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Saturday, May 25, 2019

KJ5VW's Cool uBITX Mods (Video)

Beautiful work Gary, and great to see that you are putting ideas from Pete and from Don Cantrell in your rig.  

Gary wrote:
Don and Pete,

I thought you would be interested in the QRP station accessory I added to my version 3 microbitx transceiver.  In addition to using Don's AGC and Reverse/Forward Power and SWR  circuits, I developed another board using a separate Nano and TFT display to show day, date, time, temperature and humidity as well as showing the relative audio strength in three separate bands centered on 400 Hz, 1000 Hz and 2500 Hz.  In addition, when I put the transmitter in a 'tune' mode the power out and SWR will show on the TFT display as well.  The date, time, temperature and humidity information is updated once every minute, the audio is displayed continuously during receive and the power/swr is only displayed when the transmitter is activated.

The audio frequency analyzer is based on the MSGEQ7 microchip and it actually picks up the audio strength in 7 bands covering 63 hz to 16,000 hz.  I just display the three most likely to show up in a SSB transmission.  You can see a 'live' example near the end of the video showing a 20 meter QSO and how the audio strength by audio frequency varies over time.

This project falls into that 'frivolous but fun' category that was a challenge to design but I doubt many other hams would want to replicate it. I learned a lot and wanted to thank both of you for arduino scripts, useful circuits and lots of inspiration for getting started.  I have long admired the work both of you contribute to our hobby.

Here's the link to the YouTube video. 

73,  Gary KJ5VW

Friday, May 24, 2019

Nigerian Knack: Hope Emmanuel Frank

I hope this kid has a lot of success.  He definitely has The Knack. 

Tuesday, May 21, 2019

FDIM Interview with KI4IO -- Homebrew Direct Conversion Transceiver

I've been a big fan of Jerry's for several years.  He is the homebrew wizard of Warrenton, Va.  Warrention is just about 25 miles west of us.  Cappuccio the wonder-dog was born on a farm in Warrenton.  

I'm really glad that our ace correspondent Bob Crane W8SX caught up with Jerry at FDIM.  I liked his description of the joy of using a homebrew rig, and of the advantages of direct conversion.   Inspiring stuff!   Listen to the interview here: FDIM 2019.m4a

Be sure to check out the KI4IO page on

Monday, May 20, 2019

Woz on the air -- Age 11

We discussed Steve Wozniak's early involvment in ham radio here:

Thanks to the K9YA Telegraph for relaying this great picture. 

Sunday, May 19, 2019

FDIM Interview with Hans Summers G0UPL on QSX SDR Rig, Probable Price, Features

Wow, our ace correspondent in Dayton/Xenia Ohio, Bob Crane W8SX, did a great interview with homebrew hero Hans Summers G0UPL.  

Hans discusses the success of the QCX CW phasing rig -- more than 7,300 sold.  That's amazing.  I didn't think there were that many solder melters in the world.  

Even more amazing is his description of his QSX SSB SDR rig, which is currently in development.  Click on the link below to listen to Bob's 6 minute interview.  You will be blown away by the features and the price of the QSX.  Go Hans! FDIM 2019.m4a

Thanks Bob! 

Friday, May 17, 2019

Pete sent me his SBE-34

Pete is such a great guy, and such a great ham.  Earlier this week I came home to find a box in the living room.  In it was the SBE-34 that you see in the video.  Pete had been talking about this rig about 18 months ago.  

So many cool features:  The main tuning dial is dual-speed.  There is the "Geneva" band switching method.  Hybrid, with sweep tubes in the final.  All analog.  A power supply that will take 110V AC or 12V DC (internal inverter).   Collins mechanical filter at 455 kc.   Bilateral amplifier stages.  PNP Germanium transistors. 

Pete suggested that I might want to use this rig for parts.  No way!  There is real radio history and amazing innovation in this rig. Plus, it has been worked on by Pete Juliano, N6QW.  

Here is the write up from Pete's YouTube page. Note the part about how they get the BFO signal. 

Here is an example of what an IC7300 might look like some 50 years ago. It is a hybrid rig using Germanium (mostly PNP) transistors in the low level stages. So OK a couple of NPN (2N706) in several key locations such as the VFO. The driver uses a tube similar to a 12BY7 and the finals are a pair of sweep tubes, the 6GB5's. The rig operated on four bands (mostly the then phone portions) 80, 40, 20 and 15 Meters. The power out on 80-20 was 60 Watts PEP and dropped down to 50 Watts on 15 Meters. That was a real stretch. The AGC sucked as you will see in the movie and the receiver gain was a compromise --too much on the low bands and weak on the higher. This was a bilateral design -- which predates the Bitx series by some 40 years--but not the 1st.The first bilateral design was the Cosmophone - Google that one. The major selling point --a Collins mechanical filter. Also an innovation was how LSB / USB was achieved using a single crystal. It was pure magic and innovation. The basic BFO frequency of 456.38 was doubled and then doubled and tripled again. The first 2X gave you 912.76 KHz and the 2nd 2X gave you1825.52 KHz and a tripling gave you 2738.28 KHz. Mixing that back with 456.38KHz gave you 2281.9 KHz USB or LSB. The VFO operated in the 5.5 MHz range and there were heterodyne crystals to put you on the proper bands. Now that was some clever math! You can download the maintenance manual at BAMA manuals. There were some smart guys leading our ham radio efforts back in the day.

