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!  

Hiss, Filters, QRM, and Hearing Loss: Do we need AF filters in direct conversion receivers?

L6 is the 88mH toroid

Messages on Discord about the need to knock down higher frequency audio response in the SolderSmoke direct conversion receiver got me thinking.

I agree with Rick Campbell and others on the benefits of hearing a "wide open" direct conversion receiver. But Rick and others have built DC receivers with 3 kHz low pass AF filters. This made me ask myself a question: Is an audio filter in a direct conversion receiver a good idea?

And I started wondering if perhaps I was being too dismissive about the complaints about high frequency audio -- I had been attributing them to newcomers who were just unaccostomed to radio noise or "static." But maybe there was more to it than that. Maybe a big part of the problem was in my head, specifically in my ears. So this morning I did an experiment. I took an online hearing test. First, without my hearing aids: As expected, it showed significant high frequency loss. (It was as if the US Army had installed a 3 kHz audio low pass filter in my head!) Then I put my hearing aids in and retook the test: This time I passed the test and showed no loss. I then listened to the DC receiver with my hearing aids in. Now I could hear what builders on the Discord server were commenting on: I could hear higher frequency hiss, and, more importantly, stations that were producing 4-5 kHz sounds on my speaker were audible and annoying.

So I went back to Wes Hayward's November 1968 QST article. In his receiver, he has a low pass AF filter using an 88 MILLIHenry coil and a couple of capacitors to ground. I had a few of the coils (given to me years ago by a NOVA QRP club member) so I built it. With my hearing aids in, I noticed an immediate improvement. I then did what one of the Discord builders did and put the filter in with a switch that would let me make "with and without" comparisons. The filter definitely cuts down on any AF above about 3.5 kHz. And it doesn't seem to do damage to the desired signal. This is useful. I left the W7EL diplexer in the circuit.

This filter won't solve the image or "opposite sideband" problem inherent to simple DC receivers, but it will help with signals or noise that are producing tones above about 3.5 kHz in the receiver. I think this is especially important in countries in which there is a lot of SSB crowding on 40 meters. The UK, for example, has an allocation from 7.0 to 7.2 MHz. In the US we go from 7.0 to 7.3 MHz. That is a big difference.

So the answer is probably yes, an AF filter in a direct conversion receiver is probably a good idea, especially if you can switch the filter out of the receiver. You can live without these filters. Not having the filter keeps the receiver very simple, and lets it sound really great. But having the filter in there does help reduce interference and high frequency hiss. So I think this is a useful add-on mod for builders who see a need to cut down on the kind of interference that a lack of this filter causes.

In 2019 W7ZOI noted: "Another unusual element is the 88 mH toroid used in the audio low pass filter at the detector output. A viable substitute would be a 100 mH inductor with radial leads. The muRata 19R107C (from Mouser) should work. Bourns also offers a variety of similar parts."

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/ 

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

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? 

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

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. 

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

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.  

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

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

Simplicity, Presence, Mods, and Direct Conversion Receivers

Over on the Discord server that we set up for the SolderSmoke Challenge project.  One of the guys who succeeded in building the receiver (kudos to him!) commented that, for some reason, his receiver didn't sound good on SSB.  I was kind of surprised by this, because usually we hear the opposite:  that direct conversion receivers sound GREAT on phone.  In fact, this may be the origin of the term "presence" when used to describe the audio quality of DC receivers.  So I sent this note on the issue: 

Sounds like you are on the right track in wanting to understand the circuitry .   I would just point out that even experienced users of commercial SSB radios are usually impressed by the sound quality of simple direct conversion receivers like this one.  This is the origin of the term "presence"  -- Doug DeMaw used this word when describing the experience of listening to Wes Hayward's 1968 direct conversion receiver.  He said it made the guy from the distant station sound as if he were "present" in the room with the receiver!  From an article about this event:  "This was the epiphany, the moment when Doug realized that solid-state technology had produce a new way to build a simple receiver. Doug tuned the receiver higher in the band and found some SSB. Again it was like nothing he had ever heard. It was as if the voice came from the same room. Doug used the term presence in his description."  So you should not have diminished expectations for this simple receiver.    Realize that Wes's receiver was even simpler than ours!    I don't feel a need to defend this design, but will point out that these receiver can sound great if used properly.   Here is a recording of one of these receivers in action in December 2024:  https://www.youtube.com/watch?v=JSI7YDJGAos  And this one: https://soldersmoke.blogspot.com/2024/12/listening-to-40-meters-on-dc-receiver.html  Mods are great, but remember that you CAN diminish the simplicity and thus the "presence" of these receivers by strapping on a lot of unnecessary  features:  filters, amplifiers, Digital VFOs, frequency counters, etc.  especially if these mods are put in there to address shortcomings that don't really exist.  73  Bill N2CQR

What do you folks think of all this?  

