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Sunday, April 11, 2021

RIP Isamu Akasaki -- Shared Nobel Prize for LED -- Analog Guy

From the obituary in the Washington Post: 

In addition to the Nobel Prize, Dr. Akasaki’s honors included a 2009 Kyoto Prize — Japan’s highest honor — recognizing developments in advanced technology. He found that some technology, however, needed no advancing at all. He took great pleasure, for example, in long-playing classical music records.

On that point, he joked, “I am analog.”

Thursday, April 8, 2021

N6QW On 40 Meters with a Civil Air Patrol Dentron Scout -- WYKSYCDS


Pete is in the air with his Dentron Scout.   Check it out: 

WYKSYCDS = When You Know Stuff You Can Do Stuff.  Pete proves it.  

Wednesday, April 7, 2021

"The Perfect Trap for the Engineering Mind" -- Leo Fernekes' Stirling Engine

I did a post about Leo back in August: 

Although it is not about radio, homebrewers will find much to resonate with in Leo's Stirling engine project.  

Warning:  There is a Part II.  And there may be more.  Proceed at your own risk. 

Sunday, April 4, 2021

A Satellite Ground Station (Receiver) Made from Junk

Very cool.  This guy (who brew up on an island in Alaska) really knows how to use aluminum tape and the junk that fills most workshops. I like his use of the security camera mount as an az-el antenna rotator. 

I foolishly discarded a Direct TV dish.  I could have been receiving GOES images by now! 

Just last week I got the same RTL-SDR.com V3 dongle that he is using.  Very FB.   It does HF direct sampling with no hardware mods and no upconverter. 

More from the builder, Gabe Emerson (KL1FI): 

Saturday, April 3, 2021

A VERY Successful April Fools' Day

I was worried.  It was early on the morning of April 1, 2021, and I had NOTHING. Maybe this  was because so much unbelievable stuff has recently happened in the world.  Or maybe it is because technology has been moving so fast that today's April Fools' joke is tomorrow's new device. Whatever the reason, for the first time in about 15 years, I had noting.  April Fools' Day has long been part of ham radio's culture and I was worried that I would not be making a contribution this year. 

Then something caught my eye.  Did you know that on Thursday they decided to change the rules of chess!  Yes indeed!  NO MORE DRAWS!   Fantastic!    This provided the inspiration for our announcement of the brutal FCC rule-making action regarding the banning of "legacy equipment."  

I knew that that headline would attract a lot of attention. And let me inform you that, according to the official rules of April Fools' Day,  if that headline did pull you in,  well that constitutes a "gotcha."  So far 1,758 people are in this category.  I thank you all.   

The comments attached to the announcement were really heart warming, even those that included profanity directed at my persona.  People recalled earlier April 1 events, like the time Pete was defenestrated from the QRP Hall of Fame.  Good times, my friends, good times!   

This was an especially happy April 1 for me, because I also launched two other highly successful operations: 

-- I teach a Zoom class.  On Thursday morning I told the students about new concerns regarding  the light hitting their eyes from the computer screens.  We were all being issued dark glasses and would henceforth have to Zoom with shades on (see above).  The students -- bless their hearts -- all agreed to do this.  

-- We are closely associated with a small company that has the word "native" in the corporate name.  As in "Native Vegetation."  Shockingly, last Thursday we got an e-mail from the Virginia Small Business Commission DEMANDING that we change the name of the company.  It seems that ANY use of the word "native" was now deemed unacceptable.  The people in this company (ALL OF THEM!) were really outraged by this.  I had to pull the plug before any legal actions were initiated!  

So, to all of you, Happy April Fools' Day!     

Thursday, April 1, 2021

FCC to Ban "Legacy" Equipment and Circuitry

From the FCC Newsline: 

Out with the old

In a long-expected policy move, the Federal Communications Commission today announced that starting on April 2, 2022,  all equipment in use by the amateur radio service must comply with strict emission purity standards.  The Commission's rule-making focuses on the bandwidth of high frequency transceivers.   Starting one year from tomorrow,  amateur equipment will be limited to a bandwidth of 3500 cycles per second.   Emissions outside the bandwidth limits must be at least 100 db below the average power in the bandpass.  In effect, this means that amateur equipment must make use of the kind of "brick wall"  filtering only available from software defined equipment.   Bringing the service into conformity with commercial practices, all high frequency equipment will be on Upper Sideband.  

