More on Spark Transmission and Reception -- From Germany. Spark Transmission using a Piezo Fire Starter

More spark today.  I really liked how Robert Dalby demonstrated spark transmission and reception.  He used a simple Piezoelectric flame starter (like the one that many of us have in our shacks) as the transmitter, with a homebrew coherer connected to an LED and some batteries as the receiver.  Ingenious.  As with CuriousMarcs video of yesterday, you can see how Marconi's system really worked.  Brilliant. 

This demo also shows how many devices can generate part of the noise we hear in our receivers.  We see and hear the noise generated by a nearby electric fence, and the noise made by a simple electric motor.  Many new builders have trouble accepting the reality of noise.  Noise happens. 

The entire YouTube channel is very interesting.  Check it out here: 

https://www.youtube.com/@deutscheavionik7211

It is based on the amazing collection of Dieter Beikirch (I think he is DJ5RS) and is presented by Robert Dalby. Here is how they describe the channel: 

German avionics in the era of the vacuum tube. Join us as we investigate the most critical period in the rapid development of electronics, especially airborne electronics, from the first spark-gap radios of WW1 to the advances in radar technology in WW2.

More on Agent Sonya

I had completely forgotten that my blog had at least two posts on Agent Sonya way back in 2009.  I know there is a lot of interest in her alleged radio derring-do. 

Here are the two blog posts from 2009: 

https://soldersmoke.blogspot.com/2009/08/sonya-had-knack.html

https://soldersmoke.blogspot.com/2009/09/sonyas-rig.html

And here is my 2025 post on Sonya: 

https://soldersmoke.blogspot.com/2025/04/agent-sonya-did-soviet-spies-really.html

One friend recently mentioned that we have not seen any museum evidence of these kinds of homebrew spy rigs.  If this really was a widespread practice, you would expect to find at least ONE of these rigs in a museum somewhere.   Has anyone seen this kind of thing?  

Here is something more recent about Sonya from the National WWII Museum in New Orleans: 

https://www.youtube.com/watch?v=NU9-APiIUaQ

The Macintyre interview is really interesting.  A friend told me that he is a very serious writer on the topic of espionage, whose assertions have to be taken seriously.  For our purproses, here are some highllights:

22:18   Sonya goes through Soviet Spy School and is trained on how to build radios.

24:50   In China under Japanese occupation, had bamboo poles supporting antenna over her house! 

25:40  Transferred to Switzerland, "built another radio."

34:18   Transferred to UK, built a "powerful radio transmitter in her loo." 

51:41    Macintyre refers to Sonya as "the only Soviet radio operator in Switzerland." 

So, I still don't know about the claim that Sonya was homebrewing radios.  It does appear that Sonya was building them.  But it also seems like she was more of a radio operator than she was a spy...  Perhaps the Soviets didn't see the same distinction that we do.    Still, it would be nice to find in a museum somewhere at least one example of Sonya-style homebrew radio. 

Macintyre says that "all biography is burglary."  What would autobiography be? 

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

The Copasteic Flow Blog -- German UHF Mobile CW Through a Geostationary Satellite, Agent Sonya's Homebrewing, More

It is always good to be reminded that someone out there is listening and reading,  especially when it is nice folks like Hamilton and his family. These are the people who built the TouCans rig that was (is?) suspended above San Francisco at the center of a dipole antenna.  

Following posts on the SolderSmoke blog, Hamilton has been monitoring the CW activites of a German ham who sends UHF CW signals through the sunroof of his car to the QO-100 satellite in geostationary orbit.  See above.  Very cool.  Listen live to the satellite here: 

https://eshail.batc.org.uk/nb/

Also cool is Hamilton's analysis of Agent Sonya's ability to homebrew a 1930s era CW station that could be used to communiate with Moscow Center.  Hamilton believes she could do it.  I have my doubts.  But the discussion is a lot of fun. 

Check our their blog: 

https://copaseticflow.blogspot.com/

Thanks to Hamilton and his kids! 

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

Other Kinds of Workshops -- Making a Clock with a Lathe

Somehow, this video fits well with the SolderSmoke theme.  It may be that Uri cheerfully acknowledges that the lathe can kill you (the same is true of much of our gear).  Or it may be his repeated use of the term "Bob's your uncle" (has he been listening to SolderSmoke?).  Whatever the reason, this beautiful video fits here.  This is from Uri Tuchman's channel:  https://www.youtube.com/@urituchmanpigeon.  Uri is in Germany.  Thanks Uri! 

Ragnar LA1UH's Wonderful Museums in Norway

Here are two more great museum visits by Helge LA6NCA.  In these two he visits Ragnar LA1UH.  