Wednesday, May 15, 2019

Stop what you are doing! Go to the Radio Garden!

This is really fantastic.  The screen display is like Google Earth, but all the green dots are local broadcast radio stations.  Put your cursor on the dot and listen to that radio station live.  And it works very well.  If there are several stations in the same town, just zoom in.  

In the course of a few minutes this morning I was listening to stations in Guatemala, Costa Rica, Getxo Spain, and Bengaluru India.  

Go to the radio garden: 

Sunday, May 12, 2019

Another Amazing SSB Rig: VK3HN's "Summit Prowler 6"

Here is another truly amazing compact SSB rig.   Paul Taylor VK3HN is a true homebrew wizard.  So many great homebrew rigs come out of Australia.   

More details:

Paul's page:

Friday, May 10, 2019

Peter DK7IH's Amazing Rigs and Blog

It has been a few years since we last mentioned Peter DK7IH.  He has continued to melt solder and to document his work on an excellent blog:

I was especially interested in the rig pictured above.  NOTE:  NO GLOWING NUMERALS.  That rig has an analog VFO.  The blog article provides some great pointers on how to achieve thermal stability.  Also, be sure to check out his "Old School" rig.  

I've put Peter's blog in the blog listing on the right side of the SolderSmoke blog.   

Thursday, May 9, 2019

Book Review: "Man of High Fidelity: Edwin Howard Armstrong" (Free Download)

Dave W2DAB sent me this wonderful book.  He picked up a copy at a recent Columbia University lecture on E. Howard Armstrong.  Written by the notable science writer Lawrence Lessing, the book was first published in 1956.  The paperback copy that Dave sent me came out in 1969; while 50 years old, my copy is in remarkably good shape. 

I really liked the book.  The author captures the technical achievements of  Armstrong, while also describing vividly the world in which Armstrong lived.  Being from the area, I especially liked Lessing's description of New York City and the Hudson Valley in the early years of the 20th century. This was the world of my grandparents; Lessing's book helped me understand it better. 

For the radio amateur, I think the most gripping part of the book is the way Lessing describes  the excitement of early radio.  Armstrong was a true enthusiast for the new technology, and he was -- even as a teenager -- at the cutting edge.  He was constantly striving to improve the technology, especially the receivers.  Like us, he often became obsessed with his radio work, often forgoing sleep and missing family meals as he toiled away in his workshop. Lessing tells us of Armstrong's astonishment and joy, when, upon inventing the regenerative receiver, he was suddenly able to clearly receive signals from distant stations that previously had been barely discernible.  Realize that when he was doing that, he was the only person on the planet who was doing it.  He was the inventor. He was the first. 

Lessing gives us a lot of great information about Armstrong's work as an officer in the U.S. Army Signal Corps in Paris during World War I.  We learn more about how his desire to be able to detect noise from the electrical systems of enemy airplanes led him to the invention of our beloved superhet receivers.   But my favorite Armstrong in WWI story involves his visit to the radio shack of the ship that was carrying him to the war.   In the radio shack he found a conventional station.  But he asked the operator if he happened to have one of the then new audion tubes.  On the spot, Armstrong took the tube and rigged up a regenerative receiver.  He and the ship's radioman then delighted in hearing stations that had never before been audible.   Amazing.     

I was less interested in the sad tale of Armstrong's legal patent battles, so I kind of skimmed through that.  I'm also not much of an FM guy, so I'll save those portions of the book for a later date.  

I think this is an important book about a significant part of radio history.  It is well written.  It gets almost all of the technical details right (but sorry Mr. Lessing,  radio waves are not composed of electrons).  The book deserves a place on the shelf of all radio history libraries.   If you can't get a print copy, an online version can be downloaded here:

Thanks again to Dave W2DAB.   

Wednesday, May 8, 2019

"Want one!" F6DMQ's Remote Rig

I talked to Yves F6DMQ last night on 20 meters.  I was on my all-analog BITX20.   Yves was up in Toulouse, operating his station near Cannes via this EXTREMELY COOL remote rig.   He connects to the home station via 4G.   Check out the rest of his station here: 

Tuesday, May 7, 2019

Monday, May 6, 2019

"The Bit Player" A New Movie on Claude Shannon

The Bit Player Trailer from IEEE Information Theory Society on Vimeo.

