Serving the worldwide community of radio-electronic homebrewers. Providing blog support to the SolderSmoke podcast: http://soldersmoke.com
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Thursday, September 17, 2026
Grayson Evans' Modest Proposal: NO MORE VALVES! NO MORE TUBES! THERMATRONS FOREVER! (and a great video)
Friday, July 24, 2026
A Homebrew X-Ray Machine from North Macedonia
It has been a long time since we saw anything like the X-ray machine described in CL Stong's classic book "The Amateur Scientist." Here are some other SolderSmoke blog posts about this (and related) stuff: https://soldersmoke.blogspot.com/search?q=X-Ray
This one comes to us from the fertile workshop of Mikel Pavleski in North Macedonia. We have covered his work before.
This device is built around an old DY-86 tube from an old black and white TV. Mikel describes a very simple test to determine if these tubes have leaked, or if they still have good vacuum.
Mikel uses a really scary high voltage power supply.
I like the FN-RISI radiation detector. Want one!
Note that Mikel used a remote turn-on when using this machine. I hope there are no people in the apartment next door! He does use a lead shield, but only on three of the four sides.
The use of dental X-Ray film was really cool. The development of this film in Mikel's lab reminded me of my developing of 35 mm film in a dark room I had set up in our downstairs bathroom. I couldn't afford an enlarger.
Mikel warns that you should not try this at home! Good advice!
Thanks to Mikel, and to Hack-A-Day for alerting us to this project.
Friday, May 29, 2026
A Quick Review of "Open Circuits" by Eric Schlaepfer and Windell H. Oskay
Highlights from the SolderSmoke perspective:
Page 34 Glass Capacitors. Phil W1PJE left me some.
Page 48 Ferrite Beads. Underrated. People often don't think they will work.
Page 66 Glass-Encapsulated Diodes. Yes, 1N4148's in our Direct Conversion Receiver.
Page 70 2N2222. In a metal can.
Page 72 2N3904. We use them so often.
Page 90 Color LEDs. The Green Hornet beacon in Cap Cana, Dominican Republic.
Page 116 Electromagnetic Relay. We use them a lot.
Page 142 DIP sockets I recently struggled with them with my NE602 chips.
Page 182 12AX7. Thermatron!
Page 186 Cathode Ray Tube. I have some. CuriousMarc recently fixed one.
Page 190 Mercury Tilt Switch. I had one as a kid. You can change a reflector to a director.
Page 196 Dipped Silver Mica Capacitor. We use them. A lot. Sometimes as NP0 caps.
Page 198 IF transformer. S-38E. HQ-100.
Page 206 - 207 Point Contact Diode and Germanium Diodes. Crystal radios. Great fun.
Page 210 Windowed EPROM. Was this the Rom chip in the TW-100s?
Page 212 Core Memory. Rope! As used in the Apollo spacecraft.
Page 228 Single-Side Printed Circuit Boards. Almost (but not quite) Manhattan.
Page 238 MicroSD Card. I have one in my Drone.
Page 262 Crystal Oscillator. TCXO? In a can? As in Dean's WSPR transmitter?
What do you guys think?
Wednesday, May 27, 2026
Eric KK6GZM of CuriousMarc is the Author of Open Circuits
NOTE: Our friend Walter KA4KXX checked and found that indeed, Eric is a ham! He is KK6GZM. FB!
Here is what Gemini has to say about this:
On the CuriousMarc YouTube channel, Eric is Eric Schlaepfer, a highly skilled hardware engineer and hardware reverse-engineering expert who frequently collaborates on the channel's most complex vintage electronics restorations.
Online and on social media, he is widely known by his handle, TubeTime (@TubeTimeUS).
When Marc and the team hit an incredibly stubborn digital or silicon-level roadblock, Eric is often the "reinforcement" they call in.
