SolderSmoke Podcast #251 Aurora! CBLA, Winterfest, Legal Action Against SolderSmoke, HB sBITX, SDR, Raspberry Pi, Rounded Passbands, MAILBAG

Aurora Picture by Dean KK4DAS

SolderSmoke Podcast #251  4-1-2024

Audio: http://soldersmoke.com/soldersmoke251.mp3

Videos: Podcast 251 Aurora! CBLA, Winterfest, Legal Threat, sBITX, SDR, RaspPi, Rounded Passbands, MAILBAG (youtube.com)

Travelouge:  Dean goes to the North Pole to see Aurora. 

A CBLA Call to Arms! 

Winterfest.  Lots of goodies.  MXM Industries 40 meter transceiver. 1 dollar. 

Jean Shepherd. Recording of Bill talking to Shep in 1976. 

 https://soldersmoke.blogspot.com/2024/03/listen-to-me-talking-to-jean-shepherd.html

Legal Trouble: Could put us out of operation for a while.  We need listener input. 

November 2023

December 2023

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Pete's Bench

Homebrew SDR (based on Zl2CTM’s original design) and how good it sounds.

Raspberry Pi Zero W is now working on FT-8 with digital adapter.

Ferrite Cores at Digi-Key (a replacement for the FT-37-43 where  you buy 100 and the price is 21 cents/each)

ADE-6 –great specs in HF but more expensive than the ADE-1

For Pete's recent blog posts, go to this site and click on "Archive" in the right column: 

https://n6qw.blogspot.com/2024/03/march-31-2924-happy-easter-to-those-who.html

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Dean's Bench 

sBITX progress, McGyver-ing a lifted pad, replacing crystal on the CODEC board, sBITX success! See: 

https://kk4das.blogspot.com/2024/03/homebrew-sbitx-tx-modules-pa-lpf-and-mic.html

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Shameless Commerce Division:  Please use the Amazon link on the blog to start your Amazon purchases. And please consider using Patreon to support the podcast and blog.  We try to send extra content to our Patreon supporters. Mostly DIY RF --  Boards, Kits and Pete's PSSST

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Bill's Bench

More trouble with the 15-10 rig.  Rounded passbands in 25 MHz filter. See figure 4 in both links: 

https://www.arrl.org/files/file/QEX_Next_Issue/Nov-Dec_2009/QEX_Nov-Dec_09_Feature.pdf

https://www.networksciences.com/pdfs/tutorial.pdf

Experimenting with Balanced Mixers and Product Detectors. Paul VK3HN  Suggests the MC1496 chip; Walter KA4KXX points to SSDRA circuits

But it is on the air!  Using the PA from a BITX40 module and an RD06.  

Put an OLD dial from Pericles HI8P on 15-10 version 1.  Soul in the new machine.

Pericles' Dial on the 15-10 Rig 

Mailbag: 

Grayson KJ7UM's Hollowstate video. 

Mike WU2D's amazing 10 meter DSB transceiver. 

Jack AI4SV (Dhaka Jack) liked video of recent QSO with AzoresDSB rig

Mike AA1TJ and Dave AA7EE on backwaves and 100 uW QRPpppp

Dave G3UUR  on my curved passband problem

Alan W2AEW heard my only QSO with the MXM indsutries SupeRX/TX40

Wes W7ZOI, Mike WN2A, Walter KA4KXX. Farhan VU2ESE on passband, 

Ramakrishnan sent article about Charles Proteus Steinmetz.  Beautiful. 

Justin AC8LV built a receiver!  FB. 

San Francisco QRP:   KDOFNR TouCans Rig, and N6ASD Zinc-Oxide TX

Frank KC8JJL -- Another guy who heard first ham sigs from a homebrew rig. 

Nate KA1MUQ's homebrew thermatron superhet

Dino KL0S sent info on the PAL CB VFO I picked up at Winterfest. Airborne! 

Bob W8SX will be once again doing SolderSmoke interviews at Dayton.  Thanks Bob

Peter VK2EMU  Always good to hear from him.

Tobias Feltus -- Wisdom teeth removed, wondering if he will get sBITX hallucinations...

Rick WD5L continues to work on his Herring Aid 5

Ciprian YO6DXE wants to learn CW. No alerts from his FB Blog!

Todd K7TFC -- Likes CW, says it eliminates the Blah-Blah-Blah 

F1BFU's Amazing PSSST VFO

The Beginning of MY Radio Life...

 

Unlike Pete (see below), I don't have any cool pictures of me in front of an early station.   But in the picture above,  there I am, at the Thanksgiving table in 1973 age 15.  I was on the air by this date, on CW as WN2QHL.  Armed with a Lafayette HA-600A and a DX-40, I was tearing up the ham bands, especially 40 meters.  Look at the tension in my face, the grip of my fist... I just wanted to finish that turkey and get on the air!  But no, I had to have Thanksgiving dinner. 

I recently realised that I have been a ham for more than 50 years. Is there an HCWA?    