Thanks to Bob KD4EBM for alerting us to this.  As Bob put it, Shannon definitely had The Knack.  Check out the trailer (above)  for this new movie.   It looks like the IEEE is still working on the release plan for the film.  Does anyone have info on this? 

More info on the film here:

Four years ago we reported on a video about Shannon: 

Thanks Bob! 

Sunday, May 5, 2019

SSB on the QCX? Sounds pretty good here (Video)

In SolderSmoke #211 we reported on recent efforts to generate SSB from the QCX CW phasing rig -- we said that we'd heard that the effort wasn't very successful.  But today we got an e-mail from Jim W4JED pointing us to YouTube video from Guido PE1NNZ.  

I must say the signal sounds pretty good to me, and it looks good in the waterfall.  Listen for yourselves via the video above.  His is the signal on the left. 

Guido has a great write up, along with software here: 

I hope this all works out -- it would be great to get on phone with Hans Summers' amazing phasing rig. Here is a picture that hints at the potential: 

Go Guido! 

Saturday, May 4, 2019

SDR vs. HDR - Is the Superhet Dead?

Pete N6QW had this very interesting video about Software Defined Radio on his blog.  Thanks to G3WGV for putting this presentation together. 

It is very interesting, but -- for me -- it is also troubling.   I think something important is being missed in this discussion. You have to listen carefully, but if you do the thing being missed becomes apparent. 

Like many others, G3WGV asserts that very soon, 100 percent of commercial radios will be SDR.  Traditional superhet radios will be a thing of the past. 

OK, but I will make a parallel assertion:  Looking ahead, I think 100 percent of TRULY homebrewed rigs will be HDR.  

Of course, this really just comes down to how you define "homebrew."  I'm a traditionalist here.  I think of homebrewing as actually building -- from discrete components -- all the stages that send or receive radio signals.  By my definition, I don't think you can really "homebrew" an SDR radio.  Taking an ADC chip and connecting it to a computer running SDR software is not -- by my definition -- homebrew.  Even if you wrote the software yourself, writing code is not the same as wiring up all the stages that go into a superhet-style transceiver.    

There were a few lines in G3WGV's talk that seemed to confirm this difference:  The SDR radio is defined as a "server." Commercial manufacturers like SDR because they can use the same components that go into cell phones (exactly -- and people will soon have the same relationship with these "radios" that we have with their cell phones). 

I kind of grimaced when G3WGV described the two sets of users of SDR technology: the "early adopters" who are "technology enthusiasts",  and the "pragmatists" who don't care what's in the box -- they just want to talk on it.  I think "pragmatist" is a nice way of saying "appliance operator." Even the "early adopters" are pretty far from the world of traditional homebrew.  And for me that gets to the point that is being missed in all this -- this shift away from hardware is also a shift away from homebrew.   

But hey, this is a hobby.  To each is own!  Have it your way.  For myself, I plan to continue with the hardcore, radical fundamentalist, hardware-defined, discrete component, fully analog homebrew radio.  This morning I am attempting to stabilize a cap and coil VFO.  And I'm liking it.  As the world shifts to SDR, I look forward to the appearance on e-Bay of massive quantities of old forsaken HDR rigs.  We will buy them for pennies on the dollar and use the parts for new HDR Superhet rigs.  

Viva  E. Howard Armstrong!   Viva!   

Need Some Trans-Atlantic Support -- "The Impoverished Radio Experimenter"

A friend in the UK writes: 

I'm looking for volumes 2 and 4 of the "The Impoverished Radio Experimenter" pamphlets. I've searched in the UK for them - they are available but at silly money (nigh on £25.00 each). No sign of any pdf downloads, either. pdf downloads (preferred!) or purchasing at £10 and under would do me fine, if you know any sources?

Any ideas?    Thanks,  Bill 

Saturday, April 27, 2019

SolderSmoke Podcast #211 -- Malicious Code! Spaace! Vintage Sideband! MAILBAG

27 April 2019

SolderSmoke Podcast #211 is available

Pete NOT quitting podcast!  Malicious code case RESOLVED! 

Ambiguity and the Digi-Analog Divide

Edwin Howard Armstrong biography 

   Apollo 11 50th Anniversary
   Oscar 100 in Geostationary Orbit.  Why can't we have one too? 
   Farhan puts AISAT in orbit.  FB!  
   Space is difficult
   SSTV from the Space Station

Pete's bench report. 

Vintage Sidebanders
    Recording of Midwest Vintage SSB "tune up session" 
    Vintage rigs that sound bad
    Distorted views on "distortion" 

Bill fixing old Bose Wave Radio

NOT GOING TO DAYTON.  AGAIN!  But SolderSmoke rep will be there

75 meter secrets of success (timing is everything!) 


