This is part of our “Other Kinds of Workshops” series. Newt was a little Arduino-R/C robot built for a movie called “The Lightning Code,” which apparently has something to do with Nikola Tesla.
Thanks to Hack-A-Day for the heads up.
Author: William Meara
I admit it. I am not 100% homebrew. I hang my head in shame.
Walter KA4KXX and Mike WN2A and I were recently talking about the degree to which we are 100% homebrew. Both these guys come a lot closer to this goal than I do. Here is my assessment of my gear:
I fall far from a state of 100% homebrew grace:
— I use commercial power supplies. I justify this by saying that I could use batteries, and I wouldn’t build them.
— I use a D-104 with a Tug-8 amp in the base. I justify this by saying that I COULD homebrew a mic, but I’d just be using a commercial electret element.
— My .1 kW amplifier is from a CCI kit. I find it hard to homebrew 100 watt amplifiers that do not oscillate. Kits make this a bit easier.
— I use a K4KIO Hex beam. I had a homebrew MOXON, but that got destroyed by a Northeaster. And I have to limit trips up to the roof. Like to zero. (I ask the gutter guy to do this.)
— I have a DX-100 and an HQ-100 that I use to check into the Old Military Radio Net on Saturday morning. I had a DX-100 as a kid, and John Zaruba K2ZA later gave me his dad’s DX-100. That is the one I use. I picked up the Hammarlund HQ-100 in the Dominican Republic in 1993 and have been repairing it ever since. It is not a great receiver, but it looks good atop the DX-100 and I have a sentimental attachment.
— I have an HT-37 and a Drake 2-B that I have had since I was 14 years old. I have a strong sentimental attachment to this gear. I have worked on most of this old stuff.
The three SSB dual banders that I am running are mostly homebrew. The Mythbuster uses a VFO out of the Yaesu FT-101. The 17/12 rig has an LM386 AF Amp. The 15/10 rig has an SBL-1.
I will try to increase my HB percentage.
“Unlocking the secrets of the heavens with a tool fashioned by one’s own hand.”
Click on the image for a clearer view.
This quote is obviously about telescopes, but I think in many ways it applies to homebrew radio. We sometimes use the term “first light” to describe the first signals heard through a new homebrew receiver. That term comes from astronomy, and is used to describe the first light seen through a new telescope. I think there are strong parallels with homebrew radio.
John KN6FVK’s FB Homebrew SolderSmoke Direct Conversion Receiver — Crickets Killed with Barkhausen-Be-Gone Spray!
I went to bed worrying about this one. John KN6FVK had been having a lot of problems. He had repeatedly reported hearing nothing (crickets!) when he fired up the receiver. Members of the Discord group had provided a lot of coaching, but still, CRICKETS! John had a good sense of humor. When I pointed out that oscillations in the AF amp are caused by a feedback path that meets “the Barkhausen criteria” John said he went to Lowes and bought a spray can of Barkhausen-Be-Gone. It seems to have worked. Actually I think John put some additional capacitance on the DC rail of the AF amp. In any case, he was going to wait for the evening for test out the fixed receiver. The time difference with California meant that I went to bed with fingers crossed. Happily the BBG spray and (more likely) the extra capacitance worked. John sent us some really nice videos of his receiver in action. I really like the inscriptions on his pine board. This should become “a thing.”
John writes:
I‘m very ok now…. — sigh / smile — THANK YOU ALL for your help and patience. As painful as this was, it was a lot of fun and I learned a lot. After I build an actual work bench, I might try this again (looks are important). But I’m definitely going to start playing with it and learning from it. On to Mods and Upgrades! Need to learn-up on this “Barkhausen” silliness too. -73
Here is John’s receiver pulling in CW (WB6CGJ):
Congratulations John, Welcome to the Hall of Fame.
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Documentation on Hackaday:
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Alan Wolke W2AEW’s FB Homebrew SolderSmoke Direct Conversion Receiver
It is really and honor to have Alan Wolke W2AEW build one of our receivers. Alan is a true wizard. Armed with an amazingly popular YouTube channel, he has taught electronics and ham radio to thousands of grateful viewers worldwide. A Field RF Application Engineer for Tektronix, Alan has a special knack for showing us how to get the most out of our test gear.
So many times have I gone back to videos that Alan made years ago, just in an effort to refresh my memory on the insights that he shared. For example, it was from him that we learned how the diode ring mixer really works — what it really means to say that this mixer multiplies signals by 1 and -1. Alan even showed us how to get our ‘scopes to display the multiplication. This was all very cool and very typical of Alan’s work. His videos have been an important reference for this direct conversion receiver effort.