"No more skirts" 

An FCC official -- who requested anonymity because of "threats"  -- told Newsline that part of the motivation behind today's announcement was a desire to end the unseemly discussion of the filter "skirts" of "legacy" ham radio gear:  "Obviously there were concerns about the pejorative way many hams were referring to 'the skirts.'  This is the 21st century!  It was time to be more inclusive!" 

Audio Tinkering to Continue

The FCC official told Newsline that the Commission is not in any way attempting to discourage hams from tinkering with the "audio quality" of their commercial SDR equipment: "As long as they keep the bandwidth to 3500 Hz, they can tinker and adjust to their hearts' content," said the official.  He went on to use some of the colorful language recently heard on the ham bands: "If they want to include very low audio frequencies -- what some call 'the thunder down under' they can do that.  Or if they want to emphasize the high frequencies -- for that "Krispy Kreme" sound -- they can do that too.   All they have to do is learn how to set  the menus on their equipment. We understand that the manufacturers will soon be making available software packages that will -- with just a simple download -- set the menus according to the desires of the consumer. Uh,  I mean of the radio amateur." 

The FCC official said he thinks the ruling will actually encourage and facilitate audio tweaking. "We know this is important to modern hams.  It makes them feel connected to the days when hams actually built their own equipment.  We have noticed the development of an amazingly rich  technical vocabulary, terms like 'presence'  "muddy'  'bright'  and 'punchy' are now in common use.  Clearly the Commission would not want to stand in the way of this kind of technical advancement!"

Sinking the Boatanchors

The FCC acknowledged that this ruling spells the end for on-the-air use of  older ham equipment. "Clearly none of that old junk will meet the new requirements.  I mean these guys were literally using hunks of rock to filter their sidebands.  It was practically medieval!  Time to wake up, smell the decaffeinated coffee, and get with the SDR program OM!" 

Fears of violent push-back

The FCC official did acknowledge that there are fears of possible violent push-back from certain "sub-cultures" in the ham radio world.  "Working closely with our partners in Homeland Security, we have looked closely at the possibility of violent pushback.  Of particular concern are groups that appear to be fiercely loyal to what they sometimes defiantly refer to as 'Hardware Defined Radio.'   There are some truly frightening groups out there.  One group is called the CBLA -- The Color Burst Liberation Army.   They seem especially fond of quartz crystals and are radically opposed to the new SDR requirements.  Also of concern are groups that continue to insist on using Double Sideband Unsuppressed Phone generated by equipment using vacuum tube.  Vacuum tubes! They call them 'thermatrons.'  Again this is really medieval."  The spokesman said that the FBI is monitoring these groups, but is not very concerned because of the physical condition of many of the fanatics.  "Most of these guys rarely leave their homes.  In fact, for the last year many of them seem to have been repeating a strange "Stay in the Shack" mantra.  Many still smoke, never exercise, and now refuse to take the vaccine.  So we are not too worried, " said the FBI spokesman. 

Support from Industry and the Major Ham Organization

FCC officials tell Newsline that the major equipment manufacturers -- along with the principal ham radio organization -- were very supportive of this move, seeing it as a major opportunity to "stimulate" both sales and advertising revenue. 

Wednesday, March 31, 2021

Mending vs. Ending -- The Fight Against Planned Obsolescence

We don't get a lot of mail from Darwin, Australia, so the message coming in from Phil VK8MC immediately got our attention.  When I looked into the details I realized that it was very SolderSmoke-relevant.  The Guardian article that Phil cited even mentions hobbyists tinkering with electronic devices in their sheds (that would be us!).    Phil points to the connection between our repair efforts and the struggle to save the planet: "It's not just a hobby, it's an ethical position which contributes to the well being of the planet. A higher calling indeed!" 

Here is the article Phil pointed us to:


The poster above (which hangs above my workbench) is from https://www.ifixit.com/Manifesto

Monday, March 29, 2021

"Analog Man in a Digital World" by OM Joe Walsh (music video)

After seeing my last post about SDR, the dongle, the Android tablet, and the Bluetooth mouse, Bob Keller grew concerned about my, uh, stability.  Here is our e-mail exchange. 


