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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!" 

Saturday, February 2, 2019

Friday, February 1, 2019

UK Wartime Radio -- The Secret Listeners

We had this video on the blog before, but it was seven years ago, so it it time for a re-run.

Thanks to Graham GW8RAK for reminding us of this. 

Listening to it again, I was struck by the claim that the nationality of the operator could be discerned purely by his or her CW sending style.  Is there really an Italian accent in Morse Code? 

Thursday, January 31, 2019

A SolderSmoke Message to the Vintage SSB Net

Inspired by what I heard on the Vintage SSB Net web site, I wrote to the group: 

Esteemed Vintage OTs: 

As the proud owner of an HT-37/Drake 2B station, I immediately identified with the values embraced by your inspiring preamble. It is almost as good as that other preamble that we all hear about from time-to-time.   

On our SolderSmoke podcast, we often discuss the cluelessness of many of the operators of modern appliance "radios" :   

-- How often have we called CQ on a clear frequency on 40 meters, only to be answered by a chorus  of "YOU ARE ON THE WRONG FREQUENCY!"?  (How could that be?  What was WRONG with my frequency?  It took me a while to realize that they think 40 has been channelized and that emissions must be on whole kilohertz frequencies.) 

-- How many times has someone whose "rig" is really a computer complained that your "60 over S9" signal is "too wide" on his waterfall? 

-- How many times have we had to deal with the apparent psychological trauma caused to some hams by an ancient VFO that drifts a little bit? 
"You are drifting ALL OVER THE BAND!"
"How far have I moved?" 
"More than 40 hertz!"  
Oh the humanity! 

Anyway, we really liked your preamble, especially the bit about how "smoke and flames may occur at any time." Words to live by my friends.  

Could we please have a written version of the preamble?  We want to recommend that all SolderSmoke listeners post it on the walls of their radio shacks.  Some of them may want to have it tattooed on their backs (we leave that to them). 

73 and keep warm out there (the boatanchor rigs really help with this). 

Bill  N2CQR

Wednesday, January 30, 2019

Putting the QCX on SSB

Here is a very cool mod to Hans Summers' amazing QCX CW phasing transceiver.  This rig seemed to have been crying out for an SSB mod.  Guido has come up with a very clever way to put this rig on phone. 

Guido PE1NNZ wrote: 
Jan 28   2019

Over Christmas I have been playing around with a simple modification that transforms the QCX into a Class-E driven SSB transceiver. With this setup I have been able to make several SSB contacts and FT8 exchanges across Europe and so far this experiment is working reasonable well. It can be fully-continuous tuned through bands 160m-10m in the LSB/USB-modes with a 2200Hz bandwidth, provides up to 5W PEP SSB output and has a software-based full Break-In VOX for fast RX/TX switching in voice and digital operations.

The SSB transmit-stage is implemented in a completely digital and software-based manner: at the heart the ATMEGA328 is sampling the input-audio and reconstructing a SSB-signal by controlling the SI5351 PLL phase (through tiny frequency changes over 800kbit/s I2C) and controlling the PA Power (through PWM on the key-shaping circuit). In this way a highly power-efficient class-E driven SSB-signal can be realized; a PWM driven class-E design keeps the SSB transceiver simple, tiny, cool, power-efficient and low-cost (ie. no need for power-inefficient and complex linear amplifier with bulky heat-sink as often is seen in SSB transceivers).

An Open Source Arduino sketch is used as the basis for the firmware, a hardware modification bypasses the QCX CW filter and provides a microphone input in-place of the DVM-circuit; the mod is easy to apply and consist of four wires and four component changes and after applying the transceiver remains compatible with the original QCX (CW) firmware.