Ragnar has a lot of maritime experience, so we see a lot of older ships' radios.  But his interest in the radio art is much broader and we also see a lot of other kinds of gear: 

-- Wow,  a "travel radio" in a suitcase from 1927.  Was this the idea that later lead to the Parasets of WWII? 

-- Lots of "Stay Behind" gear from the Cold War. That "Africa" receiver (that never made it to Africa!) is very interesting. 

-- We see an ART-13 with autotune, ANGRC-9s, several ARC-5 command sets.  I was hoping Raganar would fire up a Dynamotor, but no. 

-- I spotted a Galaxy V transceiver.  I have the VFO reduction drive from one of these in my homebrew 15/10 rig.   

-- We see several variometers in the emergency (500kc?) maritime transmitter.  I used a variometer in my super-simple ET-2 transceiver (with an N0WVA receiver). 

-- Lots and lots of tubes. 

Ragnar says he himself is of 1944 vintage. I hope some "stay behind" provisions have been made for these amazing museums. 

Thanks to Helge LA6NCA and to Ragnar LA1UH.  

Homebrew-to-Homebrew Contact on 17 meters with DL2RMM (Video)

 Here is short clip of a very cool HB2HB contact on 17 meters.  Thanks Jens! 

Check out his QRZ page here: https://www.qrz.com/db/DL2RMM

Some Short-Wave Listener QSL Cards

Click for a better view

I haven't received many, but I always like QSL cards from shortwave listeners.  Someone out there is listening!  

The top one is from recent contact. It arrived from Hungary via the W2 QSL bureau.  Here is Tamas HA00001: 

https://www.qrzcq.com/call/HA0002SWL

https://www.c3.hu/~ha0khw/ha00001.html

The middle one is from my youth.  in 1975 Nick in Moscow USSR heard my contact with OD5IO.   I didn't remember the contact with Lebanon.  It turns out that the operator was K4NYY (who is now a silent key.  See https://www.qrz.com/db/K4NYY/?mlab=). 

The bottom one pre-dates me by more than twenty years.   It comes from Berlin in 1936. W5AIR was heard working EI7F on 20 meter CW.   Does anyone have any info on this SWL? 

Over on The SWLing Post blog,  readers posted this info: 

Klaus WernerNovember 25, 2023 at 1:12 pm On the German SWL card, it would probably need some serious digging into records.Consider, it’s dated 1936, about 3 years before the nazis started WW2 (which included tough restrictions on all radio listeners, including death penalties for listening to and spreading enemy news).The name STOLP is fairly common in Germany.Interesting, the Bernauer Strasse in Berlin was well known during the cold war as there was a border crossing to East Berlin used for exchanging spies (I believe).
13dka

November 26, 2023 at 8:32 amDE 2518 /F was Willi Stolp, the DE number popped up in listener contest lists in “CQ” 1936 and 1944. There is an Excel spreadsheet that lists him as DE 2518 /G (/F stands for Berlin, /G for Silesia) with a (inaccessible) link to the DARC district Chemnitz, which may indicate that he survived the war and became a regular ham. That’s all there is to find out so far, there is a ham with the same name but since the name isn’t that rare it may not be the same guy.

Building a Crystal Set (Videos)

Andreas DL1AJG in Germany sent the above video to me.  Andreas is the fellow who ran the course in which his university-level students built direct conversion receivers.  

I like the presenter's technique.  But it would have been cooler if he actually used a chunk of Galena or Iron Pyrite, with a cats whisker.  (I still have some of the Iron Pyrite that Mike KL7R gave me many years ago.)  I think that all radio amateurs should (as a rite of passage) actually poke a crystal with a cats whisker in search of a signal. Like here: 

 Thanks Andreas!

A NETFLIX Series with Boatanchors and Direction-Finding -- All the Light We Cannot See

Looks good.  November 2, 2023. 

Spy Rigs, Para Sets, Bugs, and Enigma Machines -- Dr. Tom Perera W1TP (video)

This is a really amazing presentation by Tom Perera W1TP to the Fairlawn (NJ) Amateur Radio Club. 

There is so much great info in this presentation.  Some of the highlights for me: 

-- The U.S. Civil War telegraphic (wired) spy set was just mind blowing.  I had never heard of this.  

-- The way the Nazis transmitted a signal 1 kc off the BBC frequency, so that Germans who tuned their Nazi-issued receivers to the BBC could be detected by neighbors (from the resulting 1 kc tone!) and turned in to the Gestapo.  

