Building an Electronics Work Bench (and fixing an old CNC Lathe)

It is interesting to Watch Wes Work.  Recently I came across his YouTube channel when he described his effort to repair an old CNC machine.  Being the frequent beneficiary of Pete N6QW's $250,000 CNC machine, naturally I took a look (see below).  

I am really glad that Wes built a proper electronics work bench (above).  He has flux!  He has rosin core solder!   I just hope and pray that he is not using lead-free solder.  I admire his use of the 3D printer.  And he has some cool tools, especially that de-burring device.  He has a Rigol oscilloscope and he has a big collection of leads.  Is Wes a ham?  If not, he should be.  

Here is the CNC lathe video. 

Wes's YouTube channel:  https://www.youtube.com/@WatchWesWork

SolderSmoke 264: CW TX, Repair of 17-12 Rig, AI and Repair, Back on 40m, HB for 2m, VWS WSPR Makers Project , MAILBAG

QSO May 8, 2026 with Lou EA3JE.  I was using my Mythbuster

May 12, 2026

SolderSmoke Podcast #264 is available for download: 

Audio:   http://soldersmoke.com/soldersmoke264.mp3

Video:  https://www.youtube.com/watch?v=_9FcfuqjZxA

We had a small recording glitch at the beginning of this video. But we didn't lose much. We had talked about the success of the SolderSmoke Direct Conversion Receiver Project. We talked about the receivers built by Nader Omer ST2NH and Chuck Adams AA7FO. We had also gloated a bit about our April 1 post -- you know, the (bogus! ) story about how the Administration is "Supporting Homebrew Radio." (Let us know if you were taken in by this, even for just a few seconds.) At that point, we were just beginning Pete's section; that is where the recording began. Here are the notes for the rest of the podcast:

Pete: 

Three CW transmitter projects featuring low parts counts.  Good results from Reverse Beacon Network. 

The goal in these projects is to raid the junk box and severely limit any new purchases of components.  Pete had no idea of the depth of parts he bought and just stashed away.   https://www.youtube.com/watch?v=5YLZ7aZpmxQ&t=30s

Bill: 

Fixing the 17-12 Rig.  Parasitic VHF Oscillations with the SK3050.  Good advice from Gemini. Killing NE602s. Fat Finger Syndrome -- hard to work with ICs.   Different freq when on transmit -- need for .1 uF cap on pin 8. Worked South Korea -- TRGHS. 

Putting the DIGI-TIA back on the air. On 40! And SW listening with the Q-31. 

Hard to homebrew for 2 meters.  Did some beacon experiments to Puerto Rico on last day in DR. 

SHAMELESS COMMERCE DIVISION: 

The importance of Patreon!  Thanks!  patreon.com/SolderSmoke

Mostly DIY RF!  https://mostlydiyrf.com/

Universe Today Podcast with Fraser Cain.  No Ads.  Great stuff.  Listen!   https://www.patreon.com/public-rss/75186?show=1744036

Dean: 

The VWS WSPR project.  

Mailbag:  

Ed N3EML  Heard me on 40 with my Digi-Tia

Grayson KJ7UM  Liked WWII training video: https://soldersmoke.blogspot.com/2026/05/radio-receivers-1942-training-film.html

Mike WN2A  -- Pete Juliano is our Shifu! (Lexicographer Steve Silverman KB3SII approves,)

Todd K7TFC Thoughtful comments on ARRL "Clean Signal Initiative."

Danny ON1MWS's regen with unusual variable capacitors. 

Mike WU2D  S-38, Nearfest,  Mu Metal.  https://www.youtube.com/watch?v=YUQ4xml1dSY

Charlie NJ7V  Interviews Mitch NK3H who homebrewed an SSB transceiver. 

Charlie also had Don KM4UDX, President of the Vienna Wireless Society on the podcast. 

Bob KD4EBM -- El Cilindro. Radioactive Hospital Waste -- basis for a Ruben Blades song.  It was 1987 in Brasil.  Cesium 137 left in hospital waste.  