On this project, Alan dug into his junk box, only to discover to his dismay that he didn’t have the AF transformer that we recommended. I am sure that Alan could have whipped up several alternative circuits that did not require the transformer, but he wanted to build the receiver the way we recommended, so a slight delay took place while Mouser filled his order.
Alan did build the circut modularly, stage-by-stage, using the Manhattan method, but he admits to giving in to his temptation to use a very small board. This may be the most compact of our 60+ DC receivers. In an encouraging reminder that even the great ones worry about unwanted feedback, Alan writes:
Why am I always compelled to build as compactly as possible? I hope feedback doesn’t bite me in the butt!
Thank you Alan! And welcome to the Hall of Fame!
(This picture was created by displaying NTSC video from my digital camera on Alan’s old Tektronix 485 oscilloscope using a simple converter circuit that is described in a video on my YouTube page)
QR code for his YouTube site
X Y Screen
On the SolderSmoke Blog there are 41 posts tagged with “Wolke–Alan”:
Alan’s QRZ page:
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Documentation on Hackaday:
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Phil W1PJE’s Amazing MIT SolderSmoke Direct Conversion Receiver
We are really pleased to see that Phil W1PJE has completed his direct conversion receiver and has thus joined the Hall of Fame. Congratulations Phil.
We are shamelessly calling this the “MIT receiver.” But the truth is that Phil’s job at MIT was not part of this project, and in fact distracted him from his radio building efforts. There was, however, one moment in which Phil had sent us a video of his receiver in progress. There was some audible fan noise in the background. Phil apologized, noting that the noise came from a nearby receiver that monitors upper atmosphere winds using meteors. Now that, my friends, is some cool MIT stuff.
Phil writes:
Hi Bill and Dean,
After a long hiatus (and a restrung antenna), I’m happy to report the Soldersmoke DC receiver is finally done and working well. The relatively long video above shows a tour from CW to SSB to AM to digital telemetry to time signal (CHU at 7.850 MHz). A bonus frequency counter was included to show the viewers where I was in the band. It’s not pretty but it works. I need to slow down the tuning but that is a future job. Sorry for the serious wobbly attempts to zero beat the AM carriers but I can fix that later… hmm.
Thanks for the fun and reminding me of a time when I was an undergrad at the EE bench. Modifications are next when I can find a few minutes.
73
Phil W1PJE
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The Hall of Fame: 71 Direct Conversion Receivers Completed (so far) with 7 Honorable Mentions. More coming. Update.
Dean KK4DAS’s Receiver
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 (see below).
As of May 19, 2025 1717Z:
So far 71 completed receivers, with 7 honorable mentions:
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
KI5SRY Mark — Gears on PTO screw
KA1MUQ Frying pan receiver
AA1N Adam
ZL1AUN Aaron — Using SSB transmitter
W8UC Never before homebrewed.
VK4PG Phil — Nice case, “really pleased”
G7LQX Working well, video of CW and SSB.
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.
KF8BOG Jim: A long struggle, but success.
Chris Wales Fantastic video.
YD9BAX Wayan! Homebrew transformer!
N0NQD Jeff
WN3F Roy — Made new stickers!
AB5XQ Bill
KB7ZUT Andy
AA1OF Jer
VictorKees Holland
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
LU2VJM Juan in Argentina
K1OA Scott “Most fun in 50 years”
KC9DLM Ben — Had EFHW problems
PH2LB Lex Yellow, Glue Stick
AI6WR David
G6GEV Dave (It was a blast!)
KC1ONM Wayne MakerLabs NH
KB1OIQ Andy MakerLabs NH
KA1PQK Jay MakerLabs NH
W1TKO Mike MakerLabs NH
K5KHK Karl
SM0TPW Mikael
KI7LKB Brian (coat hanger tube)
M6CRD Chris
W2DAB Dave in NYC
W4JYK Wes of VWS
KA4CDN Mike of VWS
M7EFO Adrian
VK5RC Rob
KD8KHP Dave
VK1CHW Chris
KA0PHJ Brian
W0IT Louis
W1PJE Phil
W2AEW Alan
KN6FVK John (Barkhausen-Be-Gone Spray)
VU2JXN Ramakrishnan
AA0MS Doug
9V1/KM7ABZ Paul in Singapore
VK2BLQ Stephen
N3FJZ Rick
Daniel VE5DLD
Student 1 Student of VE5DLD
Student 2 Student of VE5DLD
Student 3 Student of VE5DLD
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Honorable Mentions:
*AA7U Steve No PTO
*VK7IAN Ian — No Manhattan boards
*KC1FSZ Bruce’s build on a PC board
*CT7AXD Graham — different AF amp
* DL1AJG Andreas
* Student 1 Student of DL1AJG
* Student 2 Student of DL1AJG
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Candidates for the Hall of Fame:
SA5RJS Rasmus
KA9TII James
AA7FO Chuck
K7WXW Bill
VA3ZOT Tony Surface Mount — Honorable Mention?