This and the recent movie from India led me to think about the timeline of my early radio days: 

-- Christmas 1972.  Santa brings me a Lafayette HA-600A general coverage receiver.  With jeweled movements.  Age:  14

-- April 27, 1973.  Novice Ticket becomes effective.  WN2QHL.  Age 14. 

-- July 19, 1973.  First contact (with Elmer WN2NEC).  Age 14.

-- February 1 and 2 1973.  A grumpy old-timer calls -- during the Novice Roundup! -- to tell me that I'm putting harmonics onto the 20 meter band.  I get scared and go off the air.  Geez!  I probably just needed to retune the tank circuit.  Age 15. 

-- February 23, 1974.  I go back on the air with a DX-100.  Age 15. 

-- March 5, 1974.  I take the General Class exam at the FCC office in New York City. I pass. Age 15. 

-- April 11, 1974.  I buy the Drake 2-B from WN2NEC. This revolutionizes my radio life.  Fifteen meter contacts become possible.   Age 15. 

-- April 13, 1974.  I work ZL2ACP on 15 meter CW.  I wake up my parents to tell them.  Age 15. 

-- April 21, 1974.  END OF NOVICE OPERATION.  Apparently we were still working under a one year limitation on Novice operation.  Could the expiration date have been marked on the license? 

At this point the FCC screwed up and sent me a Technician License instead of a General Class License.  My father got on the phone to Gettysburg and straightened this out.  Thanks Dad.  So I was only a Technician for a few weeks. 

-- April 9, 1974.  General Class License effective.  I become WB2QHL,  a man of substance.  Age 15. 

-- May-June 1974.  I acquire a Heathkit HW-32A 20 meter SSB transceiver from the Crystal Radio Club.  But I have to build the power supply from an old TV.  Somehow, I survive. Age 15. 

-- June 11, 1974.  First contact with the HW-32A.  Age 15.   

-- November 9, 1974.  Last contact with the HW-32A . Age 16. 

-- March 15, 1975.  First contact with my Hallicrafters HT-37. Age 16. 

Above is my only photo of my teenage ham radio station.  I can date it via the QSL card above the map. I still have that card.  I worked W7RUK on March 25, 1975.  That contact was on 20 SSB, but when this picture was taken I was on CW (the key is plugged in, not the microphone).   

-- June 1976   I graduate from High School.  Age 17.  

-- I was active and on the air through the summer of 1976. 

-- July 1976 -- QST article on the Herring Aid 5 receiver.  I try to build it and fail.  Age 17. 

-- October 1976 -- I depart for Army Basic Training. 

There is someone else who needs honorable mention here:  My sister Trish.  Here she is, next to me at the Thanksgiving table in 1973.  Trish helped me keep my ham radio log book.  Thanks Trish! 

Pete Juliano, Field Day, 1959.  With a DX-100B and (gasp!) a QF-1. 

SolderSmoke Podcast #249 -- Travel, Pete's 6BA6 rig, Books!, VFOs, SDR, Computers, Spectrum Analysers, Transistor Man! MAILBAG

New VFO for 15-10 Transceiver

Schematic below

SolderSmoke Podcast #249 is available:  http://soldersmoke.com/soldersmoke249.mp3

There is also a video version of this podcast: https://youtu.be/5xyaYivtOhw

Travelogue:  

HAPPY VETERANS' DAY TO PETE AND GRAYSON AND TO ALL THE OTHER VETERANS WHO ARE LISTENING. 

Trip out to San Francisco. Sticker placed on the corner of Haight and Ashbury:  See picture below.  Note other sticker.  Really Groovy! 

Cuban Cacharreo! Andy CO2AFV's Knack Story  https://soldersmoke.blogspot.com/2023/10/a-cuban-knack-story-and-pandemic-sits.html

Bill's DXCC-100.  DONE.   

Tribal Wisdom:  W1REX on HRWB https://soldersmoke.blogspot.com/2023/11/listen-to-rex-w1rex-lots-of-tribal.html

Pete's Bench:

Pete's 6BA6 rig

Pete's 6BA6 Rig

Pete Re-invents the Shirt-pocket SSB Rig

Pete's remake of the ShirtSleeve Transceiver

Pete Builds Two Computers 

Pete Adds a Second Band to his Homebrew SDR 

 

SHAMELESS COMMERCE DIVISION:  

BEZOS BUCKS ARE BACK!  PLEASE  BUY THERE! >>>>>>>>>>>>>>>>>>>>>>>

Mostly DIY RF:  Work proceeds in the Oregon Silicon Forest on P3ST kit development. Todd is confident the P3ST will be released on December 18th.Many other kits available now:  https://mostlydiyrf.com/ 

Sign up for the newsletter:  https://mostlydiyrf.com/subscribe/ 

Bill's Bench: 

Rebuild of the 15-10 VFO (for improved Dial Spread) (with yet another QF-1 capacitor) https://soldersmoke.blogspot.com/2023/10/dial-scale-linearity-spreading-out.html

Why Building for 10 meters is harder: https://soldersmoke.blogspot.com/2023/09/why-building-for-10-meters-is-harder.html

Copper Tape shielding of 15-10 rig. 

