Does a simple, single diode envelope detector function the same way as a product detector does?

Mike WU2D has an interesting series of videos on the simple detectors used in crystal radios.  Mike's videos touch on a discussion that I had a few years ago with a member of the Vienna Wireless Association.  I was describing how an envelope detector uses rectification to recover (demodulate) the audio from an AM signal.  The club member dismissed this explanation and claimed that what really happens is that the diode simply mixes the carrier and the sidebands to produce audio.  He claimed that the rectification "theory" was just a fable created to deal with people who really didn't know how mixers worked.  See:   https://soldersmoke.blogspot.com/2022/12/is-envelope-detection-fable-or-is-it.html

I was kind of disappointed by Mike's videos.  He seemed to take an agonostic position on this issue.  He framed it as "some people believe in the rectification explanation, and some people believe in the product detection explanation." As if both explanations are equally valid.  They are not. 

This morning, I asked AI about the two explanations.  Here is what AI says: 

 Does a simple, single diode envelope detector function the same way as a product detector does? 

AI Overview

No, a single diode envelope detector does not function the same way as a product detector because the envelope detector is a non-linear circuit that recovers the audio from a full amplitude-modulated (AM) signal by following its envelope, while a product detector is a linear mixer that recovers the audio from various modulated signals (including DSB-SC and SSB) by multiplying the modulated signal with a local oscillator. Product detectors are more versatile and offer better signal quality than simple envelope detectors, which are limited to demodulating DSB-AM signals with a full carrier. 

I know that AI sometimes gets it wrong, but I think that on this one, it has it right. 

I don't think it is necessary to include discussion of modulation percentages nor diode biasing to clearly explain what is going on. 

Even if you are using a very weak signal and are completely in the square law region of the characteristic curve,  you are still essentially dealing with a form of rectification:  portions of the signal on the positive side of the curve will experience less attenuation than signals on the negative portion of the input curve.

When we use a crystal receiver, we are relying on the rectification done by the diode -- even if the rectification happens in the square law region.  After the crystal there is some low pass filtering.  The envelope of the AM signal remains and this is the audio signal that we listen to.  That is why we call it -- correctly -- an envelope detector.   And as the AI says, an envelope detector funcions differently than a product detector. 

Why I can listen to both sides of VK-G Long Path QSOs in the Dominican Republic

Bottom line:  I think when Australians talk to Brits via long path,  in the Dominican Republic I am between the two. Both have their beam antennas aimed (generally) un my directions.  With an omnidirectional antenna (my 1/4 wave vertical) I can hear them both.  While they are on the Long Path to each other, I am Short Path to both of them. 

Here is my log entry (From the Dominican Republic): 

August 20, 2025 

20S around 0830 UTC  VK5UK Rich and G2YT Peter.  Rich was in LP contact with Peter  My  VFO was moving as the air conditioner kicked in.  I think I was hearing both of them SP.  With VK5UK I was off the side of his beam.  Same with Peter G2YT.  

---------------------------- 

Peter G2YT wrote:  

Yes, Rich and I were working Long Path… I was beaming at the top end of South America (about 240 degrees) and Rich was beaming approx 120 degrees.

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

Rich, VK5UK wrote: 

Hi, thanks for the email... My beam heading was around 150 degrees from VK long path to Europe you would have been receiving me via the shortest path between us, and I suspect you were being received by Peter on the same path? 73 Rich

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

Here is a good website that describes (using Australia to Europe) the Long Path and Short Path propagation paths:  

https://www.pa9x.com/long-path-or-short-path-propagation/

Here is a link to Google's new AI (on this subject) 

So Where is My Dominican Antipode?

There you have it.  I like the icons!  

Here is the site: 

https://www.antipodesmap.com/#coordinates-converter

An Australian Perspective on AI's Impact on the Internet

https://www.abc.net.au/news/science/2025-10-08/how-googles-ai-overviews-are-affecting-australian-news-websites/105839588

Thanks to Paul VK3HN for sending this.  The pernicious effects are so real that I almost didn't bother to post this.  People just aren't reading the blog anymore.  But for the record, here it is. 

