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. 

Heathkits and American Industrial Decline

This is an interesting video about the rise and fall of the Heathkit company, and how that company affected the rise and fall of American manufacturing.  

The Heathkit history is interesting, but I disagree about the extent to which building a Heathkit led to an increase in technical knowledge.  I guess it could, but Heath was famous for making kits that could be built by people who knew nothing about electronics.  Even when many of them were done assembling the kit, most still "knew nothing" about electronics.  Just look at those color TV kits:  Did assembling one of those kits mean that you came to understand TV?  I don't think so. 

I'm looking at my HW-101 manual.  It is 199 pages long.  It is mostly instructions on which part should be soldered where. There is a section called "Circuit Description" but it is only 19 pages long and is at the end of the book.  You could assemble the whole thing without ever reading the descriptions of the circuit.  I suspect that this is what usually happened. 

As for the fall of Heathkit, I think the video is closer to being correct.  But it puts too much blame on the advent of small surface mount parts.  That is, of course, part of it.  But another part of this has to do with the shift towards FPGA and CPU chips.  

Anyway, in spite of being AI produced, the video is worth watching.  I note that at the end, we see a prominent homebrewer in his shack.  Who is this guy?  

Thanks to Rogier PA1ZZ for sending this to me.   

UPDATE:  Mike WN2A reminded me of who that guy in the video was:  It was Greg, N8ZRY.  He has been on the SolderSmoke blog several times.  And here is his video showing his homebrew 20 meter transceiver: https://www.youtube.com/watch?v=R-k73b6ojyQ&t=21s  Ironically, Greg proves my point about the Heathkits and kits in general:  You just do not see a lot of Heath stuff in Greg's shack.  You do see a lot of homebrew stuff, and it is probably from this gear that he really learned a lot.   Thank you Mike, and thanks Greg! 

SolderSmoke Direct Conversion Receiver -- Total Receivers Built: 132 (124 plus 8 honorable mentions). Total Count: 132. Receivers built in 19 countries.

The Chuck Adams Build of the SolderSmoke DC RX

Please let us know if you spot any errors, or if we have inadvertently missed anyone.  Don't worry about being late to the game -- the challenge continues.  All of the info is still available. 

As of April 26, 2026 0855Z:

So far, total receivers built: 132 (124 plus 8 honorable mentions).  Total Count:  132.  Receivers built in 19 countries.   

NE3U (KY4EOD)  Matt 

KQ4AOP       First ham signals ever heard! 

N9TD             Derek

AC3NG          Ryan

VK3TPM       Peter Marks  

W4KAC         Ken 

W4KAC         Ken built a second one! 

N2EPE           Erik

VA3NCA        Wayde  (Canada)  

KI5SRY         Mark -- Gears on PTO screw

 

KA1MUQ       Frying pan receiver

AA1N              Adam

ZL1AUN         Aaron -- Using SSB transmitter -- (New Zealand)

W8UC             Never before homebrewed. 

VK4PG           Phil -- Nice case, "really pleased"

G7LQX           Working well, video of CW and SSB.  -- (England)

KE2AMP        John     Spring on PTO screw -- great

N9SZ              Steve  nice receiver

KD9NHZ        Piotr  Nice one

KE8ICE          Calvin, Very cool receiver. 

 

WV3V              Jayson!  Got it done!

GM5JDG         Martin.   -- (Scotland) 

KF8BOG          Jim:  A long struggle, but success.  

Chris Wales    Fantastic video.  -- (Wales)

YD9BAX         Wayan! Homebrew transformer!  (Indonesia)

N0NQD         Jeff 

WN3F              Roy -- Made new stickers! 

AB5XQ            Bill  

KB7ZUT          Andy  

AA1OF            Jer

VictorKees        Holland (Netherlands) 

KC9OJV           John -- Manhattan-style convert

WZ5M              1, 2 or maybe even 3 receivers!