Steve N8NM sends me FB National Dial
Steve N8NM aspires to complexity -- enough of this simple stuff!
Dave W2DAB goes to Columbia U session on Armstrong, sends FB book. 
Jim W4JED -- reports of QCX sideband a bit exaggerated.  Where is Allison? 
Rob Powell wins beret challenge.  VK2TPM and VK2BLQ also win. CONGRATS!
Colin G3VMU sends nice 1930s radio picture
Alan WA9IRS sends diagram of digi radio signal flow.  CLEAR AS MUD! 
Chris KD4PBJ Grandmother worked at Hammarlund. 
Steve NU0P sends info on Art Collins and the Apollo moonshots. 

Friday, April 26, 2019

BITX on the Beach in East Java (Indonesia)

Nobel Prize winner Joe Taylor, K1JT, Talks to a Radio Club

Really great to see this session with Nobel Prize winner Joe Taylor, K1JT.
I liked his comments on his use of his retirement office at Princeton, University. 
I also liked his slide on how far below the noise level you can go with various modes. 
And then there was his reminder to 1) RTFM and 2) be sure to check the EME delay box so that your software will get the timing right when working earth-moon-earth. 

"Pulsars keep good time." 

Sunday, April 21, 2019

A Beautiful Variable Capacitor (from Pete)

Is this a thing of beauty, or what?   Pete sent this to me back when I was having trouble finding a "smooth running" variable cap for my HRO dial receiver.  It has a standard Jackson Brother's reduction drive attached to the shaft, followed by a really cool gear arrangement.  Note the spring loaded teeth on the big gear -- that is to keep the gears tight when turning in both directions.  

As was the case with the HRO dial that Armand sent me, the beauty of this part will cause me to build something with it, really just for the purpose of putting it to use. We've been talking about double or triple conversion superhets with 100 or 50 kHz final IFs.  At those frequencies you can get good selectivity with LC filters.  As with the Drake 2-B.    Steve N8NM is sending me a dial that will go well with this part.  That will add to the already abundant mojo/juju.  I feel a VFO in the works.    Thanks to Pete for being so supportive of my luddite analogism.  

Saturday, April 20, 2019

Life in Appliance Land

"Sexiest Radio!"   Hmmmm.

"It's the bomb."

The 3D waterfall is kind of cool.    As is the big screen on the wall. 

Friday, April 19, 2019

Homebrew Your Own Remote Head (with a 3D Printer) (Video)

After I issued a luddite complaint lamenting the arrival in ham radio of appliance-like "remote heads", Ed KC8BSV pointed out that at least one guy -- Joe VE1BWV -- is HOMEBREWING his own remote head. (You must admit, this sounds really weird.) I still haven't completely got my head around this, but Joe's video (above) is really impressive.  

We're living in the future my friends!

Remote your heads!  With 3D printers!   

Thursday, April 18, 2019

Our Dismal Digital Future?

I'm sure some would find this device appealing -- to each his own.   But I don't like it.   It seems to mark another step down the path toward the complete appliance-ization of ham radio.  Note how the control head is looking more an more like something for your car audio system, or your cell phone.  
Count me out. 
Just say NO! 
Menus are for RESTAURANTS!  

Wednesday, April 17, 2019

From Cuba: "Technological Disobedience"

Necessity is indeed the mother of invention.  

This video made me think of the Jaguar DSB transceiver made in Cuba from the parts of Soviet-made television sets.  

Somehow I wish we were more technologically disobedient. 

Monday, April 15, 2019

"The Hobby Song" from Saturday Night Live

I kept waiting for OUR hobby to be mentioned....

Sunday, April 14, 2019

Understanding Fourier Transforms

Lots of wisdom and insight here:

Strongly recommended for those trying to understand mixers and harmonics. 

Saturday, April 13, 2019

Digital Engineering vs. Analog Engineering

In  a book review Thompson makes this observation about the digital-analog divide: 

One difference might be that human beings can deal with ambiguity, and computers really can't. If you've done any Python [coding], you make the tiniest mistake, and everything stops immediately. That’s what makes it different even from other forms of engineering. When you are trying to fix a car, if you fail to tighten a bolt on one wheel as tight as it should be, the entire car doesn't stop working. But with code, an entire app, an entire website can go down from the misplacement of a single bracket. I think that's the one thing that sometimes scares writers away, because they are more accustomed to working with ambiguity.

I am definitely more accustomed to working with ambiguity. All of my rigs are filled with ambiguity. 