Hamilton  KD0FNR   Big fans of "The most interesting man in the world."https://soldersmoke.blogspot.com/2026/04/background-from-maine-on-most.html

Rhett KB4HG -- TW-100! Used on the OMRN. https://soldersmoke.blogspot.com/2026/05/the-tw-100-fly-away-transceiver-cw-ssb.html

What happened to Glenn KU4NO's homebrew rig? https://soldersmoke.blogspot.com/2018/07/a-rig-with-maximum-soul-5-band.html

Ryan KJ7KVD is listening to OLD SolderSmoke podcasts.  He will build a Michigan Mighty Mite. 

Will N5OLA restored a Heath SB rig.  We now know why they went to HW rigs.   https://www.youtube.com/watch?v=Bt2d1Ia8lqQ 

Paul G0OER -- Thanks us for PTOing the HB world, but sends us a video of a unique Eddystone receiver with 39 permeability tuned coils!  https://www.youtube.com/shorts/L4oQHU5_kQk?feature=share

Rick N3FJZ -- A very cool video today on his homebrew HF power amplifiers:  https://www.youtube.com/watch?v=-CUVAF4HyfY

Farhan VU2ESE -- I heard from him yesterday as he was landing in Chicago. 

Background (from Maine!) On the "Most Interesting Man in the World"

I know, I know.  This doesn't really have anything to do with homebrewing.  But in a way it does.  This guy didn't get his start until age 68.  So there is hope, right?  And there is the Latino angle. 

And here are some Dos Equis "greatest hits": https://www.youtube.com/watch?v=ukosls76res My favorite from this bunch is "The last time he flirted with danger, danger got clingy." 

One prominient homebrewer says that Pete N6QW is the "Most Interesting HAM in the world."  I agree.  

Stay thirsty my friends.  

Dean KK4DAS and Pete N6QW Talk to the River City (Sacramento, Ca.) Radio Club about the 40 meter Direct Conversion Receiver

On April 7, 2026 Dean and Pete spoke to the River City Radio Club about the 40 meter Direct Conversion Receiver project (see above).  Great job guys! 

Thanks to Carol KP4MD for the invitation. 

Happy Birthday to Pete Juliano N6QW

 

That, my friends, is the look of a steely-eyed homebrewer taking a break from the soldering iron by belting out a few noodled chords for SolderSmoke on his guitar.  And in the picture he is in the garage where all the homebrew magic happens.  

Pete, we know that this has been a tough orbit for you, but we still want to wish you a Happy Birthday OM -- you bring a lot of wisdom and tribal knowledge to many, many builders.  Thanks Pete. 

73  Pete. 

SolderSmoke Podcast 262: Hybrid Wireless, 100 Watt Amplifier, Antipode VK6, Tropo DR to PR?, Mixers, MAILBAG

SolderSmoke Podcast #262 is available: 

Audio only: http://soldersmoke.com/soldersmoke262.mp3

Video:  https://www.youtube.com/watch?v=QSUyE4IaHFw&t=61s 

Intro: 

-- We are over 100 on the Direct Conversion Receiver Builds.  We talked about the receiver project at the GQRP convention.  Video on the blog.

-- G4 Geomagnetic storm November 11-12.  Messed up my computer.  Blackout in the DR?  

Pete: 

-- USMC Birthday. Having served alongside them they have my deepest respect. Veterans Day. 

-- Think about supporting those without a job this Thanksgiving. Cash to various organizations is best.

 -- 50 Hz off frequency -- What does that mean if you tune by ear and not by mouse/waterfall?

--  The Hybrid Wireless is on the air. A unique build and not often seen.

Dean:  

-- Progress on the HOMEBREW MOSFET amplifier.  Claude helped. 

Dean's 100 watt amplifier

SHAMELESS COMMERCE DIVISION:  Mostly DIY RF.   Become a SolderSmoke Patron.  Buy stuff from Amazon through the link on this blog (in the right side column). 

Bill:  

Bill's antipode from Virginia

-- VK early in the morning.  Also E51MWA and FW5K.  All homebrew SSB. My antipodes. VK6ACF Charley 11,629 miles.  Might be my most distant station worked. 

-- Preping for VHF in HI7.  Can I kerchunk Boricua repeaters with Tropo?  See: https://soldersmoke.blogspot.com/2025/09/puerto-rico-dominican-republic-tropo-on.html

-- Bill's mixer obsession. Grayson's HSD Chapter 12. The importance of knowing "the paticular go of it." EMRFD Chapter 5. 

