School for Danger -- the SOE, and Radio, in Nazi Occupied France

Hack-a-Day had a link to this film.  It is really good.  There is some stuff about radio, and especially the S-Phone system.  But the bigger message of the film is the danger faced by the heroic teams who parachuted into occupied France.  As shown in the film, many of these people were young women who risked it all in the most dangerous of airborne operations.  It is a reminder of how ridiculous the focus on masculine valor in airborne and special operations really is.  Three cheers for the SOE. For all of them. 

Farhan Talks LARCSet (CW & SSB) at FDIM (with a Lot of Homebrew Wisdom)

Watch the presentation here: https://www.youtube.com/watch?v=MefojjQ84YY

Farhan made it to FDIM 2026  (he must hold the "distance travelled" record!). We thought he might be talking about the latest version of the digital SDR sBITX, but NO!  Farhan talked about the entirely analog LARCSet, a 30 dollar SSB/CW monobander.  And in the process he shared a lot of good homebrew history and wisdom. I took notes on the video of his presentation: 

-- Farhan recounts his discussion with Steve Hartley, President of GQRP.  Farhan said he started to talk about SDR projects, but Steve steered him away from all that.  Farhan said he realized that the homes of GQRP members are often small, and projects need to fit into took boxes that are pulled out as needed.  There is often not even enough room to mount a screen.  Analog rigs just fit better.  

-- Farhan talked about the beauty of analog.  He also shared some info on the recent timeline of analog rigs, going back to 1976 with the IARU gift kits made available by W1VD.  Farhan very kindly mentioned the DC receiver that Dean and I are promoting.  He talked about the 2003 BITX 20 rig, and the subsequent uBITX.  Farhan talked about the cleanliness of all-analog rigs.  "SDR's are a mess!" he said. "With SDRs it is difficult to avoid hash." 

-- Farhan said he had trouble measuring the phase noise of the VFO in the LARCSet.  He consulted with Wes W7ZOI.  Wes told him this was NOT a measurement problem; VFOs have almost no phase noise.  The level is even lower than that of crystal oscillators.  Of course, crystal oscillators are more stable, but they also have more phase noise.

-- He noted that almost no recent homebrew design does not rely on an Si5351.  This, he said, is "not a healthy situation."  Indeed.   

  --  Farhan talked a bit about how Indian regulations seemingly require a deviation from the completly open source ethos.  Indian regs require companies to have assets.  So the PC board layouts have to remain proprietary.  

-- Farhan talked about the sharpness and shape of the BP filter in the LARCSet.  I remember talking to him about the shape of my BP filters in my dual banders -- I had to rebuild the filters.

-- On the crystal filters that form the heart of SSB rigs, Farhan noted that cheap low Q crystals often introduce a lot of loss in the filters (that may explain my problem with some styles of computer crystals). 

-- A member of the FDIM audience asked about the Sharpie written frequency readout on the LARCset that Farhan showed to the group.  Farhan told them that this was the only frequency readout used in the rig. 

  -- With the LARCSet, Farhan used varactors to vary the frequency.  But the varactors he used were cheap but horrible.  They varied the frequency as the rig hearted up.  The LM386 was the source of heat.  He also noted that they cheap varactors, while cheap, did not provide linear frequency readout. Farhan said the varactor scheme was still not perfect; he offered a PTO solution that could be used instead.  Three cheers for the PTO! 

-- Farhan said the LARCset was really an SSB rig, but when coming to FDIM he said he felt obligated to present a rig that included CW, "or they would throw me out of the room."  Farhan described a scheme to generate CW based on what was done with the Atlas rigs. 

-- Farhan said the LARCset might even work on 2 Meters.  Hmmm.  

-- On tuning, Farhan said he used a very large tuning dial (he said it was like a steering wheel) and then recommended the use of a smaller control that could serve as an SSB "clarifier." 

-- Farhan pointed out that homebrew rigs are never really done; even decades later, they can still be modified.  

Watch the presentation here: https://www.youtube.com/watch?v=MefojjQ84YY

Rick N3FJZ on the Red Summit Podcast with Charlie NJ7V

 

Check it out! 

https://www.youtube.com/watch?v=sUQA2uNskEs

I liked Rick's story about his early days in radio electronics.  Taking old TVs from the street -- been there, done that!  FB Rick, 

Rick points out that he has never used a commercial ham radio rig, so he is unfamiliar with some of the "features" of such rigs.  Sometimes, I think, the lack of experience is a good thing. 

I really like the display that Rick uses, showing the operating frequency, the VFO frequency and the BFO frequency.  This might help with our struggle with those who complain that we are 40 Hz off.  Rick then notes that he used 15,000 lines of code for this display.  Wow, that shows the benefits of being -- like Rick is -- both a real software wizard and a hardware wizard. 