Crushing Spurs with Better Bandpass Filters (see blog post) https://soldersmoke.blogspot.com/2023/09/crushing-17-and-12-meter-spurs-with.html

Another 15-10 rig in the works... for SSSS.   Boards are accumulating... 

More problems discovered with the Herring Aid 5 Receiver . Lots of SS blog posts  Comment from Rick WD5L.  ) https://soldersmoke.blogspot.com/2023/10/a-big-error-discovered-in-1976-qst.html   Did you try to build one?  Did you succeed or did you fail?  Please let us know. 

The Basil Mahon books (blog posts) https://soldersmoke.blogspot.com/2023/11/basil-mahon-is-author-for-us-he.html

The Sunburst and Luminary book of Don Eyles (blog posts) 

The Art of Electronics by Horowitz and Hill (blog posts) 

Spectrum Analysers:  Tiny SA Ultra https://soldersmoke.blogspot.com/2023/09/the-tinysa-ultra-spectrum-analyser-video.html  and Polarad 632C-1; George WB5OYP gave me one of these spectrum analysers  (I NEED a manual! Does anyone have a manual or a schematic? )  : 

Polarad 632C-1

Stabilizing the EB63A (with Pete recommended LP filters from e-Bay. 

MAILBAG:

TRANSISTOR MAN T-SHIRTS!  Thanks to Roy WN3F! 

Todd VE7BPO on AF amplifiers.  Thanks Todd.  

Wes W7ZOI -- Always a privilege to exchange e-mail with Wes. 

E-mail from Jay Rusgrove W1VD. About the Herring Aid 5. 

E-mail from Eamon Skelton EI9GQ!  Amazing! 

HB2HB with Denny VU2DGR https://soldersmoke.blogspot.com/2023/09/hb2hb-contact-with-denny-vu2dgr.html

Nick M0NTV on diode matching for ring mixers: https://soldersmoke.blogspot.com/2023/10/does-matching-matter-diode-matching-for.html

Paul Taylor VK3HN on the new Elecraft CW rig. 

Dean KK4DAS fixed the noise in his Hallicrafters SW receiver.  A long battle, finally won. 

Dean also in contact with G3UUR. 

Ramakrishnan VU2JXN helping me set up a backup of blog on WordPress.  

Mark KA9OOI noticed that SS podcast archive appears gone.  In fact just temporarily relocated to http://soldersmoke.com/podcastarchive.html

(SS PODCAST Archive temporarily relocated to http://soldersmoke.com/podcastarchive.html) 

Andreas DL1AJG - Crystal radio video. https://soldersmoke.blogspot.com/2023/10/building-crystal-set-videos.html

George N2APB on the Herring Aid 5

Grayson KJ7UM experimenting with Varactors and Thermatrons! 

Thomas K4SWL on Mattia's DC receiver. https://soldersmoke.blogspot.com/2023/10/mattia-zamanas-amazing-direct.html

Bob Weaver of Dial Bandspread Linearity  fame.  Electron Bunker

Mike Bryce WB8VGE QRP Hall of famer -- he too couldn't get the Herring Aid 5 working. 

Kirk NT0Z wrote about the Wayback machine.  But this former ARRL staffer he also tried and failed to get the Herring Aid 5 going.  Way back when... https://soldersmoke.blogspot.com/2015/03/kirks-herring-aid-tuna-tin-and-regen.html

New 15-10 VFO with schematic

Dial Bandspread (Before)

At corner of Haight and Ashbury

Bringing a Faulty Herring Aid 5 Receiver Into the Light -- Fixing the AF Amp Schematic Error (video)

I picked up this old homebrew receiver in March 2023 at the Vienna Wireless Society's Winterfest Hamfest.  It is a Herring Aid 5.   I was surprised to see that the builder (who was he?) got the windings on the VFO transformer right.  Later, I learned that he had also substituted MPF-102s for the original Radio Shack FETs called for in the QST article. This allowed him to overcome the PC board layout problem at Q5 (VFO).  With an MPF-102, he was able to get Q1 working by kind of shoe-horning the leads into the proper holes.  FB OM.  Whoever he was, he seemed like a really competent builder.

The Hamfest Herring Aid 5

But then I started wondering:  Did he also overcome the big problem in the audio amplifier?  You see, there is an egregious error in the QST schematic.  Between the collector of Q3 and the base of Q4 (the two AF amplifiers) they have a 10uF capacitor to ground.  That would send most of the audio to ground. This is clearly a mistake.  Not only does it not make any sense, but this cap to ground does not appear in the PC board drawing, nor in the photograph that went with the QST article.  I included this cap in my 2014 built of the Herring Aid 5, but with it, I found the receiver to be exceedingly deaf.  When I clipped that capacitor out of the circuit, my 2014 Herring Aid 5 sprang to life.  Did this hamfest Herring Aid 5 have the error capacitor?  Would it too be brought into the light by clipping one lead?  