And here is what Google AI says about the impact of AI search boxes on the number of people visiting blogs:  

Ha!  So Google's AI itself acknowledges that it is causing a serious decline in traffic to tradional bogs and other web sites! 

Spark Plugs -- With Polonium!

 

Hack-A-Day has an interesting post about how they put Polonium in Firestone spark plugs in the mid 1950s.  Yikes, this is some really deadly stuff.  Check out the post:

https://hackaday.com/2025/10/01/the-hottest-spark-plugs-were-actually-radioactive/

Faraday Cages and the Square Kilometer Array

 https://www.theregister.com/2025/10/02/ska_datacenter_construction_progress_report/

More Silicon Valley -- Apple, Microsoft, and IBM (video)

 More interesting computer history.  

-- Visicalc and importance of spread sheets. (I remember when I first learned to use one). 

-- Amazing that the guy who wrote the DOS program for IBM can't get a job today. 

-- Sad that the guy who was in the garage with Jobs never got stock options. (Was this ever corrected?) 

-- I liked the observation that the most powerful guy in the room is usually the most poorly dressed guy in the room. 

Silicon Valley -- The Hippies who Built the First PC (full video)

Computers are not really my thing, but the discussion of California culture and how it led to the home computer revolution is very interesting. 

-- Blue Boxes! (I should have made one.) 

-- An old telephone earpiece. (I still have one.) 

 

-- The Free University of Palo Alto (I should have gone there.) 

-- The HOMEBREW Computer Club  (Great use of the word "homebrew.") 

By the mid 1970s, "they were going to change the world not with flowers in their hair, but with soldering irons in their hands." 

Great stuff. 

Coronal Mass Ejection Causes Storm -- But I Still Hear DX in Hi7

 

So the A index is 27 and the K is 7.  That's pretty bad right? See below.  Lots of red.  Well maybe not so bad in the tropics.  This morning I could hear EA5JZ working a VK on 20 meter SSB.  And yesterday morning I worked a very strong VK3XXY, also on 20 meter SSB.  I note that the Space Weather Center warns (above) of "HF communication degradation at higher latitudes."  So maybe my location at 18 degrees north explains the openings. 

Maybe it is Tropospheric Ducting After All -- 99.5 FM WIDI Puerto Rico Received in the Dominican Republic

 

Invest 94L moved arcoss the Mona Passage yesterday, lowering temperatures, bringing lots of rain and relatively high winds to the area.   I happened to check on reception in the DR of WIDI 99.5 FM (near Mayaguez, Puerto Rico), and was surprised to find that the signal had weakened considerably.  This morning, after the storm passed, signal levels were back to their normal full quieting. This would support the idea that tropospheric ducting is playing a big role in bringing this signal into the Dominican Republic.  I had been surprised by the persistence of the signal -- for weeks it had been full quieting here.  I thought that perhaps I was just receiving it directly, line-of-sight, without the benefit of tropo ducting.  But Invest 94L has made me question this idea. 

I asked Google Gemini AI about the persistence of tropospheric ducting on FM broadcast signals in the tropics.  Here is what it said: 

AI Overview

In the tropics, tropospheric ducting is a frequent, persistent, and often strong phenomenon, especially over and around large bodies of water. Unlike mid-latitudes where ducting is a seasonal event, the meteorological conditions in the tropics are favorable year-round.
Why ducting is persistent in the tropicsHigh temperatures and humidity: Tropical climates are characterized by consistently high temperatures and abundant moisture. These conditions are the primary drivers of atmospheric ducting.

Temperature inversions: Stable high-pressure systems common in the tropics can create temperature inversions, where a layer of warm, moist air sits above cooler air. The sharp change in temperature and humidity with altitude creates the "duct" that traps and bends radio waves over long distances.

Dominance of water paths: Large tropical ocean regions are ideal for ducting. A common ducting phenomenon called the "evaporation duct" is ever-present over the sea surface due to a sharp humidity gradient and is particularly effective for trapping frequencies above 3 GHz. While the FM broadcast band (87.5–108 MHz) is at a lower frequency, coastal areas and islands frequently experience ducting over sea paths.