Have you had a comprehensive medical evaluation recently? All this digital activity from an erstwhile analog man is a concerning symptom. <g>

I suggest listening to the following number at least once each day until you have the chance to get checked out:

-- 73 de KY3R, 
    Bob Keller


I know.  It really is quite disturbing.  I've been getting a lot of "welcome to the dark side" messages!!!  

I am now trying to get back in the good graces of The Radio Gods.   Today I fired up the Fish Soup 10 and made two CW SKCC contacts on 40 meters.  I feel better already.  

Thanks for the song from OM Walsh.  I had heard it before but it is more meaningful to me now.  I will put it on the blog.  Others may need help too.  

Thanks for caring Bob.  



Tuesday, March 23, 2021

Double Sideband Transmitter using Vacuum Tubes -- From Sweden

Tommy SA2CLC has built a really nice DSB transmitter using Thermatrons.  
FB Tommy.  

Monday, March 22, 2021

My Hodgepodged Morse: Audio Tone into the Mic Jack Creates J2A not A1A. BASTA!

In SolderSmoke podcast #229 Pete and I were discussing my rather flaky effort to turn the Hodgepodge BITX40 Module into a CW rig by injecting keyed 700 Hz audio into the mic jack (see video below). We got some very helpful responses from ND6T and VK2EMU:  

Hi Bill,

You mentioned generating CW by modulating SSB: Collins did that in their
first SSB transceivers, I believe, as did SGC, but the results were less
than optimal. The problem is that you are involving the audio chain and
modulator. You know from experience how difficult it is to maintain low
intermod there and the tone is no exception. So we end up with lots of
spurs within the filter passband and then also have the opposite
sideband suppression less than perfect. If you check your transmitted
signal with a spectrum analyzer or SDR you can easily see the nasties.
Listening to a CW signal thus generated makes it obvious unless it is
buried way down in the noise. It IS a valid CW signal (not MCW) since it
is (almost) a single signal. However, in actual operation it doesn't
work very well.

I know because I have done that. I bought one of Farhan's original
BITX40 boards and wanted to put it on CW. I ended up injecting a keyed
signal from one of the spare clocks on the Si5351 into the RF amplifier
chain (thus avoiding the above stated problems) but still had garbage
from the audio and IF stages. I fixed that by shorting out that signal
during transmit by a transistor to ground. That was documented on your
BITXhacks website: http://bitxhacks.blogspot.com/2017/02/ and on my
website: http://www.nd6t.com/bitx/CW.htm . It has been a while, eh?


Don, ND6T


Hi Bill and Pete,

With putting an audio oscillator into you hodgepodge radio, your transmission is not the same as a standard CW rig.

If we have a transmitter as described in the ARRL handbooks from the 1940's or 1950's, (or even the Michigan Mighty Mite) it is a crystal oscillator and maybe a PA tube. By keying either the oscillator and/or the final PA on and off, then we can send Morse code as ICW Interrupted Continues Wave. If we check the list of emission designators, we have A1A.

However, if we feed a tone into a SSB transmitter, then we have J2A.

At the other end it may sound the same, but because it is created in a different way, it has a different designation. 

A quick look at Part 97 shows that J2A and J2B are classed as CW, so you are in the clear. However, if you put a tone oscillator into an AM signal to send CW, then that would be classed as A2A and not classed as CW, but as MCW. MCW can be used on 6 meters and above, but not HF.


73 de Peter VK2EMU


So I say BASTA with the J2A!  If I want to go CW, it's all A1A for me.  I dusted off my Fish Soup 10 and am now back on 40 CW with 200 mW.... A1A all the way! 


Saturday, March 20, 2021

SolderSmoke Podcast #229 -- G2NJ Trophy, SDR, HDR, CW! Mailbag

Soldersmoke Podcast #229 is available: 


--  G2NJ Trophy is awarded to Pete Juliano, N6QW. 

 -- Get your vaccine shot as soon as you can!  

-- More from "Conquering the Electron" by Derek Cheung. 

-- Bad fire in the chip factory.  Such a shame.  Sad!  I had NOTHING to do with it.  I was home that day.  I can prove it.

 -- Bezos is not such a bad guy.  Turns out he is a space-geek.  

 -- Perseverance was the big space news.  Very cool.  


Pete's bench:

Raspberry Pi vs. Microcontrollers

Treedix display

Conversion of the Dentron Scout

CW rigs?

