School for Danger -- the SOE, and Radio, in Nazi Occupied France

Hack-a-Day had a link to this film.  It is really good.  There is some stuff about radio, and especially the S-Phone system.  But the bigger message of the film is the danger faced by the heroic teams who parachuted into occupied France.  As shown in the film, many of these people were young women who risked it all in the most dangerous of airborne operations.  It is a reminder of how ridiculous the focus on masculine valor in airborne and special operations really is.  Three cheers for the SOE. For all of them. 

Attempting 2 meter contact, Dominican Republic to Puerto Rico

It is about 100 miles across the Mona Channel.  That is a longshot on 2 meters, but I got the idea when, this past summer, I regularly heard WIDI 99.5 FM in the Dominican Republic from western Puerto Rico.  So over the fall I gathered 2 meter gear, and got a directional antenna and sent all of this gear to the DR.  

Here is the antenna.  Seven elements. I got it through Amazon.  It came kind of incomplete and without any written or on-line instructions.  AI told me to do exactly the WRONG thing with what they assumed was a reflector.  Fortunately I ran into this YouTube video and learned that it was in fact a "ZL Special" antenna, and that it has, in fact, TWO driven elements.  It was through that video that I learned how to assemble this thing.  

My "station" consists of a Heathkit HM-2109.  It is a VHF wattmeter/SWR meter that I bought by mistake.  But I kept it, and it proved very useful in this 2 meter Mona Channel project.  There is a Baofeng UV-5R (boo! hiss!) and a Yaesu FT-470 that KD4EBM gave me.  I have a Communication Concepts 2 meter amplifier -- I must have picked this up at a hamfest.  It promises 35 watts with 5 watts of drive.  The old CCI amp gives the rig good juju. 

This morning I wrote to the hams of western Puerto Rico: 

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

Saludos desde el otro lado del canal de la Mona! 

Soy radio aficionado:  Hi7/N2CQR.   Vivimos en República Dominicana en Cap Cana seis meses cada año.

He notado que puedo escuchar WIDI 99.5 FM aquí.  Parece que hay Tropospheric ducting. 

Como radioaficionado, me gustaría averiguar si podemos hacer contacto en 2 metros usando la misma propagación. 

Tengo: 

Dos transceptores de FM

Un amplificador a 35 vatios. \

Un antenna directional de 7 elementos con un gain de 11.5 db. 

Estoy a una elevación de 7 Pisos.  Puedo ver el canal de Mona. 

Hay alguien en la costa oeste de PR (tal vez cerca de Mayagüez) quien puede hacer un schedule para probarlo? 

O hay un repetidor en la zona que puede usar para averiguar si puedo -- por lo menos -- "kerchunk"  el repetidor?  

Gracias por su ayuda! 

73  Bill  Hi7/N2CQR

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

Greetings from the other side of the Mona channel!

I am a radio amateur: Hi7/N2CQR.   We live in the Dominican Republic in Cap Cana six months every year.

I've noticed that I can listen to WIDI 99.5 FM here.  There seems to be Tropospheric ducting.

 As a radio amateur, I would like to find out if we can make contact in 2 meters using the same propagation.

 I have:

Two FM transceivers

An amplifier at 35 watts. \

A 7-element directional antenna with a gain of 11.5 db.

I am at an elevation of 7 Stories.  I can see the Mona's channel.

 Is there someone on the west coast of PR (maybe near Mayagüez) who can make a schedule to try it out?

 Or is there a repeater in the area that you can use to find out if I can -- at least -- "kerchunk" the repeater?

 Thank you for your help!

 73  Bill  Hi7/N2CQR

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

Stay tuned! 

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

 

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

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

AI Overview

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

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

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

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

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

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

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

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

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

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

 

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

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

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

AI explains where the 4/3 factor comes from: 

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

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

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

 

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

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

Here is what AI (Gemini) says about this: 

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

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

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

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

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

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

Wow! DOVAD and Doppler at White Sands Missile Range

EI7GL has a really interesting blog post about a VHF system used at White Sands to accurately track early rocket tests:  https://ei7gl.blogspot.com/2025/05/369-mhz-doppler-radar-antenna-at-white.html 

He has nice picture of the antenna.  The plaque has the interesting info: 

The plaque on display reads as follows...