A few things he is best known for on the channel and in the broader electronics community include:
Deep-Dive Troubleshooting: He famously helped Marc debug a dead IBM PS/2 Model 77 computer by hookup up a logic analyzer and using Ghidra software to reverse-engineer the custom BIOS down to the binary level, successfully tracking down a deeply hidden motherboard ASIC failure.
The Open Circuits Book: Eric co-authored the popular book Open Circuits: The Inner Beauty of Electronic Components (with Windell Oskay of Evil Mad Scientist Laboratories).
On CuriousMarc, he has featured cross-section videos where he literally slices electronic components—like old resistors, capacitors, and ICs—perfectly in half and polishes them to reveal their intricate internal engineering under a microscope. The MOnSter6502: Outside of the channel, he is famous in the retro-computing world for designing and building a fully functional, giant-sized MOS 6502 processor made entirely out of thousands of discrete, individual transistors and surface-mount LEDs so you can visually watch the data flow through the registers.
Whenever Eric shows up in the lab next to Marc, Carl Claunch, and Ken Shirriff, you know the video is about to dive deep into microscopic component analysis, logic analysis, or advanced circuit reverse-engineering.
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Here is the CuriousMarc video about the bad French resistor:
https://www.youtube.com/watch?v=z2UXwW55kAI
Here is the cover of the book:
Tuesday, March 31, 2026
Tracy Kidder, author of Soul of the New Machine, dies at age 80
Thursday, December 4, 2025
Jim Williams -- Analog Man -- Book Review: "Analog Circuit Design -- Art, Science, and Personalities"
Saturday, November 1, 2025
Another GREAT Book -- L.B. Cebik, W4RNL's "Seven Steps to Designing your Own Ham Equipment" - 1979 - FREE!
Thanks to Walter KA4KXX for alerting us to this gem of a book. L.B. Cebik is best known as an antenna guru. I did not know that he also did a book on the homebrewing of rigs.
Here is the URL: https://archive.org/details/sevenstepstodesi0000cebi/page/n2/mode/1up Just click on the "borrow" box and you can look at the whole thing. Thanks too to the Internet Archive for preserving this important piece of ham literature.
I was a bit apprehensive when I saw "designing" in the title. We have talked about how, all too often, modern hams seem to challenge the homebrew nature of our rigs by asking if we had "designed" it ourself. "Well," I answer, "I did not invent the Colpitts oscillator, nor the common emitter amplifier, nor the superheterodyne receiver... But I did build this rig myself." I worried that OM Cebik might have been plunging us into this design debate way back in 1979.
But no need for worry. His definition of "design" is quite expansive:
Thanks again Walter.
Thursday, October 30, 2025
"Troubleshooting Analog Circuits" by Bob Pease
Get this book: https://www.amazon.com/Troubleshooting-Analog-Circuits-Design-Engineers/dp/0750694998
Tuesday, October 14, 2025
Radio Shack, Mixers, Terman
Wednesday, May 21, 2025
Grayson Evans KJ7UM Interview at Four Days in May at the Dayton Hamvention 2025
Tuesday, May 13, 2025
On the importance of taking a break.
Thomas K4SWL has a good post about the importance of taking a break from radio. Following up on this, I noted that "taking a break" is often a good way of finding a solution to a difficult problem. I noted that I have confirmed this -- it has worked for me. Pete Juliano N6QW recently announced that he is taking a break from the MHST project. That is a good idea. A solution will likely emerge.
I noted that there is some evidence backing up our suspicion about the benefits of breaks. I earlier shared some comments from Harry Cliff's excellent book, "How to make an Apple Pie from Scratch."
https://soldersmoke.blogspot.com/2024/04/cloud-chamber-finale.html
Harry also wrote about the usefullness of taking breaks. In 1917 Ernest Rutherford was having trouble understanding the presence of some hydrogen nuclei. Harry writes:
"Again, he was forced to put his work on hiatus to go on a mission to the United States in the summer of 1917, but it turned out to be one of those useful breaks when stepping away from a problem lets your mind slowly work out the problem in the background. When Rutherford got back to the lab in September he had the answer..."
