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Sunday, December 21, 2025

Frank Jones W6AJF on Homebrew, Thermatrons, and VHF


We are in the Dominican Republic now. I thought SolderSmoke blog readers would like the introduction to Frank Jones W6AJF's VHF handbook. (Click on the pictures for a better view. The book was published in 1961.  Lots of good homebrew, VHF, and thermatron thinking in those pages. I will be using this book and the implied blessings of W6AJF in my upcoming 2 meter assault on the Mona Passage between the DR and Puerto Rico.  (Thanks too to W3RTV, the original owner of the book!) 


Click on the pictures for a better view. 



Click on the pictures for a better view. 


Saturday, December 20, 2025

Bricoleur -- "Someone Who Fixes Stuff with Whatever he Finds Around"


A short time ago Paul VK3HN told us about the term bricolage. It seemed to capture much of the homebrew spirit.  This morning I heard Van Neistat's video-cast  (also something that came to me from Paul VK3HN) talking about the related term "bricoleur."  His  video (above) also has some great workshop ideas.  

Here is a nice Wikipedia discussion: https://en.wikipedia.org/wiki/Bricolage


Note from the Wikipedia page: 

  • MacGyver is a television series in which the protagonist is the paragon of a bricoleur,[28] creating solutions for the problem to be solved out of immediately available found objects.

Friday, December 19, 2025

Why 3.579 MHz for Old Color TVs? The Origins of the CBLA


As the Commanding General of the Color-Burst Liberation Army, I have often wondered why so many of these 3.579 MHz crystals were made.  Heck, even the crystal filter of my first homebrew superhet receiver used these crystals.   

When we launched the CBLA effort, we used the Michigan Mighty Mite as our transmitter of choice:  I mailed out around 40 of these rocks.  Many transmitters were built.  I have received reports of guys pulling their cars over to the side of a road (with hapless family members in the car) when a discarded color TV was spotted -- the 3.579 Mhz crystal would be quickly extracted.  Such was the dedication of the CBLA members (the family members were, of course, baffled).  

Anyway, the story of the Color-Burst crystals is deeply entwined with the story of the birth of color TV.  This fellow (above) does a good job of explaining the hows and whys of 3.579 MHz. Thanks to Al Williams and Hackaday for alerting us to this, and for some really useful commentary on the video: https://hackaday.com/2025/12/18/the-miracle-of-color-tv/


Viva el CBLA! VIVA! 


Thursday, December 18, 2025

Happy Birthday to Pete Juliano N6QW

 
That, my friends, is the look of a steely-eyed homebrewer taking a break from the soldering iron by belting out a few noodled chords for SolderSmoke on his guitar.  And in the picture he is in the garage where all the homebrew magic happens.  

Pete, we know that this has been a tough orbit for you, but we still want to wish you a Happy Birthday OM -- you bring a lot of wisdom and tribal knowledge to many, many builders.  Thanks Pete. 

73  Pete. 

Tuesday, December 16, 2025

Arduino, Adafruit, Open Source, Qualcomm, and all that


This is not really my thing, but the changes to 60 meter rules recently caused me to crack open some older Arduino/Si5351 and AD9850 VFOs, so maybe this was my thing...  

Still, all of this chatter kind of disappears once you embrace analog LC VFOs.   But here is a good article about all of this: 

https://thenewstack.io/adafruit-arduinos-rules-are-incompatible-with-open-source/


Friday, December 12, 2025

15 kHz of 60 meters FINALLY Liberated! But Watch Out for the 9.15 Watt ERP Limit

My 60 meter rig in 2017

Here's a reminder of how long this took:  When Bob KD4EBM alerted me to the ARRL announcement that 15 kHz of the 60 meter band had been "liberated," I turned to my blog and found articles talking about this possible change way back in 2017.  Oh well, better late than never.  