This experiment is created to try out what can be done with minimal hardware; a simple ATMEGA processor, a QCX and a bit of signal processing to make SSB in an artificial manner. It would be nice to add more features to the sketch, and see if the QCX design can be further simplified e.g. by implementing parts of the receiver stage in software. Feel free to experiment with this modification and let me know your thoughts or contribute here:

73, Guido

Schlitz Beer and Ham Radio

Another necktie in the hamshack. Can anyone identify any of the gear? 

Tuesday, January 29, 2019

The Vintage SSB Net

This group looks like a lot of fun.  I like how they record the entire session and put it on the web.  

You should listen to their "preamble."  It describes the purpose of the net and the group's belief system.  Very well done.  These are our people!  I will request a full transcript of this important and inspirational document. 

Here is a link to a reading of the net preamble:

"Smoke and flame may occur at any time!" 


Monday, January 28, 2019

HT-37/2B QSO with K6ZA (three short videos)

On January 23, 2019 on 20 meters I talked to Barry K6ZA.  He is near San Francisco.  I was running my Hallicrafters HT-37 with my Drake 2B.  I was really pleased to discover that the guy I was talking to loves these two pieces of gear as much as I do.  

Barry said he wished I could record his voice coming out of the HT-37.   My iPhone came to the rescue.  

The Secret Life of Machines -- Radio

We had this on fhe blog three years ago, but it is so good that it deserves a second posting. 
Thanks to our old friend Stephen Walters for reminding us of this gem.  There is so much soul in these old machines. Thanks Stephen. 

Sunday, January 27, 2019

Godzilla, an SP-600, a D-104, and a Turner SSB+2 Transistorized Mic

We were in a restaurant last week and this trailer played on a TV that was all the way across the room.  The SP-600 caught my eye.  I once had one of those, but chickened out when I read about the horrors of black-beauty cap replacement.   There is also a D-104 in the trailer (several of those are with me now).  And the girl is transmitting with a Turner SSB+2 Transistorized mic -- I have one of those also. 

Thomas K4SWL over at The SWLing Post  notes that the SP-600 Tuning Dial appears to have been modified.  I'm thinking the wanted it to look like some sort of transmitter output meter. 

I think I can also see some sort of Collins antenna tuner.   

Any ideas on whose shack this all comes from?   It looks like a real ham shack.  

From the trailer, it appears that the ham gear somehow helped us establish contact with Godzilla, who then went on to save the planet.  I hope.  ONCE AGAIN, HAM RADIO SAVES THE DAY! 

The ham radio stuff is in the first minute or so of the trailer. 

Saturday, January 26, 2019

Rescued at Sea! Saved by an S-38!

Just click on the ad to enlarge it. 

Another cartoon relayed via the Facebook page of Jeff Murray K1NSS.   

Sure, there was a rescue at sea, but what about all the casualties caused by the AC/DC "widow-maker" S-38 power supply? 

Friday, January 25, 2019

When Hams Wore Neckties, and AM Transmitters Were in the Living Room

Jeff Murray K1NSS had this on his Facebook page.  Great stuff.  But I felt like yelling out, "Stay in the basement OM!  Stick with your haywire rig!" 

Monday, January 21, 2019

A Homebrew HRO Dial by DL6WD, Homebrew Hero

Take a look at that beautiful rig in the bottom of the cover pictures. (A closer shot appears below.)  That is an HRO dial, right?  Or is it?  

No, it is not.  In the picture we see the homebrew receiver designed and built during the 1960s by Rudolf Fishcer, DL6WD.  It is magnificent in every respect.  Because I have been working with the HRO dial and gearbox given to me by Armand WA1UQO, the tuning dial on this receiver caught my attention. 

Here is what DL6WD says about this part of his project:  "The main tuning gear was built around a BC-221 tuning capacitor and reduction gear. The counter dial and tuning knob are the result of four weeks of labor, The counter dial reads in tens of kHz, where the main tuning knob has a calibration of 200 Hz per division, from an HRO inspiration."  The counter is in the little window to the upper left of the tuning knob. The window to the upper right is a phase-lock indicator. (See below.)