6L6 on a wooden chassis




--  Our Patreon sponsors get an early look at our YouTube content.  So please, consider

becoming a Patreon sponsor.

--  Please continue to use the Amazon search engine on the blog page (upper right).   

Bill's bench: 


-- BITX40 Module.  

-- Ramseykit Amp. 

-- San Jian counter,  

-- CW using 750 Hz oscillator. 

-- RF-actuated piezo buzzer.  

-- SDR!  SDR using PC and tablet.  

-- Checking the output with SDR.  

-- Moving the carrier osc frequency.  

 Also, I put the Fish Soup 10 back on the air.  Nice contacts under 200 mw.

Up next:  A rig for 80/75 and 20 meters.  Single Conversion.  Using VFO from a Yaesu FT101 that runs 8.7 – 9.2 Mhz.   Quiz question:  What IF should I use?


Mark Zelesky sent me wood tokens with power and Ohm's law formulae.  Thanks!

Scott WA9WFA Built a really nice Mate for Mighty Midget RX – getting it going!

Tryg EI7CLB found board of his George Dobbs Ladybird RX.  Rebuild it OM!

Tom WX2J – We talked about “No lids, no kids, no space cadets” nastiness.

Nick M0NTV about sideband inversion.  I like the simple rule about subtraction.

Jonathan M0JGH – Always listen to Pete.  Got married, has mixing product. Leo?

Mike AE0IH.  Dad used a BC-348 in the service. Looking for one.  FB.

Adam N0ZIB – “Silent Shep” site --- with some ham radio shows I had not seen.

Walter KA4KXX in Orlando has a similar subtraction problem with San Jian counter.

Bill N5ALO sent me a really nice KLH speaker.   I’m using it now.

Jason N2NLY – interested in building SSB transceiver.  One step at a time OM…

Trevor in Annapolis sent xcsd cartoon that really hit home. 

Farhan is doing OK in India, diligently protecting his family from the virus.  

Peter VK2EMU also doing well.

Dave AA7EE Casually killed a DC receiver in Hollywood, and disposed of the remains. 

Charlie ZL2CTM doing great things with simple SSB.  Blogpost.

Phil VK8MC in Darwin sends article on "Mend not End" battle against planned obsolescence.

Bob KY3R re my SDR adventures, asked if I’ve had a recent medical/psychiatric evaluation. 

Friday, March 19, 2021

Hodgepodge: Tablet SDR with a Bluetooth Mouse (video)

I continue to find things in the shack that I can connect to the Hodgepodge.  Here it's an old Android tablet with a Bluetooth mouse.   

The waterfall is pretty, but this addition just shows why SDR is really TOO easy.  The modified RTL-SDR dongle is doing direct sampling, so there is not even any phasing circuitry to tinker with.  All the filtering and sideband selection is happening in software inside the 40 buck Android tablet.  The results look nice, but I don't find it very satisfying -- all I did was connect some cables.  So it's back to HDR for me. 

Tuesday, March 16, 2021

A REALLY Cheap Receiving Rig

Wow, lots of ingenuity in this 1921 receiver.

-- Has anyone actually made a diode out of a light bulb in the way described? 

-- The antenna coupler on the table leg is not much different from the tuner that I have attached to the wall of my car port. 

-- Note that when our hero finishes the receiver, he is able to pick up signals from Mars!  FB OM. 

Who will be the first to recreate this 1921 receiver? 

Monday, March 15, 2021

Aladdin's Lamp == The Vacuum Tube (aka The Thermatron) (Video)

After our posting of the video about 1957 transistor production, our friend Peter O'Connell VK2EMU asked for some equal time for vacuum tubes.  He sent me this 1940 Western Electric video.  It is quite interesting. 

-- I like the Aladdin's lamp metaphor.  When I was out in the Azores I thought of my homebrew 17 meter DSB rig as my "magic carpet." 

-- Lowell Thomas was brought in to narrate.  His voice sounds a lot more natural than that used to narrate the transistor film. 

-- To explain the effectiveness of transcontinental telephony with vacuum tube repeaters, they compared the system that of a relay of "hog callers" claiming that it would take 100,000 hog callers to carry a signal from New York to San Francisco.  So perhaps this could be a rival to db?   100,000 hc? 

-- Arlington to Paris 1915 caught my eye -- Arlington Va. is right down the road. 

-- The film of Edison in his lab was good to see.  And note the importance of his lab notebooks. 