BTW, you too can get involved in the project by visiting our Discord server.   Just go to Discord and set up (it is easy) you own server.  Then use this logon to get to the SolderSmoke Discord server: 

Join the discussion - SolderSmoke Discord Server:

https://discord.gg/Fu6B7yGxx2

FCC to Ban Direct Conversion Receivers

From the FCC News Line:  

The Federal Communications Commission announced today that it will soon ban a wide range of communications equipment due to interference that this equipment is causing to Starlink communications satellites in Low Earth Orbit (LEO).  The banned equipment includes a range of legacy analog-type circuitry that, according to the Commission, has "lost relevance" and constitutes "an archaic electromagnetic nuisance."  Under the proposed Commission action, banned equipment will include all regenerative, super-regenerative, and direct conversion receivers.  

The interference potential of regenerative receivers has been known since the 1920s.  Direct Conversion receivers were thought to be less prone to Problematic Spurious Emission (PSE),  but in recent months  LEO satellites have experienced serious interference from terrestrial sources.  

An FCC official was nearly apoplectic when speaking about the devices that are causing this interference:  "They have no shielding.  They are built on wooden boards, and are made with superglue!  Heck, the main tuning device is -- get this -- a screw! A screw!  To think that something like that could threaten an entire LEO satellite system.  This is really unacceptable."  The official said that two persons in Northern Virginia had encouraged the construction of these "terrorist devices."  The FCC is working with the FBI and the Department of Homeland Security to bring these people to justice. 

The vast majority of the interference is believed to come from home-made ("homebrew")  direct conversion receivers.  These devices employ simple oscillators in the 7 MHz range.  The 85th harmonic of these oscillators falls in the middle of the UHF frequencies used by the satellite system.  The interference appears when the satellites are over areas known to be used by ham radio direct conversion enthusiasts.  There have been communications issues near Melbourne  Australia, the North Island of New Zealand,  Bali Indonesia, all across the U.S. (especially in the area of Nashua, NH), Canada, the UK,  Holland,  and Sweden. Recently there have been reports of interference from Argentina. 

A satellite company CEO of has been briefed on the matter, and promised to use his influence in the U.S. government to "squash this problem like a bug."  The spokesperson for a major ham radio organization in the United States reassured members: "Don't worry, commercial SDR transceivers will not be affected by this ban." 

Homebrew Challenges Much Like Ours: The Direct Conversion Receiver of Wes Hayward W7ZOI and Dick Bingham W7WKR -- QST November 1968

 

https://www.worldradiohistory.com/Archive-DX/QST/60s/QST-1968-11.pdf

I was thinking about some of the challenges faced by the builders of the SolderSmoke Direct Conversion Challenge Receiver, and about how similar these challenges are to those described by Wes Hayward W7ZOI and Dick Bingham W7WKR in the November 1968 QST article that launched the direct conversion revolution among radio amateurs. You can read the full article beginning on page 15 in the link above.

Some observations and comparisons:    

--The November 1968 QST article said, "This receiver was designed for simplicity and ease of duplication, rather than ultimate performance."  Ours too! 

-- Wes's receiver has a single tuned circuit in the BP filter.  Ours has two LC circuits. 

-- Wes's mixer is also a diode ring.  He starts out using hot carrier (Shotkey) diodes, but later concludes that ordinary diodes would work just fine.  We reached a similar conclusion.  But I wonder if the ordinary diodes would work well with a low output level from the single FET VFO (see below). 

-- His oscillator uses a single MPF-102 in a Hartley configuration with no voltage regulation, and no buffer.  We have two active devices and a Zener diode.  This article makes me think we could have made our PTO even simpler.  

