my SOTA Blog entries. "I built it", I said. The mic seen in the SOTA blog photos is red... which is Ver 2 of the QRM Cutter mic for the KX3. The red mic is exactly the same design this article from the old website:</span></i><br />
<span face="Verdana, sans-serif"><br /><span style="font-family: arial;">Just recently retiring... I was feeling pretty frugal when purchasing my KX3 from Elecraft. "$54 for a small microphone?!" I quipped. "By God! I could build for much less"... and it'd be just as reliable. and useful.</span></span><span style="font-family: arial;"><br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjJwUBeRKhivCzhUdQQN7VqwqSHS4bF7bzG4XX-IsUa2gM7QqNvHqncvZ40RS5j6-Ag7DPTr3Mwk7pMNzKNb-FS7E0wgiUVYiSD_ielYX0im-MOuCBbBO56bCSejRAzC4FRsSMuAGTJgdw/s1600/KX3_MIC_INTERIOR.jpg" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><span style="font-family: arial; font-size: x-small;"><img border="0" height="237" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjJwUBeRKhivCzhUdQQN7VqwqSHS4bF7bzG4XX-IsUa2gM7QqNvHqncvZ40RS5j6-Ag7DPTr3Mwk7pMNzKNb-FS7E0wgiUVYiSD_ielYX0im-MOuCBbBO56bCSejRAzC4FRsSMuAGTJgdw/s1600/KX3_MIC_INTERIOR.jpg" width="320" /></span></a></td></tr>
<tr><td class="tr-caption" style="text-align: left;"><span face="Arial, Helvetica, sans-serif" style="font-family: arial; font-size: x-small;">Inside of old hamfest CB mic.</span></td></tr>
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</span><span style="font-size: x-small;"><span style="font-family: arial;"><span face="Verdana, sans-serif">Photo shows a $1 old CB microphone found at a ham radio swap-meet. Its dynamic mic element did </span></span><span style="font-family: arial;">not have enough audio output to drive the KX3. After experimenting with different mic elements, a Radio Shack Electret Microphone Element was selected.</span></span><div><span style="font-size: x-small;"><span style="font-family: arial;">
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<span face="Verdana, sans-serif">Deciding: Each Electret mic element was plugged into the PC's mic input where my voice calling CQ or Test was recorded, then compared to determine which mic best resembled a Dynamic element that produces a clear crisp sound- like a Heil HC4 contest mic element. </span><br />
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<span face="Verdana, sans-serif">After a couple of mic element candidates were selected, the computer audio editing app,<b><i> Audacity</i></b>'s EQualizer effects were adjusted make the recording as crisp sounding as possible. Then those settings were emulated in the KX3 XMT audio equalizer settings to be as close as possible. <br /><br />The old CB microphone </span><span face="Verdana, sans-serif">mic metal weight was removed.</span><span face="Verdana, sans-serif"> The plasting housing that the old mic element sat in was closed off with a piece of blank printed circuit material. A 1/16" hole was drilled in the PCB material. This is where your voice/audio will pass through to the mic element. The mic cartridge was hot melt glued to the PCB, centered to the hole. A pigtail wire was soldered to the mic element which passes through a hole drilled in the housing. All needed parts were reassembled. How heavy is it? ~3 oz. now.</span></span><br />
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<span face="Verdana, sans-serif">The PTT switch in this mic is DPDT switch. Only one set of contacts were used to operate PTT.</span></span><br />
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<tr><td style="text-align: center;"><a href="http://1.bp.blogspot.com/-5jlNgrtgb_U/UkIhjFnEQRI/AAAAAAAAAsw/ZdXtj273wUU/s1600/KX3_MIC_SCHEM.jpg" style="margin-left: auto; margin-right: auto;"><span style="font-size: x-small;"><img border="0" height="400" src="http://1.bp.blogspot.com/-5jlNgrtgb_U/UkIhjFnEQRI/AAAAAAAAAsw/ZdXtj273wUU/s1600/KX3_MIC_SCHEM.jpg" width="640" /></span></a></td></tr>
<tr><td class="tr-caption" style="text-align: left;"><span style="font-family: arial; font-size: x-small;"><span face="Arial, Helvetica, sans-serif">T</span><span face="Arial, Helvetica, sans-serif">he Mic schematic in the KX3 manual shows Ring 2 as the UP/DN control wire. This feature is not used in this project.</span></span></td></tr>
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<span face="Verdana, sans-serif">The cable in the photo below came from a 10 ft audio/video jumper from Ebay. It was advertised as a 'Phillips' cable. With the cable cut in half, ohmmeter continuity testing the TIP / Ring 1 / Ring 2 / SLEEVE colored wires to know where to connect to in the microphone.<br /><br />Note: It is not necessary to use a 4 conductor cable. Another mic was built that used a cut up Radio Shack T-R-S 1/8" cable. In this case, use Tip for Mic, Ring for PTT, and Sleeve for GND return. It works just the same. In this case- a 4 conductor cable was used because it has a right-angle plug that doesn't protrude too far from the KX3 housing... also the option to add Push Buttons KX-3 like pushbuttons can be added if desired. </span><br />
