We were very pleased that Phil W1PJE was able to visit yesterday. Phil is the Director of MIT’s Haystack Observatory. He is very knowledgeable on topics related to space and space technology. He is also a member of the SolderSmoke Direct Conversion Receiver Hall of Fame. We talked about the history of the Haystack Observatory, famous antennas (dishes), and about the SolderSmoke Direct Conversion receiver project. It was a lot of fun talking to Phil. We managed to shoot this video with him. Thanks Phil and thanks Dean.
Category: Souleles — Dean
A FIRST! K1OA Contact with N2CQR — All Homebrew with SolderSmoke Direct Conversion Receivers on Both Ends
At around 0630 EDT on June 7, 2025 I heard K1OA calling CQ on 7030 kHz CW. This was exactly where I had a crystal. I called him, but he didn’t hear me. I sent him an e-mail. We tried again — he heard me calling him and I heard him responding by calling me, but I don’t think we succeeded in exchanging signal reports. It was close, but no cigar.
I had to walk the dog. Scott and I agreed to meet on 7030 kHz at 0730 EDT. Arggh. There was a QSO there. I thought we might have to try to change frequency, but this would have been tough because both of us were crystal controlled on transmit. Fortunately, the contact on 7030 kHz wrapped up. Scott called me, I responded, and we were able to exchange signal reports. I was so excited that I almost forgot to hit the record button on my phone. But I caught the last minute or so. See above.
This was really something. This really goes to prove what Dean and I have been saying all along: this receiver is not a toy! It can be used for real ham radio contacts. And now we have had these receivers on both ends of a contact. For transmit, Scott was using a KA4KXX transmitter with about 3 watts output. I was on my Tuna Tin 2 at about half a watt output.
Thanks Scott! And thank you Walter!
SolderSmoke Podcast #260 FDIM, Hollow State Design, Pete’s Bench and the Shelf of Shame, Direct Conversion Project News, How Best to Preserve this Blog?, Dean’s Bench and the Desk of Despair, Bill’s Bench and the Garage of Grief, MAILBAG
SolderSmoke Podcast #260 is available:
Audio version: http://soldersmoke.com/soldersmoke260.mp3
Video version: https://www.youtube.com/watch?v=bZzHSjOTbSY
Quote from the Old Miltary Radio Net: “Being on the leading edge is great, but sometimes being on the trailing edge is more fun.” Indeed.
Heard from an Australian on the Southern Cross Net: “My antenna needs a lot of Viagra!”
News from Dayton/Xenia/FDIM: Dayton Xenia. Again, we didn’t go. But Bob Crane W8SX was there and got a nice interview with Grayson, Hans, and Farhan. We are presenting these and more. Michigan Mighty Mite Revival at FDIM! Jeff W9TH.
Farhan’s review of Hollow State Design: I am compelled to set aside the future of my family and to orphan my cats to resume work on the 250v power supply that I built last year. Inshallah, Allah favors those who favor thermatrons! Grayson’s book is imbued with deep experimental insights and littered with gems. You have to read it over and over to find new things each time. It goes into my reference shelf in the lab.” Buy it here: https://www.ermag.com/product-category/books/
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PETE’S BENCH:
Pete working on JF3HZB dial. Send Pete a Heath mono-bander!
MHST on shelf of shame? Even the great ones have to take a break every so often. On the importance of taking a break. Ernest Rutherford 1917 and all that: https://soldersmoke.blogspot.com/2025/05/on-importance-of-taking-break.html
Channelized 40 meter rig. Heard in Arizona by Andy KB7ZUT on a HOMEBREW SSB Reciever. Very rare. SWL HB2HB.
Pete: Thumb broken as a Novice? Early episode of Fat Finger Syndrome?
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DC RX NEWS:
Quote from N6QW: “The radios do not build themselves!”
Alan W2AEW finishes Direct Conversion Receiver. And even he worries about feedback!
Phil W1PJE MIT receiver (with cool MIT stuff). Coming to see us!
KN6FVK’s Barkausen-Be-Gone Spray :https://soldersmoke.blogspot.com/2025/05/john-kn6fvks-fb-homebrew-soldersmoke.html
Indian hams working DC RX. VU2JXN Ramakrishnan, VU2TUM Puneit Singh, Ashish N5ASD, building one in Bangalore with 3D printed form from Scott, KQ4AOP. Ramakrishnan is planning on building a second receiver with his daughter. On June 22, 2008 in SolderSmoke #86 we reported on the birth of Ramakrishnan’s daughter. This is that same daughter! See: https://soldersmoke.blogspot.com/2024/01/long-time-soldersmoke-supporter.html How to get a PTO form in India. A tip from Ramakrishnan: “I got the 3d printing done via https://robu.in with 1:1 size. After uploading the stl, I received it by post in 5 days or so.”
German students of Andreas DL1AJG. and Canadian students of Daniel VE5DLD.
Receiver built in Singapore! 9V1/KM7ABZ
John M0XJA reports 8 members of his club are building this receiver.
Chuck N4AVC got his PTO coil form 3D printed at the local library. For free! FB!
Few admit to being fooled by April Fool story. But still, inspirational. VK3HN was going for a few seconds — SOTA AI chatbots? John West liked the 85th harmonic threat.
What next after DC RX? Choose carefully! Don’t bite off more than you can chew.
Do some mods! Build something else! And remember to be a homebrew Elmer. Help someone else build the receiver.
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SHAMELESS COMMERCE DIVISION:
Check out the SolderSmoke blog on the WayBack Machine. The blog, not the podcast. www.soldersmoke.blogspot.com Would this be a useful backup if Google were to pull the plug on blogspot? Is the format OK? Is the template recoverable? How best should we backup the SolderSmoke blog?