Friday, April 12, 2019

Understanding Digital Radios

Alan WA9IRS writes: 

Hi Bill,
Thought I would drop you a brief note.  I have been catching up on my listening to past issues of Soldersmoke podcasts and was particularly interested in the discussion between you and Pete concerning the simplicity associated with non-digital, integrated circuits and microprocessors and all of the rest of the very small miniaturized circuit elements.  You rightly pointed out that you desired (along with a lot of the rest of us) to fully understand what was going on in a circuit and for that reason desired to maintain the simplicity of transistor and discrete components in your design and build projects. 
 I agree with you completely but offer the alternative to the simple circuits in the form of the attached simple diagram of the signal flow path in a digital radio. I found this some time ago in a digital electronics magazine and thought you and Pete would find it interesting.  Perhaps this might be something to spring on Pete on 4-1-2018.
Take care and thanks to both of you for many pleasant and thoughtful hours of enjoyment listening to Soldersmoke!
All for now, 73,
Allan,  WA9IRS
My response: 
Thanks Allan, Very illuminating.   It is all clear to me now.   I feel so much better.  FB OM.   73  Bill 

Thursday, April 11, 2019

Circuit for Farhan's Satellite -- Arduino in SPACE

Farhan sent me the schematic of the AISAT amateur digital satellite that went into orbit on April 1, 2019 from India.   He notes that the circuitry is very simple.   Indeed, it reminds me of the very simple but effective circuitry we saw in satellites in the early days of the space age.  Beautiful simplicity, with an Arduino on-board.   And it is great to see that Farhan did not forget the low pass filter.  FB OM.  

Tuesday, April 9, 2019

Packets from Farhan's Space Ship

Farhan's AISAT flew over this morning.   Using HD-SDR software, an RTL-SDR Dongle,  and my Dominican Republic refrig tubing quad I was able to capture some the packets.  Above you can see one of them, floating like a flying saucer in the waterfall.  Pretty amazing that that signal came from a machine put in space by our friend Farhan.  

Monday, April 8, 2019

Congratulations to Farhan on New Amateur Satellite Launched 1 April

This is not an April 1 trick.  Farhan and Exseed Sat have put another bird in orbit.  
Details here:

This site in Argentina gives pass information:

I will be listening tonight! 

Congratulations Farhan! 

More info: 

Monday, April 1, 2019

Malicious Code in the Si5351 -- Pete quitting podcast

Those of you who have been reading Pete N6QW's blog (and all of you should be reading it!) will have seen a recent post about his efforts to modernize (digitize) the VFO in an old tube-type Ten Tec Triton IV model 544.  Pete complained that --oddly -- in spite of replacing the old analog tube-type VFO, the rig with a modern, rock-stable Si5351 VFO, the old rig CONTINUED TO DRIFT.  That had Pete and a number of us scratching our heads.  How could that be?  

Pete then completely removed the Si5351 VFO from the old boatanchor.   Sitting on his bench, all by itself, THE DAMN THING EXHIBITED ALL THE CHARACTERISTICS OF ANALOG VFO THERMAL DRIFT.  Wow!  Why?  Pete was really pulling his hair out on this one. 

We immediately began to see if others were getting the same results.  Nope.  None of our Si5351 VFOs were doing this.   This was REALLY strange.  

At this point we had to turn to a real Arduino expert, a guy who I had met during my time in Italy: Luigi Bugiardo from the Arduino research center in Bocalupo, Calabria.  Pete gave him remote access to his computer and he began to poke around.  

It didn't take long.  Luigi quickly found the problem:  He found several lines of malicious code "embedded in the Si5351.h and si5351.cpp files –sort of lurking out there and not easy to spot." 

Pete then removed this code and -- BINGO -- no more drift.   

Now I know some of you guys are thinking that this was just a bit of harmless fun.   But Pete is really angry about this.  He feels like he has been played for a sucker by some ham who was pretending to collaborate with him.  Pete sees this as yet another violation of the unwritten ham code of conduct.  To him this is another intrusion of computer/hacker noob hazing into the ham radio world.  And worst yet, he thinks this malicious code came to him because of this involvement in the podcast and his blog -- that participation resulted in the widespread exposure that got him into this mess.  

Pete is so upset that he has vowed to drop out of the podcast and shut down his blog. 

So come on fellows.  It is time to 'fess up.  If you did this, or if you think you know who did this, please send an e-mail to me at   I think being able to pinpoint the prankster will help Pete deal with this whole thing, and hopefully get him back into the SolderSmoke...   

Tuesday, March 26, 2019

So Much Cool Stuff on Pete N6QW's Blog

There is so much tribal knowledge, so many good ideas.  Be sure to visit Pete's blog regularly.

He needs the meter from an SBE-33.  Somebody out there must have one.  

Check out his stepper motor antenna tuner video.  

And be sure to leave some comments or to send Pete an e-mail with feedback.  I live in fear that he will think no one is reading and then stop posting.  We can't let that happen!  

Monday, March 25, 2019

Apollo 11 -- The Documentary

My wife is a kind and tolerant person.  Proof of this is that she went with me to see the Apollo 11 documentary that we recently posted about.  

I think you have to be a geek and/or have The Knack to really like a 90 minute documentary with no audio other than Walter Cronkite's reporting and the recorded dialogue among the participants.   But of course, I loved it.  Amazing video, especially of the Saturn V.  