Rick describes how  he uses tin-plated steel boards in lieu of copper clad boards.  

I liked his approach to schematic drawing -- we benefited from this in the SolderSmoke Direct Conversion receiver project. 

When Rick talks about taking pieces of schematics from other rigs and making them work in new rigs, Charlie notes that, "this is the ham radio way."  Exactly. 

There is a lot of really sentimental stuff in this podcast.  SolderSmoke is mentioned frequently.  They mention Pete and Dean.  This starts at around 22 minutes. Rick talks about Farhan at around 26 minutes.  And he talks about Wes W7ZOI.  

Rick talks about some of his early projects.  I have a sentimental attachment to his Lakeside DC receiver: 

  

Then, a few years later, we had our first HB2HB contact.  Homebrew rigs on both sides:  

https://soldersmoke.blogspot.com/2015/10/hb2hb-n3fjz-n2cqr-si5351-and-bitx-tias.html

Finally, I agree with the last sentiment expressed by Rick in his conversation with Charlie:  The Red Summit podcast -- especially with its focus on homebrew -- is exactly what this hobby needs.  Anything that encourages hams to experience the fun of homebrewing is a good thing.  Three cheers for Rick and for Red Summit. 

SolderSmoke 264: CW TX, Repair of 17-12 Rig, AI and Repair, Back on 40m, HB for 2m, VWS WSPR Makers Project , MAILBAG

QSO May 8, 2026 with Lou EA3JE.  I was using my Mythbuster

May 12, 2026

SolderSmoke Podcast #264 is available for download: 

Audio:   http://soldersmoke.com/soldersmoke264.mp3

Video:  https://www.youtube.com/watch?v=_9FcfuqjZxA

We had a small recording glitch at the beginning of this video. But we didn't lose much. We had talked about the success of the SolderSmoke Direct Conversion Receiver Project. We talked about the receivers built by Nader Omer ST2NH and Chuck Adams AA7FO. We had also gloated a bit about our April 1 post -- you know, the (bogus! ) story about how the Administration is "Supporting Homebrew Radio." (Let us know if you were taken in by this, even for just a few seconds.) At that point, we were just beginning Pete's section; that is where the recording began. Here are the notes for the rest of the podcast:

Pete: 

Three CW transmitter projects featuring low parts counts.  Good results from Reverse Beacon Network. 

The goal in these projects is to raid the junk box and severely limit any new purchases of components.  Pete had no idea of the depth of parts he bought and just stashed away.   https://www.youtube.com/watch?v=5YLZ7aZpmxQ&t=30s

Bill: 

Fixing the 17-12 Rig.  Parasitic VHF Oscillations with the SK3050.  Good advice from Gemini. Killing NE602s. Fat Finger Syndrome -- hard to work with ICs.   Different freq when on transmit -- need for .1 uF cap on pin 8. Worked South Korea -- TRGHS. 

Putting the DIGI-TIA back on the air. On 40! And SW listening with the Q-31. 

Hard to homebrew for 2 meters.  Did some beacon experiments to Puerto Rico on last day in DR. 

SHAMELESS COMMERCE DIVISION: 

The importance of Patreon!  Thanks!  patreon.com/SolderSmoke

Mostly DIY RF!  https://mostlydiyrf.com/

Universe Today Podcast with Fraser Cain.  No Ads.  Great stuff.  Listen!   https://www.patreon.com/public-rss/75186?show=1744036

Dean: 

The VWS WSPR project.  

Mailbag:  

Ed N3EML  Heard me on 40 with my Digi-Tia

Grayson KJ7UM  Liked WWII training video: https://soldersmoke.blogspot.com/2026/05/radio-receivers-1942-training-film.html

Mike WN2A  -- Pete Juliano is our Shifu! (Lexicographer Steve Silverman KB3SII approves,)

Todd K7TFC Thoughtful comments on ARRL "Clean Signal Initiative."

Danny ON1MWS's regen with unusual variable capacitors. 

Mike WU2D  S-38, Nearfest,  Mu Metal.  https://www.youtube.com/watch?v=YUQ4xml1dSY

Charlie NJ7V  Interviews Mitch NK3H who homebrewed an SSB transceiver. 

Charlie also had Don KM4UDX, President of the Vienna Wireless Society on the podcast. 

Bob KD4EBM -- El Cilindro. Radioactive Hospital Waste -- basis for a Ruben Blades song.  It was 1987 in Brasil.  Cesium 137 left in hospital waste.  