KM5Z Mike Yancey
AB2XT John (Done, just need the video)
KO7M Jeff (Piper Cub)
KD4PBJ Chris
VU2TUM Puneit Singh
N6ASD Ashish in Bangalore
For more information on how you too can build the receiver:
Join the discussion – SolderSmoke Discord Server:
Documentation on Hackaday:
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SolderSmoke YouTube channel:
Louis W0IT Completes a Very Long-Term Goal and Finishes His Direct Conversion Receiver
Louis W0IT did what true homebrewers often have to do: he persevered in an effort to make his machine work. And he succeeded. Congratulations Louis. Welcome to the Hall of Fame.
Louis writes:
I rebuilt all the boards, new components except the band pass filter and the mica caps, all which looked to be working up to spec. I bought the squares as they are smaller than the ones I made and while harder in someways they kept the mess down. I bought some J310’s from Mouser and either the ones I had were less than optimal or I fixed something in the resolder. I ended up with 4 batches of those. They all tested different and the Mouser sourced ones had the lowest Vg (turn on voltage?) according to my 12$ tester at 1.65 V rather than 2.35 or 2.65 for the Amazon ones. The noise on it sounds almost identical to the noise on my Kenwood on the same antenna. Thanks Everyone. It’s part of a very long term goal.
A very nice post about ham radio in Thailand by Louis:
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Curiosity Rover on Mars as Seen from Orbit
The image was captured on February 28, 2025 by the orbiter’s HiRISE (High-Resolution Imaging Science Experiment) camera, and shows Curiosity’s movement over 11 drives starting at the beginning of that month. While a few weeks might seem like a long time for tire tracks to stick around in the dirt, this is normal for Mars. The tracks are “[l]ikely to last for months before being erased by wind,” NASA says. Curiosity is expected to reach its next science destination, which is home to formations thought to have been created long ago by groundwater, in the coming weeks.
Brian KA0PHJ’s CBLA SolderSmoke Direct Conversion Receiver
Brian KA0PHJ finished his receiver in early March, and has been adding mods ever since. He hopes to build another one for 80 meters and to use it with his Michigan Mighty Mite.
VIVA EL CBLA! VIVA!
Brian writes:
Bill,
I got my DCR finished in early march (built as designed), then added the RF gain, fine tune and frequency display.
Wow, what fun!!
Gave me an excuse to organize all my discrete components and finally buy a Rigol!
Now I plan to build one for 80m to go with the CBLA Michigan Mighty Might:)
Keep up with good work.
73,
Brian.
KA0PHJ
FB Brian! Congratulations!
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Building a Helio in Alaska from 75 year-old Blueprints
This video is part of our “Other Workshops” series. I like it because in the beginning it seems to have a Piper Cub vibe that reminded me of former SolderSmoke co-host Jeff Whitlatch KO7M. I also liked their discussion of how they did this with 75 year-old blue prints, how they brought the model into CAD, and how they used templates and other modern techniques to mas produce this plane. Also, it made me feel a lot better about frequently updating the schematic for our direct conversion receiver.
Chris VK1CHW’s FB SolderSmoke Direct Conversion Receiver — With A Very Innovative Homebrew PTO Coil Form
Chris VK1CHW sent us the above “proof of life” video. And alive it is! FB Chris. I especially liked the approach he took to the coil form for the PTO: He is getting a 3D printed one, but in the meantime he improvised with some electrical conduit and a bolt. Improvise satisfies! FB Chris. Congratulations and welcome to the Hall of Fame.
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Dave KD8KHP’s FB SolderSmoke Direct Conversion Receiver
Very cool build by Dave. That PTO coil form looks great. And the receiver sounds especially good on sideband. FB. Congratulations Dave!
Dave writes:
This was a fun build, and I learned something.
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Rob VK5RC’s FB SolderSmoke Direct Conversion Receiver. MDS?
Rob VK5RC has completed his SolderSmoke direct conversion receiver. Congratulations Rob. And it is good to know what we have a Medical Doctor among our builders — this adds prestige and expertise to the project.
Rob measures a Minimum Discernible Signal at -95 dbm. I think that is kind of weak performance. Much depends, of course, on how you define “descernible.” Some books say you need a 10 db increase in audio. Others say you just need to be able to tell there is a signal there. I have gone with the latter definition and have measured MDS of around -120 dbm. I wonder why there is such a difference in measured MDS.