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<span face="Verdana, sans-serif">After wiring was completed- The PTT function was continuity tested with an Ohmmeter then again plugged into the PC and audio tested one more time. Then was disassembled and spray-painted <b><span style="color: #ffa400;">Home Depot</span></b><span><b><span style="color: #ffa400;"> </span><span style="color: #ff9900;">Orange</span></b></span>. It took a couple of coats, then a coat of clear lacquer to give it <i>BLING</i>. The 10-4 label is the 'model number'. Note: I have never been a CBer.</span></span><br />
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<span style="font-family: arial; font-size: x-small;"><span><span face="Verdana, sans-serif">Back to the</span><span face="Verdana, sans-serif"> </span><span face="Verdana, sans-serif" style="color: #ff9900;"><b>ORANGE</b></span><span face="Verdana, sans-serif"> </span><span face="Verdana, sans-serif">color... After using a Yaesu FT-817 whilst out SOTAing or backpacking... I was always stepping on the black microphone. This <b><span style="color: #ffa400;">orange</span></b> mic is hard to miss when it is laying in the duff. </span></span><br />
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<span face="Verdana, sans-serif">KX-3 Testing: The <b>model 10-4</b> was plugged in with RF power output adjusted to Zero. Listening to myself with headphones and using the KX-3 MON function- it sounded pretty good- especially with the compressor turned up to 16. Note: This Radio Shack electret element has high output. The KX3 mic gain control was to approx 7 for proper ALC action.</span></span><br />
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<span face="Verdana, sans-serif">During a SOTA activation I someone finally answered my SSB CQ. Even though I sound like Kermit T Frog, I was told "Great audio Old Man"</span><br />
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<span face="Verdana, sans-serif"><u>Lessons Learned... </u></span></span><br />
<span><span face="Verdana, sans-serif"><br /></span><span face="Verdana, sans-serif">> The hole in the mic housing must be very small. Take a look at your mobile radio mics... there's a small hole to diminish the amount of wind from your voice hitting the mic element.</span></span><br />
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<span face="Verdana, sans-serif">> If your re-purposed mic has foam rubber and a metal screen in front of the mic element... be sure to reuse it. This helps keep the wind from hitting the element.</span></span><br />
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<span style="font-family: arial; font-size: x-small;"><span face="Verdana, sans-serif"><span><br />> If the mic element enhances Ss or the ESSSSS sound when you speak... a low pass filter or a filter that shunts highs to ground may need to be included. Whilst experimenting with this, it became a hassle to get it just right. After finally settling on the Radio Shack mic element and adjusting the KX3 audio EQualizer settings... it turned out OK for me. Google 'Sibilance Filter' to find out more.<br /><br />> This mic can be plugged in your PC to make audio files for SSB contests to add to your logging software. Audacity software can be used to enhance the audio. "CQ Sweepstakes"</span><br /><br /><span>> Hot Melt Glue Gun is my friend on many DIY occasions- be careful.</span></span><br />
<span><span face="Verdana, sans-serif"><br /></span><span face="Verdana, sans-serif">10-4? Over and Out... Best Regards,</span><span face="Verdana, sans-serif"><br /><br />KR7W</span></span></span></div>
</div>kr7whttp://www.blogger.com/profile/12925283975807120485noreply@blogger.com0tag:blogger.com,1999:blog-6635479951504521166.post-40054343965721062202013-01-06T21:22:00.000-08:002014-03-29T07:53:04.250-07:00kr7w.org Is Going Out of Business<div style="text-align: justify;">
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<span style="font-family: Verdana; font-size: large;">My longtime website, <a href="http://www.kr7w.org/"><strike>www.kr7w.org</strike></a> is outa business.</span></div>
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<b style="font-family: 'Trebuchet MS', sans-serif;"><span style="font-size: small;">How do we do it? Volume...</span></b></div>
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<span style="font-family: Trebuchet MS, sans-serif; font-size: small;"><b>Turn up the volume!</b></span></div>
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<span style="font-size: large;"><span style="font-family: Verdana;">I have become less active in posting info to the old </span><strike style="font-family: Verdana;"><a href="http://www.kr7w.org/" style="font-family: Verdana;">www.kr7w.org</a></strike><span style="font-family: Verdana;">... and my contract with the web host ran out... and simply didn't want to pay more $$ to re-up.</span></span></div>
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<span style="font-family: Verdana; font-size: large;">As a member of the Google online community... I will take advantage of their Free-Bee Blogspot service and attempt Blogging to express myself in my ham radio hobby.</span></div>
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<span style="font-family: Verdana; font-size: large;">Regards,</span></div>
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<span style="font-family: Verdana; font-size: large;">Rich, kr7w</span></div>
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kr7whttp://www.blogger.com/profile/12925283975807120485noreply@blogger.com0