Sadly, the erroneous third capacitor was there, and it was wired into the circuit.  The receiver worked,  but just barely.  It was very deaf.  You could not hear 40 meter band noise, and you could barely hear strong CW signals.  Builders may have thought that this was normal with such a simple receiver. 

3 10uF caps. The center one is an error.  I have clipped it out

In the video above you can see what happens when I cut the lead to the mistake capacitor.  Suddenly, you can hear band noise, and CW signals.  The receiver comes to life -- for the very first time!  

This was an error that echoed through the decades.  As far as I know there was never a published errata.  The erroneous capacitor is there in the 1977 ARRL book entitled Understanding Amateur Radio.  In 1998,  NORCAL QRP redid the Herring Aid 5.  Incredibly, THEY INCLUDED THE OFFENDING CAPACITOR in their new and improved schematic.  

NORCAL's 1998 Schematic included C14

I'm fixing up this old receiver a bit.  It was nice to have it playing 40 meter CW yesterday.  Better late than never.  

This morning I was feeling kind of guilty about paying so much attention to a receiver from 1976.  But then I opened the paper and read about the recent find of a DeLorean car.  Heck if a DeLorean from the early 80's is worthy of attention, so is a homebrew receiver from the late 1970s. 

How a Homebrewer Substituted MPF102s for the RS 2035 FETs in the Herring Aid 5 -- Who built this one? Any others out there?

The Hamfest Herring Aid 5

For background on all this, see yesterday's blog post:     https://soldersmoke.blogspot.com/2023/10/a-big-error-discovered-in-1976-qst.html

Rick WD5L noted that it was remarkable how the builder of the Herring Aid 5 that I found early in 2023 at a hamfest had built his receiver using MPF102s at Q1 and Q5.  Here is how this builder  kind of "shoe horned" MPF 102s into the QST Herring Aid 5 boards.  Pinouts for the MPF102 and the RS 2035 and the PC Board Pattern for the Herring Aid 5 appear below. 

Above  is Q5 the VFO.  You can see how he "flipped it around" to get the Drain, Gate, and source in the proper holes. You can also see how he wound the transformer for the VFO.  Looks like there was  a real battle with the soldering iron here. 

Above is Q1 (RF amp).  Again clearly an MPF 102.  But here it would not be sufficient to just flip the transistor around.  So he had to twist it and take the center lead and put it in the far right hole.  Note his markings on the board.  Looks like he made another hole for the MPF102 Gate (but he didn't really have to do this). 

DOES ANYONE KNOW WHO BUILT THIS RECEIVER?  

ARE THERE ANY OTHER HERRING AID 5s OUT THERE?

DSG

DGS! 

Click on the images for better views.

A Big Error Discovered in the 1976 QST "Herring Aid 5" Article (After 47 Years)

Click on image for a better view.  See arrows for Q1, Q5 and the parts list.

I tried as a teenager to build the Herring Aid 5 direct conversion receiver from the July 1976 issue of QST.  I could not get it to work. Important points: 1) I was attracted to the fact that this receiver used only parts available from local Radio Shack stores (I bought them) and 2) The article provided a PC board pattern (I also bought ferric chloride and etched a board). 

Looking back, I concluded that I had failed to get the VFO to oscillate.  I remember hearing signals when I tuned my HT-37 transmitter (on Cal, on 40) near the receiver.  I was very close, but I never got that Herring Aid 5 VFO to oscillate.

Thirty-eight years later I tried again to build the receiver.  Important points:  This time I used mostly junk box parts and Manhattan-style construction (no etching).  Still I could not get the VFO to work.  ZL2DEX spotted a problem -- I had wound the L6 and L7 coils with the wrong "winding sense."  I corrected this, and BOOM! the VFO sprang to life.  I assumed that I had made a similar "winding sense error" way back in 1976.  This, I thought, explained my failure to get the receiver working.  The QST article had warned that proper phasing of L6 and L7 was necessary.  I figured that I just hadn't fully understood what "proper phasing" meant.  So it was, I thought, all my fault.    

 

Here is the PC board pattern from QST.  Arrows show Q1 (DGS) and Q5 (DSG).  

But it is the same kind of FET!  Click on the image for a better view.

But then on October 17, 2023 a comment appeared on the SolderSmoke YouTube channel.  Rick WD5L had also -- back in the late 70's -- tried to build this receiver.  He recently looked closely at the recommended parts list (that we used!) and at the QST PC board pattern (that we also used). AND HE SPOTTED AN IMPORTANT ERROR IN THE QST PC BOARD PATTERN.   