Be a Patreon SolderSmoke Sponsor! Please subscribe to the YouTube channel! Buy your Amazon stuff through our link. Buy stuff from Mostly DIY RF.
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DEAN’S BENCH:
Dean has completed his Mythbuster: https://kk4das.blogspot.com/2025/05/kk4das-mb-20-transceiver-complete.html Plexiglass top!
Diode switching.
Dean: Build of the SDR receiver. Microscope required?
____________________
BILL’S BENCH:
VK6JDW and HCJB in the Kimberly.
The stages of separation: Shack, Garage, Car trunk: HP-8640B and HAMEG scope saved from garage. HP-8640B repair. HAMEG Modulation Monitor.
=================
MAILBAG
— Wouter ZS1KE. Thinks Soviet spies COULD homebrew. Hamilton KD0FNR concurs. Agent Sonya and Soviet Spy homebrew. Copacetic Flow. I dunno….I dunno…
— Hamilton KD0FNR grew up in New Mexico, supports my idea of Starlink deorbit. See : https://www.kallmorris.com/columns/goodness-gracious-green-balls-of-fire
— Adam N0ZIB Heard my 10 meter beacon from the DR. 28,233.5 MHz On now.
— Rick N3FJZ Great memory Direct Conversion messages.
— John KN6FVK had fun with DC RX. Tattoos on Board. We need a high sign! Like the Little Rascals.
— Adrian M7EFO DC RX builder in GQRP. FB.
— Steve KW4H Kits not the same as homebrew, but old Boatanchor kits have value.
— Mike WU2D — Old buddy Charles Kitchen SK.
— Craig — Some really nice feedback on Hack-A-Day re DC RX and Dean’s videos.
— Peter VK3TPM proposes a certificate for SolderSmoke DC RX Honor Roll.
— Michael WN2A used a 3 inch reflector from Northern New Jersey. Edmunds Scientific “Space Conqueror”
— Phil W1PJE and Mike WN2A lament that our eyes don’t pick up radio frequencies. This would be a great troubleshooting tool! I can SEE the IMD! Perhaps some tin foil hats?
— John WPE9IRS SW listener! Heard my beacon. Many SWLs switching to tuning in ham stations.
— Peter VK3YE found a homebrew 160 meter double-sideband transciever at a hamfest. He also found “Solid State Basics for the Radio Amateur — A QST Anthology” NOT SSDRA. But good!
— Peter VK2EMU From the Southern Cross (I took a picture of it in the DR!) Building the DC RX!
Ramakrishnan VU2JXN
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!
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Thanks to Andreas DL1AJG. Welcome to the Hall of Fame.
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Join the discussion – SolderSmoke Discord Server:
Documentation on Hackaday:
https://hackaday.io/project/
SolderSmoke YouTube channel:
Chris G7LQX’s SolderSmoke Challenge DC Receiver
It looks and sounds really good. It is inhaling SSB, CW, and digital signals on 40 meters. Great job Chris.
More details here. It is NOT to late to build one of these.
Join the discussion – SolderSmoke Discord Server:
Documentation on Hackaday:
https://hackaday.io/project/
SolderSmoke YouTube channel:
SolderSmoke Podcast #257 — Wrap up of the SolderSmoke Direct Conversion Receiver Challenge
SolderSmoke Podcast #257 is available.
Video version: https://www.youtube.com/watch?v=xOoZiHbC4Ag
Audio version: https://soldersmoke.com/soldersmoke257.mp3
Join the discussion – SolderSmoke Discord Server:
Documentation on Hackaday:
https://hackaday.io/project/
SolderSmoke YouTube channel:
https://www.youtube.com/@
SolderSmoke blog DCR posts:
https://soldersmoke.blogspot.
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Lot of success! So far 22 completed receivers: 35 others are being built.200 or so people are on the Discord server.
What a great achievement this is! Folks are homebrewing receivers.
Scott KQ4AOP heard his very first amateur radio signals through this receiver. FB!
Lots of great ham homebrew spirit. NE3U, N9TD and others 3d printing coil forms for others. FB
It is not too late. Dean’s videos and the Discord server will remain up, even when we ourselves have moved on.
Big Picture: Farhan’s Four Stages — All you need to build a rig: Oscillator, Filter, Mixer, Amplifier.
Homebrew and Manhattan vs. Kit built with PC board. We think Homebrew is a better experience. Dean recently assembled some Ikea kit furniture. Does that make him a carpenter? No.
We do update the schematic as we learn. This is similar to what happens to software. Github? Version 2.3? In the old days, when QST came once a month, we lived a harder life. We don’t have to do that anymore.
Let’s talk about the boards one by one:
The Oscillator (VFO or PTO):
— Started out as an amalgam of Farhan circuits: We liked the very simple oscillator he used in his Hyderabad DC receiver project for the girls schools. No need for a hard-to-find variable cap. But we found we needed a 3.3 k ohm resistor in the emitter to make it go. We took the buffer/amp from Farhan’s “Daylight Again” circuit, but later (much later!) added a .1uF cap across the source of the J-310.
— With brass screw, not really a permeability tuned oscillator. Brass has same permeability as air. Works via Eddy currents. But the screw thing is very reminiscent of the old Collins PTOs, so we call it a PTO. And it IS s PTO if you used a steel screw. You should study the doc in the mods section about how to modify the PTO. Metalurgy matters!
— We used silver mica caps in the frequency determining circuits. This is important.
The Mixer:
— We started with a simple two diode, single transformer singly balanced mixer. Only LO signal would be balanced out. This would work, but we got a lot of AM breakthrough from Radio Marti, just above the 40 meter band. So we went with a homebrew diode ring mixer.