-- "Things don't land gently when dropped by parachute." Indeed.  This was a reminder of the courage of the young women who parachuted into Nazi-held territory during WWII.  Like Paulette.  It was great to see her with her Paratrooper wings on.  AIRBORNE!  And the picture of the operator with the bicycle generator was of Virginia Hall.  See: https://www.npr.org/2019/04/18/711356336/a-woman-of-no-importance-finally-gets-her-due  That portrait hangs in the hallway of the National War College. 

-- How they put the schematic of the PRC-5 right into the box.  Great idea.  But it had a terrible receiver.  One of the schematics showed a 455 kc IF and a BFO.  So they sent in superhets, not just regens. 

N2CQR operating the Para Set of G3ROO around 2009

This video makes me want to build a Para Set. 

Thanks a lot to Tom W1TP and the Fairlawn ARC. 

SolderSmoke Podcast #247 -- Hating on the IC-7300, Pete Goes FT-8 with a KWM-1, Bill's 15-10 Rig, MAILBAG

Bill's 15-10 Rig -- Click on image 

SolderSmoke Podcast #247 is available: 

Audio Podcast:  http://soldersmoke.com/soldersmoke247.mp3

Video:  (482) SolderSmoke 247 -- Hating on the IC-7300, Pete goes FT8 (with a KWM-1), Bill's 15-10 rig, Mailbag - YouTube

Bill’s Bench:

The 15-10 Dual Bander.

n  10 pole crystal filter at 25 MHz.

n  G3UUR, Dishal, AADE and all that..

n  Testing woes.  Looked bad.  But it was a bad test cable. Duh.

n  VFO (Colpitts) at around 3.5 MHz.

n  Buffer blues:  Bad J-310s.  Beware!  

n  Variable cap from a Heath Q Multiplier

n  A bit of a black art – competing goals. Freq coverage, etc.

n  BFO needed an amp to turn on the diodes in the balanced modulator

n  TIA amps.   SIX dual direction TIAs.  18 transistors.

n  On a pine board (like Frank Jones)

n  Will use the N6QW all discrete AF amp.

n  Maybe an RD16 in the final?

n  Will build a second one for the DR.

 Shameless Commerce:  Mostly DIY RF and the PSSST kit.  Todd K7TFC reports:  “The P3ST is on track for Lee Deforest's birthday release (August 26th). I'm going to send out another newsletter on July 4th, and I'll give some details on P3ST development.” Results of Todd’s Survey.

Pete’s Bench

n  FT-8 on the KWM-1!

n  Presentation to the ham club.

n  Why the Icom 7300 is the anti-thesis of homebrew.

MMAILBAG:

-- SPRAT 195  Summer 2023, in the mailbox.  A happy day at N2CQR

-- Armand WA1UQO sent a wonderful book about Faraday and Maxwell… And told me Jim K8OI was heading to our area.  I met Jim at the VWS Field Day event.  FB.  Thanks Armand.

-- Tony G4WIF sent Father’s Day greetings.

-- Alvin N5VZH asking about electrolytics for his 2-B.  Hayseed Hamfest!

-- John AC2RL replacements for the IBEW.  We need to start over!

-- Steve “Snort Rosin” Smith WB6TNL was in the area.  Sorry I missed him.

-- Joh DL6ID helping us to track down origins of a homebrew receiver Grayson saw in Berlin.

-- Grayson KJ7UM was in Europe visiting his wife’s relatives.  But I think he is back in the USA.

-- Walter KA4KXX sent a QRP HB family portrait. 

-- Wouter ZS1KE sent info on surface mount soldering.

-- George Zaff KJ6VU Ham Radio Workbench – re-runs! Recommended audio processor.  Let me know how it sounds. 

-- Michael AA1TJ   Great to hear from him. 

-- Alan Wolke W2AEW on the toroids  he used in Diode Ring video.  Thanks Alan!

-- Dean KK4DAS, AI and SWR meter project  And new lexicon word:  Hamsplaining. 

-- Bob N7SUR --  Let me know we are semifinalists in the Hack-A-Day prize!  

The 15 - 10 rig from above -- Click on image

Germany: Direct Conversion Receiver Success!

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 (below) 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!  

 

Can you ID this Receiver? Grayson Finds a Homebrew Receiver in Germany. From the GDR. Circuit? Schematic? Thermatrons?

 

Grayson Evans KJ7UM (the author of  Hollow State Design) was recently in Germany where he spotted this museum display of a homebrew receiver built in the GDR (the old East Germany) around 1983 by a 13 year-old.   Very cool. 