Take a look at the pattern for Q5 above (see arrow).  That is the VFO FET.  A Radio Shack 2035 FET has a DGS pinout (see below).   The Gate is the center pin.  If you put this transistor into the PC board pattern above you would definitely be grounding the Gate.  There is no way the VFO would work under these circumstances.  Note too that the only other RS 2035 FET in the receiver is Q1 (the RF amplifier).  In the PC board pattern above Q1 is marked correctly as DGS.  This confirms the error in the Q5 PC board pattern.  There is no way an RS 2035 transistor can simultaneously have two different pinouts! 

Wow.  So this failure to get the VFO working may not have been my fault after all.  I may have actually gotten the transformer winding correct, but even if I did, there is no way this VFO would have worked using the part called for by QST and the PC board pattern shown above.  As a teenager I just did not know enough to spot the error or the inconsistency.  I kind put blind trust in QST.  I just couldn't get the thing to work.  

Rick searched the QST archives to see if they ever put out an errata on this.  So far, nothing. Worse yet, the scan of the PC board pattern on the QST site is very unclear and may have the pin designations on Q5 scratched out. This would make it more difficult to spot the problem.  (The image above is not from ARRL.  It is from a high quality scan of the original QST article done this week by a fellow Vienna Wireless Society member.)  Please let us know if you find any kind of errata or any acknowledgment of error.  

This is really pretty bad.  This was a project aimed at novices.  Far from encouraging homebrewing, this type of mistake is the kind of thing that would push people away from the soldering iron.  

Ironically, I may have been doomed by opting to use the QST PC board.  If I had used Manhattan-style construction (as I did in my more recent build) I would not have fallen victim to this PC board pattern error.  Also, if I had built this thing stage-by-stage (as we always now recommend) I would have more clearly realized (back in 1976) that the problem was in the VFO stage.  But I was 17 and didn't know.  I put blind faith in the QST article.  It never occurred to me that something in print could be wrong.  This realization came much later. 

There is more to talk about on this ill-fated project. In future posts I will discuss another error, this one in the AF amplifier.  And possible additional errors...  And I'll write about the 1998 resurrection of this project by NORCAL QRP and the New Jersey QRP clubs.  

Thanks to Rick WD5L for spotting the PC board error. 

SolderSmoke Podcast #245: Cuban DSB, DC Receiver?, Can you spot the AI? (Prize), Winterfest Loot, Gina's Podcast, 6BA6 buy, MAILBAG

 

DC RX Example by KK4DAS

SolderSmoke Podcast #245 is available for download: 

Audio Podcast:  http://soldersmoke.com/soldersmoke245.mp3  

Video:  (68) SolderSmoke #245: Cuban DSB, DC Receiver?, AI, Winterfest Loot, Gina's Podcast, 6BA6 buy, MAILBAG - YouTube

Travelogue: Cuba DSB and AM. Jose CO6EC and the Islander. We need more info, especially on the solid state Jaguey rig.

Bill’s bench:

Will the High School DC receivers get finished? Future uncertain. But the project was technically interesting. Great working with Dean KK4DAS. Battling AM breakthrough from Radio Marti. We joked that Dean has been listening to Radio Marti so much that even though he doesn’t speak Spanish, he has noticed an increased urge to liberate Havana.

Audio amps: Harder than we thought. Lots of variation in Hfe of 2n3904s. Oscillations.
Not using feedback amps nor LM386s, nor push-pull. Simplicity is a design goal.

Fixing the tuning (bandspread) problem on the VFO was fun.

Antennas? A quarter wave with ground or counterpoise works well. We tried it. (59) An Antenna for the TJ 40 Direct Conversion Receiver - YouTube
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Back to work on the uBITX. I chickened out on replacing the predriver with a BFR-106, but then – Just in time Todd K7TFC and his Mostly DIYRF came out with BFR106 boards! TRGHS. I will do the mods on two uBITX transceivers. I even bought a solder-sucking iron for the second job.

Winterfest Hamfest. Big success. Thanks VWS. HERRING AID FIVE! Simpson 260! QF-1, Another Radio Shack DMM, Eamon Skelton’s Homebrew Cookbook, Knobs, SWR meter.
----

SHAMELESS COMMERCE: 

-- Todd’s Mostly DIY RF and the BFR106 boards, and much more: https://mostlydiyrf.com/

-- Become a Patreon sponsor of SolderSmoke: https://www.patreon.com/join/4785634/checkout?ru=undefined

----

Pete's Bench: 

Technical Note: Skype problems. Pete's Skype kept dropping out. Bad in the last podcast (#244). Three minute gap. I was ready to scrap the whole podcast when Dean KK4DAS offered to help. And he is obviously well qualified: https://potomacofficersclub.com/speakers/dean-souleles/ Dean went to work with AI. And he was able to fill the audio and the video gaps. Can you spot the three minutes of AI? Send me an e-mail with the time segment of the AI/Deep Fake portion of SolderSmoke 244. The first one with the correct answer will win a prize. 

SolderSmoke #244:

https://soldersmoke.blogspot.com/2023/03/soldersmoke-podcast-244-pete-is-back-tr.html 

Thanks Dean!