— Important to unserstand how the diode ring really works: LO just switches on and off the diodes. Very cool that several builders sought to understand how diode ring works.
— Best way to test the PTO and the Mixer? Put them together and look at the waveform at the mixer input. Is it flat topping? Then both stages are working.
— Diplexer: From QRP legend W7EL’s Optimized QRP transceiver. Seemed to help knock down Radio Marti. But we kind of knowingly disregarded AF amp input impedance. It would have been too complex to fix. We were going for simplicity.
BP Filter:
— We actually got to do the NanoVNA test with one set of the high school students. This was very cool. Proves the worth of the NanoVNA.
— Again good to learn the theory.
AF Amp:
— Kind of an amalgam of a Forest Mims amp and the amp from the Herring Aid 5.
— Sure, an LM386 would have been simpler. But we did not want to use ICs. And IC AF amps oscillate too. You learn more by going discrete.
— We used a transformer. For simplicity. We know the push-pull circuit, but wanted to avoid it. Some guys are going to other AF amp circuits becasue of the transformer. See this as an interim measure… You can fully meet the challenge later, when you get the transformer.
— We also — in the name of simplicity — did not use feedback amps. We have an optional bandaid resistor across the oscillator to lower overall gain.
— It can oscillate. But keeping leads short, keeping inputs away from outputs, putting adequate electolytics on the 12V power rail can prevent this. This is a good lesson in good construction practices. And with the real world of amplifiers (they all aspire to be oscillators!)
——————-
Some Tales of Woe:
- Simple mis-wiring – need to learn to read schematics
- Transistors in backwards – importance of checking the data sheet for your brand – sometimes different brands of same part have different pinouts
- Lying Test Equipment
- Jay W3V3 unreliable measurements from old Fluke auto-ranging multimemter
- Phil, W1PJE – using a 10X probe with scope termination set to 50 ohms
- Peter, VK3TPM – faulty component tester (mixed up collector and emitter on NPN transistor)
- And many, many setup issues with scopes, signal generators, TinySAs, NanoVNAs
- Bad parts
Some “lessons learned” taken from the Walk of Fame Channel
- Wayde, VA3NCA – taking care when choosing junque drawer components, solidifying concepts introduce in the licensing material – benefit of hand-son experience “building them made them more real”
- Peter VK3TPM – don’t trust your transistor tester, transistors can pass signals even when wired backwards. Importance of 10X probles. NP0/C0G caps for frequency stability
- Ken, W4KAC – learned to better use his test equipment to trouble-shoot, and finally learning to trust his troubleshooting after changing out a faulty transistor.
Parts sourcing: We were surprised at how much time people spent on this. Parts sourcing struggle reminds us of the importance of 1) understanding the circuit and 2) having a decent junkbox. 3) scrounging old parts when necessary.
Looking ahead: Antennas are important! You probably can use Cat 5 cable instead of real coax. Noise is natural. Mods are fun. CW in some ways harder than DSB. Lot of antenna info on the internet.
You can modify the PTO for easier tuning. See the doc. Add a front panel, or a case. Once your basic receiver is done, you can experiment with better circuits. See the mods doc for ideas.
Final Comments:
— It is ultimately the builder who has to make the machine work. Homebrew means that YOU the builder are going to make it work.
— Be careful about who you take advice from or give advice to. Don’t be afraid to say “I don’t know.” Ask yourself: Is the guy who is giving me advice really an experienced homebrewer? Am I?
— We learned a lot in this process. You guys have made this a better receiver.
— Be careful about starting over… Bill and Dean’s homebrew nightmare!
SolderSmoke Challenge — Direct-Conversion Receiver Video #5 — Building the Audio Frequency Amplifier
SolderSmoke Challenge – Direct Conversion Receiver – the Audio Amplifier Build and Receiver Demonstration
In this episode Dean, KK4DAS wraps up the initial build of the SolderSmoke Challenge DCR. He takes us through the audio amplifier stage and demonstrates the newly built receiver just moments after connecting the audio module to the mixer and hooking up a speaker. The audio module is conceptually simple – three nearly identical stock-standard common emitter audio amplifiers which provide the 80-100 dB of amplification you need to go from microvolts of RF to volts of audio to drive a speaker. The challenge with all that amplification in a small board is to keep it amplifying but to stop it from oscillating and as you’ll see in the video, good construction technique is critical to good performance.
And wow! We now have more than 30 builders working on the SolderSmoke Challenge, with more builders completing the challenge every day. And those are just the ones who are active on tour Discord server. If you have completed the DCR or even if you have just started building it, we want to hear from you. Send a picture or better yet a video – make it a selfie and you can join the SolderSmoke challenge hall of fame!
And if you are not yet building it, you must ask yourself one question:
What are you waiting for?
Join the discussion – SolderSmoke Discord Server:
Documentation on Hackaday:
https://hackaday.io/project/
SolderSmoke YouTube channel:
https://www.youtube.com/@
SolderSmoke blog DCR posts:
https://soldersmoke.blogspot.
SolderSmoke Direct Conversion Receiver Challenge: A Short Video from Dean about the Virtues of Building the AF Amplifier ONE STAGE AT A TIME
Dean will soon post his longer video on how to build the fourth and final board of the SolderSmoke Direct Conversion Challenge receiver, but we know many builders are chomping at the bit, and are going ahead with the building of the AF amp board. We hope that this short preliminary video will help. Here Dean descibes the benefit of building the three stage amp, ONE STAGE AT A TIME.
Response to the challenge has been great. There are at least 30 receivers under construction around the world. Many are already inhaling RF. All of the problems that arise with true homebrew are being identified and fixed. Dean’s full AF amp video will be out shortly. Thanks Dean!