Here is today's task for SolderSmoke:  Can you provide any more info on this receiver? The card indicates 0-V-1 which would be a regen with no RF amplifier, right?  Maybe something like this: 

https://www.qsl.net/pa2ohh/15tuberx.htm

 Look carefully at the pictures and try to gather any additional information on the receiver or its builder.  

Thanks Grayson! 

Polyakov (RA3AAE) Direct Conversion Receiver: 40 meter DC RX with VFO at 3.5 - 3.6 MHz (with video)

I've been reading about Polyakov (or "sub-harmonic") Detectors for a long time: 

https://soldersmoke.blogspot.com/search/label/Polyakov--Vladimir

But until now, I never built one.  Recently,  Dean KK4DAS and the Vienna Wireless Makers group have been building a Direct Conversion receiver.  Their receiver uses an Si5351 as the VFO, but of course Dean and I have decided to try to do things the hard way by building non-digital VFOs.  At first we just came to the conclusion that my earlier Ceramic Resonator VFO wasn't much good (it drifted too much).  This led us into standard Colpitts and Armstrong VFOs, and the fascinating world of temperature compensation.  Then I remembered the Polyakov circuit -- this would allow us to use a 3.5 MHz VFO on the 7 MHz band.  Lower frequency VFOs are easier to stabilize, so I started building my first Polyakov receiver.  You can see the results (on 40 meters) in the video above. 

I started working with a circuit from SPRAT 110 (Spring 2002). Rudi Burse DK2RS built a Polyakov receiver for 80 and 40 that he called the Lauser Plus.  (Lauser means "young rascal" or "imp" in German.) For the AF amplifier, I just attached one of those cheap LM386 boards that you can get on the internet.  With it, I sometimes use some old Iphone headphones, or an amplified computer speaker. 

The Polyakov mixer is a "switching mixer."  The book excerpt below shows how I understand these circuits.  The enlightenment came from the Summer 1999 issue of SPRAT (click on the excerpt for an easier read): 

Leon's circuit shows us how a simple switching circuit in which the switches are controlled by the VFO can result in an output that has the sum and difference components. That is the hallmark (and most useful part) of real mixing.  Remember -- we say that mixing happens in non-linear circuits when the passage of one signal depends on what is happening with the other signal.  A switch is as non-linear as you can get! And that switch is being controlled by the VFO.  

In a Direct Conversion receiver we usually run the VFO at the operating frequency. This results in audio just above and just below the operating frequency. 

The Polyakov Direct Conversion circuit is a bit different.  It has the switches (the diodes)  turned on twice each cycle:  When the VFO voltage goes to a positive peak, this turns on one of the diodes.  When the VFO goes to a negative peak, this turns on the other diode.   So in effect the switch is being turned on TWICE each cycle.  So with the Polyakov you run the VFO at HALF the operating frequency.  For a DC receiver designed to run around 7.060 MHz, you build a VFO at around 3.53 MHz.  This has some immediate advantages.  My favorite is that it is easier to get a VFO stable at a lower frequency.  It is easier to stabilize a VFO at 3.53 MHz than it is at 7.060 MHz. 

When you open that SW 1 switch in the Lauser Plus, you no longer have a Polyakov mixer.  Now you just have a diode mixer.   It will be opening and closing once each cycle at the VFO frequency.  DK2RS used this to cover not only the 40 meter band (in Polyakov mode) but also the 80 meter band (in single diode detector mode).  That is why DK2RS has that big variable capacitor in the input circuit -- that LC circuit needs to tune all the way down to 3.5 MHz and all the way up to around 7.3 MHz.  (I used a coil of about 6.5 uH to do this.) 

With just one diode and operating at 80 meters, it works, but not as well as it does in the Polyakov mode on 40.  I can pick up 80 meter signals, but in this mode there seems to be more of an "AM breakthrough" problem. "Experimental Methods in RF Design" on page 8.11  describes what is going on (the last sentence is most relevant here): 

Here are some very good links with information on the Polyakov receiver: 

LA8AK on Polyakov: http://noding.com/la8ak/c21.htm

LA8AK's Home Page: http://www.agder.net/la8ak/index1.htm

LA8AK SK: http://www.agder.net/la8ak/   Almost seventeen years after his death he continues to help his fellow radio amateurs through his web sites.  TNX OM!  FB! 

BH1RBG: https://sites.google.com/site/linuxdigitallab/rf-ham-radio/dc-polyakov-based-first-dc-receiver

Hack-A-Day on Polyakov: https://hackaday.com/2015/11/15/polyakov-direct-digital-synthesis-receiver/

I will post a video tomorrow showing the receiver in operation on 80 meters.  