Hamilton  KD0FNR   Big fans of "The most interesting man in the world."https://soldersmoke.blogspot.com/2026/04/background-from-maine-on-most.html

Rhett KB4HG -- TW-100! Used on the OMRN. https://soldersmoke.blogspot.com/2026/05/the-tw-100-fly-away-transceiver-cw-ssb.html

What happened to Glenn KU4NO's homebrew rig? https://soldersmoke.blogspot.com/2018/07/a-rig-with-maximum-soul-5-band.html

Ryan KJ7KVD is listening to OLD SolderSmoke podcasts.  He will build a Michigan Mighty Mite. 

Will N5OLA restored a Heath SB rig.  We now know why they went to HW rigs.   https://www.youtube.com/watch?v=Bt2d1Ia8lqQ 

Paul G0OER -- Thanks us for PTOing the HB world, but sends us a video of a unique Eddystone receiver with 39 permeability tuned coils!  https://www.youtube.com/shorts/L4oQHU5_kQk?feature=share

Rick N3FJZ -- A very cool video today on his homebrew HF power amplifiers:  https://www.youtube.com/watch?v=-CUVAF4HyfY

Farhan VU2ESE -- I heard from him yesterday as he was landing in Chicago. 

A Very Impressive Workshop from the UK

This one is almost scary.  There is an amazing number of machines crammed into that workshop.  There is even more stuff in the drawers down below.  Honestly, I sometimes thought that we radio homebrewers would be the worst offenders in this regard, but I see here that most of us are not even close.  This guy wins!  

At the end, at about the 24 minute mark, he demonstrates the use of a "scissor table" that can be used to bring the item he is working on to the needed height.  That is pretty cool, and would be quite useful for those working on really heavy gear -- think DX-100s or R-390As.  I have heard of hams installing small cranes in their shacks to move these heavy boatanchors around (they do seem to get heavier with time!).  The scissor table would take care of this.  

After showing the scissor table, he hits a button and an empty work table top drops from the ceiling to cover the scissor table.  Very cool.  Very useful.  

One note of caution.  I found myself worried about all those propane torches that he seemed to have stashed in odd corners of the workshop.  I would be worried about the danger of fire.  It might be wise to add a fire suppression sytem to the impressive inventory of gear in that shed.  

Sorry for that nanny-state suggestion.  That said, this workshop is magnificent.  Three cheers for the owner.  

WA4CHQ -- A Virginian QRPer and Homebrewer

    

This guy had a Drake 2-B,  Heathkit DX-35 with VF-1, and an FT-101EE.   He builds homebrew rigs.  He sailed from England to Virginia on a reproduction of a 1607 ship. 

He notes that Wes W7ZOI was and is his mentor. FB OM.  

Check out his QRZ page:  https://www.qrz.com/db/WA4CHQ 

Radio Receivers -- 1942 Training Film -- Crystal Sets to Superhets

This 17 minute film provides a good but simplified description of the state of the art at the start of World War II. 

--  The description of how a signal gets to the input coil of a receiver is quite good.  Imagine if that coil had no good ground, and no counterpoise.  We see the importance of the counterpoise in this video: https://soldersmoke.blogspot.com/2023/03/an-antenna-for-high-school-direct.html

-- I like the repeated demonstration of the reality of envelope detection.  Too often people have bought into the idea that envelope detection is not real, and that some form of mixing using the carrier in lieu of the local oscillator is what is really happening.  That is just not true.  Envelope detection as described in this film is real. 

-- The description of mixing is very simplistic.  They describe the generation of the difference product, but not the sum.  But hey, the film is only 17 minutes long!  It takes a lot longer than that to fully describe mixing (ask me how I know!).  

-- At the very end, there is a shout-out to the BC-348.  FB. 

The TW-100 "Fly Away Transceiver" --- A CW-SSB Rig I Never Heard of Until Today

I was listening to the Old Military Radio Net this morning.  Rhett KB4HG checked in on Upper Sideband.  He was using a loaner TransWorld TW-100 "Fly Away" CW-SSB transceiver.   I had never heard of this rig.  It is very interesting.  See the W7UUU YouTube video above for more details. 

OM John W3JN called into the net and commented on Rhett's rig.  John noted that the State Department had sold at auction a number of these rigs.  John reported that the ROM had been removed from MOST of these rigs.  But one of them still had the memory.  This allowed all the other TW-100s to be put back on the air.  FB.  

BTW:  W7UUU has a very FB YouTube channel.  Check it out: 

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

The Agony of Troubleshooting -- Shielding, Bypassing, Testing, Throwing Things at the Wall

This might not seem like it has a lot to do with homebrew radio, but I had it playing as I was going through a similar level of agony with a recalcitrant NE602 frequency readout.   I found it reassuring that I was not alone in my agony. 