In any case, it is great to see Rob’s receiver inhaling all of that great Australian SSB (see video above). Thanks Rob, and congratulations.
Adrian M7EFO’s FB SolderSmoke Direct Conversion Receiver
Adrian has completed a very FB direct conversion receiver. Really nice work. It is especially pleasing to see that Adrian is a member of GQRP. FB Adrian. SSB above, CW in the video below. I think that China Radio International signal would be a good early target for your tinkering and mods. We fought a similar battle against Radio Marti.
Adrian writes:
Did it!!! It Works.! Receives CW, SSB,FT8. Awesome. Thanks Bill. Thanks Dean. It was fun. Now for the tinkering and modifications.
CW too. As an added bonus it picks up China Radio International radio whether I like it or not.😄
Hello. I live in East Barnet a suburb of London, UK.
I work as an electronic technician and tech support for a small company.
My rig is a Xeigu G90 with a home made dipole cut for 20 metres and 40 metres and run QRP at 5-10 watts, 5 watts FT8, I’ll save the kilowatts for boiling the kettle! I’m using an old PC server power supply.
The shack computer is a Raspberry Pi3 Raspberry Pi400 (Stolen Borrowed from my daughter
). I am surprised at how well my set up works. Sometimes.
I am a member of the GQRP club and have started building some kits and homebrew in the Manhattan style.
Currently studying for my UK Intermediate licence with Bath Based Distance Learning.
The Copasteic Flow Blog — German UHF Mobile CW Through a Geostationary Satellite, Agent Sonya’s Homebrewing, More
It is always good to be reminded that someone out there is listening and reading, especially when it is nice folks like Hamilton and his family. These are the people who built the TouCans rig that was (is?) suspended above San Francisco at the center of a dipole antenna.
Following posts on the SolderSmoke blog, Hamilton has been monitoring the CW activites of a German ham who sends UHF CW signals through the sunroof of his car to the QO-100 satellite in geostationary orbit. See above. Very cool. Listen live to the satellite here:
https://eshail.batc.org.uk/nb/
Also cool is Hamilton’s analysis of Agent Sonya’s ability to homebrew a 1930s era CW station that could be used to communiate with Moscow Center. Hamilton believes she could do it. I have my doubts. But the discussion is a lot of fun.
Check our their blog:
https://copaseticflow.blogspot.com/
Thanks to Hamilton and his kids!
A New Distance Record with an ESP-32 Module? Sort of. A cool video from HB9BLA.
It was nice to watch a video from Andreas again. And to be reminded of the presence in geostationary orbit of QO-100. Really sad that we STILL have no equivalent over the United States.
Andreas engages in a lot of the kind of digital wizardy that I have learned (because of my own shortcomings) to stay away from. Still, this is a very interesting experiment, with lots of focus on antenna gain and path loss at UHF. I plan on again listening to QO-100 via the website. Thank you Andreas!
SolderSmoke Podcast #259 FCC ban of DC Receivers. Pete and Stickers, Mouse Knob, MHST. DC RX Update. Dean and SDR RX, Mythbuster Transceiver, Frequency Counter. Bill’s Shack — Suburban Renewal, Boatanchor Removal, DJI Drone . MAILBAG
Dean KK4DAS’s 20 Meter Transceiver
Video Version: https://www.youtube.com/watch?v=RslKbpBuYDI
Audio Version: http://soldersmoke.com/soldersmoke259.mp3
Reports of FCC action against Direct Conversion receivers. Outrageous! They are going to prosecute Dean and Bill. The 85th harmonic was apparently interfereing with Starlink satellites over Melbourne Australia, Bali, New Zealand’s North Island, the UK, Sweden, Holland and Argentina. Who knew?
Here’s the question: How many paragraphs of this post did you read before you realized this was an April 1 thing? C’mon, please let us know. Bill falls for one or two every year. This year he believed that Warren Buffet really had bought Tesla. So, don’t feel alone. Fess up.
Travelogue: Pete’s trip to Los Olivos. DMV Real ID Blues. Going back to San Francisco? Pete, we have some new stickers…
Pete’s Bench: MHST progress. Raspberry Pi. VWS. Transceiver. K7TFC’s Mouse Knob.