Atmospheric stability: The general stability of high-pressure systems in the tropics allows ducting conditions to persist for many months at a time. This is observed in areas like the Caribbean and the Persian Gulf, where long-distance radio reception is a common occurrence.

Impact on the FM broadcast band (VHF Band II)Favorable frequencies: The FM broadcast band (VHF Band II) is particularly susceptible to tropospheric ducting. While ducting can occur across a range of frequencies, signals above 90 MHz generally propagate more favorably during ducting events than lower frequencies.

Signal interference: The most noticeable effect of this regular ducting is co-channel interference, where distant stations can override local ones. During an event, a listener may pick up two different stations on the same frequency, or experience temporary loss of reception from a nearby transmitter.

Extended reception: For radio hobbyists, this high frequency of ducting means that signals from FM stations hundreds or even thousands of kilometers away can be received clearly.

Diurnal cycle: Ducting events in the tropics often peak during the evening and overnight hours when surface cooling creates a stable nocturnal boundary layer. Conditions may "burn off" after sunrise, but ducting is common throughout the day during periods of stable weather.

In summary, the specific meteorological and geographical conditions found in tropical regions—consistent heat, humidity, and the presence of large bodies of water—make persistent tropospheric ducting on the FM broadcast band not just possible, but highly probable throughout the year.

GQRP Convention 2025 -- SolderSmoke Direct Conversion Receiver Presentation

We were really pleased to have been invited to speak to the GQRP club's 2025 convention.  We talked about the SolderSmoke Direct Conversion Receiver project.  There were some recording glitches, but we managed to re-create the presentation.  Video appears above.  Thanks again to GQRP!  

Here is the audio only (podcast) version:  http://soldersmoke.com/DCRXGQRPAUDIO.mp3

Flying in the U-2

So cool.  This was always one of my favorite planes.  

So hey, BE CAREFUL!

 

The vessel "Tally Ho" sailed into San Francisco bay recently.  They went to a very cool machine shop in Sausalito, where they found this warning sign posted near one of the machines.  Yikes! 

Here is the Tally Ho video:  https://www.youtube.com/watch?v=yHf9K_dOgsY&t=422s

Todd W2TEF's FB SolderSmoke Direct Conversion Receiver

 

Admirably, Todd W2TEF proved that you can build this receiver even if you don't have an oscilloscope. He used a lot of simple tests, including listening for the band noise when he had all four boards finished. He got the kind of help from friends that all of us use while homebrewing.  And he tuned in SSB signals for the first time.  FB.  SSB in the video above, CW below. 

Todd writes: 

1. ... thanks to Dean and Bill for putting this together and guiding me into a great beginning project. And to Chris and others offering guidance here in Discord. I love seeing a project through to completion, and am still amazed that twisted up coils of wire can grab intelligence out of the air!

The People Who Hunt Old TVs (Really, Old CRTs)

These are our people. 

 https://www.bbc.com/future/article/20250911-the-people-who-hunt-down-old-tvs

50 Things to Do with an SDR -- The International Beacon Network

 https://blinry.org/50-things-with-sdr/

Lots of good ideas from blinry's site.  It reminded me of the International Beacon Project:  https://www.ncdxf.org/beacon/  I can receive the 20 meter CW signal on my homebrew rig here in the Dominican Republic.  On 17 September before dawn I could hear the station in Madeira (CS3B) and the one at the UN in New York (4U1UN).  This will be a useful way to monitor the band for openings to the South Pacific. 

Hiding a Solar-Powered Mesh Node in Alaska -- Can you find it?

 Even though it deals with some high-tech, SDR, IC stuff, there is a lot to like in this video. 

Some of the guys in Vienna Wireless have been playing around with Mesh nodes.  This video made me think about building one and leaving it on the roof of our apartment overlooking the Mona passage. I already have the solar panels (from the old Volkswagens)...  

