G0UPL at Dayton: SSB for the QMX, and Thoughts on Homebrewing

 

Click on the diagram for a better view.

Listen to the interview here: 

http://soldersmoke.com/G0UPL at Dayton 2025.mp3

I think this is what Grayson was talking about when he said that Hans is a genius, and that his SSB project for the QMX was very complicated.  On his website Hans says as much:  "This is a very complex project."  Indeed it is.  Just take a look at the bloc diagram above.  This is not for the faint of heart.  In this interview, he talks about a full year of intense work on SSB for the QMX.  Wow. 

I think Hans makes some good points on why we still homebrew.  I liked his fish analogy:  we can buy all the fish we want at the supermarket, but people still go fishing.  Why? Because they like fishing.  

I'm not too sure about "the IKEA effect."  He seems to be saying that people derive homebrew-like satisfaction from assembling IKEA furniture.  Well, maybe some people do, but I think this is a long way from what we would consider true scratch-built homebrew.  Dean KK4DAS, for example, recently observed that he assembled two IKEA tables, but that this assembly does NOT make him a carpenter.  This is related to our discussion about the differences between ham radio kits and true homebrew:  IKEA flat packs are like the kits.  I think Hans is right about the pride and satisfaction that people get from building their own radio gear.  

Thanks to Hans GOUPL and to Bob W8SX for doing this interview. 

Mitch NK3H's FB SolderSmoke Direct Conversion Receiver -- "Incredibly satisfying!"

Wow, Mitch NK3H has built a really nice receiver. (He says it is not pretty, but those of us who have built one or who are in the process know that it looks great.) The SSB really sounds good also. 

Mitch writes: 

It's not pretty but it works! Incredibly satisfying. In answer to the questions, (1) though I 'd built a few small Manhattan style boards (e.g., Michigan Mighty Mite) this was more complicated. I've been using W1REX's island cutter to create isolated areas on the copper clad board, rather than pasting on pieces of circuit board. But the islands are a little small for as many as four connections on one island, as in most of the transistor bases. Inevitably a component lead would inadvertently contact the ground plane and all bets were off. Tracking down the shorts was challenging. (2) Once I got to the audio amplifier board I carefully laid out all of the components before starting to solder. But as I finished each stage and was ready for the next, I always seemed to be missing a resistor or two. I'd search the desk and the floor -- very frustrating. Turns out the speaker magnet was collecting and hiding the missing resistors. Lesson learned. (3) Next I'm hoping to build a transceiver. Still looking for the right project, probably a little more digital than this wonderful DCR.

Mitch obviously learned a lot during this project.  I had similar experiences with pads on the same level as the surrounding board -- I found that the 1 or 2 mm of elevation provided by the Manhattan pads prevented a lot of inadvertent shorts to ground.  And I too "lost" (temporarily) a lot of components to the magnet in the speaker.  

Good luck with the next projects Mitch.  With the Michigan Mighty Mite and the DCR under your belt you are ready to go.  Maybe a Double Sideband transmitter to go with the DCR? Or, as you said, perhaps something more digital.  There is a lot of good ham experience with the Si5351 digital VFOs.  Or maybe even an SDR rig.  

Thanks Mitch.  Congratulations and welcome to the Hall of Fame. 

Grayson Evans KJ7UM Interview at Four Days in May at the Dayton Hamvention 2025

 

LISTEN TO THE INTERVIEW HERE: 

http://soldersmoke.com/KJ7UM at Dayton 2025.mp3

Grayson said quite a lot in this short 4 minute interview: 

-- At FDIM he was selling his wonderful book "Hollow State Design for the Radio Amateur."  Buy one here: https://www.ermag.com/product-category/books/ 

-- Grayson was also selling a Thermatron version of our beloved Michigan Mighty Mite transmitter.  It is crystal controlled for the 40 meter band, but the Color Burst Liberation Army approves! Here is a wonderful video on this rig:

https://soldersmoke.blogspot.com/2024/09/excellent-new-video-from-grayson-kj7um.html

And be sure to watch Grayson's excellent course on Thermatron Homebrewing: 

https://soldersmoke.blogspot.com/2024/02/grayson-evans-kj7um-video-on.html

-- Asked why someone should build with tubes when so much good solid state stuff is available, Grayson makes some especially excellent points:  The solid state gear is often filled with mysterious little black boxes -- we often don't really know what goes on in there.  Thermatron construction provides a break from complicated SDR nonsense "that is not really radio."  That last comment will generate some criticism, but not from here.  I think Grayson is right,  He earlier expressed admiration for complex circuitry, but he also rightly defends simple, understandable rigs.  