Bob Scott KD4EBM found this great interview with the film maker: 


Audio only (downloadable)

Tuesday, March 19, 2019

Amazing New Geostationary Amateur Satellite -- LISTEN ONLINE!

Wow, quite a step forward in the amateur satellite world.  Qatar and AMSAT-Germany have collaborated to put an amateur radio repeater in geostationary orbit.  That's pretty amazing.  Read more here:

Read about a group of Norwegian students working on a satellite station for this bird:


We can't hear this thing from North America -- it is flying over the Congo.  But stations in its footprint are putting their receivers online -- you can listen to the 10 GHz downlink via WebSDR: 


Brazil WebSDR:

Sunday, March 17, 2019

DISAPPOINTED! No Takers on Mechanical Filter Question! SAD!

So, in our last podcast I asked the group to take a look at two pictures of a mechanical filter that I had recently taken out of its case.   These pictures appear above and below. After a discussion of magnetostriction,  I asked the group if they could spot anything unusual about this particular device. 

I expected many responses.  What did I get?  CRICKETS!!  What is wrong with you guys?  Are you spending so much time with software and FT-8 and lines of code that you can't deal with a simple analog question like this?  SAD! I guess I will have to answer the question myself.  Scroll down. 

The diagram below presents the conventional Collins arrangement for a mechanical filter.   Note that at the input and at the output there is a coil.  This coil creates from the signal a varying magnetic field.  Because of the principle of magnetostriction, this field causes the resonators/rod assembly to flex and vibrate, much like a musical tuning fork.  At the output, this means that inside the core of the output coil there is a piece of metal vibrating at the signal frequency.  This will produce an output signal.  

But take a look at my little mechanical resonator.  Where are the input and output coils?  
THERE ARE NONE!  See those little rectangular things at either end?  Those are piezo-electric crystals that are MECHANICALLY connected to the disc/rod assembly.  So when the signal comes in, it is applied electrically to the piezo material which then physically vibrates. This vibration passes through the filter and to the piezo device at the other end. There the mechanical vibration results in an electrical signal at the output.  

So, I think it is time for you all to hang your heads in shame. Perhaps go to the doctor to see if you still have The Knack. Ask for forgiveness from the radio gods.  

Wednesday, March 13, 2019

We have lost our spiritual leader: George Dobbs G3RJV, SK

Yesterday we received the very sad news that George Dobbs, G3RJV has died. 

I think it is no exaggeration to say that with George's passing, we have lost our spiritual and  philosophical leader.  The founder of the G-QRP Club and Editor of our beloved SPRAT journal, George took his strong technical skills and his talent for writing and combined it with the wisdom about life that came from his religious vocation. He was a prolific writer and speaker, and in all his work you will find a unique combination of the technical and the philosophical.  Not only did he teach us how to build our own rigs, but he taught us why we should build them.  

We talk a lot about tribal knowledge -- George was definitely the source of much of that.  But he went beyond that and also became a major source of what we can call tribal wisdom.  He was one of our tribal elders. Instead of speaking to the tribe around a roaring fire, George spoke to us through SPRAT, through articles in other ham magazines, through his books, and through his talks at rallies and hamventions, many of which have been preserved in YouTube videos.  George's friend Tony Fishpool sent us the one embedded below. 

We are of course very sad to see George go, but we can all take comfort in the fact that he will -- through his writings and through his recorded talks -- remain with us. For years to come people who feel a strange urge to build their own radio equipment will find themselves reading George's work or listening to recordings of his melodious voice.   They will find there not only the needed technical information, but also the encouragement and tribal wisdom needed to carry on.  There will be a bit of George Dobbs in all their rigs.  In that way G3RJV will stay on the air.  And I know that George would be delighted by that.  

73 G3RJV.     

Friday, March 8, 2019

Viking Rigs Save the Day!

I attribute the success to the Times Sequence Keying.  And, of course, to the analog VFO.  
Thanks again to Jeff Murray. 

Saturday, March 2, 2019

SolderSmoke Podcast #210 Boatanchors, Magnetostriction, VFOs, AM, CW, SSB, Mailbag

2 March 2019 

SolderSmoke Podcast #210 is available:

Alexa, Marie Kondo, berets, and ham radio

Bi-Coastal Boatanchors
BATTLE CRY: The Vintage SSB Preamble! "We are NOT ashamed!" 
Bill's HT37 and Drake 2B 
Pete's National National NCX-3  TRGHS
Mechanical Filters
Why did Collins go with mechanical vice crystal filters? 
The foam deterioration syndrome in mechanical filters.  Sad. 
Please send any unwanted Mechanical Filters to Bill. 
BONUS QUESTION:   Look at the filter below.  What is different/special about this one?