-- The new look for the SolderSmoke blog. 

MAILBAG:  

-- Todd VE7BPO -- Doing well. 

-- Grayson KJ7UM on the loss of Jim Tonne W4ENE.  Gone, but through his writting, continuing to contribute.See: https://web.archive.org/web/20220429224036/http://tonnesoftware.com/appnotes/demodulator/EnvelopeDemodulators.pdf

-- Camden is a 23 year-old blind ham who is looking for some homebrew help. He lives in Pleasant City, Ohio, about an hour east of Columbus.  Can you help him? camden@bopp.net

-- Dale Parfitt into the QRP Hall of Fame!  The Radio Gods Approve! 

-- Paul VK3HN -- Bricolage, Cacharreo, Artilugio, and Jugaad.  SA612 going obsolete. 

-- Mike WN2A Mixers and all that. Tropo.  "Greetings from the National Radio Noisy Zone!" (NJ) 

-- Peter Marks VK3TPM -- SolderSmoke template help -- Digital HF Voice

-- Walter KA4KXX -- A great book by L.B. Cebik

-- Bob KD4EBM  -- The Bob Pease Analog Troubleshooting book. Pease quote: "My favorite programming language is solder," 

-- Cor PA3COR  Difference between mixers and adders

-- Mike WA3O  I still have his HW-7.  Amazing water-cooled amplifier.   VK3MO.  

-- Samuele IU2QBW     An Italian Homebrewer  https://soldersmoke.blogspot.com/2025/10/a-wonderful-homebrew-direct-conversion.html

-- Pil Joo VA3GPJ  Experimenting with TIA amps. 

-- Farhan VU2ESE -- USB and LSB LC filters -- Applicable for crystal filters too? 

-- Rogier PA1ZZ Thanks for the great videos! 

-- Captain Mike  KX4WC   Aeronautical Mobile --Santiago, Chile to Panama!  With Mike WA3O and Ian VK3MO:  https://soldersmoke.blogspot.com/2025/11/vk3mo-and-wa3o-brotherhood-of-ham-radio.html 

-- Dave AA7EE  A completely AI SolderSmoke? "Open the pod bay doors Hal." 

-- Pat W3RGA heard my 1 watt HI7 beacon.  Thanks Pat. 

-- Patrick Voets -- A Belgian living in the Netherlands -- supports our defiant NIMCEL position! 

-- Brian "Moses" Hall K8TIY, Father of Robert of "Crank it in Robert" fame.  Check out the video.  Young Robert appears around the 45 minute point:  https://youtu.be/Xqs2Ihucr6I?t=2730

-- Will Harris KI4POV -- an esteemed homebrewer -- asks about using 75 ohm coax. I say yes, Pete tells him how to do it right. 

"Rig Here is Homebrew" -- The Joys and Sorrows of Building your own Rigs

This is kind of a re-run.  I came across it today on YouTube and thought it was pretty good.  So here it is again.  

 -------------------

Dean KK4DAS asked me to speak to our local radio club, the Vienna Wireless Society.   It was a lot of fun.  I talked about my evolution as a homebrewer, some of the rigs I made, the moments of joy, and the tales of woe.   You can watch the presentation in the video above. 

I was really glad to be able to explain in the presentation the importance of people like Pete, Dex, Farhan, Wes, Shep and even Dilbert. 

I was also pleased to get into the presentation the N2CQR sign that Peter VK2EMU made for me.  Thanks Peter! 

Here is the URL to the YouTube video (also above): 
https://www.youtube.com/watch?time_continue=3414&v=VHSr-v4QO7Q&feature=emb_logo

And here are the PowerPoint slides I used: 
https://viennawireless.net/wp/wp-content/uploads/2020/06/VWS-presentation-Rig-here-is-homebrew.pdf

SolderSmoke Podcast 261: Travel, AI-Apocalypse, ARRL Award, Amplifiers (with Claude) , Transcoms, Smoke released in DR, QRP, CW, MAILBAG

SolderSmoke Podcast #261 is available for download: 

Audio:  http://soldersmoke.com/soldersmoke261.mp3

Video:  https://www.youtube.com/watch?v=1rzw8lxBzRo

Alaska, Colorado, Dominican Republic

Opening:   Travel notes:    Pete to Denver.  Dean to Alaska.  Bill in the Dominican Republic. 