Here is the ARRL announcement: 

https://www.arrl.org/news/fcc-allocates-60-meter-world-wide-amateur-band-approved-at-wrc-15-continues-amateur-use-of-four-addi

Here are a couple of references from the SolderSmoke blog and one from the BITX Hacks blog in which Don ND6T shifts the BITX40 module's bandpass filter to 60 meters. 

https://soldersmoke.blogspot.com/2017/03/channelized-bitx-60-with-five-channels.html

https://soldersmoke.blogspot.com/2017/03/bitx-sixty-with-three-short-videos.html

https://bitxhacks.blogspot.com/2017/02/cap-stack-hack-putting-bitx40-on-60.html

I reached into my junk box this morning and found the digital VFO I was using way back in 2017.  I may turn to Don again for help in getting the VFO segment to work. 

I got a chuckle about the FCC power limit:  9.15 watts ERP.  Wow, such precision! Can you imagine the FCC breaking down a radio amateurs shack door after, perhaps, measuring 9.16 watts ERP?  BUSTED!

Thursday, December 11, 2025

Homebrew Radio from Southern India


I came across this channel yesterday -- there is a lot of FB homebrew content here.  And it is partially in the Malayalam language of Kerala state in Southern India.  

About 38 million people speak Malayalam: https://en.wikipedia.org/wiki/Malayalam

Check out his channel:  

 https://www.youtube.com/@MrtechElectronics

Tuesday, December 9, 2025

"Homebrew you say? But did you DESIGN it yourself?"

Raymond A. Heising  (1922)

That is a question we get fairly regularly when we tell the other fellow that our rig is homebrew.  I often get the feeling that the question stems from a certain insecurity -- the guy who asks it may feel a bit insecure because the "rig" he is running is completely commercial and his only role in its production was to flash a credit card number.  

But lately I have been reading through Jim Williams' wonderful book "Analog Circuit Design -- Art, Science, and Personalities" and I can see that there may be something to this question. 

It was the chapter by Barrie Gilbert that made me think more about this. Barrie is the legendary designer for whom the Gilbert Cell is named.  This circuit is at the heart of the NE602 chip that many of us used to build our first "Neophyte" receivers and other homebrew rigs.  Barrie's chapter is entitled "Where do Little Circuits Come From."  Uh oh. 

Barrie grew up in the post-war United Kingdom.  He father had been killed in a German bombing raid. As a kid, he built crystal radios and, with his brother, "shortwave sets" on softwood bases.  He used a TRF receiver that employed Manhattan-style construction.  Barrie, it seemed, was one of us.  

But then, he suddenly seemed more advanced.   He wrote:  

"Later, I began to build some receivers of my own but stubbornly refused to use circuits published in the top magazines of the day, Practical Wireless and Wireless World.  Whether they worked as well or not they had to be "originals" otherwise, where was the satisfaction?  I learned by my mistakes but grew to trust what I acquiered in this way:  it was 100% mine, not a replication or mere validation of someone else's inventiveness."  

Wow, that is certainly hardcore.  I will note,  however,  that in getting back to the the question about whether I have "designed" the rig myself, I have NEVER had the questioner come back to say that HIS rig was homebrewed from HIS OWN original design.  Never.  Not once. 

And I will note that building a rig from the schematic is an enormous challenge.  It is not easy.  It is not the mere replication of someone else's inventiveness.  Anyone who thinks it is easy should try to homebrew a simple direct conversion receiver.  They will discover that it is NOT easy. 

I guess this comes down to what we mean by "homebrew."  I prefer to stick to the old ham radio meaning of the term:  It is homebrew if it was built at home, even if it is built from a schematic done by someone else. When Jean Shepherd built his Heising Modulator, was he working off a schematic from a ham radio magazine?  He almost certainly was.  But he gathered the parts, laid out the chassis, and put the circuit together.  Most importantly, when trouble cropped up, he was able to step in and make the needed corrections.  Was his modulator "homebrew?" Of course it was.  Did he design it himself?   No, his name was not Heising! 