Here is a description of his YouTube channel: 

A collection of DIY boats, devices, and other projects built out of junk. Almost everything on this channel is made from scrounged, hoarded, and salvaged parts. I grew up on an island in Alaska, so I know the value of never throwing anything away! I may not be an expert craftsman, but I know my way around a roll of duct tape! I'm also always on the lookout for crazy free or cheap stuff, whether it be electronic parts, boats, aircraft engines, or even a monorail train! Check out www.saveitforparts.com for even more projects!

Here is the YouTube channel: https://www.youtube.com/@saveitforparts

Thanks to Jenny List of Hack-A-Day for alerting me to this. 

A Flight from Chile to Panama: Aeronautical Mobile Contact with KX4WC/AM, with VK3MO in the Group

WA3O sent me an e-mail alerting me to the fact that Mike KX4WC/Aeronautical Mobile would be flying up from Santiago, Chile to Panama City this morning. So I fired up the 20 meter rig and hoped for the best.

Not only was I able to talk to Mike, I was also able to work WA3O, VY2WW, and VK3MO in Melbourne. It was a very FB morning. VK3MO was really booming in. I have worked Ian before -- his 5 over 5 over 5 over 5 array on 20 meters really helps. https://www.qrz.com/db/VK3MO

I was not hearing Mike KX4WC very well until the sun came up over our north-south path. You can see this in the picture below. Thanks to all for this very cool contact.

Ian VK3MO's 20 meter array

Peter VK3TPM had done a very nice profile of Ian and his station: 

https://www.mrarc.org.au/member-profile-ian-vk3mo/

Do I really NEED Tropo to hear the Puerto Rican FM Broadcast Station? Or are we just close enough to do this line-of-site?

 

WIDI 99.5 FM from western Puerto Rico continues to put a full quieting signal into the eastern Dominican Republic.   The station is so regularly strong that this made me wonder if I am really using tropospheric ducting to hear it.  If I was using tropo ducting, I think there should be some variation in signal strength over the course of 24 hours right?  But it is always strong.  Why?  

I checked the distance:  97 miles.   With its antenna at 2800 feet, its visual horizon will be 64.8 miles away.  I am about 98 feet above the ocean.  This means my horizon is 12.22 miles away.  There appears to be a gap, right?  I mean 64.8 + 12.22 = 77.02 miles.   So it looks like there is a gap of about 20 miles.  

But wait!  Mike WN2A reminded me that there is a difference between radio line of sight and visual line of sight.   Radio line of sight = 4/3 of visual line of sight. 

AI explains where the 4/3 factor comes from: 

The radio horizon appears longer than the visual horizon by a factor of about 4/3 due to atmospheric refraction, which bends radio waves slightly downward. To simplify calculations, this effect is modeled by treating radio waves as if they travel in a straight line over a larger, "effective" Earth with a radius 4/3 times the actual radius. This increased effective radius allows radio waves to "see" further over the Earth's curvature, extending the line-of-sight range compared to what is seen by the human eye, which is not affected by atmospheric bending to the same degree. 

So that puts WIDI's radio horizon at 86.4 miles.  My radio horizon is 16.16 miles.   86.4 + 16.16 =  102.56 miles No gap.  We should be able to hear WIDI, even without tropospheric ducting.   

Philippe F1GMA's Fantastic SolderSmoke Direct Conversion Receiver

SSB

Wow, congratulations to Philippe F1GMA for his wonderful build of the SolderSmoke Direct Conversion Receiver. Phillipe deserves extra credit for achieving this goal while working in a foreign language, and with parts acquisition even more of a challenge for him.  That AF transformer was hard to get in France.  And I see that a companion CW transmitter may be in the works.  FB.

The SSB signal that Philippe provides includes a clip from special event station TM120ESP.  That station commemorates the 120th anniversary of the first Esperanto congress.  FB.  TRGHS! 

Congratulations Philippe and welcome to the Hall of Fame.  I think you are our very first French builder.  