The future of the podcast.  We will embrace our NIMCEL status and fight on in spite of the AI Apocalypse.   Thanks to Peter VK3TPM, Hamilton KD0FNR, Sam AI7PR, Todd K7TFC  and the WayBackMachine for providing backup and transfer options for the blog. Google could end Blogspot at any time.    

Dean and Bill win the 2025 ARRL Technical Service Award.  Thanks to Bruce KC1FSZ for the nomination. And thanks to Bill Morine N2COP for letting us know.  91 receivers completed so far!  

SolderSmoke East was pleased to host Phil W1PJE, a distinguished MIT radio astronomer AND member of the SolderSmoke Direct Conversion Receiver Hall of Fame.   

Dean:   Amplifier design,  woes, triumphs, tribal knowledge.  And help from Claude. 

KK4DAS 100W MOSFET AMP

Pete:  Project X  -- The Transcom SBT-3,  Crossroads and Decisions. 

Transcom SBT-3

SHAMELESS COMMERCE DIVISION:   FIGHT THE AI-APOCALYPSE -- BECOME A PATREON SPONSOR.

GET BEZOS TO SEND US BEZOS BUCKS!  Use the Amazon link on the upper right.   

BUY PARTS AND STUFF FROM MOSTLY DIY RF. 

Bill: 

-- Smoke released in TWO RD06 finals.  Scrounged IRF-510s to the rescue.   

-- Working VK6 on 20 SSB.  

-- My old HW-101 -- inspired by Pete and by Will N5OLA.   

-- High frequency hearing loss and direct conversion receivers. 

-- Eleven contacts on 40 with the DC RX and a Tuna Tin 2. Mike Bryce WB8VGE came back to my CQ! First ever QSO with SolderSmoke DC receivers on both sides:  K1OA-N2CQR.  

-- Do real hams use ALC? Do we really NEED ALC? 

Mailbag: 

Who is the Project 326 Guy?  A British engineer resident in China for last 20 years. 

Steve EI5DD  Ham Radio Ireland magazine.  Hey -- Why no Irish DC RX builders? 

Paul K9ARF -- Thanks for the very kind e-mail about SolderSmoke. 

Rogier PA1ZZ -- Many nice videos and suggestions on blog backup. 

Grayson KJ7UM on the EF-50 valve (thermatron!) 

Bruce KC1FSZ  Four DC RX builders at the Wellesley Mass radio club. 

Chris KD4PBJ -- Long trip to pick up two directional beacons possibly for 630m or 2200m bands! 

Alan W2AEW did a Minimum Discernible Signal test on the DC RX.  FB! 

Mike WN2A  -- Many great comments on MDS in its various forms. 

Philippe F6GUH is a FB homebrewer.  

Mike EIOCL -- Always great to talk on the air with an old friend. 

Walter KA4KXX -- I checked into the Sunrise net!  With my HW-101!  Thanks Walter. 

Farhan VU2ESE -- Watched our interview with Phil W1PJE

Phil W1PJE was an SWL with an old Halli receiver.  VOA?  Boo!  But Radio Marti is BACK! Also, the hydrogen line from the cosmic dark ages has red shifted to... 7.1 MEGA hertz!  So LISTEN UP! 

Phil W1PJE with a Halli and the Haystack Observatory Dome

Oscillation! Negative Resistance! Barkhausen Explained Very Well!

It is not every day that we find a web site or a YouTube video that discusses negative resistance and the Barkhausen criteria.  But that day has arrived my friends!  

This All Electronics fellow appears to be Italian.  I really like his enthusiasm. The universe!  Differential equations! The passion seems to jump out of the video when he talks about how the negative resistance "enhances the oscillation!"  It is really great.

He even talks about how thermal noise gets the oscillation going.  This is something that I struggled with as a kid.  It took me a while to find a good source that explained this.  He explains it very well. 

Thanks to master homebrewer Pete Juliano (another Italian!) for alerting us many years ago to the Barkhausen criteria.  And thanks to Al Williams at Hack-A-Day for alerting us to this great video. 