Pete's antenna trouble
Pete's FB amplifier troubleshooting
Recent improvements in the uBITX finals
Pete's design for a VFO for Bill (and an indoor antenna tuner!)

Bill's VFO for Pete:  HRO dial and gearbox driving a rotary encoder

Guido PE1NNZ puts the QCX on SSB
"The Secret Life of Machines -- Radio"
HB HRO dial from DL6WD
WA1QIX's USB D-104
"The High Frequency Oracle" 
DeMaw's LC filter receiver
Godzilla and Ham Radio
Bill's poor quality SSTV images from space (what happened?) 
Listening to AM on an SSB receiver
Mixed feelings about CW 

M0KOV's mom took him to the doctor due to THE KNACK. 
M0JGH getting married (ALWAYS LISTEN TO PETE!) 
Jac's FB Receiver

What is different/special about this one?

Sunday, February 24, 2019

An Update on Jac's Homebrew Receiver

About four years ago we posted a report on the FB homebrew receiver of Jac KA1WI     Here is the original report:

As most of us do, Jac has continued to work on his creation.  He sent me an update:


Basically I have finished it, from a tentatively working model to a more definitive set. For example there are three IF filters, LSB, USB and CW switched by relays grounding the un-used filters.  The AGC was optimized for a good sound. So was the multistage audio circuit, avoiding unnecessary filtering which in my opinion masks the sound of some very good sounding transmissions, not to mention the terrible ones.

The front end works very well, with a SBL-1 DBM terminated with a low noise 2N5109. You notice it when a strong signal is nearly covering the weaker one you are listening to and it remains readable without loosing strength! No many receivers can do that, either because poor front end, noisy LO or bad AGC or all of the three. Not with this receiver!  

The BP filter bank is not my design but removed from a German receiver from the early 1970’s I had to align it to specs and it works pretty well, although I would have preferred  to use a tunable pre-selector. I am planning another set with three IF 9mHz filters which will include a pre-selector for optimum image rejection. I hope. 

In general I am happy with the set, despite the birdies of the DDS, most of them well under the level of most received signals. I wsh I could build a simple PLL to clean up the DSS LO signal. It is worth exploring issue as I see new VCO designs are available. I could try at least one ham band for starters, a PLL covering 350 kHz locked to the DDS,  instead of 2-30 mHz covering, should be feasible. 

Have more videos of the set I will send to you. 

73s de Sac


Note how well you can hear the band's noise floor when the antenna is reconnected in the third video.  

Saturday, February 23, 2019

The Shortwave Radio Audio Archive

Dig out those old tapes and make a contribution to the archive. Lots of good stuff in there.  The Sandinista recording from 1979 was quite something.  Radio Moscow's Mailbag brought back Cold War memories.    Check it out:

Thursday, February 21, 2019

Wednesday, February 20, 2019

Shortwave Radiogram

On 18 Feb 2019 I talked to Kim KD9XB on 40 meter SSB.  Kim -- who is retired from the Voice of America -- told me about a really interesting retirement broadcast project of his. "Shortwave Radiogram" uses a variety of amateur digital modes to transmit what are essentially text and image bulletins.  The really cool part is that Kim uses commercial shortwave broadcast transmitters to get his programs out. He uses transmitters in the U.S. and in Europe.   Listeners around the world tune in via shortwave (sometimes through WEB-SDR receivers) and then use FLDIGI or similar software to read the messages. You can see one of the radiograms being received in the video above.  There are more like it on YouTube.

Kim's site has more information, including his broadcast schedule on his web site: 

All of this reminded me of our old idea about putting the SolderSmoke podcast on a commercial shortwave transmitter.  I have my eye on the Bulgarian station... Stay tuned.  

Thanks Kim! 

Monday, February 18, 2019

RE-RUNS OF VINTAGE SIDEBAND NET -- To fill those lonely hours between SolderSmoke podcasts...

I really enjoy listening to these guys, and I suspect SolderSmoke listeners will too.  Like the SolderSmoke podcast, it is the perfect thing to have playing in the shack while you are working on something.  

Mike N9MS has recorded and placed online many of the net's sessions, some going back to 2015.  FB OM.  We thank you.  Please keep doing this.  

Back issues are available at the site below.  Just put the letter V in the search box and click.  The back issues will then appear. 

My message to the group: 


I have now listened to the mp3 recordings of three of your Saturday morning sessions.  They are really great.  I tried to listen via the airwaves, but I am too far east.  To whoever is recording and posting these sessions:  please keep up the good work!  These recordings allow the FB ham spirit of the net to reach a GLOBAL audience. Please make the older sessions available -- many of us only recently learned of the net and would like to listen to earlier episodes. If server space is a problem, maybe I could help.  Let me know. I don't know if you realize it, but you guys are producing a very cool podcast every Saturday morning.  