Click here for a CW clip

Puerto Rico -- Dominican Republic Tropo on 99.5 FM? Yes, probably

 

Our friend Todd K7TFC in Portland found this in the 1950 ARRL Handbook at an, uh, opportune moment.  TRGHS.  This seems to describe what a I am hearing, especially that "airmass boundary" in the lower left of the diagram above.  

I'm not a VHF guy, and I am a bit surprised at the persistence of this propagation path.  It is 4:30 am here and the adult contemporary rock from Puerto Rico (Kokomo by the Beach Boys!) is full quieting here in the Dominican Republic.  And it is of the same strength during daylight hours. I don't remember this from the winter months, but I may have just missed it. 

Here is what AI (Gemini) says about this: 

https://share.google/aimode/M1HvC7Y893eE5gAcn\

One other factor to consider:   The island of Mona is about halfway across the path.  There are few people there, and there is almost certainly not a repeater of any kind.  But there may be a metal tower or two... 

Gianfranco IU1DZZ and Mike WN2A  both support the tropo hypothesis.  Mike mentions the Hepburn Index.  I will have to read up on that.  Hamilton is also looking at this propagation path.  Thanks guys.  

Puerto Rico FM Broadcast Station Heard in the Dominican Republic -- But How? WIDI 99.5 FM

WIDI 99.5 FM. Booming in during daylight here on the eastern tip of the Dominican Republic. Their antenna is about 2100 feet above average surrounding terrain. That would put the horizon at about 56 miles. But the path is about 100 miles. What do you folks think is the likely propagation mode?

https://en.wikipedia.org/wiki/WIDI

Chris KN4GAH's 100th! SolderSmoke Direct Conversion Receiver

This was the 100th SolderSmoke receiver!     It was really cool to see Chris KN4GAH's  receiver inhaling CW (sbove)  and SSB (below).  I especially like the ink pen markings on the pine board.  FB.  Maybe make note of memorable QSOs heard, or -- later -- contacts made with this receiver.  

Chris is an electrical engineer, so it was particularly useful for us to get his perspective on this project.  We started this at the High School knowing full well that most of the students would spend their careers in the high tech, digital world, and might never again touch a soldering iron.  But we thought it would be good for them to build something like this at least once.  Chris comments on this idea below.  

Chris writes: 

Thank you for putting this all together for all of us and creating such a great community full of knowledgeable and helpful people. I work as an RF engineer and mentor a few junior RF engineers and will be proposing this challenge to them as a learning opportunity. As this challenge provides a lot of insight into how common blocks used in RF designs operate. It is just too easy to go on mini-circuits and find a filter, amp or mixer that meets ones needs. Actually building these components provides valuable knowledge that all us RF engineers should have.

Thanks Chris, Congratulations and welcome to the Hall of Fame!

Chris KD4PBJ's FB SolderSmoke Direct Conversion Receiver

Chris KD4PBJ is one of SolderSmoke's most loyal fans.  Over the years Chris has supplied many of the parts and ideas used in SolderSmoke projects.  We were really delighted when Chris took on the Direct Conversion challenge.  As you can see,  his build was superb. 

Chris had promissed to have the receiver completed by September 2, 2025.  As it happens, that was the day of some very powerful solar activity and very poor band conditions.  So the video above doesn't really do justice to Chris's receiver.   We hope he will send us some more video, perhaps under better conditions, and perhaps with some more SSB. 

As you can see from this message from Chris in mid-July, he is a busy guy.  We were pleased that he found time to build this receiver.  Chris wrote

Good Morning guys!
I spent my July 4 weekend and 1200 round trip miles heading up to Richmond to pick up two 50 watt decommissioned airport non directional beacons that I hope to get working on either the 630m or 2200m bands. I'll most likely just use the amplifier, power supply and matching sections as they are modulated CW which isn't permitted. 
At least I have a nice high current power supply, outdoor enclosure and inner workings. I was told one worked and one doesn't.
I got them off eBay and the seller is a television engineer in Richmond named Greg. He listens to Soldersmoke too and is a builder like I am.
He said these are government surplus from a place called Camp Peary in VA.