We see a lot of applicable stuff in this video.  Note how he tries to suppress some toublesome noise using electrolytics, resistors, and ceramic caps.  He thinks he has the problem solved, until he loads the entire thing in the case, at which point the problem returns.  Sound familiar?  Indeed, he found that inside the case an unshielded cable ended up too close to a noise-carrying wire. 

He also comments on the need to do a full system check before flight.  Good point.   

It will be cool to watch the video that this device is built to capture.  Stay tuned. 

Homebrew Cylindrical Variable Capacitors: What the Steering Wheels are Controlling in Danny's Regen Receiver

Grayson KJ7UM asked a very good question about Danny ON1MWS's regen receiver:  What were those two very cool "steering wheels" actually controlling?.  

Perhaps because of our recent experience with Permeability Tuned Oscillators, I kind of assumed that we were talking about some form of variable inductor.  But no, I was wrong.  They are for homebrew variable capacitors.  That just makes it a lot cooler.  

Danny explains: 

Dear Grayson,

Tnx for the compliments. I used to build normal square boxes while I was a mechanic in a light advertisement factory. We had a one hour lunch break and were allowed to work for ourselves during the break. But I left that firm in 2019, as a consequence I had to find a way to build rigs without custom square boxes… the result is wood, tin cans of all sorts and a simple ground plate. After posting my CW rig on the FB group ‘the art HAM radio homebrew’ in 2023, Steve Fabricant noted ‘It could be a radiosonde that they sent down from a saucer to detect intelligent life, and failed.’ LOL, I found that very funny actually. 

 

As for your question, all of my homebrew tuning capacitors have a shaft made off a M8 (about 8mm) threatened rod. The rod turns through a steel girder bracket. I am not sure how these things are called in English, but they are easy to find on the net and very cheap. The rod is the ‘ground’ of the capacitor. The ground plate is clearly visible in the pictures of the solid state regen and the ground plate is hidden under the wood in the tube regen. In the case of the tube regen, the left tube has an inner diameter of 10mm and the right one about 13mm. The right one is coarse and the left one fine tuning. Not sure about the capacitance. 30pF at most I think. The tube regen tunes from 7 to 7.25 Mhz so that's ok.

As you turn the rod the rod will shift in or out the metal tube. The tube is obviously the ‘hot’ side of the capacitor. The M8 rod moves 1.25mm for one turn of the rod. If memory serves me right the tube is 80mm for the tube regen, so we have a tuning gear reduction of 80/1.25= 64. The hot side is connected to the main tuning coil to create a tank circuit.

I did try different designs before but this is the best one. The tube/treaded rod capacitor is just as good as a commercial one. One thing I learned is that any friction must be avoided in a homebrew capacitor or it is useless in practice.

I am going to try to build a similar 400pF version for a homebrew crystal set as I wrote to Bill. It will be huge I guess.. I think I will need a 2”tube… But my current homebrew projects are insulating our house better as our natural gas prices are rising.

Like the way you call tubes Thermatrons. Yes, sound much cooler and more fitting for these beautiful devices. My ultimate aim is building a one band thermatron SSB exiter. No time for the moment.

Kind regards Danny.

This technique could prove very useful in homebrew projects.  We found it very difficult to source suitable variable capacitors for our direct conversion receiver.  That is why we went with the PTO circuit.  But this technique makes it possible to actually homebrew the capacitors.  FB Danny.  

Thanks Danny.  Thanks Grayson.

Other Workshops: Homebrew Sailboats

In the Dominican Republic I sometimes find myself wanting to take sailing lessons on Juanillo Beach.  Maybe next winter. I've also been following the far more sophisticated wooden boat-building effort of Leo Sampson and the Tally Ho.  All of this helps explain why I watched this video.  And a big part of this is simply an interest in "other kinds of homebrew workshops."  

There is some practical advice for us:  The importance of pilot holes.  The fact that Philip head screws sometimes break (who knew?). 

Check it out.  Thanks to Hack-A-Day for alerting us to this.  And thanks to the Cumberland Rover guy. 

Don KM4UDX Talks about Homebrewing and the Vienna Wireless Society on Red Summit Video-cast with Charlie NJ7V

It was a really nice surprise to see Don KM4UDX on the Red Summit Video-cast with Charlie NJ7V. Don talked about homebrewing and the Vienna Wireless Society (he is the current President of the club). 

Check it out: https://www.youtube.com/watch?v=uAIcltCbF0c

Thanks Don.  Thanks Charlie.