Andy KB1OIQ’s FB SolderSmoke Direct Conversion Receiver

Andy has a lot of homebrew projects underway, but I think this one must have been the most rewarding. He has done something that 95% of hams never do: He has homebrewed a receiver. Congratulations Andy!

Check out Andy’s presentation on Linux to the 2025 Dayton Hamvention:
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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:

Wayne KC1ONM’s FB SolderSmoke Direct Conversion Receiver

Wayne KC1ONM built a very nice direct conversion receiver. He has done something that 95% of hams never do: He has HOMEBREWED a receiver. FB Wayne. Congratulations!

After his completion of the receiver, Wayne put it all in a beautiful homebrew case:

To mark the PC boards, Wayne says, “MakeIt Labs has a MOPA laser. They were marked after construction of the board (the focus is high enough not to interfere with the components), but before attaching them to the box.”

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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:

Dave G6GEV’s Very FB SolderSmoke Direct Conversion Receiver, with an Innovative Bic Pen PTO!

This is a really nice one. In the “proof of life” video we find a lot of proof, and a lot of life. SSB from the UK sounds really good. This is one of the beauties of the Direct Conversion architecture — you end up with a receiver that sounds very good. Doug DeMaw said these receivers have “presence” — it sounds like the other fellow is present in the room with you.

Dave’s happiness and satisfaction really shines through in his comments. Dave writes:

I’ve just completed my DCR, and it’s been an absolute blast!

I’m a retired EE, where PCBs and surface-mount components are the norm. I’ve occasionally prototyped using dead bug or Vero-board, but this is my first exposure to Manhattan construction – and I’ve thoroughly enjoyed it. Electronics and radio were my childhood passions, but inevitably, they lost some of their appeal once they became a career. Thank you, Bill and Dean, for helping me regain some of that lost joy!

My biggest challenge was trying to locate parts from a single UK source to minimize shipping costs (yes, I’m cheap). I briefly contemplated building a push-pull audio amp to avoid purchasing the transformer from Mouser, but in the end, I found most parts there, then padded the order with common junkbox parts to get free shipping. I’m so pleased that I heeded Bill and Dean’s advice to build the receiver as presented (well, almost). The results are so much better than I expected, with great-sounding, room-filling audio when connected to the passive half of an old active stereo speaker pair. Tuning is a bit fiddly but improves with practice. Luckily, I had no problems with any of the stages, and it just worked when the boards finally came together.

To save money (did I mention that I’m cheap?), I decided to use NP0 capacitors in the PTO instead of silver mica. The thermal coefficient should be similar, and if they didn’t work out, I planned to swap to mica later on. It turns out NP0 works great for me, with no noticeable drift after several minutes.

I don’t have easy access to a 3D printer, so I decided to roll my own PTO former. I wound the coil on a Bic Biro with a layer of heat-shrink tubing to bring the diameter to 10mm. This was glued to a wooden support, and the M6 threaded brass bar was a perfect fit inside the Biro. I finished it off with a tuning knob made from an old RC aircraft prop spinner. After experimenting with coil spacing, I ended up with wide spacing under the actively tuned area of the coil and tight spacing at the other end. This reduced the tuning sensitivity, and I now get around 40 kHz per revolution.
I’d really like to make a home-brew 2-way contact with this receiver, so maybe I’ll try a DSB transmitter next…
Thanks again to Bill and Dean for providing this fantastic resource. I’ve been a SolderSmoke listener since episode #1, and after 20 years of constructing radios vicariously, I’ve finally built one myself!
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FB Dave! Thanks and congratulations.
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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:

SolderSmoke Podcast #258 — Travelogue, SDR, Direct Conversion Receiver Project, Homebrew HDR SSB, Mailbag

Falcon 9 from our apartment in Cap Cana DR

SolderSmoke Podcast #258 is available:

Video Version: https://www.youtube.com/watch?v=75ewswI7CcA

Audio Version: http://soldersmoke.com/soldersmoke258.mp3

Travelogue: I am back from the DR. Trying to get a real HI7 call. Lots of science and nature: Earthquake (5.9) . Falcon 9. But no Starship. Two possible Starlink de-orbits. Whales. Hawks. A drone. (Pictures on Patreon.) A total lunar eclipse. A 10 meter CW beacon, with an LED, thanks to WN2A. Lots of great people. But it is good to be back. Planning for a better antenna for DR.