SolderSmoke Challenge – Direct Conversion Receiver – the Band Pass Filter
The SolderSmoke DCR challenge is going well. Our Discord server is bustling with activity and we are impressed that several intrepid homebrewers have already completed the receiver. So, we know that you can too! In this episode Dean, KK4DAS walks us through the design and construction of third of our four boards, the 40-meter band pass filter. The band pass filter ensures that the only signals that get through the receiver to the speaker are those that are in the 40-meter band. Dean also gives an update on the Challenge and discusses some recent improvements we’ve made to the circuits based on feedback from our builders.
Join the discussion – SolderSmoke Discord Server:
Documentation on Hackaday:
https://hackaday.io/project/
SolderSmoke YouTube channel:
https://www.youtube.com/@
SolderSmoke blog DCR posts:
Update from KK4DAS on the SolderSmoke Direct Conversion Challenge: BP Filter Added to Circuitry — Full Video on BP Filter Soon
Dean now has the PTO, the Diode Ring, and now the 40 meter bandpass filter. Dean fires up his signal generator and, using his ‘scope we see audio coming out of the mixer. FB.
Dean says he will have the complete build video for this stage soon. Thanks Dean.
SolderSmoke Direct Conversion Challenge The Mixer and Diplexer
SolderSmoke Challenge – Direct Conversion Receiver – the Mixer
The mixer is the heart of the direct conversion receiver. It’s the circuit that makes a receiver a receiver. It takes the RF from the antenna and mixes it with the local oscillator to extract the audio. In this video, Dean, KK4DAS walks us through the design, build and testing of the double balanced diode ring mixer we chose for the SolderSmoke Challenge DCR. He also explores some of the myths, legends, and lore around mixer design. If you are not yet convinced, we can make an effective receiver with just four simple boards you definitely want to watch this vido to the end. Mixers have been a passion (some say obsession) of mine for a long time. If you search for “mixer” on the SolderSmoke blog you will find many postings over the years. Whenever I want to learn more about some RF circuit or other I always turn to Alan Wolke, W2AEW’s excellent YouTube video series. In the video linked below Alan does an excellent job of explaining mixer theory and demonstrating how the switching action of the diodes produces the sum and difference frequencies.
Related links:
Alan Wolke, W2AEW – YouTube Video #167:
How a Diode Ring Mixer works | Mixer operation theory and measurement
https://youtu.be/junuEwmQVQ8?
SolderSmoke Blog on Mixers:
https://soldersmoke.blogspot.
Join the discussion – SolderSmoke Discord Server:
Documentation on Hackaday:
https://hackaday.io/project/
SolderSmoke YouTube channel:
https://www.youtube.com/@
SolderSmoke blog DCR posts:
https://soldersmoke.blogspot.
SolderSmoke Direct Conversion Receiver Challenge — Soldering!
The DCR challenge is going well, and we have several builders making good progress. We noticed that some first-time builders are having a little trouble with soldering. Cold or weak solder joints are the bane of the of the homebrew builder’s existence. It happens to all of us. A board that was working fine suddenly is not working – you poke around and touch some part and the board springs to life – you just found a cold solder joint. Dean, KK4DAS put together a short bonus video just on soldering. He covers the tools you need for a basic soldering station, and step-by-step instructions for reliable soldering Manhattan Style.
SolderSmoke Direct Conversion Receiver Project — Video #2 — Building the PTO/VFO
The response to the SolderSmoke DCR challenge has been terrific -with nearly 7,000 views of the first episode! Thanks so much for checking it out. The goal is to convince you that you can build your own receiver and then go get you started on Homebrew ham radio. We already have confirmation that it can be done! Congratulations to Peter, VK3PTM and Matthew, KY4EOD who have both completed the receiver. The boards look good and, even better, they sound great. Videos and descriptions are here on the blog and on the SolderSmoke Discord sever. Speaking of the Discord server, we already have a very robust conversation going, It’s a great place to give feedback and to get your questions answered. Builders are helping builders and we at SolderSmoke are trying to answer as many of your questions as we can. This is a beginner’s project, so all are welcome.
In episode 2 of the SolderSmoke Direct Conversion Receiver challenge we tackle the PTO. We discuss a bit of the theory, walk through the schematic, and take you step-by-step through building and testing the oscillator and buffert. By the time we are done we will have achieved JOO! (the Joy of Oscillation). And when you build it you will be 1/4th of the way to having build your own 40 meter receiver.
Links:
Join the discussion – SolderSmoke Discord Server
Documentation on Hackaday
https://hackaday.io/project/
SolderSmoke YouTube channel
https://www.youtube.com/@
SolderSmoke blog
The 10 meter Beacon at HI7/N2CQR (and reception reports)
Above is the 10 Meter beacon at HI7/N2CQR.
The first one to hear the beacon was Dean KK4DAS in Northern Virginia, within hours of it going on the air. Here is Dean’s recording of what he saw and heard:
Later, Mike WN2A heard it. Pete N6QW in California may have heard it too. A number of stations are reporting reception via the Reverse Beacon Network (RBN): It is being picked up almost daily (gray-line?) by Rico DF2CK who has an amazing station in Germany. K1RA in Warrenton Virginia (also an amazing receive set-up) is also picking up the station. W3OA in North Carolina is also hearing it and reporting by RBN. TI7W in Costa Rica has also heard it. Sadly, RBN is kind of clunky with beacons — it seems to obstinately insist that I am in Northern Virginia.
Rico DF2CK writes:
Hi Bill,
thanks for info. 3 Watt can be loud on 10 if condx are good 🙂
The west direction skimmer setup on 10 m is a 6 el Yagi into a SDR with
AD9255 adc and XC7Z020 fpga.
A design by Pavel Demin which I am testing for a while now.