Dean and Bill update on the SolderSmoke Direct Conversion Challenge: 56 receivers built. And 56 is a lot! Info and especially Dean’s videos are still up on the Discord server and on YouTube. Not to late to build! All builders should try to encourage at least one other person to build this receiver. In this way, builders become Elmers and homebrewing can spread. Others have already done this — you can do it too! W4KAC built a second one for a friend. WZ5M built one, helped a friend do a second, and a third one may be on the way. MakeIt Labs in Nashua, NH is responsible for 4 DC receivers. See all the completed receivers here:
https://soldersmoke.blogspot.com/search/label/DC%20RX%20Hall%20of%20Fame
Once you have the receiver going, start the mods! Front panels! Antennas! Better tuning! Si5351s! DSB transmitters! Tell us about your mods.
SHAMELESS COMMERCE DIVISION: Become a Patreon Sponsor! MostlyDIYRF. Buy Amazon stuff through the Amazon link on our blog site. Subscribe to our video YouTube channel.
Dean’s Bench: SDR Receiver project. 20 meter Mythbuster build (a thing of beauty). Homebrew Frequency Counter. Balloons!
Bill’s Bench: Suburban renewal. New floor, new paint, got rid of a lot of junk. New operating table from Husky. DX-60, DX-40, VF-1, and maybe even the Lafayette HA-600A receiver have to go. Many books and magazines too. Lightening the load! But keeping the DX-100, HQ-100, HT-37 and, of course, the Drake 2-B. Boatanchors station. Beacon operations.
N2CQR’s new operating table
Boatanchor Corner at N2CQR
Bought a new DJI Drone, but will use it in the Dominican Republic (not here!). And I got my Drone TRUST Certificate.
Mailbag:
Dave W2DAB doing Manhattan building on the island of Manhattan!
Rich K2GJ (ex WA0CGM) — Nice ham radio memories of his HT-37. Thanks Rich.
Wes W4JYK — A VWS DC receiver.
A nice note from Farhan VU2ESE.
Todd K7TFC — Simple vs. Complex
Paul WA1MAC Gluestick 80 meter QRP
Armand WA1UQO Regen receiver highlighted by AA7EE
Dave AA7EE — FIGHT BACK AGAINST THE FCC! Build the DC Receiver!
Rogier PA1ZZ Many great videos, including one on Heathkit
Bruce KC1FSZ — Nominated us for ARRL award. Thanks Bruce.
Bob KD4EBM– Looking into Polar Modulation. https://qrp-labs.com/qmxp/ssbbeta.html
Peter VK2EMU — Thought of Peter when I briefly took down the N2CQR sign he made.
Victor HI7S — 46 km away from my place in the DR. Says I won the lottery… He is right.
Jim KI4THC Got his Extra ticket. Congratulations Jim.
Kirk NT0Z — On Kits, Hombrew, and the influence of Russian Homebrewers.
Were Russian spies taught how to homebrew their own spy radios?
Rich K2GJ with his 2B, and Heath GR-91
Inside Dean’s Transceiver
Agent Sonya — Did Soviet Spies Really Homebrew Their Rigs?
Ursula Kuczynski (Agent Sonya), 1936.via Peter Beurton
My recent blog post about the intrepid Soviet hams who homebrewed versions of the UW3DI SSB transceiver led to a comment about early Soviet era overseas intel officers who — supposedly — homebrewed their own transmitters and perhaps receivers.
Here is a New York Times review of the book that mentions the homebrewing by spies:
Here’s the Wiki page on Sonya:
Tony Percy took a look at the homebrew claims:
Percy seems quite well informed about radio and about how believable Sonya’s claims about her radio activities were. He uses the Morse acronym QRP, talks about Maximum Useable Frequency, discusses antennas and the relative difficulty of building a receiver. He also talks about the need for crystal controlled transmitters if the QRP transmitter was to have any hope of reaching Moscow Center. In sum, he thinks the reports of Sonya’s radio derring-do are just nonsense.
I agree with Tony Percy. I just think it would be impossible to take a newcomer, show them how to scratch-build a radio, send them to a foreign country, have them buy the needed parts, expect them to build the rig and the antenna… oh and learn to use the Morse Code along the way. I just don’t think that is possible.
Is Tony Percy a ham? What do you folks think about the plausibility of the claims about Sonya’s radio prowess?
“Seems Like Radio is Here to Stay” — Old Radio, Radio Magic
The first 12 minutes of this podcast are pretty good. I think it captures well the wonder of radio — magic carpets, signals taversing the Himalayas and all that — but the presentation is kind of confused. The PRX podcasters keep saying that it was recorded in the 1930s, but then we hear references to the Nuremburg trials and the possibility of sharing the atom bomb. So there is some confusion in the presentation.
https://podcasts.apple.com/us/podcast/champions-of-old-radio/id453044527?i=1000702716017
Can anyone find the original recording from the 1930s about the wonder of radio, without the references to things that happened in the late 1940s?
Thanks to Rogier for sending this to me.
Norman Corwin