"36.9 Megahertz Helix Antenna Doppler Velocity and Position (DOVAP)

Reference Transmitter Antenna

Developed during World War II by the Germans as part of a V-2 guidance and control system, DOVAP traced the course of a rocket using the Doppler Effect caused by a target moving relative to a ground transmitter and receiving stations.

Unlike radar, Dovap did not allow scientists to "see" the rocket on a screen. Instead, it sent up radio waves, which were received and rebroadcast back to earth by the rocket. The returned waves combined with the original ground broadcast and produced a musical tone which varied with the rocket's speed - the faster the rocket, the higher the pitch.

DOVAP data was extremely accurate: it could place a rocket's position at 100 miles up within 50 feet. It could collect data at the extreme altitudes of 100 to 300 miles. Dovap's disadvantage was that it took 3 to 4 weeks to reduce the data.

The antenna is a helix because of its physical and electronic characteristics. A helix is simple to construct and operate, provides necessary signal gain and directivity, and can be operated in several modes or polarizations.

The DOVAP system provided trajectory data and ground guidance for most of the early rocket systems: Corporal, Sergeant, Honest John, Little John, Redstone, and Aerobee Upper Atmosphere programs.

This particular antenna was built in the mid-1960s near C Station. Like much of the early instrumentation used here, it was designed and built at White Sands Missile Range.

Erected by White Sands Missile Range Museum. (Marker Number 06.099.)"

Amazing Homebrew from Japan -- 7L4WVU's All Homebrew Station

Thanks to Roy WN3F for alerting me to this.  Tadashi-san has really built some beautiful stuff.  Especially impressive to me is his use of the spectrum analyser and two-tone audio tests to look at IMD of the entire transceiver.  See video above. FB OM.  

Be sure to check out 7L4WVU's YouTube channel: 

https://www.youtube.com/@7L4WVU

And his QRZ page heralding his all-homebrew station covering 1.8 to 430 MHz: https://www.qrz.com/db/7L4WVU

Farhan VU2ESE FDIM Interview (#6) by Bob Crane W8SX: VHF Rig, sBITX, and Good News on Raspberry Pi 4

It was great that Bob was able to catch up with Farhan and talk to him about his VHF rig and about the sBITX. 

    

Farhan said that the VHF rig (the BITX23) was presented at the homebrew show-and-tell as a project.  The idea was to encourage others to get into VHF homebrewing.  Farhan points out that many of us are reluctant to go into VHF building, thinking that we need special or exotic test gear. No true says Farhan.   He is trying, with this rig, to bust this myth.  FB.

    

On the sBITX, Farhan points out that he too -- coming as he does from the homebrew tradition -- finds some of the modern rigs quite intimidating.  So he designed the sBITX to be less intimidating.  It is, he says, a tinkerable rig that could be homebrewed. It is all open source.  

    

Farhan points out that the rig is built around the Raspberry Pi 4, a device that has recently been hard to obtain.  This has driven up the price of the sBITX a bit.   But good news:  Farhan says that the word on the street is that the Raspberry Pi 4 will be available in quantity starting at the end of June.  

Here us Bob's interview with Farhan: 

http://soldersmoke.com/VU2ESE23.mp3

BITX23 VHF Rig

And here is a video of Farhan describing the BITX23: 

https://soldersmoke.blogspot.com/2023/05/farhan-describes-his-new-2-meter

Thanks Fathan!  Thanks Bob! 

Rick Campbell KK7B at FDIM: Interview #5 by Bob Crane W8SX

/KH6

Having recently been involved in an effort to teach students about radio electronics, I found Rick's comments especially interesting.  

At FDIM,  he and his daughter were presenting a hidden transmitter hunt using rigs and Yagis at 432 MHz.  This was in part the result of his students having wanted to do something new with ham radio.  It was very impressive that the students had done this all with gear that they had built themselves.  Rick also made sure that they all learned how to solder.   

Rick ended the interview with a nice shout-out to SolderSmoke. 

Here is the interview: 

http://soldersmoke.com/KK7B23.mp3

And here is a paper Rick did on VHF.  It is a bit old, but it is good.  

 http://www.pnwvhfs.org/conference/2009/Introduction-to-VHF-Experiments.pdf

 Thanks Rick!  Thanks Bob! 