Here are Grayson's Technical Documents (a real treasure trove):  https://kj7um.wordpress.com/

Three cheers for Grayson.  And thanks to Bob Crane W8SX for doing this interview.  

Bill K7WXW's FB SolderSmoke Direct Conversion Receiver

This is a very nice build.  Bill K7WXW fought a long battle to get this receiver working, and -- more importantly -- to understand why it is working.   

Bill writes: 

The cycle of design, sim, build, debug, update, repeat can teach you a lot.

FB Bill.  Welcome to the Hall of Fame! 

Hall of Fame: The SolderSmoke Direct Conversion Receiver -- 73 Completed Receivers, 7 Honorable Mentions, Many More Receivers Being Built.

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 21, 2025  1500Z:

So far 73 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

K7WXW          Bill 

NK3H               Mitch

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

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 

* Matthew      Student of DL1AJG

* Arash           Student of DL1AJG 

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

Candidates for the Hall of Fame: 

SA5RJS              Rasmus

KA9TII               James

AA7FO              Chuck 

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:

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

Daniel VE5DLD's FOUR FB Saskatchewan SolderSmoke Direct Conversion Receivers

Daniel VE5DLD is a teacher in Regina, Saskatchewan, Canada.  Back in early 2023 several lucky students joined him in building the SolderSmoke Direct Conversion receiver.  We had asked people to build the receiver -- we wanted to test the design before asking the local high school students to build it.  Daniel and his students came through for us, and ended up having far more success than we did.  Congratulations Daniel!  Welcome to the Hall of Fame. 

Daniel wrote: 

Hi Bill!  Yes, I had my own DC Receiver that I use every so often for fun and 3 built by my students.  All working.  We didn't get any video because we just finished the school year and the kids left, but I've kept in contact with them and they told me they have been able to receive signals from their homes.  The kids developed excellent troubleshooting skills gained large amounts of confidence in their ability to fix things.  Over the next year, my students told about fixing their gaming consoles and fixing problems in their parent's electronics.  They are certainly no longer afraid of opening something up to see what is going on!  And that's what makes me the most happy!  Yeah, you can just recognize myself and only mention that 3 students were able to build DC receivers.

And yes, the Michigan Mighty Mite was a fantastic gateway to home brewing!

Thanks for thinking of me and my students!

73

Daniel D.

VE5DLD

On June 19, 2023,  Daniel wrote: 

We got everything going and all 3 students now have receivers capable of inhaling RF.  We 3D printed some knobs and hot glued them.  We took one outside but didn't hear any signals.  Mid afternoon is not good for 40m.  We will try again later this week and I'll bring my KX3 to make sure there is a single for them to listen.  This issue on that last radio was an improperly installed J310.  The angle is was installed hid the problem well!  Here are a few pictures of the completed rigs. 

Back in 2015, Daniel built a Michigan Mighty Mite.  I was pleased to be reminded that I had sent him the crystal.  Go CBLA!  For more info on Daniel's transmitter see: 

https://soldersmoke.blogspot.com/2015/10/saskatchewan-mighty-mite-video.html

Thanks Daniel! 73  

Honorable Mention: Andreas DL1AJG's THREE SolderSmoke Direct Conversion Receivers for Biologists

 

Andreas DL1AJG was another of those intrepid hams who,  in the dark of winter 2023 took up the SolderSmoke Direct Conversion Receiver Challenge in order to test our receiver (before we pushed high school kids to build it).  Andreas came to the task with a lot of useful teaching experience. At the time he was an academic  biologist and had been teaching a course called "Applied Electronics for Biologists."  See: 

https://soldersmoke.blogspot.com/2022/08/can-biologist-fix-radio.html

Some of Andreas's students

I put these receivers in the "Honorable Mention" category only because they deviated a bit from the basic schematic:  they used an indoor ferrite antenna, had an RF amplifier ahead of the mixer, and did not use a transformer in the AF amp.  But they are very clearly the SolderSmoke DC receiver, they succeeded in inhaling RF, and Andreas and his students built them to help us.  