Here is the All Electronics channel on YouTube:  https://www.youtube.com/@AllElectronicsChannel

A Nice Quick HW-101 Restoration Video

 This video is almost enough to get me to work on my old HW-101. 

Pete N6QW has been working on an HW-32A monobander. Some of the info in this video might be applicable. 

Phil W1PJE, Director of MIT's Haystack Observatory, visits SolderSmoke East, Talks Radio with N2CQR and KK4DAS

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.

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

Chuck N4AVC's FB SolderSmoke Direct Conversion Receiver: "I enjoyed the build and testing."

Chuck N4AVC's use of the frequency counter in his digital multimeter is pretty cool and innovative. And it is nice to have yet another receiver in Virginia; he is down in the Richmond area.  And of course the Sharpie callsign tattoos on the wooden board are really nice. 

Chuck writes:  

Completed!!! For Pete: "She ain't pretty, but she sure can cook!". Thanks Bill and Dean, I enjoyed the build and testing. It's funny, the audio oscillates on an older 9v battery, but is clean on the 9.5v bench supply. Going to put Bill's mod on the inductor to make tuning a little finer and spread the boards out a little more. I used the double sided boards I had and there is some interaction between the boards.

Congratulations Chuck! Welcome to the Hall of Fame!

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!  

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

Thanks to Andreas DL1AJG.  Welcome to the Hall of Fame.   

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

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

On the importance of taking a break.

Thomas K4SWL has a good post about the importance of taking a break from radio.  Following up on this, I noted that "taking a break" is often a good way of finding a solution to a difficult problem. I noted that I have confirmed this -- it has worked for me.  Pete Juliano N6QW recently announced that he is taking a break from the MHST project. That is a good idea. A solution will likely emerge. 

I noted that there is some evidence backing up our suspicion about the benefits of breaks.  I earlier shared some comments from Harry Cliff's excellent book, "How to make an Apple Pie from Scratch." 

https://soldersmoke.blogspot.com/2024/04/cloud-chamber-finale.html 

Harry also wrote about the usefullness of taking breaks.  In 1917 Ernest Rutherford was having trouble  understanding the presence of some hydrogen nuclei.  Harry writes: 

"Again, he was forced to put his work on hiatus to go on a mission to the United States in the summer of 1917, but it turned out to be one of those useful breaks when stepping away from a problem lets your mind slowly work out the problem in the background. When Rutherford got back to the lab in September he had the answer..."

There are many other examples. 

So, if you get stuck, take a break!   

Derek N9TD's SolderSmoke Direct Conversion Receiver -- With a Double Sideband Transmitter

 

Derek N9TD was another of the early builders of the Direct Conversion receiver; he has done really magnificent work.  He is an Electrical Engineer, and you can see in his work (and in the email below) the tension that exists between the desire for simplicity and the urge to improve.  In the above photo, for example, we see that Derek had already gone ahead with the installation of an RF gain control. We also see his use of a steel screw and an outboard coil in series with the PTO coil.  All of these mods are fine -- I have used all of them. We just advise newcomers to build the basic receiver first, then put in mods from there. 

Derek has gone the extra mile (many miles in fact) by building a Double Sideband transmitter to go along with his receiver.  We know many will want to do this.  Our advise remains:  Build the basic receiver first, get it working, then do the mods, perhaps culminating in the build (as Derek did) of a Double Sideband transmitter and the creation of a DC-DSB transceiver. 

Here is a video of just the receiver in action.  

Note that the DSB transmitter circuitry is on the board:     

And here is Derek demonstrating a phone contact with the resulting DC-DSB transceiver:  

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! 

73s,

 Derek N9TD

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

Thanks Derek.  And thanks for helping other hams get the 3D printed PTO coil forms that they needed. 

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 

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

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, 24x7 with Redpitaya SDRs and KiwiSDR/RaspSDRs

https://docs.google.com/presentation/d/1NPwjQe1am2Ym5GMV8L2V8fnQ_W9J0EbH/edit?usp=sharing&ouid=103988113912782027869&rtpof=true&sd=true

15 minute map view through PSKreporter here:

https://pskreporter.info/pskmap.html?preset&callsign=k1ra&timerange=900&hideunrec=1&blankifnone=1&hidepink=1

73 & good DX'ing!

andyz - K1RA