Three cheers for Vlad Polyakov, RA3AAE

SolderSmoke Podcast #239: Hex DX, VFO Temp Comp, DC RX, Polyakov!, DX-100, Wireless Set, Farhan's "Daylight Again" HDR rig, MAILBAG

N2CQR Hex Beam Aimed at Europe

SolderSmoke #239 is available for download: 

http://soldersmoke.com/soldersmoke239.mp3

TRAVELOGUE: 

James Webb Space Telescope.  Mars returning to opposition in early December.   

BILL'S BENCH

Hex Beam K4KIO - on roof – TV Rotor – 20-17-12  Lots of fun.  Working Japan regularly, Australia, South Africa on long path 17,000 miles.  52 countries SSB since July 11.

VFOs and Temp stabilization.  Dean KK4DAS found my ceramic resonator VFO for DC receiver drifty. He was right.  So I built a real LC Colpitts VFO.  Got me into temp stabilization.  A new hobby!  An obsession.  HT-37 and Ht-32 parts. Ovens?  WU2D’s second VFO video.  Understanding thermal drift and how to address it. Split stator caps.  Cut and try.  

Built a Polyakov DC Receiver. https://soldersmoke.blogspot.com/2010/03/polyakov-plus-dual-band-receiver-with.html  Lauser Plus.  Lauser = Imp or Young Rascal!  DK2RS.  He used a ceramic Resonator VXO at 3.58 MHz.   Mine works great on 40 with VFO running 3.5 -- 3.65 MHz. See schematic below. 

On 40 AM with DX-100 and MMMRX.  DX-100 died.  12BY7 VFO buffer went bad.  How common is failure in this tube type?  Nice QSO with Tim WA1HLR about the DX-100.

Got my Dominican license:  HI7/N2CQR!  SSSS on the way.   Thanks to Radio Club Dominicano and INDOTEL.

Getting more active in the Vienna Wireless Society.  

BOOK REVIEW:  

"The History of the Universe in 21 Stars” by Giles Sparrow.  Written during the pandemic.  Published by Welbeck, in London. https://www.amazon.com/History-Universe-21-Stars-imposters/dp/1787394654  Also:  From “Atoms to Amperes” by F.A. Wilson available for download.  See blog.

SHAMELESS COMMERCE DIVISION:   

Todd K7TFC getting ready to launch “Mostly DIY RF.”   I used his TIA boards in my 1712 rig.  He will have boards like this and much more.  Stay tuned.

I need more viewers on YouTube.  They want 4,000 hours IN A CALENDAR YEAR!  Please watch!

FARHAN’S NEW “DAYLIGHT AGAIN” RIG.  Analog.  VFO.   Comments, observations. We need to get him on the podcast.  Maybe two shows: SDR and HDR. 

PETE'S BENCH

Time very limited. But still sharing lots of tribal wisdom.

Wireless set with tubes!

Tool recommendation – Air compressor

 MAILBAG:

Farhan VU2ESE – Speaking of big antennas “Whenever I look at the huge construction cranes in Hyderabad, I always think how one could make 160m, 4 element yagi using it as a boom..”

Todd K7TFC in Spain, spotting Log Periodics in Madrid.

Andreas DL1AJG:  Can Biologists fix Radios?

Janis AB2RA Wireless Girl.  Expert on Hammarlunds.  And was my first contact with the Tuna Tin 2. She too was HB!

Peter Parker VK3YE on Owen Duffy VK1OD

Lex PH2LB on homebrew radio

Would this really be homebrew?  Mail from H-A-D article on FM receiver

F4IET a DSB rig from France

Ciprian got his ticket YO6DXE    

Josh G3MOT sent us a good video about the Vanguard satellite and IGY.

Dave Wilcox K8WPE bought Chuck Penson’s Heathkit book.

Rogier -- So many great articles and links from PA1ZZ

Bill AH6FC  Aloha. Retiring.  Wants to build.  Mahalo!

Grayson KJ7UM  Working on an Si5351.  Gasp.

Mike KE0TPE viewing YouTube while monitoring 6 meters.   He will have a lot of time to watch!

Chris KD4PBJ spotted Don KM4UDX from VWS FB

Mark WB8YMV building a superhet.  Having trouble with 455 kc IF can filter.

Walter KA4KXX Great comment on the Daylight Again rig. 

Ramakrishnan Now VU2JXN was VU3RDD.  Found lost Kindle with SolderSmoke book on it. Building SDR rig from junk box.  Trouble with the LM386. 

Pete, Farhan and Tony:  Shelves of Shame

Daylight Again by Farhan

The Polyakov receiver I built yesterday (from SPRAT 110, 2002!)