Here is the schematic they used: 

Click on the image for a better view

Here is an e-mail exchange I had with Andreas when the scholatic dust had settled in June 2023: 

Dear Bill,

Please my apologies for my late update on our DCR project. We started with the course in the semester break and once the semester started only a handful of students were able to finish their receiver. A long shelf of shame .... 

Here is what we've got so far (those were finished at the end of April already). 3 nice DCRs completely sufficient to copy CW indoors without additional antennas starting from late afternoon. Strong stations can be heard all day. I found that coupling some 6m of wire with one or two windings to the ferrite core can boost the signal dramatically but can also increase noise. 

The PTO is based on your design (Bill Meara N26QR &  Dean KK4DAS) which was sparked by Farhan  (VU2ESE) , except that I've swapped the FET for a NPN. The input amplifier and antenna is from the JUMA active ferrite antenna by Matti Hohtola (OH7SV), the band pass filter is from Hans Summers (G0UPL), the mixer and the headphone amplifier is inspired by Pete Juliano (N6QW), you told me that the diplexer (as well as the whole DCR idea) is attributed to Wes Hayward (W7ZOI) and the perfect schematics of Rick Scott (N3FJZ) where crucial to get me started in the first place. I enjoy keeping track of original sources, as I would do in science. This shows that even little achievements are based on the ideas of many other great people -  and this is nothing to be ashamed of. 

This was a lot of fun! Thank You!

Best and yours sincerely,

Andreas

Wow, the direct conversion re-engineering of education continues, this time at graduate-school level with biologists in Munich!  Amazing.  

Andreas points out that his group was also plagued by semester-related problems that caused many additions to the German shelf of shame.  Let's hope that someday soon these builders will come to their senses and join the ranks of those who have finished their homebrew projects.  

Looking at the schematic (above) of Andreas's project, there are a couple of significant differences from ours:   

-- Their AF amp used a transformer-less push-pull design.  We had considered this but abandoned it thinking that it would be too complicated to explain the workings of this circuit to our students.

-- Most significant, is Andreas's use of a ferrite rod antenna and an RF amplifier.   I think a simple 33 foot quarter wave antenna (with a ground or a counterpoise) might work better.  But hey,  to  each his own!   The important thing is that a number of these receivers were successfully built.  They look beautiful.  

Congratulations to Andreas and the successful Munich homebrewers!  

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

Thanks to Andreas DL1AJG.  Welcome to the Hall of Fame.   

Duct Tape and a Hero of Apollo 13

"If it moves and its not supposed to, you use duct tape."

Ed Smylie

https://www.nytimes.com/2025/05/16/science/space/ed-smylie-dead.html?unlocked_article_code=1.IU8.trNH.Cdleh2CdY7HB&smid=url-share

Rick N3FJZ's Early Completion of the SolderSmoke Direct Conversion Receiver Challenge

 It was a cold day in early February 2023.  Rick N3FJZ had responded to an early version of the SolderSmoke Direct Conversion Challenge: 

I wrote: 

Rick N3FJZ has completed his the direct conversion receiver that we will soon be building with students at a local high school.   See video above. 

We are hoping that a number of people will build the receiver as we designed it.  Some folks have sent us versions of the receiver that they have built, but these versions often include significant deviations from our design, rendering them less-than-useful in checking our work.  Rick built it just as we prescribed.  His build is very useful in confirming the validity of our design.  So if you are working on one of these receivers, I would encourage you to -- for the moment -- dispense with innovations and build it the way Rick did:  as per the design we have been using. 

We know that our design is not perfect.  But we have decided to stick with it because it is very simple and very easy to explain.  Examples:  We know there is an impedance mismatch between the mixer and the AF amp.  But fixing this would introduce complexity that we want to avoid.   And the receiver works fine with the imperfection.   We know that a push-pull AF amp would probably work better than the one we have.  But we do not want to have to explain push-pull amps, biasing schemes, and PNP transistors in this short introductory course.  So we stuck with three common-emitter AF amp circuits and an 1K-8ohm transformer. 