-- Wes's receiver has a low-pass filter between the mixer and the AF amp.  The cutoff is at around 2 kHz.  This seems quite low in frequency and may reflect a preference for CW.  It features 88 mH coils that are now quite hard to find. The goal of this filter seems to be to prevent signals from beyond the audible frequency range from overloading the AF amp.  We ended up using the diplexer from the W7EL optimized QRP rig.  I think this diplexer takes care of the problem.  

-- The W7ZOI/W7WKR receiver has no AF nor RF gain control.  When encountering a strong SSB signals, the article recommends detuning the BP filter.  I think our AF gain control, and the mod calling for an RF gain control will give the operator, well, more control and will prevent strong SSB signals from overloading the AF amplifiers.  The RF gain pot might also help prevent SW broadcast AM breathrough. 

-- One big difference between our receiver and the November 1968 QST receiver:  isolation of the VFO.  The QST article puts the VFO in an aluminum box above the chassis.  We have the PTO without any shielding right alongside the other circuits.  Builders might want to experiment with the kind of isolation recommended by the QST article.  Would this kind of isolation and shielding improve performance? 

-- Wes also obviously contended with oscillation by the AF amplifier, as did many of our builders.  The QST article contains a number of recommendations: First test the amplifier to see if you can hear noise.  If it oscillates, try increasing the value of the decoupling resistors. (Many of our builders added electolytic caps to the DC power line in the AF amp.)  The article recommends trying a .01uF cap across the output.  It also recommends keeping the output of the amplifier away from the low pass filter at the input.  Wes's design has no transformer as it makes use of high Z headphones. 

-- The QST article says that the product detector performed adequetly with an LO injection level of .6 volts peak-to-peak.  This seems quite low to me,  but perhaps this would work with hot carrier diodes in the diode ring?    This might be one good reason to use diodes that have a lower turn-on voltage -- you could get away with using a super-simple VFO even if it provides lwer voltages to the mixer.  It might be fun to experiment in this area.  

As readers can see, the challenges faced by the builders of the SolderSmoke DC receiver were very similar to those face by the builders of  the November 1968 machine.  I think all of us should find this very encouraging.  

Thanks again Wes and Dick. 

Andy KB7ZUT is a Good Sport -- He Built the Direct Conversion Receiver HIS WAY, then OUR WAY. Great StarTrek Cartoons

 

Early on, Andy sent in a report on a Direct Conversion receiver that he had built.  It looked kind of like ours, but it was clearly NOT ours.  It even had a 20 db RF amplifier ahead of the mixer.  We politely (I hope) pointed out the differences.  Andy quickly came back with the receiver picutred above.  Yes, that is ours!  Thanks Andy! 

Andy writes: 

I'm calling it done (for now)! 1) Biggest challenge for me was "coloring inside the lines". In other words, building the actual DCR challenge to the schematic vs. getting too creative with other circuits in my head.  2)My biggest breakthrough was developing a much better understanding of the diode ring mixer.  And how brass displacing air in the PTO works. 3) What's next? I want to try some transformer-less audio amps to see if I can find a design for the folks that are having trouble finding a cheap source for the 1000/8 transformer.  A super big thanks to both Bill @N2CQR and Dean @Soldersmoke for all the hard work bringing the DCR challenge and the Discord community to life. Bravo! And I would also like to thank Pete (N6QW) our guiding light and spiritual leader too. If it wasn't for the SolderSmoke Podcast and the Blog, I would still be living life as an appliance operator.  73 KB7ZUT ..

Andy posted these to the Discord server: 

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 

Erik N2EPE's SolderSmoke Direct Conversion Receiver

Erik built a really nice receiver.  I was glad that he took to heart our advice on the need for a large, insulating tuning dial.  He made one!  As he made this entire receiver. 

Eric wrote:  

I would like to make a homebrew QSO! I am learning CW, mainly because I find it easy to use QRP/POTA. I have a Michigan Mighty Mite, but it has not reached farther than my backyard yet, so a CW transmitter in the single Watt range would be a great next project. 

Congratulations Erik! 

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

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 

Ryan AC3NG's FB SolderSmoke Direct Conversion Receiver

All the way through, Ryan displayed a desire to really understand each of the four circuits included in this receiver.  He wanted, as Maxwell said,  to know not only the "go of it" but "the particular go if it." FB! 

Ryan wrote: 

Here's a short video of my receiver in action.  I'm very pleased to be receiving real radio!    I'm too inexperienced, so don't really know if this is good or bad performance for this receiver.  This is about as good as I've gotten so far.  A few people I can understand well, but many are not really intelligible.  Thanks to everyone, this is a fun project!