K1KJW             Jim in Vermont

KC5DI              Dallas -- friend of WZ5M

Gary                 Australian -- Wooden PTO form (Australia) 

LU2VJM          Juan in Argentina  -- (Argentina)

K1OA               Scott "Most fun in 50 years"

KC9DLM         Ben -- Had EFHW problems

PH2LB             Lex  Yellow, Glue Stick -- (Netherlands)

AI6WR             David

G6GEV            Dave (It was a blast!)  (England)  

KC1ONM        Wayne  MakerLabs NH

KB1OIQ          Andy    MakerLabs NH

KA1PQK         Jay       MakerLabs NH

W1TKO           Mike    MakerLabs NH

K5KHK            Karl

SM0TPW         Mikael  -- (Sweden)

KI7LKB           Brian (coat hanger tube)

M6CRD            Chris  (England) 

W2DAB           Dave in NYC

W4JYK            Wes of VWS

KA4CDN          Mike of VWS

M7EFO             Adrian 

VK5RC             Rob  (Australia) 

KD8KHP          Dave

VK1CHW         Chris (Australia) 

KA0PHJ           Brian

W0IT                Louis

W1PJE             Phil

W2AEW           Alan

KN6FVK          John (Barkhausen-Be-Gone Spray) 

VU2JXN           Ramakrishnan -- (India)

AA0MS            Doug 

9V1/KM7ABZ   Paul  --  (Singapore)

VK2BLQ          Stephen -- (Australia)

N3FJZ              Rick

Daniel               VE5DLD  -- (Canada)

Student 1          Student of VE5DLD

Student 2          Student of VE5DLD

Student 3         Student of VE5DLD

K7WXW          Bill 

NK3H               Mitch

KN4ZXG         Ted

WA1MAC        Paul

N4AVC             Chuck 

K3IY                 Kevin

N6ASD             Ashish in Bangalore (India)

W1DSP             Rick

WD4CFN         Steve

KM5Z             Mike

KF5DAN         Dan

Fritz                 Fritz

N9OK              Joe

WA5DSS         Bill 

K0GDB           Grant

G0JNR            Shane Glow-in-Dark Coil Form

KK7BCO        Tobias

K2BVR            Bob

Robert              Sutton

K5YFO           Dave (Texas) 

KD4PBJ          Chris

KN4GAH        Chris -- EE perspective

F1GMA           Philippe  -- (France)

W2TEF            Todd

EI9ITB            Karl  -- (Ireland)

VU2TUM         Puneit Singh (India) 

AA7EE             Dave Richards

KI5VIR            Jay

CT7AXD       Graham -- Promoted from Honorable Mention! (Portugal)

G3MOT           Josh (England)

KW4H             Steve

NJ7V                Charlie (RedSummit)

N2ETZ            Denny

AB9LM           James

W9XT              Gary

G0PJT             Alex

KF8FZZ         Tyler

N7HPR           Steve (Instructor) (N7HPR Group)

Clark               (N7HPR Group)

KQ4ZHO        Kurt (N7HPR Group)

KQ4OBR        Brian (N7HPR Group)

KR4CUF         Justin (N7HPR Group)

Amanda          (N7HPR Group)

David               (N7HPR Group)

KM4AED       Jamey (N7HPR Group)

KN4MVH      Larry (N7HPR Group)

N5GVW          Dick (N7HPR Group)

W7KAL          Kal

KC9LFP         Joe

SP9DEL         Marian (Poland) 

LB8VA           Ivar (Norway)  

AA7FO          Chuck Adams! 

WE6Z            Doug

-------------------------

Honorable Mentions: 

*AA7U            Steve No PTO

*VK7IAN        Ian -- No Manhattan boards -- (Tasmania)

*KC1FSZ        Bruce's build on a PC board

* DL1AJG      Andreas -- (Germany)

* Matthew      Student of DL1AJG

* Arash           Student of DL1AJG 

*KA4KXX     Walter -- FB 20 Meter version

*M9KCA-ST2NH  Nader - LM386 in place of AF amp

Nader M9KCA-ST2NH's Beautiful Build of the SolderSmoke Direct Conversion Receiver: NO SMOKE!

 Nader wrote: 

Hello everyone! After more than 30 years, I've rebuilt the DCR again. I wanted to share the fun of the 40m SolderSmoke DCR Challenge with all of you. It was a fantastic project — fully documented, with many people sharing their experiences online. I'm truly delighted to show you my prototype. The best part? It ran from the very first power-up — no smoke, no tuning needed! Yes, all on one board. The audio amp isn't quite ready to challenge the role yet, but it's still a lot of fun.