There are many other examples.
So, if you get stuck, take a break!
Monday, September 16, 2024
"QRP Classics" The Book that Got Me Started in Homebrew
A question this morning from Scott KQ4AOP caused me to Google this old book On page 59 I found the article about my first transmitter. Someone has put a copy of the entire book on the interenet. Here it is:
Monday, February 5, 2024
"The Soul of a New Machine" -- Re-reading the Classic Book by Tracy Kidder
This book is especially important to the SolderSmoke community because its title has led to one of the most important concepts in our community and our lexicon: That we put "soul" in our new machines when we build them ourselves, when we make use of parts or circuits given to us by friends, or when we make use of parts (often older parts) in new applications. All of these things (and more) can be seen as adding "soul" to our new machines. With this in mind I pulled my copy of Tracy Kidder's book off my shelf and gave it a second read. Here are my notes:
-- On reading this book a second time, I found it kind of disappointing. This time, the protagonist Tom West does not seem like a great person nor a great leader. He seems to sit in his office, brood a lot, and be quite rude and cold to his subordinate engineers. Also, the book deals with a lot of the ordinary stupid minutia of organizational life: budgets, inter-office rivalry, office supplies, broken air conditioners. This all seemed interesting when I read this as a youngster. But having had bosses like West, and having lived through the boring minutia of organizational life, on re-reading the book I didn't find it interesting or uplifting.
-- The young engineers in the book seem to be easily manipulated by the company: They are cajoled into "signing up" for a dubious project, and to work long (unpaid) hours on a project that the company could cancel at any moment. They weren't promised stock options or raises; they were told that their reward might be the opportunity to do it all again. Oh joy. This may explain why West and Data General decided to hire new engineers straight our of college: only inexperienced youngsters would be foolish enough to do this. At one point someone finds the pay stub of a technician. The techs got paid overtime (the engineers did not), so the techs were making more money than the engineers (the company hid this fact from the engineers). The young engineer who quit probably made the right move.
-- The engineers use the word "kludge" a lot. Kidder picks up this term. (I'm guessing with the computer-land pronunciation that sounds like stooge.) They didn't want to build a kludge. There is one quote from West's office wall that I agree with: "Not everything worth doing is worth doing well." In other words, don't let the perfect be the enemy of the good. Sometimes a kludge will do.
-- Ham radio is mentioned. One of Wests lead subordinates was a ham as a kid. Kidder correctly connects this to the man having had a lonely childhood. Heathkit is also mentioned once, sarcastically.
-- The goal itself seems to be unworthy of all the effort: They are striving to build a 32 bit computer. But 32 bit machines were already on the market. The "New Machine" wasn't really new.
-- Kidder does an admirable job in describing the innards of the computer, but even as early as the 1978 models, I see these machines as being beyond human understanding. The book notes that there is only one engineer on the hardware team who has a grasp of all of the hardware. The software was probably even more inscrutable.
-- I found one thing that seemed to be a foreshadowing of the uBITX. The micro code team on this project maintained a log book of their instructions. They called it the UINSTR. The Micro Instruction Set. Kidder or the Microkids should have used a lower-case u.
-- The troubleshooting stories are interesting. But imagine the difficulties of putting the de-bugging effort in the hands of new college graduates with very little experience. I guess you can learn logic design in school, but troubleshooting and de-bugging seem to require real-world experience. We see this when they find a bug that turns out to be the result of a loose extender card -- a visiting VP jiggled the extender and the bug disappeared.
-- Kidder provides some insightful comments about engineers. For example: "Engineering is not necessarily a drab, drab world, but you do often sense that engineering teams aspire to a drab uniformity." I think we often see this in technical writing. Kidder also talks about the engineer's view of the world: He sees it as being very "binary," with only right or wrong answers to any technical question. He says that engineers seem to believe that any disagreement on technical issues can be resolved by simply finding the correct answer. Once that is found, the previously disagreeing engineers seem to think they should be able to proceed "with no enmity." Of course, in the real world things are not quite so binary.