----Interview on his Pete's daughter’s podcast. https://soldersmoke.blogspot.com/2023/03/listen-to-pete-juliano-on-his-daughter.html

-- 6BA6 e-bay buy. Will we see an all 6BA6 rig from Pete?

-- The NCX-5 on e-bay

PETE’S NEW BLOG: https://hamradiogenius.blogspot.com/

Mailbag:

-- A New SPRAT arrived in the mail. PH2LB’s Gluestick on the cover.
-- Will KI4POV – Awesome homebrew – on the blog.
-- Sands, VK9WX listening to SolderSmoke on Willis Island! Wow. 
-- Andreas DL1AJG in Germany continues with the Electronics for Biologists DC RX build.
-- Dean KK4DAS and his homebrew 10 meter DSB rig.
-- Jim W2UO built a Michigan Mighty Mite and made a contact.
-- Dave K8WPE and the E in IBEW. We need new stickers.
-- Bob KC4LB – Surface Mount is SMALL.
-- Bruce KK0S on the Herring Aid 5 Board.
-- Chuck WB9KZY on Nuclear Monopole Resonance very cool video – on the blog.
-- Alan WA9IRS wants a CW editor for his phone. Really.
-- Vic WA4THR also working on uBITX power out improvement.
-- Tobias weighs in on Kludge. As in Fudge.
-- Tony G4WIF notes that when he changes his oil he often removes sludge, not slooge.
-- Consultations with Lexicographer Steve KB3SII.
-- Walt AJ6T says CW operating declined after FCC ruling in 1970s about callsigns.
-- Ramakrishnan VU3RDD now VU2JXN has joined the VWS. An old friend of SolderSmoke. Urged us to launch a blog back in 2008. We announced his daughter’s birth - - now Ram is getting ready to build a DC receiver with her.

SolderSmoke Podcast #243 -- HI7/N2CQR, uBITX mods for 10 meters, High-School Direct Conversion Receiver Project Launched (Success!) Mailbag

 

DC RX and one of the PTO boards we built as demos last night. 

February 10, 2023

SolderSmoke Podcast #224 is available. 

http://soldersmoke.com/soldersmoke243.mp3

Video here: (32) SolderSmoke Podcast 243 (video) Hi7/N2CQR, uBITX, Success with High School Receiver Project - YouTube

Pete N6QW had technical difficulties this morning.  He insisted that the show must go on.  Pete will be back for the next episode. 

 

Travelogue: 

Bill in the Dominican Republic for all of January.  

HI7/N2CQR  Eastern tip of the island. uBITX and dipoles. 

20, 17, 10.  CW and SSB.  SSB was tough and I had reports of RF getting into the signal.

Went to CW. 

Worked VWS Mike KA4CDN, and Walter KA4KXX on 20CW.

Finally moved up to 10 CW.  Lots of contacts. Even though uBITX very QRP on ten.

I am modifying the uBITX now.  

Copper tape shielding to keep RF out.

 Low power out not the fault of the IRF-510s.  The problem is the 2N3904s.

Will replace with 2N2222 in To-18 cans.

Dean KK4DAS putting KD8CEC software into Arduino.  I gave up.

Who sent me this orphan uBITX?

SolderSmoke Shack South in final phase of construction.

 

SHAMELESS COMMERCE DIVISION:

Patreon!

Bezos Shopping!

 

DC Receiver Project

Local High School radio club. 

Simple:  Like Herring Aid 5 and Wes’s original.

Farhan’s four stages:

BP Filter, Diode Ring, PTO, AF amp. 

Simple Colpitts PTO SURPRISINGLY STABLE.

Simple and easy.  No chips.  No complicated circuits.

Guys have helped test out the design:  Rick N3FJZ, Walter KA4KXX,

Daniel VE5DLD, Stephen VK2BLQ and others. 

First session last night:  We demonstrated build of the PTOs.  

They worked (thank God).

 

Open Circuits book.

Envelope Detection Controversy

Save the Antenna – Book “Losing the Nobel Prize” K1JT

 

MAILBAG

--Dean KK4DAS 10 meter DSB!  Tiny SA ULTRA! FB

--John AC2RL on Elmer W3PHL DSB guy

--AC3K reports inventor of Fender Stratocaster guitar was a ham: W6DOE

--AF8E was doing POTA.  I worked him. He said my rig had presence. FB

--Alain F4IET FB DSB rig with mic in Cigar can!

--Daryl N0DP worked him on SSB.  He is homebrewing

--Steve N8NM was in for repairs but is on the mend.

--Rick G6AKG working with sub-harmonic mixers and logic chips

--Paul HS0ZLQ Built DC receiver but looking for something else to build. No DSB!

--Steve AB4I – Coherer, Jagadish Chandra Bose, and Marconi

--Eldon KC5U    Worked VK5QD right after me and mentioned SolderSmoke FB

--Todd K7TFC is building the DC RX.

