A Really FB HB QRP QSL Card from New Zealand

 

That's the spirit!  The solder is melting.  Note the oscilloscope.  Note the books on the shelf. This amazingly good QSL card was sent to us by homebrewer Paul VK3HN, who made the contact with ZL2BNE.  

This card reminded me of my first real DX:  ZL2ACP many years ago.  15 meter CW with my new Drake 2B receiver.  I had crossed the Pacific before I had crossed the Atlantic.  I ran upstairs and woke my parents to tell them of this amazing feat!  I still have that QSL card.  

The RT-6 and RR-6 Motorola "Spy Set"

I don't know if this rig really qualifies as a "spy set" but it nevertheless is very interesting.   It is a tube rig, designed for use by B-47 bomber crews who could not make it back from the Soviet Union after dropping their nuclear bombs.  Supposedly they would bail out, then use these radios to call for help. Good luck with that!  Note the fold-out CW key. 

This rig was also reportedly hidden in European countries as "stay behind" assets to be used in the event of a Soviet invasion. 

 Here is a web site with more info: https://www.universal-radio.com/catalog/hamhf/rs6.html

First QSO by Chris (aka Morny) G7LQX and it was Homebrew CW!

I must have missed this five months ago, but better late than never: Congratulations to Chris G7LQX for his first ham radio contact.  And he was using a homebrew CW transceiver. 

Details here: https://www.qrz.com/db/G7LQX  

Chris has a very nice fist, and he is one of the only YouTubers I have seen who holds the straight key properly, with his forearm resting on the table.  All of the others seem to keep the forearm floating in the air, above the key. 

Canadian Ham to Include SolderSmoke Direct Conversion Receiver in Teaching Materials for Canadian Ham License

Good morning Bill N2CQR.

I currently teach Canadian amateur radio certification courses.

The Advanced certification (akin to the FCC Extra Class license) has topics nicely showcased with the NorCal 40a transceiver.

Happily, the SolderSmoke DCR project will be included in my next editions of teaching materials (books, zoom presentations, monthly newsletters) once the Canadian question bank revisions are published later this year.

I really learned a great deal from the YouTube videos for each module in the DCR. Especially appreciated were the recommendations for trimpots and how to use them in the RF filter and the back-to-front build-test procedure for the cascaded audio amplifier. And these are just 2 of the many precious circuit building strategies learned from the documentation supporting this project.

Kudos to you and Dean and all the people involved at SolderSmoke.

All the best, 73 de VA2GJ, Gérald Julien Lemay.

Sputnik, IGY, Korolev, 1 Watt

Here is the Wikipedia on Sputnik 1:  https://en.wikipedia.org/wiki/Sputnik_1

I didn't know how badly Korolev had been injured while in the Gulag. 

The transmitter had 1 watt at 20 and 40 Mhz. 

Why It Makes Sense to Take a Break When Stuck on a Problem: "Unleashing Your Creativity" -- Hidden Brain Podcast

Wow.  For years we have been telling other builders that when they get stuck on a technical radio problem, when they can't fix a rig or get something to work, they should NOT stick with it, pull their hair out, and bang their heads against the wall.  Nor should they do what many of us do in our troubleshooting nightmares:  start pulling components off the board until, in the end, the board is empty.  No, don't do that.  Take a break, take a walk, do some gardening, do something different.  Then, when your mind is clear, suddenly the solution will come to you.  "Of course," you will think, "R16 should be 10K not 10 ohms!"  Or something like that. 

But why does that happen, and how does it happen?  It seems that many creative people through the centuries have been aware of this phenomenon.  

Listen to this podcast.  They discuss the benefits of taking a break and clearing your head. 

https://www.hiddenbrain.org/podcast/unleashing-your-creativity/

Q Dope, AI, and Homebrew Q Dope: Putting Packing Pellets to Good Use

 

Our friend Grayson KJ7UM recently asked about something that brought back old ham radio memories: Q Dope.  No, this not some new scary narcotic.  It is an old liquid that many of us had on our shelves until it dried out.  It turns out that AI knows all about it: 

"Q dope" was a specialty product—essentially a high-quality polystyrene lacquer—widely used by radio builders and amateur radio operators, particularly in the mid-20th century. It served as a protective coating for hand-wound coils and transformers in RF (radio frequency) circuits.

Why it was "Special"

Its primary value lay in the combination of two properties essential for high-performance radio gear:

• Low Dielectric Loss: When you wind an air-core coil for a tuned circuit, you want the "Q factor" (Quality factor) to be as high as possible. The Q factor measures the efficiency of the inductor, representing how well it stores energy versus how much it loses to resistance and dielectric absorption. Standard varnishes or glues could introduce "lossy" materials into the magnetic field of the coil, effectively lowering the Q and broadening the bandwidth of the tuned circuit (which reduces selectivity). Q dope was formulated specifically to have an extremely low dielectric constant and low loss tangent, meaning it wouldn't "dampen" the energy in the circuit.