-- This book won the Pulitzer prize, and there is no doubt about Kidder being a truly great writer, but in retrospect I don't think this is his best book. This may be due to weaknesses and shortcomings of the protagonist. I think that affects the whole book. In later books Kidder's protagonists are much better people, and the books are much better as a result: for example, Dr. Paul Farmer in Kidder's book Mountains Beyond Mountains.
-- Most of us read this book when we were younger. It is worth looking at again, just to see how much your attitudes change with time. It is important to remember that Tracy Kidder wrote this book when he was young -- I wonder how he would see the Data General project now.
-----------------------
Here is a book review from the New York Times in 1981:
https://archive.nytimes.com/www.nytimes.com/books/99/01/03/specials/kidder-soul.html?CachedAug
Here's one about a fellow who also re-read the book and who provides a lot of good links:
https://auxiliarymemory.com/2017/01/06/rereading-the-soul-of-a-new-machine-by-tracy-kidder/
Saturday, January 20, 2024
K0IYE's Thoughts on Homebrewing and Workshops
I like Frank Harris K0IYE's book so much that I don't mind posting about it frequently. "From Crystal Sets to Sideband" is must-read material for all homebrewers.
The picture above is especially significant. I first came across it in the old pulp-style magazine called World Radio. The picture, like Frank's book, is truly inspiring.
This week I stumbled across a relatively new chapter in Frank's book. Chapter 3A deals with his approach to homebrewing (Luddite, analog, HDR) and his advice on how to set up a home ham-radio workshop. There is a lot of wisdom in this chapter.
The opening paragraph of Chapter 3A really grabbed me. Check it out here. Click on the text below for a better view:
Sunday, December 17, 2023
Make Your Own SDR Software! And, "Analog Man" by Joe Walsh of the Eagles (WB6ACU)
Friday, November 24, 2023
A FREE Book from the Early Days of Ham Projects with Transistors: The CK722 -- The Device that Got Pete Juliano Started in Homebrew
You can get the book for free here:
We are really lucky to have Pete Juliano sharing his vast tribal knowledge with us.
Friday, November 10, 2023
SolderSmoke Podcast #249 -- Travel, Pete's 6BA6 rig, Books!, VFOs, SDR, Computers, Spectrum Analysers, Transistor Man! MAILBAG
Bill's DXCC-100. DONE.
Tribal Wisdom: W1REX on HRWB https://soldersmoke.blogspot.com/2023/11/listen-to-rex-w1rex-lots-of-tribal.html
Pete's Bench:
Pete's 6BA6 rig
Pete Re-invents the Shirt-pocket SSB Rig
BEZOS BUCKS ARE BACK! PLEASE BUY THERE! >>>>>>>>>>>>>>>>>>>>>>>
Mostly DIY RF: Work proceeds in the Oregon Silicon Forest on P3ST kit development. Todd is confident the P3ST will be released on December 18th.Many other kits available now: https://mostlydiyrf.com/
Sign up for the newsletter: https://mostlydiyrf.com/subscribe/
Rebuild of the 15-10 VFO (for improved Dial Spread) (with yet another QF-1 capacitor) https://soldersmoke.blogspot.com/2023/10/dial-scale-linearity-spreading-out.html
Why Building for 10 meters is harder: https://soldersmoke.blogspot.com/2023/09/why-building-for-10-meters-is-harder.html
Copper Tape shielding of 15-10 rig.
Crushing Spurs with Better Bandpass Filters (see blog post) https://soldersmoke.blogspot.com/2023/09/crushing-17-and-12-meter-spurs-with.html
Another 15-10 rig in the works... for SSSS. Boards are accumulating...