--Tony G4WIF and Ian G3ROO using automotive relays for antenna switching. FB.

--Dave WA1LBP Great to hear from my fellow Hambassador (Okinawa)

Older post comments:

--Scott VO1DR was also in CF Rockey’s class! (Blog comment)

--Aurora Aug 4, 1972: Twelve people shared memories.  (Blog comment)

--Will WN1SLG Googled novice call and was led to my Novice log.(Blog comment)

A Call for Builders! Please help us Test this Receiver! Please Build this Receiver!

 

This is the Direct Conversion receiver that Dean and I have built.  We plan to have students at a local high school build it, starting in early February.   We would like to have some others build it, to make sure that the design is re-producible without problems.  

Please build this receiver!  But we ask that you build it exactly as per the schematic above and below. Innovation can come later -- for now we just want to make sure this thing works, that there are no errors in the schematic, and that it can be built by the students with minimum woe.  Thanks in advance! 

Dean or others with 3D printers may be able to supply the plastic form for the PTO inductor.  

We know of one other builder, but he is having some trouble.  We would like to confirm that this design is sound.  

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Above is the screenshot of the LTSpice model of the 40 meter Direct Conversion receiver that Dean KK4DAS and I have been working on.  I will post a larger scale version of the picture below.  Click on the images for a better view.  Comments welcome.  Please let us know if you find any errors or mistakes.  Realize that we wanted to keep this all simple, discrete, and entirely analog. 

Here (I hope!) is the net list for the LTSpice model: 

http://soldersmoke.com/DCRXLTSPICE.net  

First, one of the surprising things about the LTSpice model: IT IS ALIVE!  I never had a VFO or PTO actually turn on for me in LTSpice.  This one did!  So I just connected the PTO to the Mixer and the receiver works in LTSpice.   I just put an RF signal at the receiver input, and you can see the resulting AF across the 8 ohm resistor at the audio amp output.  I was even able to calculate the precise frequency of the PTO:  7078 kHz.  As in the real world, in an effort to stabilize the frequency, I changed the capacitors to NP0 in LTSpice.  Very cool.  Dean joked that all we need is a way to get RF in and audio out and we will have made an SDR receiver.  

About the receiver:  

--  Four stages that will be built by students Manhattan-style on four copper clad boards: Bandpass filter, diode ring mixer, Permeability Tuned Oscillator (PTO),  AF Amplifier.  

-- The bandpass filter is a simple dual-tuned circuit device based on the info on the QRP Labs site.  (Thanks Hans!)  We out a 10k pot as an RF gain control between the antenna and the filter. 

-- The mixer is a standard diode ring.  We included a diplexer at the output using a circuit from the famous W7EL  Optimized transceiver. (Thanks Roy!) 

-- The Permeability Tuned Oscillator is a very simple and very stable Colpitts design developed by Farhan VU2ESE.  We added a simple FET buffer using the circuit in Farhan's Daylight Again rig.  (Thanks Farhan!) 

-- The AF amp is a very simple three transistor amplifier based loosely on designs from Forrest Mims and from the Herring Aid 5 receiver. Both these designs use just two stages -- we added a third and put an AF gain pot between the first and the second stages. There is an impedance mismatch between the diode ring and the AF amp, but we found that most of the proposed solutions were more trouble than they were worth, so we left it as is.  

--Thanks to Wes W7ZOI for his November 1968 QST article on the solid-state DC receiver. Wes's article inspired our efforts.  

Dean and I have both built these receivers.  They work very well.  Dean has even decoded FT-8 with his. We used Radio Marti at 7355 kHz to test for AM breakthrough -- with the diode ring, the diplexer, and the RF gain control we were able to bring the AM breakthrough down to acceptable levels. You can see many videos of my receiver in action over on my YouTube channel:  (355) SolderSmoke - YouTube

Here is a larger image of the schematic (click for a full view): 

And here is a nicer schematic done by our friend Walter KA4KXX: 

The 40 Meter Direct Conversion Receiver We Have Been Working On -- Comments Welcome

Above is the screenshot of the LTSpice model of the 40 meter Direct Conversion receiver that Dean KK4DAS and I have been working on.  I will post a larger scale version of the picture below.  Click on the images for a better view.  Comments welcome.  Please let us know if you find any errors or mistakes.  Realize that we wanted to keep this all simple, discrete, and entirely analog. 

Here (I hope!) is the net list for the LTSpice model: 

http://soldersmoke.com/DCRXLTSPICE.net  

First, one of the surprising things about the LTSpice model: IT IS ALIVE!  I never had a VFO or PTO actually turn on for me in LTSpice.  This one did!  So I just connected the PTO to the Mixer and the receiver works in LTSpice.   I just put an RF signal at the receiver input, and you can see the resulting AF across the 8 ohm resistor at the audio amp output.  I was even able to calculate the precise frequency of the PTO:  7078 kHz.  As in the real world, in an effort to stabilize the frequency, I changed the capacitors to NP0 in LTSpice.  Very cool.  Dean joked that all we need is a way to get RF in and audio out and we will have made an SDR receiver.  