The DC receiver is still coming along, I've just been overwhelmed with things on my to do list as well as a new job (learning lots about  high power lasers) so I promise it will get done soon. 

Chris 

Here are a couple of pictures of Chris's receiver.  Thanks Chris, and Welcome to the Hall of Fame.     

 

Dave K5YFO's FB Texas SolderSmoke Direct Conversion Receiver

The pine board is key.  Frank Jones (W6AJF) would approve. FB Dave.    CW video above and SSB below. 

Dave writes:  

Bill,

After many diversions from the work bench I finally got the Solder Smoke Challenge Receiver to operate.  There were the usual problems with the audio amp but my main problem was a faulty trimmer in the BP filter.

 

I hope I’m in the first 100 to complete the project. 

 

Hopefully the attached videos make it.  One is a CW and the other is SSB. 

 

73 de Dave K5YFO

Robert Sutton's Amazing SolderSmoke Direct Conversion Receiver

It is amazing that Robert (who is not yet licensed) got this receiver to work.  Check out his homebew coil form.  Excellent work Robert.  Congratulations and welcome to the Hall of Fame.  

Here is a Dicord exchange with Robert.  I think we see the true homebrew spirit here: 

Hall of Fame Update: 96 Completed SolderSmoke Direct Conversion Receivers, and 7 Honorable Mentions. Total: 103 receivers as of October 19, 2025 1649Z. More receivers are being built.

Please let us know if you spot any errors, or if we have inadvertently missed anyone.  Don't worry about being late to the game -- the challenge continues.  All of the info is still available (see below). 

As of October 19, 2025 1649Z:

So far 96 completed receivers, and 7 honorable mentions.  Total Count:  103.       Receivers built in 17 countries.   

NE3U (KY4EOD)  Matt 

KQ4AOP       First ham signals ever heard! 

N9TD             Derek

AC3NG          Ryan

VK3TPM       Peter Marks  

W4KAC         Ken 

W4KAC         Ken built a second one! 

N2EPE           Erik

VA3NCA        Wayde    

KI5SRY          Mark -- Gears on PTO screw

 

KA1MUQ       Frying pan receiver

AA1N              Adam

ZL1AUN         Aaron -- Using SSB transmitter -- New Zealand

W8UC             Never before homebrewed. 

VK4PG           Phil -- Nice case, "really pleased"

G7LQX           Working well, video of CW and SSB.  -- England

KE2AMP        John     Spring on PTO screw -- great

N9SZ              Steve  nice receiver

KD9NHZ        Piotr  Nice one

KE8ICE          Calvin, Very cool receiver. 

 

WV3V              Jayson!  Got it done!

GM5JDG         Martin.   -- Scotland 

KF8BOG          Jim:  A long struggle, but success.  

Chris Wales    Fantastic video.  -- Wales

YD9BAX         Wayan! Homebrew transformer!  Indonesia

N0NQD         Jeff 

WN3F              Roy -- Made new stickers! 

AB5XQ            Bill  

KB7ZUT          Andy  

AA1OF            Jer

VictorKees        Holland

KC9OJV           John -- Manhattan-style convert

WZ5M              1, 2 or maybe even 3 receivers!

K1KJW             Jim in Vermont

KC5DI              Dallas -- friend of WZ5M

Gary                 Australian -- Wooden PTO form

LU2VJM          Juan in Argentina  -- Argentina

K1OA               Scott "Most fun in 50 years"

KC9DLM         Ben -- Had EFHW problems

PH2LB             Lex  Yellow, Glue Stick -- Netherlands

AI6WR             David

G6GEV            Dave (It was a blast!) 