• Mechanical Stability: Without a binder, hand-wound coils can be microphonic or physically unstable; if the wire moves due to vibration or thermal expansion, the inductance changes, causing the frequency to drift. Q dope acted as a cement that locked the turns of wire in place without adding the electrical losses of common adhesives.

Modern Context

While the term "Q dope" is less common in modern surface-mount or PCB-based electronics, it remains a topic of interest for those working with vintage radio restoration or homebrewing equipment where the specific electrical characteristics of air-wound inductors are required.

Because it is essentially just polystyrene dissolved in a volatile solvent (like toluene or acetone), it was also notorious for being simple to "home-brew." Many hobbyists simply dissolved scrap pieces of clear polystyrene (often from discarded plastic items) into a solvent to create their own batch, which served the exact same purpose as the commercial product.

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

And wow, here is a video on how to homebrew your own Q dope.  Finally those annoying packing pellets are useful for something: 

Troubleshooting in "2001 -- A Space Odyssey" -- And Trouble with the AI (HAL 9000)

Steely-eyed troubleshooters on Discovery

Their test gear

Here is Arthur C. Clarke's description of the procedure: 

This is probably our first entirely fictional description of troubleshooting. The amazing thing is that it comes to us from 1968, which is 58 years ago! 

YouTube's algorithm sent me a short video on how Stanley Kubrick made the movie, and how Arthur C. Clarke wrote the book:  https://www.youtube.com/watch?v=vJUBK1K84P8 

I remember going to see the movie in 1968.  Our neighbor Leonard's father (a Russian refugee), took all of us up to Haverstraw, New York to see the film.  It was obviously a memorable occassion.  

Ongoing discussions of AI and the possibility of AI consciousness make all of this even more relevant today. 

The Snake Shack of the Amazon

https://www.nytimes.com/2026/05/29/science/snake-collector-mera-ecuador.html?unlocked_article_code=1.o1A.2O0_.gzrRsoBWgWvH&smid=url-share 

Think of this as part of our "other kinds of workshops" series.   In this case, it is literally another kind of shack. 

The article describes an understandable cultural message that says snakes must be killed.  Like the people in this story, we have to fight against similar cultural issues in the Dominican Republic.  

Anyway, I liked the story.   I hope the link survives.

Pete N6QW's "Last Ditcher" CW Thermatron Rig -- Frank Jones would approve. A new installment of the FMLA series?

I like this rig.  Perhaps I like it too much.  I find myself plotting to build it myself.  I mean, I have tubes.  I have a bunch of old parts (many sent to me by Pete himself).  

Alas, I have to fight the temptation.  I have to tell myself that this is for CW (a mode that I have come to be impatient with).  And it is a thermatron rig that requires potentially lethal voltages. 

Still, Pete's construction technique is really neat.   It combines old style slat-board construction with modern copper clad boards.  Frank Jones would approve.  

I think we need someone to write another episode of the FMLA series, this one using Pete's build.  And maybe featuring Pete himself. 

Here is some needed background info on Frank Jones and the FMLA articles: 

https://soldersmoke.blogspot.com/2021/07/summer-reading-for-homebrewers-frank.html

I look forward to hearing from protential authors.  If the new articles are good,  I will put them on the SolderSmoke blog.

Helge LA6NCA's Norwegian Paraset

This is a very cool video.  I even liked Helge's creative use of AI for the narration.  It was amazing that this old rig still works.  

Thanks you Helge.  And thank you to all the brave members of XU, who so valiantly risked it all in the fight against Fascism. See: https://en.wikipedia.org/wiki/XU 

A Possibly Blasphemous Redraw of the Michigan Mighty Mite Schematic

Ryan KJ7KVD is building a Michigan Mighty Mite.  I sent him some parts, and mentioned that I had redrawn the schematic.  I find that it sometimes helps me understand a circuit if I just re-draw the schematic.  

Above you will see what I came up with.   Here is what I told Ryan: 

Attached is my re-daw of the MMM schematic.   The emitter and base resistors just needed some clarification.  The original schematic led some to believe that the two resistors should be connected.  Not so!  I think the redraw clarifies this.  

The most significant re-draw is in the coil.  All I have really done is to "pull out" the tapped "tickler" coil.  You will read in the literature that the two are equivalent.  This just shows that L1 can be seen as a separate coil, imparting RF to the parallel LC tank circuit that is tuned to the operating frequency.  The phase shifts introduced by the transistor, the tank, and the crystal all add up to the needed value in order to meet the Barkhausen criteria:  Oscillation results! 

Go ahead and build the coil with the tap as in the original schematic.  This re-draw may help you understand how the thing works.  Understanding is important.  

Here is one of the orignial schematics (from https://www.qsl.net/wb5ude/kc6wdk/transmitter.html):