Enjoy the Caribean, here its minus 2 C and boot high snow.
73, Rico
DF2CK
thanks for info. 3 Watt can be loud on 10 if condx are good 🙂
The west direction skimmer setup on 10 m is a 6 el Yagi into a SDR with
AD9255 adc and XC7Z020 fpga.
A design by Pavel Demin which I am testing for a while now.
Enjoy the Caribean, here its minus 2 C and boot high snow.
73, Rico
DF2CK
Check out Rico’s amazing station here: http://df2ck.de/
Andy K1RA wrote from Warrenton (Northern Virginia):
Hi Bill
Cool on spotting your beacon. With good conditions I’m surprised you’re not being heard elsewhere.
I’m running a multi-band, multi-mode skimmer for CW, FT8, FT4, WSPR & JS8CALL continuously and simultaneously covering 160m-6m, 24×7 with Redpitaya SDRs and KiwiSDR/RaspSDRs
15 minute map view through PSKreporter here:
73 & good DX’ing!
andyz – K1RA
Scott KQ4AOP’s PTO Coil Forms for the High-School Direct-Conversion Receiver (Video)
Scott KQ4AOP listened to amateur radio signals for the first time using a homebrew receiver. That is really something. See: https://soldersmoke.blogspot.com/search?q=KQ4AOP
Scott then very kindly offered to 3D print the coil form for the PTO that is one of the four stages of our High School receiver project. The above video shows the coil forms being 3D printed on Scott’s machine, and explains where some of them are going.
Dean KK4DAS will soon launch a video and e-mail-based build of the receiver. Stay tuned. Dean’s series should clear up any remaining questions about how to build this receiver. As Scott so rightly said:
“This was my first receiver build and, it was great fun. When you finish the build and prove you are able to tune through the band, you are welcomed into the secret society! The build is the initiation. I am happy to print and ship the PTO if needed.”
Derek N9TD’s Magnificent Build of the TJ Direct Conversion Receiver
I think it is magnificent. Derek N9TD fought his EE tendencies and recognized that the perfect can be the enemy of the good. So he went ahead and built this receiver pretty much as we intended it to be built: Four stages: BP filter, PTO, Diode Ring Mixer, Super-simple AF amp.
He went several steps further and added a fixed coil to slow down the tuning and keep it in the 40 meter band. He added an RF gain control. And he went with a steel (vs. brass) screw. But these are all things that I myself have done. (We still advise people to build it the simple way first.) FB Derek.
The challenge is still out there. The gauntlet has been thrown down. Derek’s completed project shows us that this project is entirely do-able. Do it!
Derek wrote:
Bill,
Let me introduce myself, I am a recent electrical engineering graduate from Purdue and a long-time listener of the podcast. I want to thank you and Pete for being one of the reasons I chose to pursue my degree in the first place. I’ll admit that in the more difficult stretches of getting my degree, I often pulled out the podcast to be reminded of the fun that can be had with radio and electronics.
Until recently I had to hang my head low along with the majority of the other ‘appliance operators’ out there having never built anything with my two hands that can be used to pull signals out of the ether.
I am no stranger to building projects, PCBs, and melting solder but I usually chose to either stick to the dreaded digital domain or focus on antennas, filters, and other ancillary equipment. The logic being that I like to have a “known good” radio for the shack and that I would focus on other equipment to supplement the radio. I still follow this logic when I want to contest and we all know that antennas are well worth the effort, I’ve just finally had enough of being an appliance operator and have your podcast to thank for the extra push.
I had been following the original effort of the TJ DCRX with interest from the start and earmarked this project as one I would like to build based on its inherent simplicity and good performance. However, the demands of school and a recent (at the time) abortive attempt to build an AM superhet with an SA602 the year prior made me (I got as far as feeling the joy of oscillation but regretfully petered out after that) put this one the backburner for about two years until December 2024.
By coincidence, I independently decided to start this project just before your show with the HRWB folks and the gauntlet being thrown down, which has spurred many to build this receiver. It has been great to see the extra coverage on the receiver, and the commentary has been very insightful for someone trying to build this for the first time and with as many of the “improvements” as possible.
For better or for worse, I’m the type of guy who wants to understand the “why” behind all the design choices and, from there, try to incorporate as many lessons and improvements as possible to make the “best” version possible. I’m not saying I make the best version of anything, but it’s just a quirk of the way I think and justify doing a project. It always has to be “this and some additional improvement;” otherwise, I would decide against doing it.
Rambling aside, I ended up building the DCRX, adding the RF attenuator from N3FJZ’s website, and incorporating the lessons you learned after experimenting with improving the tuning on the PTO. I added an external series inductor wound on a dowel rod and used a zinc-coated steel screw as opposed to brass. I found that this gave solid tuning performance across 40m and was easy enough to tune in CW or SSB signals (after 3D printing a large knob for the PTO bolt). Alan W2AEW’s video on mixers was a great tutorial to use to verify that my mixer was mixing. With the radio assembled I was treated to the joy of hearing my receiver breathe in the sounds of 40m for the first time last weekend and even managed to copy some Croatian DX during last week’s contest. As Farhan said to do, I have spent the last few days enjoying the receiver and figuring out its quirks before moving on to the next step.
The only “issue” I have noticed is that I still get some AM breakthrough despite tuning in the bandpass filter. The problem is very noticeable if I accidentally put my finger on the wires going to the AF gain pot. If I do that the AM station is the only thing I can hear. This makes me think the problem is after the bandpass filter and more investigation is needed. Maybe using coax on the control lines to shield it will help? Regardless I am impressed with how well the receiver sounds, the stability of the oscillator, and the effectiveness of the simple audio amp….