Farhan Describes his New 2 Meter SSB Transceiver (Video)

On May 16, 2023 Farhan gave us a look at his new BITX23 2 Meter Transceiver. Two days later he made a presentation on this rig at the Four Days in May event. Highlights: -- Use (and non-use) of the Cascade tool -- Cascade and the original BITXs -- ADE-1 -- SI570 -- Raspberry Pico -- Diplexer -- Different Grounds to get rid of digital noise -- Gimmick Capacitors (and gimmicks made from coax) -- Ugly SMD Capacitor Soldering -- Tombstoning! -- Melting RG-174 Coax -- No need to learn Arduino programming -- Dilbert! -- Bill and Pete -- Techie Tatts! Thanks Farhan!

Two days later, Farhan presenting the rig at FDIM

PA3CRX's 6 Meter BITX in an Old CB Case

Thanks to Rogier PA1ZZ for alerting me to this video and to the PA3CRX YouTube channel. 

I like what Chrix did with the old CB transceiver case -- this gives me ideas about the old transceiver that I picked up at a hamfest a while back.  I also like Chrix's practice of running coax and power leads UNDER the main BITX boards.  

Chrix has been building some great stuff and making some very nice videos -- I have put his channel on the SolderSmoke links in the right-side column of this page. 

SolderSmoke Podcast #234: PSSST, KWM-1, VHF Woes, Mighty Midget, TinySA, 17-12 Dual-Bander Advice Needed. MAILBAG

http://www.gadgeteer.us/17SSB.HTM

SolderSmoke Podcast #234 is available: 

http://soldersmoke.com/soldersmoke234.mp3

Roots of SolderSmoke: The "Click and Clack" of ham radio? 

Influences: Jean Shepherd, CarTalk, Shortwave stations.

Steve "Snort Rosin" Smith WB6TNL?  No. Steve "Aching Sinus" Smith WA6SOC  

Pete's Bench:
PSSST Super Simple SSB -- 7 Transistors. Switching IF Module: 

PSST Details:  https://www.n6qw.com/PSSST_20.html
DC RX.
KWM-1 Resurrection "Shame Shelf".
How to make things work:

http://n6qw.blogspot.com/2021/10/how-to-make-things-work-tribal.html
Diode Switching or Relays?

(Why the T/R diodes in the BITX 20 amplifiers?)
National Receiver.

Bill's Bench
Farhan's Talk to RSGB got me thinking of VHF 2 meter AM.
2 meter Benton Harbor lunchbox madness. SuperRegens Super Strange.
I broke my Maplin AF Sig Gen in the process. Fixed it.
Playing with MMMRX again. Put in 6 kHz ceramic filter. Sounds great SSB and AM.
Swept IF with noise, TinySA, and NanoVNA. Need better noise gen.
Mod to listen with TinySA (on blog).
Thinking of 17 meter /12 meter Dual-Bander IF around 21.4, VFO around 3.41 Mhz. Thoughts?
Sweeping double half lattice filter from Swan 240.  UGLY.  

MAILBAG:
--- ROOTS OF MAILBAG: Radio Moscow, Havana Cuba, HCJB, others.
-- Thomas K4SWL of the SWL Post: Could have been worse! Stairbag?

-- MY NOVICE LOG -- Heard back from ex-WN2RTH ex-WN2FLK ex-WB2RKK.
-- Drew N7DA worked Wes W7ZOI in Sweepstakes. FB.
-- Peter VK2EMU The movie Frequency and the Magic of Heathkits. Good, but not that good!
-- Thomas KK6AHT! Our old friend. Minima! Now has a young son! FB
-- Chuck WA7ZZE Saw QST profile. Sympathizes with Two-er trouble.
-- Tim M0CZP. Spell corrector. Vatican Diodes. Infallible!
-- Ramakrishnan VU3RDD Working on a NORCAL and a noise cancellation arrangement.
-- Skip NC9O said I was 40 Hz off on 17. But he had a reason to KNOW!
-- Steve K9NVD Glad he's a listener.  
-- Bob KY3R Novice Nostalgia. Should he use 75 watt bulb for dummy load? Yes! 
-- Todd K7TFC Video about why solder smoke goes into the face.
-- Anthony VU3JVX  Homebrew Antuino. I ask for help in moving freq to 450 kHz.
-- Jack NG2E Building Pete's DC RX.
-- Scott WA9WFA HBR-13 and MMMRX.
-- Stephen 2E0FXZ also got a FT-101 VFO.
-- Bob K7ZB on the air with 56 mW and a big antenna.
-- Dean AC9JQ Retired.
-- Allan WA9IRS Right to Repair update.
-- Farhan Invited us to Lamakaan ARC, Dec 11 or 12. Will be on QO100 Satellite Live! 