I think it sounds great.  Tuning in an SSB station with a DC receiver is an aquired skill -- we all get better at it over time.  

Congratulations on building a really nice receiver Ryan. 

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

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 

Ken W4KAC's Wonderful SolderSmoke Direct Conversion Receiver -- with a Leaf Blower Tuning Dial

Ken W4KAC tells me that the tuning knob that he used to minimize hand-capacitance effects on his PTO started out as a gear in a leaf  blower.  I commented that the engineers who designed that gear surely never thought that it would someday be used in a homebrew direct conversion receiver.   

Ken lamented the polemical nature of the SSB discussion captured in the above video, but the clip does give a good demo of the SSB capabilities of Ken's receiver. And the video gives some nice close-ups of the receiver itself.  

Ken is a CW guy, and he has already homebrewed a QRP CW transmitter that he hope to pair-up with the receiver.  Here it is: 

Ken reports 160 mW output with a 377 mile reception report on the Reverse Beacon Network.  I made a contact with something similar: https://soldersmoke.blogspot.com/2023/02/first-qso-with-high-school-receiver-100.html

Ken wrote about the importance of persistence: 

Good morning. Just wanted to say, don't give up if your receiver is not quite right. Mine was working, I even posted a video here. When building the AF amp from the transformer end back, the Q4 stage was fine. I added Q3 and had a "motor-boating" oscillation when I applied a signal. I tore it all off the board and started over. I still had the problem, so being stubborn I continued on and kept adding more filter caps to quiet it down all I could. The receiver worked and sounded pretty good during the day when I copied WA4FAT and others. That evening was a different story when the band was working well and very full of signals. Very strong stations were ok, but I was getting lots of "hash" and noise other than normal band noise. FT8 was breaking through weakly all over the band along with other unidentified stuff. Yesterday morning I grabbed a new piece of copper clad and built and entirely new AF amp. It tested properly all through the build. Instead of installing that board I decided to find the problem with the original. I "thought" I had used new transistors when I rebuilt it the first time. Turns out I had probably put the original Q3 back, because replacing it cured the problem. I had an entirely different receiver last night. A pleasure to listen to. Don't give up like I did at first!!

Ken went the extra mile by building a SECOND Direct Conversion receiver.  So he may soon get TWO Hall of Fame credits.  Here is the second one that Ken built: 

 https://www.youtube.com/watch?v=HUSWKJZdc8E&t=39s

Thanks Ken!  

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

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 

Jim KF8BOG Completes the SolderSmoke Direct Conversion Receiver after a Long, Hard Journey of Discovery

Herodotus once said that "learning is not child's play -- we cannot learn without pain." I think Jim KF8BOG proved that in this build.  I'm sure he burned his fingers at least a few times.  I remember fondly almost seeing the light buld turn on when Jim came to understand how the diode ring mixer really works.  He struggled to tame a rebellious AF amplifier (we've all been there).  Throughout Jim demonstrated the persistance and determination that are needed to turn a bunch of parts into a well-functioning receiver.  He did it. He built it.  Congratulations OM!  

 Jim wrote: 

I am not just an appliance operator now but only half way through. Time to make a transmitter!   

A little about me I became interested in Ham radio about 45 years ago in Boy Scouts I tried really hard with my Radio shack straight key and morse code chart to learn code by myself and just could never get it.  Fast forward to last year and I had a friend who did CERT and he told be about it and said he used 2 meter for communications I was impressed and said “how did you learn morse code?” he replied “ I didn’t you don’t need it anymore”  I promptly signed  up for Ham in a day in June and got my technician license and my then my general in August. I have been studying radio ever since.  This project was perfect for me. I like to make things I have been a mechanic for 40 years plus ASE master.  Fixed all sorts of crazy electrical issues but DC and RF are way different lol. 

Again Thanks Bill and Dean you don’t know what you have started.  73s KF8BOG

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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:

https://www.youtube.com/@soldersmoke 

John W8UC Ends 48 Years of Appliance Operator status -- His beautiful build of the SolderSmoke Direct Conversion Receiver

In many ways it was for guys like John W8UC that we launched this project.  These are guys who have been hams for a long time, but -- like most hams -- never built anything.  Most guys don't see this as a problem.  But some guys just don't like to think of themselves as "appliance operators." For years the ARRL and others told hams that receivers were just too difficult for them to build.  We found this not to be true.  So we launched this project, first at a local high school, then to a larger group. 