Again thank you and Pete for your work on the podcast and for helping inspire countless homebrew radio operators!
As a thanks for reading through this long email, I’ll leave you with some photos of my build as a reward.
73s,
Derek N9TD
SolderSmoke Podcast #255 — Accept the HB Challenge!, DeMaw SSB, Brilliant TR-3, Tube Talk, Ground Truth, Tales of Woe, SDR RX, Pico Balloons, MAILBAG
Mythbuster II — 20 meters only
SolderSmoke Podcast #255 is avalable:
— First: Happy Holidays! I have on a Santa Claus hat!
— December 18. Pete completes another orbit. Happy Birthday Pete. Please send him birthday greetings.
— Bill was on Ham Radio Workbench: https://soldersmoke.blogspot.com/2024/11/bill-n2cqr-appears-as-guest-on-ham.html Our challenge to HRWB. Gauntlet thrown down… OUR CHALLENGE HAS BEEN GRACIOUSLY ACCEPTED! We now extend the challenge to the entire SolderSmoke community: Build one of these: https://hackaday.io/project/190327-high-schoolers-build-a-radio-receiver
Homebrewing is not for the faint of heart! Accept the challenge! Build stuff!
Our question: Did Doug DeMaw ever build an SSB transceiver? Starting in September 1985 he wrote a five part series on an SSB TRANSMITTER for QST. But he prefaces it by asking, “Why would anyone build an SSB transmitter today?” He says it would be fun “for the experience and understanding it would provide.” But not for use, you see… And it is not a transceiver.
Bill’s theory about DeMaw, SSB,CW and sideband inversion: He was a CW guy so sideband inversion did not really matter. He could get it wrong and still make it work.
Pete’s Bench:
Brilliance and the TR3. https://www.youtube.com/watch?v=2C-eYB8yFzg&t=13s
A tale of woe. Done in by a light bulb.
Thanksgiving dinner and SSB transceivers. https://n6qw.blogspot.com/2024/11/11292024-how-to-homebrew-thanksgiving.html https://www.pastapete.com/
Hybrid plans: https://www.youtube.com/watch?v=zKUjHZMf3Fs&t=5s
Dean’s Bench:
Travelogue – Falcon 9 Launch
Building a homebrew T Match tuner for the end-fed long wave – sourcing the parts, winding the coil – taps, testing
VWS Makers Projects
SDR Receiver Project – starting in January
VWS Pico Balloon – Traquito – Traquito – WSPR Pico Balloon
Revisiting the 10M DSB rig
Soldersmoke listener challenge – build a DCR with KK4DAS – overview then one board a week
SHAMELESS COMMERCE DIVISION: Mostly DIY RF. Please subscribe to our YouTube Channel. And use the Amazon link on our blog. Become a Patron via Patreon (on the blog). SolderSmoke is now on Blue Sky and Threads — follow us or at least like us there. Please turn on automatic downloads on your podcast app — most podcast apps will only store a few episodes. This will help bump the numbers, which will improve visibility. Please give the show five stars and, if possible, a nice review on your podcast service, That will help with the discovery rate for people looking for new podcasts.
Bill’s Bench:
Is “The Ground” a Myth? ARRL VP says Ground is a Myth: https://www.youtube.com/watch?v=KdX-978tvkY. Bill disagrees. Helicopter story. Refrigerator story. Original single wire telegraph system. https://en.wikipedia.org/wiki/Single-wire_earth_return
Front Panel and Freq Counter for the Mythbuster II.
Another Tale of woe: A mysterious audio problem on the 15-10 II rig. Done in by…. Duh! Comparing sideband suppression with Mythbuster I. Differences in Hfe? Notes on Mythbuster II build.
TinySA Ap — A cure for Fat Finger Syndrome? : http://athome.kaashoek.com/tinySA/Windows/ How to get and load the Ap (you might want to start watching at 1:11) https://www.youtube.com/watch?v=zu4X5dyUlpo&t=2s General info video on the TinySA Ultra: https://www.youtube.com/watch?v=6C24RnYNOWQ&t=1143s
For the DR shack — I got a Swan SWR-1A on E-Bay.
MAILBAG:
— Scott KQ4AOP trying to track down the DeMaw SSB transceiver mystery. On the DC Receiver: This was my first receiver build and, it was great fun. When you finish the build and prove you are able to tune through the band, you are welcomed into the secret society! The build is the initiation.I am happy to print and ship the PTO if needed.
— Bill WA5DSS has built a High School Direct Conversion Receiver!
— Grayson KJ7UM liked the 1971 video on old THERMATRON AM radios: https://soldersmoke.blogspot.com/2024/11/basic-radio-circuitry-1971-film.html
— Chris KD4PBJ sent nice electronic care package.
— Walter KA4KXX is honored that Dean named his dog for him (Walter was just kidding)
— Thanks to Bob W8SX for FDIM 2024 interviews.
— Tony G4WIF insomnia driving him to podcasts. Amazed by quantity of food eaten on Thanksgiving.
— Nice comment from Trigger about the podcast.
— Clint says “valves” when he means THERMATRONS. Kindly asks about “Oooo Thats Awesome”
— Eric 4Z1UG faced with a new challenge. Get well soon OM.
— Sam WN5C and his Chat GPT AI Elmer.
— Paul VK3HN on using AI for electronic design. I dunno… Apocalypse Now in the DR?
— Tommy SA2CLC FB old military gear on QRZ site. Helps with HP8640B repair.
— Mike WN2A nice comments on Chappy Happy’s FB Tezukuri DC RX https://soldersmoke.blogspot.com/2024/11/tezukuri-and-chappy-happy-amazing.html
— Allison KB1GMX. Good info on ground truth.
— Phil W1PJE Had to throw out 15 test leads. Fake wire!