About the receiver:  

--  Four stages that will be built by students Manhattan-style on four copper clad boards: Bandpass filter, diode ring mixer, Permeability Tuned Oscillator (PTO),  AF Amplifier.  

-- The bandpass filter is a simple dual-tuned circuit device based on the info on the QRP Labs site.  (Thanks Hans!)  We out a 10k pot as an RF gain control between the antenna and the filter. 

-- The mixer is a standard diode ring.  We included a diplexer at the output using a circuit from the famous W7EL  Optimized transceiver. (Thanks Roy!) 

-- The Permeability Tuned Oscillator is a very simple and very stable Colpitts design developed by Farhan VU2ESE.  We added a simple FET buffer using the circuit in Farhan's Daylight Again rig.  (Thanks Farhan!) 

-- The AF amp is a very simple three transistor amplifier based loosely on designs from Forrest Mims and from the Herring Aid 5 receiver. Both these designs use just two stages -- we added a third and put an AF gain pot between the first and the second stages. There is an impedance mismatch between the diode ring and the AF amp, but we found that most of the proposed solutions were more trouble than they were worth, so we left it as is.  

--Thanks to Wes W7ZOI for his November 1968 QST article on the solid-state DC receiver. Wes's article inspired our efforts.  

Dean and I have both built these receivers.  They work very well.  Dean has even decoded FT-8 with his. We used Radio Marti at 7355 kHz to test for AM breakthrough -- with the diode ring, the diplexer, and the RF gain control we were able to bring the AM breakthrough down to acceptable levels. You can see many videos of my receiver in action over on my YouTube channel:  (355) SolderSmoke - YouTube

Here is a larger image of the schematic (click for a full view): 

And here is a nicer schematic done by our friend Walter KA4KXX: 

Bill Talking about Homebrew Radio with L’Anse Creuse Amateur Radio Club (Michigan) -- February 2, 2022 (Video)

This was a very nice meeting.  We just talked homebrewing and why it is such an important part of ham radio.  Video above

Topics included:

-- Jean Shepherd

-- Being "Electrically Inclined" 

-- The Herring Aid 5

-- Radio Clubs around the world

-- The Shame Shelf

-- Making mistakes, releasing smoke

-- Errors in ham radio magazines and schematics

-- The importance of understanding the circuit

-- The Michigan Mighty Mite

-- Building a power supply for the HW-32A

-- The origins of the SolderSmoke podcast

-- Knack stories, the IBEW and what we all have in common

-- The importance of books

Thanks to The L'Anse Creuse ARC for the invitation. 

FLASHBACK: The Herring Aid 5 Direct Conversion Receiver and Frank Jones (Video)

The Radio Gods seem to be pushing me towards Direct Conversion receivers.  This week I was speaking via Zoom with the very FB L'Anse Creuse Amateur Radio Club in Michigan.  My Herring Aid 5 tale of woe came up (see video above).   Then Dean KK4DAS was sharing video of the amazing fidelity of the Pete Juliano Direct Conversion Receiver.  Then I started thinking about Frank Jones W6AJF, and the story (fictional) of his build of the Herring Aid 5 by Michael Hopkins AB5L: 

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I gave Frank a board for the Herring Aid Five redux from the April 1998 QRP Quarterly and challenged him to build one up. It took maybe two hours and that includes his own touches which included refusing to buy any parts.

For the transformers, he calculated the turns ratios from the impedances and tested a bunch of TV set pulls 'till he found something close. But he made the output 1:1 because his Brandes phones are close to 1000K Ohms as it is. 

He was willing to use toroids, but not to buy one, so I gave him an Amidon circular and he calculated the values of the 18 specified units. Then he wound them on unidentified cores from my junk box after learning the permeability of each with his homebrew dip meter. 

A store bought Zener was out of the question so he mixed and matched regular diodes with transistors hooked up as diodes until he got close enough to 10 volts. The mosfets came out of a TV tuner and Frank will use any plastic bipolar that says "C" or "D" on it for a 2N2222. 

Of course it worked the first time. He rigged up a patch to a pair of Class A push-pull 6L6s so Christie could hear it and she said it was "Also cute but bigger than the other one." 

Now a real QRPer would cry at that, but not Frank who sees no advantage in miniaturization at all. In fact, he mounted the whole thing in an old case from a Collins 6 and 2M transceiving attachment he junked out for the parts and no two knobs matched as Frank thinks matching knobs slow you down in a pileup. He wanted to take it back to his own shack and try it out with his breadboard MOPA and pair of 100THs because he does not run QRP, saying it "transfers the burden to the other guy."  

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Frank Jones was one HARD CORE HOMEBREWER.  No store-bought Zener diodes or toroidal cores for him! 

All of the SolderSmoke Herring Aid 5 articles can be found here: 

https://soldersmoke.blogspot.com/search?q=Herring