-- The explanation of thermionic emission was quite good.  But of course too much credit was given to Lee DeForest. 

-- The breathless description of the amazing uses of tube technology was for me a reminder of how recent this technology is.  My father started as New York City cop in the 1950s.  He always referred to his police car as a "radio car." 

Hey, are any radio amateurs out there using one of those big water-cooled tubes?  If not, why not? 

Sunday, March 14, 2021

A Homebrewer


That is Homer Price, the lead character in two books by Robert McCloskey, published in 1943 and 1951.  The thing in the valise is Homer's pet skunk.  Of course. 

More info here: 

Homer is clearly a fellow we need to know more about.  I have ordered the book. 

Saturday, March 13, 2021

Making Transistors in 1957

Thanks to Thomas K4SWL for alerting us to this video -- he had it on his excellent SWLing Post blog

Many things crossed my mind as I watched this video: 

-- Pocket protectors!  Pete recently noted that this was a common fashion accessory among electronic techs and engineers back in the day. 

-- HP test gear. 

-- "Extreme cleanliness" that doesn't seem quite so clean.  

-- 550 transistors per hour.  Now we have upwards of 50 billion on a single chip. 

-- The Germanium salami that Pete mentioned in our last podcast. 

-- Hints of Silicon's impending replacement of Germanium. 

-- A transistor factory in Spring City, Pa. that "hums with excitement" (seemed kind of sleepy). 

-- The 1957 assumption that Philco transistors would be in the first orbiting satellite.  Then came Sputnik.

-- The transistor that moves like a "Gulliver through Lilliputian lands."  

-- Our voices or accents seem to have changed, at least the voice used in products like this.  No one talks that way today. 

-- As I watched, I tried to remember if Pete's CK722 was made by these folks.   But no, that was a Raytheon product.   Here is a nice short description of the early days of the CK722:   https://en.wikipedia.org/wiki/CK722   We need to learn more about the hobbyist Carl Todd.

Friday, March 12, 2021

The Secret Life of LEDs -- A new Tim Hunkins Video

Thanks to Tony G4WIF for alerting us to this really nice video from the fellow who made all those great "Secret Life of Machines" videos.   This video on LED's makes me want to improve the lighting in my work shop.  And I think I need some more high wattage resistors.   I'm really glad Tim Hunkins is making more videos.  His look at the Secret Life of  Radio was a real masterpiece. 

Thursday, March 11, 2021

Hodgepodge: Moving the Carrier Oscillator Frequency (and a Flashback to 2002) (Video)

As explained in the video, in the course of using my RTL-SDR dongle I noticed that the signal being put out by my Hodgepodge rig had some problems.  There was poor opposite sideband rejection, and in terms of audio quality I has putting out too many lows and too few highs.  I figured the problem was the result of the carrier oscillator frequency being a bit too low, a bit too close to the flat portion of the crystal filter passband.   I needed to move that carrier oscillator frequency up a bit. 

BITX40 Module BFO 

In the actual BITX40 Modules, L5 was replaced by just a jumper wire, and the C103 trimmer was not on the board.  Farhan and his team instead selected X5 crystals to match the passband of the 12 MHz crystal filter. Mine was originally at 11.998653 MHz.  But I wanted to tweak mine a bit -- I wanted to move it up about 500 Hz.  Reducing the capacitance would move the frequency up. Putting capacitance in series with C102 would have the effect of reducing the capacitance in the circuit.  I just removed the jumper wire and used the holes for L5.  First I put in a single 30pf capacitor.  This dropped the capacitance between X5 and ground to 18 pf.  That resulted in too large a shift.  So I added another 30 pf cap in parallel with the first one.  This resulted in a total capacitance from X5 to ground of 26 pf.  This was about right -- the carrier oscillator/BFO frequency was now 11.9991 Mhz.  I had moved the carrier oscillator frequency up by 447 Hz -- just about what I was hoping for.  

This was a very satisfying fix.  it was a chance to put to use experience with other SSB rigs, to make use of the RTL-SDR dongle as a diagnostic tool, and to tinker with the BITX40 Module in the way that Farhan had intended for it to be tinkered with.  

I'd done this kind of adjustment before, but without the benefit of an SDR display.  Below is the story of one such adjustment. 