-- Many suggestions about my Apollo 11 Time Capsule. Still looking for ideas.

Happy Thanksgiving to all who celebrate this holiday!

https://shortwavearchive.com/archive/lsn2565kv5vg2l7s5qanx1mbnwvce5#commenting

JPL, Mars Helicopter, Cube Sats, Ham Radio and more: N5BF talks to Eric Guth 4Z1UG

This morning Eric Guth has a really interesting interview on his QSO Today podcast.  

Courtney Duncan N5BF had a full career at JPL and is the current president of the San Bernardino Microwave Society.  There is a lot of interesting stuff in this interview, much of it about space exploration.  Courtney tells us about how experience with re-purposing radio gear came in handy at JPL.  For example, the helicopter that they have been flying on Mars has a very cheap and light off-the-shelf Zigbee transceiver.  He also talks about the origins of the Cube Sats.   

Here is Eric's page on this interview, with useful show notes: 

https://www.qsotoday.com/podcasts/n5bf

I like to listen to Eric's shows on YouTube -- here is the YouTube recording of the N5BF interview: 

https://www.youtube.com/watch?v=Fbr4jE11vfg

Here is N5BF's ham radio web site: 

http://cbduncan.duncanheights.com/HamRadio/HamRadio.html

Here is the club page of the San Bernardino Microwave Society:

http://www.ham-radio.com/sbms/

Thanks to Eric and Courtney! 

Farhan's Amazing Knack Story: From a Boyhood SW Receiver to the Design of the sBITX SDR

The presentation starts at about the 4 minute point. 

I think if I were only allowed to watch one YouTube video in the next year, I'd make it this one. 

In this amazing RSGB video, Ashhar Farhan VU2ESE takes us back to his earliest days as a radio amateur.  He tells us about his very early desire to build radios, his early projects, and his personal evolution as a designer and builder,  from a simple DC receiver, to the BITX, the Minima, the uBITX and now the hybrid HDR/SDR sBITX.  

There is a lot of  homebrew wisdom and tribal knowledge in this video. And we learn so many hitherto unknown details about the rigs that have become so important to us:  

-- Farhan had the EMRFD book with him on the famous flight from Sweden to India during which the BITX was designed. 

-- We learn about the origins of the BITX oscillator circuits, and that the VFO and BFO are essentially the same.  

-- I was really pleased that Farhan included a picture of my HB BITX17 rig in his presentation. 

-- Farhan discusses the difficulties he faced in obtaining needed parts in India. 

-- We actually see the nylon washers that Farhan used in the original BITX. 

-- Farhan discusses his early system for measuring coil inductance. 

-- In addition the huge contribution of EMRFD,  Farhan talks about how he was helped by Pat Hawker G3VA's writing, and the ARRL's SSB Handbook. 

-- Farhkan talks about his Tex 465 'scope and his building of a Spectrum Analyzer. 

-- We see his evolution to dual conversion. We see the conceptual birth of the Minima and the birth (thanks Wes!) of the TIA amps.  I didn't know about the HF-1.  Then Farhan designed the uBITX and now the sBITX.  

 -- Farhan talks about his practice of taking the pictures of new rigs with the new rig sitting atop the book that was most important in its design and construction.  FB. 

-- I was really blown away by Farhan's presentation of how the uBITX advertisement was inspired by and in many ways based on the Heathkit ad for an HW-101.  Amazing. 

-- I learned a lot from Farhan's discussion of SDR theory.  I pledge to spend more time with this.  I really like Farhan's hybrid HDR/SDR approach. 

-- But I have a question:  Farhan seems to say that we'd need a big expensive GOOGL computer to do the direct sampling HF SDR.  But doesn't the little RTL-SDR do just that?  Without a GOOGL?  

-- Great to see Wes's AFTIA being used in the sBITX.  