Pete’s bench: Pete is building a seismograph! CL Stong had several in his book “The Amateur Scientist.” The MHST. Help from Oliver KI3P of VWS.

Shameless Commerce Division: Please continue to use the Amazon link on the right. Mostly DIY RF! Link on the blog page. And please become a Patreon sponsor. People have asked, what is happening to the blog and podcast. Well, listen to this one for a sobering description of what is happening on the internet to things like SolderSmoke: https://share.fireside.fm/episode/2YAGasSP+_rbTJaWN Patreon might be the answer for us too.

Dean/Bill: Lessons learned from the SolderSmoke Direct Conversion Receiver Build project: — 45 successful builds! Wow. See: https://soldersmoke.blogspot.com/search/label/DC%20RX%20Hall%20of%20Fame — Differences between kit-build and true homebrew. — Discord, Questions, Mods, Creativity vs. Build it our way the first time. Dean and the trials and tribulations of being the electronic problem go-to-guy. HRWB (what happened?) We used copper clad boards and Manhattan technique with no fatalities. DSB TX seems the most popular next step — some have already been done.

Dean’s Bench: The VWS SDR receiver build. The 20 meter Yaesu VFO transceiver build (ANOTHER one?). Why is this Yaesu VFO different? Filter building Balloons!

Bill’s Bench: Checking into “The Old Military Radio Net.” South Pacific and Australia on 20 SSB in the morning. Approaching “Worked all Rarotonga.” Makes me think I need a directional antenna for the DR… Beacon left on in the DR. A 10 meter AM QSO using the converted GE rig. G3YPZ! Dean has the JC Penny. Hamfest report heard on the OMRN: DX60s stacked like cordwood. Buy one and get one free.

MAILBAG:

Bob: Software for SSB on the QMX.

Roy WN3F new stickers

Rogier PA1ZZ- Capacitors replace batteries in French electric bikes.

Walter KA4KXX — Lots of help on the DC RX project

Aaron ZL1AUN Doing an article for Break-in (NZ) about the DC RX

Farhan VU2ESE On DC RX: “They have mastered the Alchemy of turning lifeless components into living and breathing radios. May the tribe grow!”

Ramakrishnan VU2JXN — We need an Indian DC receiver Ramakrishnan!

Grayson KJ7UM — Discord gang discovering Hollow State Design for the Radio Amateur

Mike WN2A Sent keyer for beacon and good advice on diplexer.

Alan W2AEW JOO, but we are hoping for more!

Mike WU2D FT-101 videos. Son is making coils! https://www.ebay.com/usr/blakertree

Buzz W3EMD One guy complained of the noise of his Dynamotor. Pete knows a guy…

Dave W2DAB We NEED an upper east side DC Receiver

Phil W1PJE We need an MIT DC receiver. But we understand the delay.

Wes W7ZOI A nice email from Wes.

Jeff WA7MLH Homebrewing and the number of homebrewers.

Dave AA7EE put a nice comment out about Armand WA1UQO’s regen.

Sticker by Roy WN3F

Honorable Mention: Graham CT7AXD’s Reassembled SolderSmoke Direct Conversion Receiver

Graham was another good sport. When I asked him about the receiver, he had already moved on, and — is often happens — had separated the stages and replaced some of them. He agreed to put the receiver back together and to shoot a video of it in action. Above you can see it, happily inhaling SSB from nearby Spain. He used a different AF amplifier cicruit — that is why this is in the Honorable Mention catergory.

Graham writes:

It has been an interesting exercise as I’ve tended to use active mixers before, but I think I am converted to DBMs now. The other rx I’ve been working on with a VCO is performing very well. I need to move the preamp over to the PTO one and see how it performs.

Thanks Graham and congratulations.
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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:

David AI6WR’s Beautiful SolderSmoke Direct Conversion Receiver

David AI6WR was a patient craftsman during the build of his receiver. He diagnosed and fixed defects in the AF gain controls that he was trying to use. He hung in there, found the problem, and fixed it. Even with a challenging antenna situation his receiver is pulling in SSB signals on 40 meters.