By the way, by the time DL6WD got finished with this all solid state receiver it weighed in at 52 pounds.  Rudolf noted that "excessive shielding pays in electrical performance, but not in weight!" 

DL6WD earns the title "Homebrew Hero."

Saturday, January 19, 2019

Switching to a Mechanical Filter from 1967 for my HRO-ish Receiver (with video)

From RSGB Handbook 1982

Having overcome the difficulties with the National NPW Dial and Gearbox, I turned my attention to the 455 kHz filter.  I had been using this old Toyo CM - 455 kc filter (Date stamped August 1969).  CM stands for "Crystal-Mechanical."  These filters are hybrid with some of the features of a crystal filter and some of the features of a mechanical filter. For more details go here:

I was disappointed by the CM filter.  It seemed very lossey, and it just didn't seem to be of sufficiently high Q -- it seemed very broad. I could hear the other side of zero beat.  It was barely a "single signal" receiver,  and being "single signal" is the whole point of a superhet. 

I remembered that Pete Juliano had sent me a Japanese-made 455 kc mechanical filter. Maybe this would do better.  Last night I did a quick comparison test and -- wow -- Pete's filter was much better.  The Fifth Edition of the RSGB Handbook seems to agree with my assessment, noting that mechanical resonator filters were superior to the Crystal Mechanical hybrids (see pages 4.17 and 4.18) 

Pete's filter is from the Kokusai Electric Company.   Part# MF 455 ZL.  (Date stamped May 1967). "ZL"indicates lower sideband.   I checked and indeed the passband goes from just above 452 kc up to about 454.5 kc.  This is a 40 meter receiver and SSB on 40 is LSB, so this filter would work perfectly right?  Not so fast!  Sideband inversion had to be considered.  

I was running my VFO from about 7455 to 7755 kHz.  This means that the modulated incoming signal would be SUBTRACTED FROM the VFO signal to get to  the 455 kHZ IF.  And when that knd of subtraction happens, we have sideband inversion.  The LSB signal will look like a USB signal when it reaches the filter. 

My BFO was running right at 455 kHz, using a ceramic resonator at that frequency. I briefly considered just shifting it down to 452 kHz, but this proved to be difficult.  Then I got a better idea. 

I could just shift the VFO down to 6545 to 6845 kHz.  This would mean that the VFO frequency would be subtracted from the incoming modulated frequency.  There would be no sideband inversion.  I had been thinking about doing this frequency shift anyway, thinking that VFO stability gets better as you go lower in frequency. 

REMEMBER THE RULE:  If you are subtracting the modulated (signal) frequency from the frequency of the local oscillator or VFO, only then will you have sideband inversion.  See:

Moving the VFO was easy. I am using a variable capacitor with several variable caps on the same rotor.  I just moved from the smallest variable cap to the middle variable cap -- this added capacitance to the system and lowered the frequency.   I also added three additional turns on the coil.  This put me very close to where I needed the frequency to be.  I added one additional 9 pf cap and this put the VFO freq right where I wanted it. 

I was really  glad to include Pete's filter in this receiver.   The mechanical resonator technology fits very well with the very mechanical old-tech theme of this project (it already had a gearbox -- a mechanical filter seemed to fit right in).   It is a fascinating device -- it is almost like having a set of tuning forks all tuned to 455 kc (see above for the RSGB description of how it works).    And having it from from Pete adds a TREMENDOUS amount of mojo, juju, and soul to the new machine. 

Icing on the cake: As I type this, I am listening to Fred K3ZO converse in Spanish with hams all through South America.  Fred preceded me by three decades at the U.S. Embassy in Santo Domingo, but when I got there the local hams were still talking about him  -- he was much loved and admired by the Dominican hams.  TRGHS. See Fred's story here (scroll down a bit): 

Designer: Douglas Bowman | Dimodifikasi oleh Abdul Munir Original Posting Rounders 3 Column