-- Really cool that Farhan has his mind on VHF transverters when designing the sBITX.   I liked use of the TCXO module to free up one of the Si5351 clock outputs.   FB.  And great to include an idea from Hans in this rig. 

Thanks very much to Farhan (who stayed up until 3 am to do this!) and to the RSGB for hosting.

Super-Regeneration is Super-Strange

Farhan VU2ESE is largely responsible for this.  He has recently been talking about VHF.  (More about this in due course.).  This started me thinking about my failed effort in London to get on 2 meter AM.   My plan was to use the transmit portion of this HW-30 (above) with a 2-to-10 downconverter and my trusty Drake 2-B for receive.  

Tony G4WIF also bears some responsibility:  When I expressed interest in Farhan's VHF work, Tony sent me two articles from SPRAT.  Both of them were about super-regenerative receivers.  

Farhan's comments caused me to pull the HW-30 out of storage.  I started poking around the transmitter.  But then I noticed something:  On receive, the AF amplifier was obviously working.  Then, when I tuned through the 2 meter band, the rest of the receiver seemed to be working too.  I fired up the HP-8640B sig gen on 2 meters and turned on the AM modulation.  Indeed, the old receiver was inhaling!  

This launched me into an effort to understand how super-regenerative receivers work.  There are a lot of really weak explanations out there. You get the distinct impression that the person explaining the circuit does not understand it himself.  This makes explaining it very difficult.  I am not the only one to notice this phenomenon:  Mike WU2D commented on this in one of his excellent super-regen videos.  This one:  

https://www.youtube.com/watch?v=QOhNPLT8R10

Mike very kindly said the operation of this circuit seems like "magic."  I was thinking more in terms of Voodoo.  

Howard Armstrong discovered super-regeneration years after he invented plain old regeneration.  The new discovery came around 1921.

It looks like VHF guru Frank Jones had very early misgivings about super-regeneration.  In his 1934 classic 5 Meter Radio Telephony, Jones seems unenthusiastic about the circuit and about our ability to understand it:  "To explain, simply, exactly how this form of detection takes place is not a simple matter, but some of its characteristics are easy to visualize."  In this book, Jones goes on to predict that super-regens will be superseded (!) by superhets.  Indeed, in his 1961 book VHF for the Radio Amateur there are no super-regen circuits; all the receive systems are down-converters to HF receivers. 

Still, with that HW-30 hissing away right next to me, I feel I need to understand how the super-regen works.  I'm not there yet, but I'm trying.  Here are some good resources: 

A good article from Wireless World 1946:  

http://www.r-type.org/articles/art-285.htm  

A student's write up of his effort to understand: 

https://folio.brighton.ac.uk/artefact/file/download.php?file=597679&view=111191

But the best so far (for me) is from Frederick Terman (one of the founders of Silicon Valley) in  his 1943 classic Radio Engineer's Handbook.  Click on the images for a clearer view. 

I will definitely try to get the HW-30's 5 watt AM transmitter going.  I am not so sure I'll do anything with the receiver.  I think this is a matter of picking your battles and "finding joy."   I didn't find joy in FT-8, so I stopped working with it.  Same with my HA-600A, DX-40 Novice rig.  Same with CW in general.  And the same with SDR.  I suspect that super-regen receivers may also fall into this category.  I mean, let's face it, if you are not fond of ordinary regens, is there any real chance that you will like SUPER-regens?  Even Frank Jones seems to have disliked them.  And there is a reason Howard Armstrong moved on to superhets -- they are better! But still, that receiver is hissing away at me...  Stay tuned. 

2 Meter Homebrew: The Fredbox (Video)

I predict a rebirth of interest in 2 meter homebrew.  This will probably hit around Christmas time.  The impetus will come out of Hyderabad, India.  At this point, I can say no more. 

I was thinking about all of this today.  I remembered "The Fredbox."  G3XBM's report on this fantastic rig was carried on this blog before it was even a blog.  And the Fredbox goes back much further in time -- back to the mid-1970s.  It must have been great fun to have QSOs with this rig in Cambridge England back in the day.  G3XBM actually crossed the English channel with this 10 mW rig.  FB.  