Rick did a really excellent job not only in building this receiver, but also in documenting it.   His diagrams and drawings are really superb.  We will probably use these in our presentations to the students: 

http://www.remmepark.com/circuit6040/SolderSmoke-DCR/SolderSmoke-DCR.html#AUDIO_AMP

We will keep all of you informed on the progress of this project.  We will begin this week.  But if you are still working on the receiver, please send us your work,  even if it comes in after we begin the course.  

Thanks Rick! 

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

Thanks indeed Rick.  Sorry it took so long to put you in the SolderSmoke Challenge Hall of Fame, but you are in now, and you definitely deserve it.  Congratulations OM.  

I especially like your finding the audio ourput transformer in an old transistor radio.  Too often we see builders quit after discovering that Mouser or some other supplier no longer stocks the needed part.  You show that homebrewers have other sources available, if they are willing to scrounge a bit.  FB.    I also liked the switch that helped compare the outputs of the two AF transformers.  Very useful.  

Thanks too for all the great videos and your really nice documentation -- we have used your work quite a lot. 

73 and welcome to the Hall of Fame! 

Rick N3FJZ

Stephen VK2BLQ's Very FB EARLY build of the SolderSmoke Direct Conversion Receiver

 

This was back in the old days, long before we had Discord.  It was early 2023, and we were getting ready to start the Direct Conversion receiver project at the local high school.  I put out a version of the SolderSmoke Challenge:  I asked people to build our receiver and let us know if it worked for them.  Stephen VK2BLQ took us up on this and built the beautiful receiver you see above.  

Thanks Stephen.  Welcome to the Hall of Fame!  

Stephen wrote:  

Bill,

Don't worry, you are not alone out there.

Here is my build; sorry that the front panel is overexposed and hard to see, but it is plywood.

I did follow the schematic but due to the contents  of the junk box there have been some component changes.

The only thing that I had to buy was the 3/16 x 50 mm (2 inch) brass screw.

My calculations for the coils for the PTO and  BPF  were  a little  bit off necessitating padding down the PTO with a further 100 pF (easier than remaking the coil and mounting)  and removing a few turns from the T50-6 toroids.

Like other people have found: the audio takes off at full volume; I am thinking but not yet tried adding decoupling between R5 (15K) and C2(47 uF). It isn't the actual values of the electros as I had to use 100 uF so might be the audio output getting back into the earlier stage.

The tuning range I get is  our 7000 to 7200 KHz and some shortwave stations above and below, Turning the screw is a little bit fiddly, but once tuned the vfo is quite stable and the audio sounds good.

Best wishes,

Stephen

VK2BLQ

MIT's Haystack Observatory and Dr. Herb Weiss

We are really privileged to have among us (and in the SolderSmoke Direct Conversion Hall of Fame) Phil Erickson W1PJE.   Phil is the Director of the MIT Haystack Observatory. 

Phil writes: 

Hi Bill, Dean, and Pete,

  I surfed over today to Soldersmoke and noticed you had put up a very nice film from the 1960s made by MIT "Science Reporter" on the DSKY design for the Apollo Guidance Computer.

  In the same vein, you might enjoy viewing something from the same era on the Haystack 37m telescope / radar in its early mid 1960s days:

https://youtu.be/Xjvr5qCKYWc?feature=shared

 

  The video features Dr. Herb Weiss who is still with us at nearly 106 years old (he visited a couple years ago).  

https://www.haystack.mit.edu/news/founder-herb-weiss-celebrates-haystack-history/

  Herb built the observatory for its original ballistic missile radar / satellite imaging mission and was involved in early MIT microwave radar development.  

"Growing up in Elizabeth, New Jersey, Herb liked gadgetry. As a teenager, he became a ham radio operator and built a primitive television set at the same time NBC was trying to get its first signal on the air. His shop teacher was so impressed by Herb’s genius that he contacted MIT, which invited Herb to attend the college.