David writes:

Thank you everyone for the suggestions! I have tried a bunch of them out, those that I could try without making a ton of changes. I have made a couple of changes and it’s working much better now. It turned out that one of the major contributors to the unpredictable noise was the audio pot itself. It had poor mechanical connections between the input leads and and the internal traces that go to the resistor and wiper. They were actually wiggling around and constantly disconnecting and reconnecting randomly. I took it apart, cleaned the wiper with some rubbing alcohol, tried to get a better connection on the inputs by crimping them down and putting some solder on them, and then put it back together. Once I put that back into the circuit, it was still humming at high volume settings, but much more predictably. I also cut off the unused center tap lead on the primary side of my audio transformer. That wasn’t the source of the problem, but it wasn’t helping things. Finally, I put a 470u cap from the power rail to ground. That doesn’t totally eliminate the hum, but along with the other changes, it reduces it enough that nearly all of the volume range is reliably usable. It will still hum if I turn it all the way up, or if there is no antenna plugged in, but I think it is working in ordinary circumstances.

Congratulations David.

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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:

The Electrolytic Capacitor Plague

So, what caused it? Maybe a variety of factors? Perhaps different factors explain different circuit failures? The video, for example, focuses on CPUs that drew a lot of current and got real hot. OK, but we also see failing electrolytics in small, very low current Sony receivers.


Hack-A-Day has a good post about this:


The Hack-A-Day comments are also (mostly) good. I agree with the fellow who said he never heard anyone call electrolytic capacitors “E capacitors.” Me neither.

Lex PH2LB’s Fantastic, 3-D Yellow, Glue-Stick, SolderSmoke Direct Conversion Receiver from the Netherlands

Lex PH2LB has been a valued member of the SolderSmoke team for a long time. It was he who took our stickers into the bars and coffee shops of Holland, spearheading our efforts on Continental Europe.

He didn’t have to, but Lex took up the SolderSmoke Challenge. And he did it with panache. 3D yellow panache. Glue-stick panache!

Lex has a complete description of his build here:

Here is another video of Lex’s receiver in action

Indeed, it is working!

Bravo Lex. Thank you and congratulations.

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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:


Ben KC9DLM’s SolderSmoke Direct Conversion Receiver

Ben had to overcome some antenna problems, but as you can see here, he got it going.

He also had to overcome a capacitor shortage. He did it, using parts on hand. FB. Ben writes:

I forgot to order the 470uF caps for the audio stage, so I used some amusingly large 220uF I had in parallel.

Thanks Ben. Congratulations. 73 Bill

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:

Scott K1OA FB SolderSmoke Direct Conversion Receiver

Scott K1OA has been a licensed ham for more than 50 years, but he tells us that this was his first Manhattan-style project. He reports having built a lot of kits and even a DC receiver from EMRFD using an SA602 chip, but he says the SolderSmoke direct conversion receiver was the most fun. That comment meant a lot to us. We continue to believe there is value in homebrewing from scratch.

Scott writes:

Hi Bill,


This will be my 50th year as a licensed ham and my first

Manhattan style project. I’ve built a dozen kits in the past

15 years or so and bread-boarded a simple crystal

controlled DCR from a circuit in EMRFD

using an SA602, but the Soldersmoke DCR

challenge has been the most fun!


The most challenging aspect has been trying to get the

PTO tuning range close to 7-7.3 MHz. I’m still

experimenting with that.Audio output is loud and

sensitivity is pretty good.


I’m thinking my next project might be a simple crystal

controlled CW transmitter to pair up with the DCR, and

considering the Pebble Crusher 1/2W design from the

ARRL Handbook that uses a pair of 2N2222A

transistors. I’m interested in your thoughts on that.


Thanks for putting forth the challenge and for all the

great support you and Dean have provided!


73,

Scott K1OA


p.s. – love the podcast and your Soldersmoke Adventures

book!

Thanks Scott and congratulations.
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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:

Juan LU2VJM’s Beautiful Argentine SolderSmoke Direct Conversion Receiver

I was really pleased to see Juan LU2VJM’s rapid completion of the SolderSmoke direct conversion receiver. But I wasn’t really surprised — Juan is an experienced homebrewer who has successfully completed Farhan’s BITX transceiver. Juan and I talked about how it is worthwhile for even an experienced homebrewer to go back and build a direct conversion receiver. Farhan did this. Farhan said that we do this because we are tool makers. We have opposing thumbs that allow us to grab a soldering iron. Indeed. And you can hear the happiness in Juan’s voice when he says in the video, “Today we have reception!” Excellent.

I was also pleased to see this receiver enter the Hall of Fame becasue this marks our first receiver from Latin America. We hope there will be many more.