Nader's Sudanese callsign rang a bell with me.  I had talked about him in SolderSmoke podcast #58 on May 13, 2007.  Here it is:  https://www.soldersmoke.com/soldersmoke58.mp3    And I included a long quote from him in the SolderSmoke -- Global Adventures book.  So Nader is an old friend indeed.  

He clearly built the receiver, with excellent results.  He used the innards of a glue stick to build the support for the PTO inductor.  But he has not yet built the three-transistor AF amplifier.  So, in the interim, I am placing him in the "Honorable Mention" category.  When he completes the AF amplifier, he will be promoted to full membership in the Hall of Fame. 

The REALLY BIG Dish: China's Sky Eye

The technology used is really interesting, as is the struggle to maintain a radio quiet zone around the telescope.  The limestone geology with lots of useful sinkholes was very helpful in selecting the site (we have similar geology in the Eastern part of the Dominican Republic).  The contrasts with Arecibo are also quite telling. 

Thanks to Rogier PA1ZZ for sending this. 

Dean KK4DAS and I Receive the G QRP G2NJ Trophy

This award means a lot to us.  It is for making "the greatest contrbution to international QRP."  Dean and I are both big fans of G QRP and of their journal, SPRAT.  (As we say on the SolderSmoke podcast, if you are not a member of G QRP and are not getting SPRAT, you are just WRONG.)  

This award is a real honor.  Thanks very much to G QRP, and especially to their chairman Steve Hartley, G0FUW.  

Mitch NK3H Talks Homebrewing with Charlie NJ7V of Red Summit RF

This is a really cool interview.  Both Mitch NK3H and Charlie NJ7V are members of the SolderSmoke Direct Conversion Receiver Hall of Fame.  Mitch has built a dual-band superhet rig, which is the subject of this interview: 

https://www.youtube.com/watch?v=wK_EVt5iAQ4

Here is a video Mitch did about his SolderSmoke DC receiver:  

https://soldersmoke.blogspot.com/2025/05/mitch-nk3hs-fb-soldersmoke-direct.html

Mitch also built the Michigan Mighty Mite.  And he did an SSB version! 

Mitch is a very interesting guy.  He was a professor,  he worked in biotech, founded his own company which was funded by venture capital, later retired, got interested in astronomy,  and came to ham radio at the start of the pandemic.  Wow, great stuff. 

In Charlie's video, Mitch provides a lot of good explanation of his experimentation process.  I had to chuckle when Mitch pointed out that he did NOT invent the Colpitts oscillator.  Good point Mitch!

Mitch credits Pete N6QW as one of the people who helped him design his superhet transceiver.  He also mentions Farhan VU2ESE, Alan Wolke W2AEW and several others.  FB.  And he credits SSDRA, EMRFD and ChatGPT.   Mitch also likes the videos of the IMSAI Guy.  

Mitch has already made 50 contacts with this rig. 

Mitch makes excellent use of microcontrollers and digital VFOs.  He provides great info on the speed and cost of various sources of commecial PC boards. 

Quote of the day from Mitch:  "Electrons don't care how pretty or ugly your board is!"

Mitch concludes with a quote from Pete N6QW: "You gotta know stuff to do stuff." But Mitch adds to this an important coda:  "But the process of doing it is the learning experience."  Exactly right Mitch.   
 

Thanks to Mitch and Charlie for a really great video:  https://www.youtube.com/watch?v=wK_EVt5iAQ4

Pete N6QW is our Shifu

In a comment to a recent post, Mike WN2A wrote: "N6QW is the Shifu.

( https://en.wikipedia.org/wiki/Shifu )"

I found this term intriguing.  I think we should consider including it in the SolderSmoke Lexicon.  Steve?  BTW, I agree on the designation of Pete N6QW as the Shifu. 

AI Overview

In the context of electronics, Shifu (师傅) generally refers to a skilled craftsman, technician, or master tradesperson, such as a master electrician, repair technician, or electronics expert. It is a Chinese term denoting respect for someone with high-level technical expertise in areas like welding, circuit design, or device repair.

Here is more info on the origin of the term and its useage: 

Thanks Mike!

Another 40 meter DSB Transceiver

 I like the homebrew spirit in this one, how it started out as a Direct Conversion receiver and expanded into a full double sideband transceiver.