In his comments John says he has been an appliance operator for 48 years.  Well, you are an appliance operator no more John -- you have built a receiver.  

John wrote: 

I can hear the signals on a receiver I built so I am super happy about that... I have learned more in the last month about how a receiver works than I have in the last 48 years of being an appliance operator. Thank you Dean and Bill. 3. Would like to build a transmitter next. Also a receiver for another band.

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

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 

VK4PG's Wonderful Australian Direct Conversion Receiver from Sunny Queensland

It was really great to hear those Australian voices coming from Phil's receiver.  Check out the video above. 

Phil writes:  

Completion!  So pleased, it works really well.  And there were lots of lessons for me along the the way.  Thank you Dean, Bill and Pete, it's been a great way to get me into homebrewing.  73s from sunny Queensland.  Phil VK4PG

I also like Phil's front panel.  Note how he put to use the circular piece that remained after cutting the speaker hole; that became the tuning knob.  FB Phil.  Thanks. 

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 

Scott KQ4AOP Built the SolderSmoke Direct Conversion Receiver, and Listened to his FIRST EVER Ham Signals with it

Scott KQ4AOP's build of this receiver is especially noteworthy, becasue he used the receiver to hear the very first ham radio signals he ever received.  I don't think any of us can make a similar claim.  

Scott wrote:  "Those first sounds were my first time ever hearing any Amateur Radio first hand!" You can see Scott's deep commitment to homebrew: "I want to build my own gear for 40m. I want to learn morse code. I want my first contact to be on my own gear."  Wow Scott, the building of the receiver is the hard part, and you have already done that.  I think you are well on your way.  In the video above you can watch Scott tune the entire 40 meter band and a bit beyond. You hear CW at the low end.  Then FT-8.  Then SSB.  Up just above the top of the band I think you can hear our old nemesis Radio Marti.  And this powerful broadcaster is NOT breaking through on the rest of the band.  FB Scott.  Congratulations.  

Check out this blog post and the comments: 

https://soldersmoke.blogspot.com/2024/02/scott-kq4aop-successfully-builds.html

Scott has also exhibited true ham spirit by 3D printing PTO coil forms for those who need them.  This has helped many other hams build the receiver: https://soldersmoke.blogspot.com/2025/01/scott-kq4aops-pto-coil-forms-for-high.html  

Thanks Scott 

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 

 

Matt NE3U (ex KY4EOD)'s SolderSmoke Direct Conversion Receiver (and his Globe-circling Balloons!)

Matt was one of the first builders of this receiver (see above). He heroically stuck with the very small speaker that we had used in the high school receiver. 

Matt wrote: 

I just wanted to publicly thank you for doing this. I’m sure it’s been a lot of work but I’m very grateful for the experience. I’ve always wanted to home brew and I’ve done a few little things such as filters and attenuators but this has really given me the motivation to really dive in deep.

I’m 44 and I’ve only been a ham a few years so hopefully I have lots of time ahead to get others excited about home brewing. We have a very active club here in KY and there are quite a few folks mildly interested in home brewing, I’m going to push some of them to start a builders group in the club with me. This is entirely due to the effort you have put into this project!

Thank you. 

Matt also builds balloons with tiny solar-powered ham radio transmitters aboard.  These balloons fly around the world.  He is advising Vienna Wireless Society on their balloon project.  Just last night Matt wrote: 

In case anyone is interested, my balloon that has been spending a lot of time in the northern latitudes popped back up again today after being quite for nearly two weeks. Looking at the path prediction on HYSPLIT it's going to make another loop to the north but at least the earth is tilting back to give me a more favorable solar angle. It's only going to get better as spring rolls in.This balloon lost a little altitude shortly after launch for unknown reasons so it's not quite a high as I would like but as long as it can stay away from spring storms, it should still have quite a bit of life left in it. This one is still flying on my old callsign. I got my vanity callsign when I thought the balloon had gone down, then it showed back up. Whoops, oh well, I tried. Matt NE3U

Spot Search Dashboard - Traquito

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Matt is a veteran.  Thank you Matt! 

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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:

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