Here are some pictures of Juan’s receiver during construction:

Juan’s AF Amplifier

Juan’s Diplexer with homebrewed coil

Another shot of the AF amplifier

The mixer, getting ready for construction

The completed receiver. FB!

Thanks Juan! And congrastulations!


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:

CuriousMarc Gets an Apollo DSKY Running. FPGA AGC Computer. Rope Memory.

I really liked this video. So much amazing wizardry in it. Just the FPGA Apollo AGC simulator that Mike whipped up. Wow. Kudos!

Their occassional references to “rope” brought back fond memories of “Sunburst and Luminary” by Don Eyles: https://soldersmoke.blogspot.com/search?q=Apollo+rope

Victor’s FB SolderSmoke Direct Conversion Receiver from Holland Pulls In Stations from All Over Europe… and One from Japan

Victor is a retired Electrical Engineer from the Netherlands. He doesn’t have a ham radio call sign, but as I have said about other receiver builders, he deserves one. Note the truly homebrew approach that Victor used on the PTO coil form. And he had to rebuild this part to get the receiver on 40 meters. As we can see in the above video, Victor’s homebrew receiver is pulling in stations from across Europe. Victor even reports hearing a Japanese station. FB!
Victor writes:

Hi Bill, I changed the PTO tuning unit, more stable this way. I m a retired electrical engineer, revamping on a more daily basis tube radios from the 50’s 😉 I include a Bluetooth interface too so they can be used again by “young” people with their smartphones.. I had great fun and learning experiences building the DCR !!


Thanks for the video, pictures, and messages Victor. Congratulations!

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:

Garry’s FB Australian SolderSmoke Direct Conversion Receiver with “Free Tree Printed” PTO Coil Form

Garry built a really nice receiver. I think he is in Australia. His PTO coil form is “a piece off an old rotten Australian red cedar door.” FB Garry.

Garry did a really nice blog entry on his build experience:
As with Chris, if there was any justice in the world, Garry would be issued a ham license based solely on this receiver build. He has done something that 95% of hams have never done: he built a receiver!

Congratulations Garry!

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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:

Tapesponding — Who Knew?

I didn’t realize that “tapesponding” had become so widespread. I know of two very prominent homebrewers (one now a Silent Key) who exchanged tapes. When I learned of this I asked if those tapes (which would have been a real treasure) were still around. Sadly, they had been destroyed, as, I suspect, were most of the tapes mentioned in this video.

I sometimes think that some of the on-the-air conversations about tech topics really should be saved for posterity (most conversations clearly should NOT be saved!). The internet provides a great forum for this kind of preservation. This happens, but only very sporadically and mostly in the AM world.

Thanks to Hack-A-Day for alerting us to this.

Nate KA1MUQ Turns His Frying Pan DC Receiver into a Double Sideband Transceiver and Works Idaho from California

Wow, you can see the look of homebrew satisfaction as Nate works Idaho from California with his homebrew Double Sideband Transceiver. It is a good thing that Nate got that frying pan into the shack before he was banned from the kitchen.

Nate writes:

I finally got my DCR to be a DSB transceiver. I had a lot of trouble with transmitted RF getting back in to the VFO and causing distortion. While I imagine I could have tried putting the VFO in metal box, I instead opted to move the VFO to a 4.7-5 MHz range and then mix that with a 12 MHz crystal oscillator. Now the VFO is at a frequency unaffected by transmit RF. This mixer and crystal oscillator are on the breadboard and from SSDRA. The transmit amplifier chain was taken from Fahran’s Daylight Again radio. I just got a 570 mile contact on 5 watts – conditions are good. If there is interest let me know and I’ll share my schematic.

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I looked this morning and I have 100 DSB posts on the SolderSmoke blog. There are lots of ideas there on how to homebrew for DSB, many of them from Cuba, many covering DSB rigs that I built in the Azores, and others that I used in the Dominican Republic. Check it out:

Dallas KC5DI’s SolderSmoke Direct Conversion Receiver

Dallas is a friend of Lyle WZ5M — Lyle encouraged him to build this receiver. Dallas’s son is also working on a receiver — we hope to see that one completed soon.

FB Dallas and congratulations.

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:

Lyle WZ5M’s SolderSmoke Direct Conversion Receiver

Lyle WZ5M did a great job on his receiver, and in the finest ham radio tradition encouraged two other builders to take up the SolderSmoke challenge. FB Lyle. I really like your receiver. That looks like a genuine pine board. Frank Jones would approve.

73 and congratulations!

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: