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Sunday, June 1, 2025
Ashish N6ASD's Beautiful SolderSmoke Direct Conversion Receiver -- Built in Bangalore -- "This was such a fun project. This was my first direct conversion build, and I learned a lot along the way."
Saturday, May 24, 2025
Ted KN4ZXG's FB SolderSmoke Direct Conversion receiver: "This project is the greatest gift to homebrewing..."
There it is, a thing of beauty. The best part is that Ted built this receiver himself. That is something that most hams NEVER do.
Ted writes:
This project is the greatest gift to homebrewing since I got interested in radio nearly a decade ago. Lot's of great projects out there but most go into a mysterious black hole of obsolete parts like the NE612 mixer that's hard to get, or even the LM386, which is plentiful but not as cool as this amp. Everything's divided neatly on it's own board and explained. The builder has wiggle room on the layout and ways to test each module whether that's with nice or budget equipment. Not only did I learn a ton about each stage, but also about making RF probes and making use of my modest but super useful equipment like the Nanovna. Although there were no mysteries, it all comes together to make magic. If you know stuff, you can do stuff! Thanks again de KN4ZXG, Ted.
While he has some great plans for modifications and improvements, at this point I think Ted should follow Farhan's advice and spend some time just listening to the receiver that he has built. Direct conversion receivers sound especially good. It is as if they are closer to the ether.
Here are some clips of Ted's receiver in action:
Congratulations Ted. Welcome to the Hall of Fame.
Monday, May 19, 2025
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
Dear Bill,
Join the discussion - SolderSmoke Discord Server:
Documentation on Hackaday:
https://hackaday.io/project/
SolderSmoke YouTube channel:
Friday, May 9, 2025
Ramakrishnan VU2JXN's FB SolderSmoke Direct Conversion Receiver: "Extremely thrilled! Hooked!"
This is a really important Hall of Fame entry for us. This is our first completed SolderSmoke Direct Conversion Receiver from India (more will come).
Most importantly, this receiver was built by our good friend Ramakrishnan VU2JXN (ex VU3RDD). Ramakrishnan goes way back in SolderSmoke history. He was the one who first suggested (in 2006!) that our podcast needed a blog to go with it. This was the origin of the SolderSmoke Daily News. A short time later we announced the birth of Ramakrishnan's daughter. That same daughter now has her ham license and will build a second receiver with her dad.
The roots of this receiver are deep in India. When Dean and I first went to the local high school to talk about ham radio support, I carried with me a Direct Conversion Receiver inspired by Farhan VU2ESE. In fact, that receiver had a picture of Farhan and quotes from him taped to the wooden base. When Dean and I designed the receiver that we tried to build with the High School kids, we used an oscillator based on the DC receiver that Farhan was building with youngsters at Indian girl's schools. That is the receiver design that we are using in this SolderSmoke Challenge.
Ramakrishnan is in Bangalore now, which is where he built this receiver. Ashish N6ASD is also there now, and is building a receiver.
Ramakrishnan writes:
Needless to say, you folks convinced me to get back into homebrew
and you have hooked me into it with this project.
Again, couldn't turn off from it even though I am at work! The bug has
caught me.
Join the discussion - SolderSmoke Discord Server:
Documentation on Hackaday:
https://hackaday.io/project/
SolderSmoke YouTube channel:
Sunday, March 16, 2025
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:
For more information on how you too can build the receiver:
Join the discussion - SolderSmoke Discord Server:
Documentation on Hackaday:
https://hackaday.io/project/
SolderSmoke YouTube channel:
Sunday, March 9, 2025
Nate KA1MUQ Turns His Frying Pan DC Receiver into a Double Sideband Transceiver and Works Idaho from California
Wednesday, February 19, 2025
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!)
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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!
Sunday, February 16, 2025
Why Should We Build Analog Gear When the World has Gone Digital?
Our friend Todd (Vasily) had recently been thinking about this on his excellent Popcorn Electronics blog:
https://qrp-popcorn.blogspot.com/
There are many answers to this question. Todd's post made me think about a message from Farhan VU2ESE on this same subject. See: https://www.vu2ese.com/index.php/2022/08/04/daylight-an-all-analog-radio/ My comment and a quote from Farhan appears below:
Hello Todd! I have been thinking about the same things. As you know there is a lot of magic in using gear that you have built yourself. And it is still possible to do this. But I think the builder has to make some choices: Building it yourself might -- as you say -- require you to move away from the perfection, bells and whistles of the modern ICOM 7300 style rigs while embracing the simple functioning of analog rigs. Farhan was thinking of this three years ago:
"So here we are, talking analog radios in 2022. Here is the memo : The analog never died. The world is analog all the way, until you descend into Quantum madness. The antennas are analog, Maxwell died a content, analog man. Our radios, ultimately, are analog machines and we are all analog beasts too. Amateur Radio technology has evolved into the digital domain. However, it has only made it easier for us to do analog with computers to simulate and print our circuits. So, it’s time to bid good bye to our Arduinos and Raspberry Pis and build an Analog Radio for ourselves. So let’s see what we can achieve in hindsight, a return to our native land and a rethink of our approaches. The radio is called Daylight Again, a nod to being back at the FDIM in 2022 after a gap of two years. It is named after the Crosby, Stills, Nash and Young’s song that had been humming all the time while put this radio together, emerging after 2 years of lockdown. This radio that took two days to come together, no actually two years! That’s: parts of it got built and stowed away, thoughts were struck in the shower, questions popped up during early morning cycle rides and notes and circuits were scribbled in the notebook. I must take the first of many diversion here: I hope you all maintain a notebook. Write down the date and whatever you thought or did on the bench and the result. Nothing is trivial enough to leave out. Wisdom comes to those who write notes. I started to build this on Saturday the 14th May and I checked into the local SSB net on Monday morning, the 16th May 2022. Back to the radio. What can an analog radio do that will appeal to us homebrewers?"
More to follow. 73 Bill Hi7/N2CQR
Wednesday, January 1, 2025
Happy New Year from the Dominican Republic! SKN from HI7/N2CQR
Tuesday, December 24, 2024
So Many Great Pictures, So Much Radio History
Thursday, November 14, 2024
FDIM 2024 Interview with Farhan VU2ESE
Thanks to Bob Crane W8SX we have some great interviews with those who made presentations at the Four Days in May event (FDIM 2024). Sorry for the long delay -- it is all my fault, but I have excuses. Our thanks to Bob W8SX, our correspondent at the FDIM event.
Here is the interview with our friend Farhan, VU2ESE, the ham who has brought so much homebrew goodness to the hobby, starting years ago with the BITX 20 schematic.
http://soldersmoke.com/FarhanVU2ESE.mp3
Thanks Bob! Thanks Farhan!
Friday, November 8, 2024
Video Update on the Mythbuster II 20 meter SSB Transceiver
We will discuss this further in an upcoming Ham Radio Workbench Podcast, and in SolderSmoke Podcast #254 (mid-November 2024)
Wednesday, October 30, 2024
Bill N2CQR Builds Yet Another Mythbuster Transceiver
This one is for 20 meters (no need for 75) and will go to the Dominican Republic.
6 crystal filter at 5.2 MHz. VFO from old Yaesu FT-101 Termination Insensitive IF amplifiers using boards from Mostly DIY RF No RF amp ahead of the mixer. First mixer is homebrew diode ring. Bandpass filter has 4 LC circuits. Steep skirts. Low insertion loss. Bal Mod/Product detector has two diodes (singly balanced) Carrier osc is crystal controlled and homebrew. Audio amp starts with a 2N3904 amplifier followed by an LM386 board. Transmitter portion will be done next.Monday, October 14, 2024
Monitoring Maritime Radio Messages with YADD
Monday, September 30, 2024
Homebrew Receiver -- AG5VG's 20 Meter "Mythbuster" Receiver
Thursday, September 26, 2024
AI Podcast #2: Here is Another Short Podcast ABOUT SolderSmoke.
Click here for the second "About SolderSmoke" podcast.
http://www.soldersmoke.com/About SolderSmoke 2.mp3
This one looks not at the SolderSmoke Daily News blog, but instead at the SolderSmoke podcast itself.
I was delighted to see the inclusion of Pete, Dean, Farhan and Mike Rainey! This was really great.
Look, it is not perfect. There are errors. But probably about the same number of errors that you would get from real, human hosts, right? Voltaire told us not to let the perfect be the enemy of the good. And I find this to be amazingly good. Look, it is so good that it is kind of scary, right?
Before you get too critical realize how this has been done: I did nothing more than load the SolderSmoke Podcast Archive website into GPT-like model. Then I asked it to produce a deep dive podcast. That's it. About 5 clicks. It developed the podcast in about 3 minutes. I did the same thing yesterday but with the SolderSmoke blog. And this is only the beginning.
Wednesday, July 10, 2024
A Paraset and the Heathkit SG-6 Signal Generator (Video)
Mike WU2D put out this nice video (above) about whether or not he should part out his Heath SG-6 signal generator, using the parts in a Paraset construction project. I faced a similar question years ago:
https://soldersmoke.blogspot.com/search?q=SG-6
I just solid stated the SG-6. I was influenced by Farhan and the drinking straws that he picked up with his kids at a McDonalds in Hyderabad.
As with the QF-1, I say to Mike: GO FOR IT OM! You need those parts for other projects. Don't feel bad about the SG-6. But keep that switched coil assembly -- it is quite useful.
Tuesday, June 25, 2024
Field Day with Farhan, his Family and an sBITX Near Hyderabad, India
Farhan and his son Rayyan with an sBITX
The SolderSmoke crew thought it had a tough time this Field Day: Pete N6QW had hoped to do something, but was stymied by hot California weather. Dean KK4DAS had even worse weather. Bill HI7/N2CQR was at a remote QTH with an HW-8 and a wire antenna -- he managed just ONE contact (W7RN in Nevada on 15 CW). But none of us had as much trouble as our friend Farhan had. In his account of Field Day in Hyderabad, we see an intrepid ham standing up against the slings and arrows of outrageous fortune that Field Day often throws at true radio amateurs. Here is Farhan's Field Day story:
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You asked for it, so here it goes...