He spent the bulk of his career developing radar when there was none in the United States. He joined the Radiation Lab at MIT, which was just being established to support the war effort during World War II, designing radars for ships and aircraft. In 1942, when England was in the throes of its air war with the Nazis, Herb went to England and installed radar in planes with a novel navigation system that he and a team had designed for the Royal Air Force. He later spent three years at the Los Alamos, New Mexico, laboratory improving instruments for the A-bomb. After seeing the need for a continental defense network against the Soviet missile threat, he returned to MIT to build it. If not for Herb, there also likely would be no MIT Haystack Observatory, a pioneering radio science and research facility."

  As you can see from above, Herb is also a ham:

https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=913698

"Weiss:

Okay. I was born in New Jersey, and my first acquaintance with electronics was about the age of 12 or 13. We had a battery-operated radio, which didn't work, and I asked around about what do we do about it. They referred me to a man two blocks away, who was a radio ham it turned out. So I carried this monster with the big horn and, I guess, the dog sitting on the speaker to his house. We went down in the basement, and I was just fascinated. I was hooked right then and there. A year later I became a radio ham at the age of 13, 14 and literally have been in the field ever since, until I retired. I was fortunate enough to go to MIT as an undergraduate, and most of the people I ran into of that vintage didn't really have a hands-on feeling for electronics. By the time I got to MIT, I had built all kinds of things, including a TV set. Then it turned out that NBC was just trying to get their TV set on the air in New York on top of the Empire State Building."

https://ethw.org/Oral-History:Herbert_Weiss

  Herb and his wife Ruth had another career after MIT as a wind power pioneer and he is still an avid sailor:

https://maineboats.com/print/issue-178/still-boating-after-all-these-years

  One of our inspirations, and it came from building ham radio sets as a youngster.  Enjoy the history.

73

Phil W1PJE

--

----
Phil Erickson

phil.erickson@gmail.com 

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

I would really like to get more info on Herb's homebrew TV receiver.  His was significantly earlier than the one described by Jean Shepherd. 

Thanks Phil!  And thanks Herb! 

Paul 9V1/KM7ABZ's FB SINGAPORE SolderSmoke Direct Conversion Receiver

Wow, I had been feeling a bit discourged about the slow-down in receiver completions, then I woke  up this morning and found this e-mail from Singapore.  My faith in ham radio was restored.  Welcome to the Hall of Fame Paul.  You get extra credit for doing it from far-off and exotic Singapore. 

Paul includes in his "proof of life" video not only some Malaysian SSB and some CW,  but also some very close-by China Radio International.  FB Paul.  

I also liked the way Paul used the local library to burn the schematic of the receiver burned into the board upon which it was placed.  And the library also 3D printed his PTO coil form.  

And ET confirmed Proof of Life!  FB! 

Be sure to check out the really nice build description in Paul's blog and Github page (links below): 

Paul writes:  

Hi Bill, Pete, and Dean,

I've finally made a "proof of life" video for you, plucking some CW, voice and shortwave signals from the 40 and 41m bands here in Singapore. What fun this was, and I am amazed at how well this works, even from the confines of my 15th floor apartment.

https://www.youtube.com/watch?v=Pek-wT96I2Q

Thank you so much for laying down the challenge - it came at just the right time for me, rekindling my enthusiasm and electronics and radio. It even encouraged me to finally get my license - I'm newly minted general class KM7ABZ (yet to get a 9V1 conversion license for my home here in Singapore). I can honestly say that listening to the SolderSmoke and Ham Radio Workbench podcasts since 2018 or so was worth *at least* 50% on the exam... somehow I already knew a bunch of stuff by pure osmosis!

Everything went pretty smoothly with the build. The only real issue I had was adding some caps to tame persistent motor-boating in the audio amp. Other than that, the build follows the official SolderSmoke schematic and parts selections.

I used the laser cutters at our local library to cut and etch a custom base. The library is a great resource: it’s also where I printed the PTO former.

To get on the air from my apartment in Singapore, I’m using an MLA-30 Active Loop antenna, with a PLJ-1601 frequency counter attached to the PTO to take some of the guesswork out of tuning.

All the details of my build are published at https://leap.tardate.com/radio/soldersmokedcrx/ (from GitHub).

Cheers,

Paul

KM7ABZ from 9V1 land

https://leap.tardate.com