–Todd K7TFC Thoughtful comments on AI and ChatGPT, Help with TinySA Ap
— Steve KW4H Boatanchor guy. Likes that we often scratch our heads trying to understand.
— Nick M0NTV built a 40 meter DC receiver: https://soldersmoke.blogspot.com/2024/12/a-40-meter-direct-conversion-receiver.html
— Dave AA0KU asks about CCI amp (AN762) Also woking on Drakes.
— Jack (Dhaka Jack!) F4WEF/AI4SV Good thoughts on how to bolster SolderSmoke’s ratings.
–Tobias thinks the decline IS ALL HIS FAULT!
— Tony VE7JUL building a TJ DC RX. Go Canada! Dean says: 3D print PTO former at 110%
— Jim KI4THC getting his uBITX on the air.
10S November 23, 2024 1517Z SV1AER Kostas in Athens. Said a very sincere “Oh my goodness! Congratulations! That is not a very common thing!” when I told him rig was homebrewed. Nice fellow. Great response.
SolderSmoke #254 (Audio and Video Versions): Australian Hex Beam Eaters, Fake Wires, Hybrid Rig, Antennas, Mythbuster II Transceiver, Mailbag
Hex Beam Eater
November 13, 2024
SolderSmoke Podcast #254 is available:
Audio Version here: http://soldersmoke.com/soldersmoke254.mp3
Video Version here: https://www.youtube.com/watch?v=ZiZwWY1CQgI
Opening: Disturbing news from Australia! VK5RS reports that his Hex beam was EATEN by Cockatoos! So stop whining about your HOA problems, OK? It could be much worse!
FAKE WIRES FROM CHINA! Oh no! Even the wires? There is a good video from Mattias. I have it on the SolderSmoke blog. https://soldersmoke.blogspot.com/2024/11/clip-leads-made-with-fake-wire-buy-good.html Important to note that Parts Candy doen’t have this problem. Buy your test clip leads from our sponsor, Parts Candy. Link in the column on the right or go to partscandy (that’s one word).com
Bill’s appearance on the Ham Radio Workbench. (Bill made some overly harsh comments about radio rejuvenation, and was trying to make amends.) But now we throw down the gauntlet. WE CHALLENGE the HRWB guys to build — to homebrew – our TJ DC RX. They will experience JOO, JVO and the elite status that comes with having built their own ham radio receiver. And if they go on to build a 10 minute transmitter, they can use it for CW contacts. Like on POTA (Thomas!)
Anniversary approaching: In August 2025 we will mark 20 years of the SolderSmoke podcast. And we have already passed TEN YEARS OF JULIANISMO! Pete joined the podcast on May 26, 2013. Thanks Pete!
Question for the group: Which SSB transceivers did Doug DeMaw build?
Pete’s Bench: Thermatron-Transistor Hybrid Goodness. https://n6qw.blogspot.com/2024/10/blog-post_20.html
Dean’s Bench: The new Hex Beam (watch out for Cockatoos!) Now that Dean and I both have Hex Beams, we plan on pointing them at Southern California in an effort to talk to an elusive RADIO GENIUS. Stay tuned!
Dean’s Hex Beam — A Thing of Beauty
Also homebrew random wire with T match tuner for attic. RF Burns!
SHAMELESS COMMERCE: Please link to our blog and podcast! Please become a Patreon supporter (I have been posting special content there). Be sure to make use of the great boards, parts and kits available at Mostly DIY RF. Still use the Amazon link on the SolderSmoke blog page.
Bill’s Bench: The new Mythbuster II (20 meters only). Built in about 3 weeks. On-the-air, while still on the bench! Worked Euope and South Africa QRP. https://www.youtube.com/watch?v=6o9QerQ7jzg
Getting another CCI amp for the Dominican Republic.
MAILBAG:
— Paul VK3HN, talks about the nice sound of the Mythbuster II’s receiver, and a new QRP rig from Dave Benson K1SWL.
— Rick N3FJZ sent some very kind words in support of the SolderSmoke podcast. Thanks Rick.
— Chris KD4PBJ sent us a very nice message. Thanks Chris.
— Kevin from Belgium sent a nice blog post in support of SolderSmoke.
— John WB4BTL spotted his old call (from 1974) in my Novice Log.
— Dave KD2E spotted his Novice call in my Novice log: WN2TBB. He also saw a good friend WN2EHE.
— Mehmet who has the awesome and useful WEBSDR of NA5B helped me with a Facebook problem. Thanks Mehmet!
— Mike WN2A asked about the Yaesu FT-101 9 MHz VFOs.
— Phil W1PJE (from MIT!) writes about old broadcast radio shows. And some really nice words of encouragement.
— Grayson KJ7UM sent kind words of encouragement, and great background on hybrid rigs.
— Peter VK3TPM writes about the decline of blogging, but notes that blogs are useful repositories.
— Todd K7TFC sent me some additional Mostly DIY RF boards. Thanks Todd!
— Ed DD5LP/G8GLM Kind words on SolderSmoke, nice info on the G-QRP 50th edition.
— Bill AH6FC Encouraging words and good info on solar. Mahalo Bill!
— Michael AG5VG Building LC VFOs for 7 MHz. FB OM!
— Bob K7ZB An EE who likes the treatment of mixers in the SolderSmoke book.
SolderSmoke Podcast #253 AUDIO VERSION: NYC, SF, DR, PC, DSC, PODCAST IN DANGER, SPRAT, sBITX, CW, IMD, AI, PNP, MAILBAG
SolderSmoke Podcast #253 is available:
http://soldersmoke.com/soldersmoke253.mp3
October 16, 2024
Sponsor! Parts Candy is back! Handmade in Chicago! Standard test leads, Hook clips, alligator clips in 12″ and 32″ and multimeter leads
Travelouge/Intro
Bill’s trip to NYC — The Empire State Building
Dean goes to the Bay area.