KC1ONM        Wayne  MakerLabs NH

KB1OIQ          Andy    MakerLabs NH

KA1PQK         Jay       MakerLabs NH

W1TKO           Mike    MakerLabs NH

K5KHK            Karl

SM0TPW         Mikael  -- Sweden

KI7LKB           Brian (coat hanger tube)

M6CRD            Chris

W2DAB           Dave in NYC

W4JYK            Wes of VWS

KA4CDN          Mike of VWS

M7EFO             Adrian 

VK5RC             Rob

KD8KHP          Dave

VK1CHW         Chris

KA0PHJ           Brian

W0IT                Louis

W1PJE             Phil

W2AEW           Alan

KN6FVK          John (Barkhausen-Be-Gone Spray) 

VU2JXN           Ramakrishnan -- India

AA0MS            Doug 

9V1/KM7ABZ   Paul  --  Singapore

VK2BLQ          Stephen -- Australia

N3FJZ              Rick

Daniel               VE5DLD  -- Canada

Student 1          Student of VE5DLD

Student 2          Student of VE5DLD

Student 3         Student of VE5DLD

K7WXW          Bill 

NK3H               Mitch

KN4ZXG         Ted

WA1MAC        Paul

N4AVC             Chuck 

K3IY                 Kevin

N6ASD             Ashish in Bangalore

W1DSP             Rick

WD4CFN         Steve

KM5Z             Mike

KF5DAN         Dan

Fritz                 Fritz

N9OK              Joe

WA5DSS         Bill 

K0GDB           Grant

G0JNR            Shane Glow-in-Dark Coil Form

KK7BCO        Tobias

K2BVR            Bob

Robert              Sutton

K5YFO           Dave (Texas) 

KD4PBJ          Chris

KN4GAH        Chris -- EE perspective

F1GMA           Philippe  -- France

W2TEF            Todd

EI9ITB            Karl  -- Ireland

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

Honorable Mentions: 

*AA7U            Steve No PTO

*VK7IAN        Ian -- No Manhattan boards -- Tasmania

*KC1FSZ        Bruce's build on a PC board

*CT7AXD       Graham -- different AF amp -- Portugal

* DL1AJG      Andreas -- Germany

* Matthew      Student of DL1AJG

* Arash           Student of DL1AJG 

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

Candidates for the Hall of Fame: 

SA5RJS              Rasmus

KA9TII               James

AA7FO              Chuck 

VA3ZOT           Tony  Surface Mount -- Honorable Mention? 

AB2XT             John (Done, just need the video)

KO7M              Jeff (Piper Cub)

VU2TUM         Puneit Singh

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

Bob K2BVR's FB SolderSmoke Direct Conversion Receiver

Bob K2BVR homebrewed a really nice SolderSmoke Direct Conversion receiver.  On his "Proof of Life" video we hear some nice SSB signals, some great CW signals (including N7DZ/6 POTA) and even the well-known tones of FT8.  FB Bob.  Congratulations OM!  Welcome to the Hall of Fame. 

Bob writes: 

Hi Bill,

I wanted to send you a quick note of thanks. I’m very grateful to the SolderSmoke Discord users for their help, and to you and KK4DAS for all of the work you’ve both done in developing this project and sharing it through your videos.

I’ve been making progress on my build and thought I’d share a little update. I ran into some challenges with the bandpass filter – it turns out that reducing the trifilar winds per inch helped improve the performance. I also fought with a shorted test fixture along the way, which made things more confusing than they should have been.

On the audio side, my first amplifier module is still giving me trouble. I hated not getting it fixed right away, but I’ll be coming back to it. I did have to add a 470uF cap to the power rail to control oscillation but I haven't added the 220 ohm resistor. I’m thinking about putting the different modules into their own boxes so that I can experiment with them more easily in the future.

Thanks again for all of the inspiration and guidance — I really appreciate it.

73s

K2BVR

 

Tobias KK7BCO's FB SolderSmoke Direct Conversion Receiver

Sounds great Tobias!   Congratulations -- Welcome to the Hall of Fame! 

Tobias writes: 

Bill, I have joined the few. 

You guys created a project that even I could build. Thank you for the journey!

Now I plan to make duplicates of some elements, and create some kind of a terrifying musical instrument. 