More problems discovered with the Herring Aid 5 Receiver . Lots of SS blog posts Comment from Rick WD5L. ) https://soldersmoke.blogspot.com/2023/10/a-big-error-discovered-in-1976-qst.html Did you try to build one? Did you succeed or did you fail? Please let us know.
The Basil Mahon books (blog posts) https://soldersmoke.blogspot.com/2023/11/basil-mahon-is-author-for-us-he.html
The Sunburst and Luminary book of Don Eyles (blog posts)
The Art of Electronics by Horowitz and Hill (blog posts)
Spectrum Analysers: Tiny SA Ultra https://soldersmoke.blogspot.com/2023/09/the-tinysa-ultra-spectrum-analyser-video.html and Polarad 632C-1; George WB5OYP gave me one of these spectrum analysers (I NEED a manual! Does anyone have a manual or a schematic? ) :
Stabilizing the EB63A (with Pete recommended LP filters from e-Bay.
MAILBAG:
TRANSISTOR MAN T-SHIRTS! Thanks to Roy WN3F!
Todd VE7BPO on AF amplifiers. Thanks Todd.
Wes W7ZOI -- Always a privilege to exchange e-mail with Wes.
E-mail from Jay Rusgrove W1VD. About the Herring Aid 5.
E-mail from Eamon Skelton EI9GQ! Amazing!
HB2HB with Denny VU2DGR https://soldersmoke.blogspot.com/2023/09/hb2hb-contact-with-denny-vu2dgr.html
Nick M0NTV on diode matching for ring mixers: https://soldersmoke.blogspot.com/2023/10/does-matching-matter-diode-matching-for.html
Paul Taylor VK3HN on the new Elecraft CW rig.
Dean KK4DAS fixed the noise in his Hallicrafters SW receiver. A long battle, finally won.
Dean also in contact with G3UUR.
Ramakrishnan VU2JXN helping me set up a backup of blog on WordPress.
Mark KA9OOI noticed that SS podcast archive appears gone. In fact just temporarily relocated to http://soldersmoke.com/
(SS PODCAST Archive temporarily relocated to http://soldersmoke.com/
Andreas DL1AJG - Crystal radio video. https://soldersmoke.blogspot.com/2023/10/building-crystal-set-videos.html
George N2APB on the Herring Aid 5
Grayson KJ7UM experimenting with Varactors and Thermatrons!
Thomas K4SWL on Mattia's DC receiver. https://soldersmoke.blogspot.com/2023/10/mattia-zamanas-amazing-direct.html
Bob Weaver of Dial Bandspread Linearity fame. Electron Bunker
Mike Bryce WB8VGE QRP Hall of famer -- he too couldn't get the Herring Aid 5 working.
Kirk NT0Z wrote about the Wayback machine. But this former ARRL staffer he also tried and failed to get the Herring Aid 5 going. Way back when... https://soldersmoke.blogspot.com/2015/03/kirks-herring-aid-tuna-tin-and-regen.html
Wednesday, November 1, 2023
Basil Mahon is an Author for Us -- He explains Faraday, Maxwell, and Heaviside
PERSONAL:
Born May 26, 1937, in Malta; married Ann Hardwick (a teacher of chemistry), April 1, 1961; children: Tim, Sara, Danny. Education: Attended Royal Military Academy, Sandhurst, 1955-57; Royal Military College of Science, B.Sc., 1960; Birkbeck College, London, M.Sc., 1971.
British Army, career officer, serving with Royal Electrical and Mechanical Engineers in Germany, Aden, and United Kingdom, 1955-74, retiring as major; Government Statistical Office, civil servant, 1974-96. Consultant and trainer on censuses and statistics, including work for clients in Russia, Estonia, Croatia, and Republic of Georgia.
From the Netherlands, Manu Joseph explains why he loves Mahon and Forbes' book on Faraday and Maxwell:

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