Harry Caul, Marty Klein W3VCG , “The Conversation” and THE KNACK.https://soldersmoke.blogspot.com/2024/08/harry-caul-had-knack-movie-review.html
Joe Piscopo in Bell System video! https://soldersmoke.blogspot.com/2024/08/soldersmoke-quiz-question-who-is-actor.html
Bill’s Bench
Bill’s report from SolderSmoke Shack South: The tropics: What this means. Guapo wouldn’t go out when the sun was overhead.
Skies not great for astronomy now. But we see a lot of satellites, and meteors.
Antenna developments: 1/4 vertical on a fishing pole.
Lightning suppression coming for the building. Lightning suppressors. Got 2. Good video from the IMSAI guy: https://www.youtube.com/watch?v=7EyABPuNDMA Argon gas suppresion tubes.Need to crimp!
Hurricane prevention. Metal storm curtains.
Thinking of solar panels. 12 panels, 5 kW system. Probably without batteries. What do you think?
A golf cart.
New PC. BeeLink. Very tiny! (palm of your hand) 24 inch screen. Works well https://www.amazon.com/dp/B0BVFKN7ZL?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1
A very satisfying fix on the 15/10 rig — loose connection to RF amp. The highly suspect Ramsey Kit Amp was NOT the culprit! Got to use the new Rigol DS-1102. A fun fix. Will build a second CCI amp.
Digital Selective Calling — listening to ships and shore stations on HF. https://soldersmoke.blogspot.com/2024/10/monitoring-maritime-radio-messages-with.html
SHAMELESS COMMERCE: Our blogs and the podcast are in danger! Pete is already on a permanent blog hiatus. I have seen a big decline in readership. Frankly, if no one is reading or listening, we just may decide not to do it anymore. We don’t want to do this. So please, link to the blogs. Talk up the blog and podcast on your own blogs and social media.
Parts Candy Test Leads are back as our sponsor. Pete has them. Dean has them, I have them in two different countries! DON’T SCRIMP WITH A CRIMP!
SPRAT Summer 2O24 Special EXTRA 50th Anniversary issue! https://www.gqrp.com/sales.htm
Dean’s Bench
First CW contact: With KK4DAS on his HB sBITX and Alan W2AEW POTA. TRGHS.
Dean fixes the sBITX problems. Again. SUB-THRESHOLD CONDUCTION! Lots of patience and stick-to-it-ivness. LPF leakage! https://kk4das.blogspot.com/2024/08/homebrew-sbitx-lpf-leak-stopped.html
IMD IMD IMD and the Tiny SA Ultra https://soldersmoke.blogspot.com/2024/09/sherwood-its-time-to-clean-up-our.html
AI AI AI — Experimental AI Podcasts about SolderSmoke (no kidding — (NOT April 1) Where they came from https://soldersmoke.blogspot.com/2024/09/where-ai-podcasts-came-from.html
AI Podcast #2 https://soldersmoke.blogspot.com/2024/09/here-is-another-short-podcast-about.html
AI Podcast #1 https://soldersmoke.blogspot.com/2024/09/a-new-experimental-podcast-about.html
Pete’s Bench
An all PNP rig — A notional look, https://n6qw.blogspot.com/2024/08/august-30-2024-pnp-20m-ssb-transceiver.html
Videos on old Boatanchors. https://www.youtube.com/watch?v=mnboJ75NCmY&t=1s
MAILBAG:
Lex PH2LB making some new stickers. Look out San Francisco!
Rogier PA1ZZ sending lots of good ideas and links.
Todd K7TFC great idea on SS readersip decline
Todd VE7BPO aka Vasily — great info on how to stabilize LC oscillators. https://soldersmoke.blogspot.com/2024/09/qrp-homebuilder-shows-us-how-to-build.html
Eric 4Z1UG Welcome words of encouragement on the blog and podcast
Dave W2DAB says that AI just can’t replace the Tappit Brothers of ham radio. Now the Tappit Triplets.
Michael AA1TJ Thoughtfully skeptical about AI.
Grayson K7JUM on the cleanliness of the 32S-3. Also amazing video on Thermatron MMM.
Mike WN2A working on DC receivers and hum!
Floran OE7FTI building Farhan’s JBOT amp!
Mike Murphy WU2D building 1930 replica rigs using a Frank Jones circuit
Dave K8WPE always great to hear from such a strong SolderSmoke supporter.
Walter KA4KXX Great ideas from the Wizard of Orlando.
Paul G0OER — Reacting to the 1970s Ham Radio video. Didn’t remember being so cool.
Thomas K4SWL — Struggling with the hurricane in NC. Hang in there OM.
Nick M0NTZ building another Direct Conversion receiver — with videos about it.
Michael AG5VG building a Mythbustrer-style 20 meter rig. FT-101 VFO. FB
Tony G4WIF — Readership problem advice
John AB2XT sent us 6000 47 pf NP0 capacitors. So we are now good for caps! Thanks John.
Paul VK3HN Was suitably impresses by the AI podcasts we put on the blog. Thanks Paul.
SolderSmoke Podcast #253 VIDEO VERSION : NYC, SF, DR, PC, DSC, PODCAST IN DANGER, SPRAT, sBITX, CW, IMD, AI, PNP, MAILBAG
SolderSmoke #253 is available in video form. See above or:
https://www.youtube.com/watch?v=DQBojTLL7VY
The audio version is available in the post immediately above this one, here:
https://soldersmoke.blogspot.com/2024/10/soldersmoke-podcast-253-audio-version.html