A Flashback to 2001-2002
(From my book "SolderSmoke -- Global Adventures in Wireless Electronics")

Now it was time for some debugging and fine tuning.  I needed to make sure that the frequency of the carrier oscillator was in the right spot relative to the passband of the crystal filter.  If it was set too high, the filter would be chopping off high notes in my voice that were needed for communications clarity, and it would allow too much of what remained of the carrier (residuals from the balance modulator) through. If it was set too low, the voice signal transmitted would be lacking needed base notes.  I didn’t have the test gear needed to perform this adjustment properly, but my friend Rolf, SM4FQW, up in Sweden came to my aid.

One night, during a conversation with Rolf, I explained my problem and he offered to help me make the adjustments… by ear.  Performing an electronic version of open-heart surgery, with power on and Rolf on frequency, I opened the case of the new transmitter.  The carrier oscillator has a small capacitor that allows the frequency of the crystal to be moved slightly.  With Rolf listening carefully, I would take my screwdriver and give that little capacitor a quarter turn to the right.  “Better or worse?” I would ask. 

I think this little adjustment session captures much of the allure of ham radio.  There I was, out in the North Atlantic, late at night hunched over a transmitter that had been forged from old Swans and Heathkits, from cell phone chips, and from bits of design from distant members of the fraternity of solder smoke.  Pericles, the source of many of the key parts, was gone.  So was Frank Lee, the amateur whose SPRAT article had inspired the project.  But Rolf and I carried on with the core tradition of the radio fraternity: hams help their fellow hams overcome technical difficulties.  

Tuesday, March 9, 2021

Straight Key Night 2021 at SA2CLC in Sweden

Wow, check out the FB gear of Tommy SA2CLC in Sweden, in use on Straight Key Night 2021. There is some German WWII gear,  a BC-348,  a homebrew transmitter, and some FB QRP kits. 

More on Tommy SA2CLC here: https://www.qrz.com/db/SA2CLC 
The culvert under the road for coax to the antennas is very cool. 

FB Tommy!  A belated HNY to you OM. 

Taking Care of an Old Analog Machine -- The Scanimate

Of course, I understand and sympathize completely.  

Thanks for Rogier PA1ZZ for sending this.  

Monday, March 8, 2021

AA7EE Casually Kills a Direct Conversion Receiver, then Coldly Discards a Diode Ring Mixer

I was really glad to see that Dave AA7EE has -- after a long absence -- posted another article on his blog.   The article has some great personal reminiscences about his involvement with direct conversion receivers.  Here is one passage: 

I spent many happy hours tuning around and listening on 80M with the DSB80. It was this first experience that cemented my affinity for direct conversion receivers built with commercially available diode ring mixer packages. It just seemed so simple – you squirt RF into one port, a VFO into the other, and (after passing the result through a diplexer) amplify the heck out of the result. The seeming simplicity of the process of converting RF directly to baseband audio has held great appeal for me ever since. Unfortunately, that project didn’t survive. One day, in later adulthood, in my apartment in Hollywood, I reversed the polarity of the 12V DC supply and, discouraged at it’s subsequent refusal to work, tossed the whole thing away. Now, I cannot quite believe that I did that, but it was during a long period of inactivity on the ham bands, and complete lack of interest. If only I could go back, and not have thrown it into the dumpster of my apartment building! Hollywood is ridden with recent notable history. My little double sideband transceiver met it’s unfortunate end just 100 feet from the spot where Bobby Fuller, of The Bobby Fuller Four, was found dead in his car, in 1966, the subject of a still unsolved mystery to this day. The death of my little DSB rig was a lot less mysterious. To think that I heartlessly tossed an SBL-1 mixer into a dumpster, is a mark of how far I had strayed from my homebrewing roots, forged in a little village in England. Now, a few years later, in a city known for it’s sin and excess, I had cruelly ended the life of a stout and honest diode ring mixer. I suppose I should spare a thought for the polyvaricon but, well, you know – it was a polyvaricon!