Perhaps a Theremin Tobias?  AKA Etherphone!  This was reportedly one of Neil Armstrong's favorites! 

https://en.wikipedia.org/wiki/Theremin

Shane G0JNR's FB SolderSmoke Direct Conversion Receiver -- With a Glow-In-The-Dark PTO Coil Form

I was really pleased to see Shane G0JNR finish this receiver. He has been an active member of the SolderSmoke community for many years.  For example, back in 2018 we see him commenting on KU4NO's FB rig: 

https://soldersmoke.blogspot.com/2018/07/a-rig-with-maximum-soul-5-band.html

Shane writes: 

Shane G0JNR here. I've just got my Soldersmoke DC rx up and running! The thing that put me off earlier in the year was the 3d printed coil former. But my son has now got one and printer and printed one for me - as an added bonus, it glows in the dark! It didn't work straight away but perseverance has paid off. 73

Thanks Shane! Congratulations and Welcome to the Hall of Fame.

Glow-In-The-Dark PTO Coil Form

One (of several) SolderSmoke Blog Backups: This one in .pdf form

The SolderSmoke Daily News blog now has more than 4,000 posts, and some 10,000 comments.  This is both good news and bad news.  The good news is that there is on this blog site a vast repository of useful information.  The bad news is that I sometimes fear that all this info might be lost if Google someday decides that its blog service should disappear.  It could happen, and that is kind of scary, so I have been looking for backups, for ways to safeguard this information. 

Several members of the SolderSmoke community have been helping me create WordPress sites that backup the blog. More info will be coming soon.  The Internet Archive and the WayBack machine have also been of great help. 

While here in the Dominican Republic, I have been working on a kind-of compilation of blog articles, with a bit of an intro.  I think readers of the blog and listeners of the podcast might find this entertaining. 

So here it is.  Please download it to your computer.  That will increase the survivability of the blog.  I will probably do a few updates to the .pdf file: 

http://soldersmoke.com/SolderSmoke Blog Book Compilation.pdf

The World's Largest Radio Telescope -- It is in the Netherlands

This video is in Dutch, but you can easily turn on the English subtitles.   I put this on the blog for a couple of reasons:  Radio astronomy is very interesting; I am a former member of SARA, the Society of Amateur Radio Astronomers. SolderSmoke celebrates the INTERNATIONAL Brotherhood of Electronic Wizards; this blog serves the WORLDWIDE community of radio electronic homebrewers. 

Thanks to Rogier PA1ZZ for sending this.  

Brian KI7LKB's FB Modifications to the SolderSmoke Direct Conversion Receiver

 

Although we had strongly suggested that builders FIRST build the receiver in accorandance with Dean KK4DAS's excellent videos, we also told builders that once they got those receivers working, there was, of course, no limit on the modifications and circuit changes they could make. We are very pleased that Brian KI7KLB has followed this advice.

Brian writes:

The KI7LKB DCR has been modified to include the KK4DAS 3rd stage of the audio amp, a QRP guys frequency counter, and an enclosure made from scrap aircraft aluminum and hardware. My favorite mod, however, is the WB6AMT (SK and former Elmer) voltage regulator circuit. It allows me to power the DCR from the shack 13.8 volt power supply while simultaneously providing 9.5 volts for the radio and 12 volts for the frequency counter. While I ordered components from Digi-Key, it was fun to include a coat hangar, spare aircraft hardware, scrap wood, and repurpose the frequency counter from another project.

Grant K0GDB's FB SolderSmoke Direct Conversion Receiver

Congratulations to Grant K0GDB on his FB SolderSmoke Direct Conversion receiver.  Welcome to the Hall of Fame Grant! That PTO former is especially FB!  Grant is a relatively new ham, making his smooth construction of this receiver even more admirable. 

Grant writes: 

Proof of life video! Many thanks for the helpful YouTube tutorials, everything went together pretty smoothly.

The windings are actually as close to the specification as I could get them on the nanoVNA. It's been a bit since I built that part, but if memory serves I had one fewer turn and had to do some bunching to get it to read correctly. The main difference in the PTO is that I made the former on a laser cutter from slices of quarter-inch plywood since I don't have a 3d printer. The center cyllinder is actually just rolled up paper.