More than 100 people built our SolderSmoke Direct Conversion Receiver.  We resisted pressure to turn this project into a kit.  The folks who built it worked off schematics that we had prepared.  They gathered the parts and built their own circuit boards, Manhattan style. They struggled to get the whole thing to work, to make sure the VFO was on the right frequency and at the right level, that the AF amplifier was not oscillating.  Were these receivers "homebrew?"  Of course they were. 

Jim Williams warned that Analog Circuit Design was "A wierd book."  He strongly discouraged collaboration between the authors, and noted that this would probably result in "a somewhat discordant book."  We see that discord in the hardcore position taken by Barrie Gilbert.  Many of the other designers seem to take a more flexible, less austere position.  Some even seem to downplay the role of mathematics.  

I think Barrie had a right to be proud of his fundamentalism.  But not all of us are capable of that.   Writing in Jim Williams' book,  Samuel Wilensky sums it up nicely: 

"I classify analog designers into one of two categories.  There are those who do truly original work, and these I consider the artists of our profession.  These individuals, as in most fields, are very rare.  Then there are the rest of us, who are indeed creative,  but do it by building on the present base of knowledge."   

Some Great Analog Pictures from MIT Building 20 and other Analog Locations

Here is a picture of Jim Williams taken through a Tektronix oscilloscope camera.  I never used one of these things, but Dean KK4DAS did.  Here are the details of the shot: 

I took this great photo of Jim Williams with a Tek scope camera sometime around 1977 or so. There was no digital (or analog) manipulation. It was a simple double exposure. I first shot a scope waveform, then just to see what would happen, I pulled the camera off the scope, stuck it Jim’s face and snapped another shot before pulling the film. I never expected it to look this good….a view from inside the oscilloscope!

Here is the collection of pictures that this 'scope shot came from: 

https://lensprojects.com/analog-history/

Thanks to Len Sherman for the pictures.  On his site you will see, among other things, the upside down Christmas Tree of dead parts, and Bob Pease's Volkswagen Beetle. 

More info on MIT's Building 20: 

https://en.wikipedia.org/wiki/Building_20


Saturday, December 6, 2025

SSTV! Slow Scan Television


https://www.qsl.net/on6mu/rxsstv.htm

Time for something completely different.  As a kid, I lusted after the ROBOT SSTV systems that were advertised in QST.  Yesterday, on a lark, I downloaded this program, tuned my Mythbuster transceiver to 14.230 MHz, and put the podcast microphone in front of the speaker.  BOOM!  SSTV signals started pouring in.  The program automatically set the kind of SSTV format that was coming in, so there was no need for me to try to figure out if it was Scottie 1 or Martin 1 or whatever.  I've done this before, but this program made it easier.  The invention of SSTV by Copthorne MacDonald (another GREAT ham radio name!) is really interesting: 

https://soldersmoke.blogspot.com/2011/07/early-days-of-sstv-by-copthorne.html

I note that the first article in QST appeared in the month of my birth, and the FCC decided to allow SSTV in the phone bands when I was 10 years old. 

Here are some signals received yesterday at N2CQR: 





An Analog Life -- A Video about Jim Williams


Sometimes the YouTube algorithm gets it right.  This morning it sent me the above video from the Computer History Museum about Jim Williams. The video is 13 years-old, but that says something about the enduring impact that Jim Williams had.  I especially liked the references to the need for understanding of analog circuits.  As many have noted, Jim was very good at explaining this stuff. 

Friday, December 5, 2025

Dave Richards AA7EE Builds and Documents the SolderSmoke Direct Conversion Receiver


As always with Dave's builds, " 'tis a thing of beauty."  His photographs and documentation make it even better.   Please go directly to Dave's site and enjoy his look at the SolderSmoke HOMEBREW Direct Conversion Receiver:  

https://aa7ee.wordpress.com/2025/12/04/the-soldersmoke-direct-conversion-receiver/

Thanks Dave!