When I was in London (2003-2007), G3XBM's post on the Fredbox got me interested in 2 Meter AM.  I had a down-converter that let me listen, and I went as far as modifying a Benton Harbor Lunchbox for the proper AM transmit frequency.  I don't think I made any contacts, but I still have the bits and bobs of this rig, so if anyone in the Northern Virginia area wants to get on,  please let me know -- I will blow the dust off this project and will build a 2 meter antenna.  

Here are more details from G3XBM on The Fredbox:  

https://sites.google.com/site/g3xbmqrp3/vuhf/fredbox 

Hans G0UPL got into the Fredbox in 2009 and 2016: 

http://www.hanssummers.com/fredbox.html

Possible Victory for Frank Jones and the FMLA? Could We Get the 5 Meter Band Back?

 

EI7GL reports some very interesting IARU activity that could possibly result in the 5 Meter band coming back to amateur radio use:  

"The 60 MHz or 5 metre band has the potential to be a future allocation for the Amateur Radio service. The International Amateur Radio Union (IARU) are currently encouraging member societies to try and obtain small allocations at 40 MHz and 60 MHz."

https://ei7gl.blogspot.com/p/60-mhz.html

Regaining 5 meters was, of course, the objective of Frank Jones and the Five Meter Liberation Army.  Wouldn't it be great of Michael Hopkins' fictional tale actually ended up coming true!  

Summer Reading for Homebrewers: Frank Jones and the FMLA by Michael Hopkins AB5L (SK)

 

Frank Jones W6AJF (SK)

I read these stories when they were first coming out and I really liked them.  Here are all the FMLA episodes.  Don't try to read them all in one sitting.  Spread them out.  Savor them.  Think about the message that Frank was sending us.  

All of the FMLA episodes:  https://tomfhome.files.wordpress.com/2019/12/frank_and_the_fmla.pdf

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Related articles, books and links: 

Frank's obit: https://www.pressdemocrat.com/article/news/frank-jones/

Frank's book "5 Meter Telephony": https://w5jgv.com/downloads/5-Meter%20Radiotelephony%20by%20Frank%20Jones.pdf 

Frank's 1937 Antenna Handbook: http://rfcec.com/RFCEC/Section-3%20-%20Fundamentals%20of%20RF%20Communication-Electronics/23%20-%20RADIO%20ENGINEERING%20DATA/1937%20-%20Jones%20Antenna%20Handbook%20(By%20Frank%20C.%20Jones).pdf

About the author, Michael Hopkins AB5L: https://www.rantechnology.com/index.cfm?key=view_resource&TransKey=615604E8-9DAA-40A3-9E48-4160806D893D&CategoryID=8E884CE4-9CED-4957-872B-5EBDB058D540&Small=1

Michael Hopkins AB5L (SK) 

Thanks to Dave Wilcox K8WPE for reminding us of all this, and for sending us the link to the FMLA archive. 

Viva el FMLA!   Viva el CBLA!  Vivan! 

SolderSmoke Podcast #230 is available! Apr 1, Mars, Group Build, SDR, SSB, Mich Mighty Mites, Mailbag

SolderSmoke Podcast #230 is available for download

http://soldersmoke.com/soldersmoke230.mp3

N2CQR was down for maintenance 

A few words about April 1

The Ingenuity helicopter

China lands on Mars

Brood X Cicadas arriving in NOVA 

Pete's Bench

The Dentron Project

The Spillsbury Tindall SBX-11A

KK4DAS and the Simple SSB Group Build

TenTec mods

Shack Mystery solved.  Maybe 

Changing the channels at age 9 

Bill's Bench

Why LSB below 10 MHz? The "SSB Legend" Rig

WU2D RTL-Dongle Up converter

Understanding the Gilbert (Jones) Cell

SDRSmart  RTL-SDR.com V3 Dongle 

VK3HN and 2 meter SSB

Jack NG2E, MMM and the 10 minute transmitter

KD4EBM sends me SST by Wayne Burdick. DX!  

A new computer 

Mailbag: 

MM0ACN

VK2EMU

N5VZH

VE3KZJ

HS0ZLQ

AD0JJ

VK8MC

KK0S

VE3VVH

KB3SII

WA9WFA

M0NTV

W2DAB

 60 Minutes Story on Mars Ingenuity Helicopter: 

https://www.cbsnews.com/news/nasa-drone-mars-60-minutes-2021-05-09/