My buddy Steve N8NM tried to check in with his S line last weekend but you guys couldn't hear him.  I'm sure he will try to somehow get more fire in the wire.  Please be listening for Steve. 

As for myself, I find myself plotting the use of one of those WEB-SDR sites to check-in.  But I fear the wrath of the brotherhood.  

73  Bill N2CQR

Sunday, February 17, 2019

SSTV from SPAAAAACE! International Space Station Sends Images

The crew on the space station have been transmitting SSTV images.   This morning I threw together a receiving system:  I used my four element refrigerator tubing quad feeding the an RTL-SDR Dongle with HD-SDR software in the computer.  For the SSTV decoding I downloaded a program from Japan: MMSSTV (very nice).  To get the signal from HD-SDRto MMSSTV I just plugged a cheap little electret computer mic into the computer and taped it to the speaker.  

At 0838 local today ISS flew almost directly over me.   I aimed the quad south-west, and almost as soon as it was above the horizon very strong signals started pouring in.  They produced the first picture (above).  

ISS went silent as it passed over head. I swung the quad to the north-east hoping to catch another image as the station moved away.  That is the second image (below). You can see that I was losing the signal about halfway through.  

The distortion in the video image may be the result of me manually adjusting the receiver for Doppler shift. 

Here is a little video of the action in the shack during the first half of the pass. 

Here is the RTL-SDR Dongle Receiver in an Altoids Box: 

Here is that the programs looked like on the screen -- HDSDR on top, MMSS on the bottom:  

Here is what the orbital pass looked like. ISS was East of New Zealand when I took this picture.  ISS came up over the Eastern Pacific and Mexico before passing over N2CQR.  This display comes from the excellent Heavens Above web site:  

Tuesday, February 12, 2019

Listen to our Podcast while wearing a beret!

This is the official headgear of the Color-Burst Liberation Army. 

For a mere 16 dollars, you can wear the kind of beret worn by Pete Juliano, N6QW. 

Here at SolderSmoke, we are all about style, panache, savoirfair,  je ne se qua... 

If you send us a picture of yourself wearing a beret while either operating or building a rig,  you will win FOR FREE a one year subscription to the SolderSmoke on-line podcast.  ACT NOW!  Please tell them that SolderSmoke sent you. 

Saturday, February 9, 2019

Thursday, February 7, 2019

Indie Documentary: Apollo 11

Thanks to Bob Scott for the alert on this.  This new Indie film promises to be even better than the recent "First Man" movie (which was somewhat disappointing, with too much focus on family drama).   Armstrong looks so young in this trailer. 

Sunday, February 3, 2019

The Wizard of Wimbledon M0JGH: "Always Listen to Pete!"

Dear Bill and Pete,

Sincere apologies for my chronic lack of correspondence but life has proven exceedingly eventful of late. As a long-standing member of our international brotherhood I am aware of a reoccurring, often subliminal, theme: “Always listen to Pete!”. What follows is a cautionary tale of one humble ham following the sage advice offered to him during Soldersmoke 186’s Mailbag…

You might recall the report of my Christmas 2015 escapades from rural Italy, making homebrew CW contact with friends operating GB2RN aboard HMS Belfast, whilst trying to fend-off curious locals from tampering with the wire I’d strung through their trees. Throughout these shenanigans my remarkably-understanding girlfriend was nearby minding her own business (albeit with a certain degree of eye-rolling).

The following year we returned to the same summit above Frascati. Before setting off I advised her that, being a generous chap, there were now two miniature radios in my coat pocket: one for each of us to enjoy. She was politely thrilled by the prospect... but still faithfully assisted with antenna rigging. 

Once operational I insisted that we should try her radio first and, following Pete’s advice from SS186, I slipped the tiny red box out of my jacket pocket and knelt down on one knee... (Fear not, Pete, other sage opinions were consulted in the matter first too!).

Remarkably, she said yes! And, exceedingly generously, I was allowed me to make a few contacts too... after all, we had gone to the trouble of lugging it from London and setting up the antenna. Owing to poor telephone reception the first person to learn of our wonderful news was an unsuspecting DL on 40m CW.

We are now happily married so I’m pleased to report that, unsurprisingly, the SolderSmoke tribal knowledge offered to me back in 2016 appears to have been spot on. To return the favour here is my own life lesson to take from the story:

Should one ever need to conceal a surprise gift from a loved one, a radio shack is a cavernous world which even the most curious spouse is unlikely to dare explore.

Furthermore, if one “has previous” (as British policemen say) for smuggling tiny boxes of radio wizardry away on holiday, what better cover could there be for the unsuspected transportation of an engagement ring? 

The power of QRP knows no bounds...

All the very best for 2019 and thanks again for the life-changing advice.


Editor's note:   In case you don't remember SS186, Pete's advice -- upon hearing of the ham radio tolerance of Jonathan's then-girlfriend -- strongly advised him to "marry that woman!" 

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