Sunday, March 7, 2021

EXORCISM! 40 Meter RFI Problem Resolved


David W. suggested I use my RTL-SDR dongle to look for the source of the 40 meter RFI that I have been mentioning.  (It appears as an ugly stipe in the waterfall of my Hodgepodge transceiver.) So I fired up the RTL-SDR -- there were the tell-tale spikes, spaced neatly every 50 kHz.  The ARRL Handbook says this is typical of a switched power supply.  Before I started patrolling the neighborhood with a tin-foil hat and a portable receiver, I decided to check my own house for any recently installed electronic devices.  It didn't take long -- when I unplugged the new (mid-pandemic) treadmill the spikes disappeared.  This treadmill was located about ten feet above my rigs, and between the rigs and the antenna.  Duh.  I should have thought of this earlier. Mystery solved.  Thanks David. 


Saturday, March 6, 2021

ZL2CTM's Simple SSB Transceiver

Congratulations to Charlie Morris ZL2CTM for his first contact with his Simple SSB rig.  

There are so many cool things in Charlie's video, starting with his mention of having been woken up early (2 am)  by the very strong earthquake off New Zealand.   Exhibiting true homebrew spirit, Charlie apparently went straight for the shack and worked on his rig.  FB OM. 

Al fresco!  I love the spacious layout on the board and the obvious division into stages.  And I like the wooden board that holds it all together. 

I like the idea of two bandpass filters -- this is simpler than switching one from transmit to receiver.  

Hooray!  Homebrew diode ring mixers!   Yes! 

I think Charlie follows the UK convention with his T/R switch -- they have up as off.  I may be wrong but I think most US homebrewers have up as on, and up as transmit.  Cultural differences. 

Notice Charlie touch-testing the heatsink during that first QSO.  We all do that. 

I like the 24 volts on the IRF-510 drain.  Allison always said that IRF-510s run better at 24V than they do at 12V. 

Of course I disagree a bit on the issue of analog VFOs. But this is just a matter of personal circuit preference. 

Charlie's calculations and notes are really wonderful.  His candid discussion of impedance matching is especially useful.    I think his use of loose-leaf  sheets of paper is wise and it paves the way for a useful folder for each HB rig. 

Here is the introductory video for Charlie's Simple SSB project: 

Here is Charlie's 10 part video series on his simple SSB rig: 

And here is Charlie's YouTube channel: 

Thanks Charlie! 

Friday, March 5, 2021

Over the Waterfall into the Dark Side: Hodgepodge SDR

This one's for Pete. My effort to add features and modes to my Hodgepodge transceiver took a dramatic turn when I connected the rig to my computer via an RTL-SDR dongle. Woohoo! A Hodgepodge waterfall! Check it out.
The dongle was modified for direct sampling at HF. In the box with the dongle I have one amplifier stage, consisting of a 40673 dual gate MOSFET and one parallel tuned circuit, now tuned to the Hodgepodge IF of 11.998 MHz. I tap the the Hodgepodge's BITX40Module at the output of the first mixer, just before the crystal filter. This was a lot of fun. I can even check my own signal on transmit! This is like having the best of both worlds.

Thursday, March 4, 2021

"The Secret Life of..." Tribal Knowledge!

It is great to hear that Tim Hunkins is producing this new series.  It looks like it will be largely about "know-how" -- about what we'd call "tribal knowledge." 

Wednesday, March 3, 2021

The SolderSmoke Team Talks to the River City Amateur Radio Communication Society (Video)

Pete and I had a great time speaking to this really nice California ham radio club (video of the event appears above).  Special thanks to club president Dr. Carol Milano, MD.  Wow, what an impressive person and ham radio operator she is:  https://www.qsl.net/kp4md/#New%20York

This club is doing a group build of a version of the famed Tuna Tin Two.    I mentioned that I had held the original TTT in my hands, and that Rex Harper had conducted a "Mojo Transfer Ceremony" that imparted TTT Mojo to my BITX17 transceiver (which was also discussed).  I promised to share the video of that momentous event.  Here it is: https://youtu.be/9RZRaFUtTcc

Thanks to Carol and the members of the RCARCS.  This was a lot of fun.  

Monday, March 1, 2021

A Frequency Counter for the Hodgepodge -- An Analog Solution to a Digital Problem

Imagine my dismay when I discovered that I could not use my $5 San Jian PLJ6-LED frequency counter with my Hodgepodge transceiver.    The problem is described here: 

This video describes my solution.  I took some pleasure in using an analog solution to solve a very digital problem.   I know this could have been fixed with one or two changes to lines of code, but I liked doing it this way.  This was all kind of fun, and it allowed me to use yet another bit of circuitry that was sitting idle in the shack.  That is the whole point of the Hodgepodge project.  

