Month: April 2025

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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Join the discussion – SolderSmoke Discord Server:

https://discord.gg/Fu6B7yGxx2

Documentation on Hackaday:

https://hackaday.io/project/190327-high-schoolers-build-a-radio-receiver

SolderSmoke YouTube channel:

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:

https://discord.gg/Fu6B7yGxx2

Documentation on Hackaday:

https://hackaday.io/project/190327-high-schoolers-build-a-radio-receiver

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:
https://louiskatz.net/wpt/
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Join the discussion – SolderSmoke Discord Server:

https://discord.gg/Fu6B7yGxx2

Documentation on Hackaday:

https://hackaday.io/project/190327-high-schoolers-build-a-radio-receiver

SolderSmoke YouTube channel:

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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Join the discussion – SolderSmoke Discord Server:

https://discord.gg/Fu6B7yGxx2

Documentation on Hackaday:

https://hackaday.io/project/190327-high-schoolers-build-a-radio-receiver

SolderSmoke YouTube channel:

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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Join the discussion – SolderSmoke Discord Server:

https://discord.gg/Fu6B7yGxx2

Documentation on Hackaday:

https://hackaday.io/project/190327-high-schoolers-build-a-radio-receiver

SolderSmoke YouTube channel:

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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Join the discussion – SolderSmoke Discord Server:

https://discord.gg/Fu6B7yGxx2

Documentation on Hackaday:

https://hackaday.io/project/190327-high-schoolers-build-a-radio-receiver

SolderSmoke YouTube channel:

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 daughtercheeky). 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.Credit…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:
https://www.nytimes.com/2020/09/15/books/review/agent-sonya-ben-macintyre.html

Here’s the Wiki page on Sonya:
https://en.wikipedia.org/wiki/Ursula_Kuczynski

Tony Percy took a look at the homebrew claims:
https://coldspur.com/signal-sonyas-wireless/

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

Homebrew vs. Kits — The influence of Russian Homebrewers

Click on the image for a better read.
Like Kirk, I too was influenced by the Russian and Eastern European homebrewers. As a kid, every issue of QST seemed to contain (especially in the “How’s DX?” column) pictures of intrepid Russian homebrewers seated next to their HOMEBREW stations. I wanted to be like them.

When I first launched the Direct Conversion Receiver Challenge, someone decided that it would be better to make the receiver into a kit. He criticized me for deciding to keep this project homebrew. There seemed to be a lack of understanding of the difference. This morning I got an e-mail from Kirk NT0Z. He attached his column from the February 2013 issue of Monitoring Times. I think he captures very well the difference between kits and homebrew. An excerpt from the column appears above. I need to get a portrait of UW3DI to hang above my workbench. Thanks Kirk.

Here is more info on the UW3DI transceiver:
https://www.cqdx.ru/ham/ham-radio-news/the-legendary-diy-russian-uw3di-transceiver/

Use Google Translate on this site: https://uarl.com.ua/bylsluchay/autor/ux0un_vivat_uw3di.html



The Amazing Technological Development of DJI Drones

Yes, the ability to hover is a really big deal.

Kalman filtering. Who knew?

GPS, compasses, intertial navigation, redundancy. Great stuff.

NZ showed DJI that quadcopters were the way to go.

The importance of brushless motors.

It is really amazing how quickly quadcopters took over from ordinary helicopters. The regs in the DC area that prevent us from flying quadcopters here were probably developed BEFORE the quadcopters were developed.

I still wonder about why we still fly normal helicopters: Take you hands off the controls of a helicopter and it will soon start to flip and fall. Take you hands off the controls of a quadcopter and it will just hover in the sky. When the batteries get low, it will return to the start point and land.

I have a video taken by my Hanmilt drone on my Patreon channel. I have already bought a DJI Mini 4K to fly in the DR.

Completed Receivers

So far 54 completed receivers, with 4 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
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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
—————————————–

Possible Candidates for the Hall of Fame:
SA5RJS Rasmus
KA9TII James
W2AEW Alan
AA7FO Chuck
K7WXW Bill
W1PJE Phil MIT
VA3ZOT Tony Surface Mount — Honorable Mention?
KM5Z Mike Yancey
AB2XT John (Done, but we just need the video)
M7EFO Bingo
KO7M Jeff (Piper Cub)
K7WXW Bill