The best is yet to come.   Especially for those of you who like waterfalls.... Stay tuned. 

Novice Rig Roundup -- This Year in Memory of Bry AF4K


Bry was a good guy and one of our sponsors.  RIP OM.  And the Novice Rig Roundup was his thing. 

Sunday, February 28, 2021

Putting the Quarantine Hodgepodge Rig on CW (Video)

Putting this rig on CW posed a real Hodgepodge challenge: What did I have laying around that would let me do this? Then I remembered: Years ago I built a little 750 Hz audio tone generator. So I pressed that into service. I also needed a sidetone so I built a little RF-actuated circuit that turns on a piezo buzzer when I go key down. And I put a little DC monitoring device (recommended early in 2020 by the Ham Radio Workbench podcast) between the power supply and the rig. There is more to do! Stay tuned.

Saturday, February 27, 2021

Jean Shepherd Goes to a Hamfest -- And Much More

Here is something nice to listen to in your shack...  

I hadn't heard this one before.  It is about Shep's teenage trip to a hamfest, but it also about his youthful enthusiasm for ham radio and electronics.  Many of us can identify with this very easily. 

He talks about what must have been a very early use of "blue boxes" -- the audio tone generators that allowed young miscreants (including the Woz) to make long distance phone calls for free. I wish I had gotten into this.  It sounds like fun. 

He talks about how painful it was to be on phone (AM phone) with just 2.5 watts homebrew, when everyone else was running a lot more power. 

And wow, they played a baseball game at the hamfest.   Phone guys vs. CW guys. 

I won't spoil it by telling you the results of the hamfest raffle.  

Update from the Wizard of Wimbledon -- "Always listen to Pete"

In a recent podcast, Pete mentioned that Leo Sampson (the young Brit who is rebuilding the sailing yacht "Tally Ho") should seal the deal with his girlfriend.   Well, it seems that "life coach" should be added to Pete's already impressive list of abilities (homebrew hero, pasta chef, guitar player, etc.)  A while back Pete gave similar advice to Jonathan, M0JGH.   This morning, Jonathan reported in, confirming that Pete's advice was completely correct.  A "mixing product" arrived early in the lockdown. Congratulations to Jonathan and his remarkably radio-tolerant wife.  It seems Leo should be shopping for a ring. 


Dear Bill and Pete

I hope that you and your families are staying very well during these extraordinary times.

I wanted to thank you both for the reminiscent shout-out during the last podcast, whilst you were suggesting that Leo Sampson of sailing yacht Tally Ho should "seal the deal" with his girlfriend. If our case study is indicative of his future prospects, he absolutely should do! Not only are we happily married but we welcomed a bubbly baby girl into our family at the start of lockdown. (I note that hams refer to children as “harmonics”, but wouldn’t mixer products be a more appropriate metaphor?) 

Apologies for my radio silence of late. Circumstances have allowed me the rare and special opportunity to take more of a lead with parenting, and so my soldering iron has only been wielded for maintenance purposes rather. Your discussion about the intrigue of distant voices emerging from homebrew rigs has whetted this CW addict's appetite to build something for SSB or even DSB, and likely for one of the higher bands...

I feel that I should briefly stick up for the art of CW, though. As a keen amateur musician the ability to communicate through rhythm will always hold a special charm, particularly when you consider that many of my regular EU chums on 40 and 80 are easily identifiable by their “distinctive fists”. I recall a true WW2 spy story in which a double agent, I forget which, was rather unwell but still had to be carried into the radio tent to send his CW whilst lying on a stretcher, otherwise the Germans might notice the absence of this distinctive fist and realize that the game is up!

73 from Wimbledon


Friday, February 26, 2021

EI7CLB's Ladybird Receiver (George Dobbs Design), and Voice over the Internet


I suggested that Tryg once again gather the parts to build George Dobbs's Ladybird receiver.  He should use the same wooden base.  That would be great.  

As for VOIP, I told Tryg that SolderSmoke got its start in a VOIP program  called Echolink -- Mike KL7R and I used to converse from London to Alaska.   Mike recorded one of  our conversations, and that became SolderSmoke #1.  I was using VOIP even before that -- from the Dominican Republic in the mid 90's I was connecting my Radio Shack 2 meter HT to an early VOIP program Internet  Phone or I-phone.  The company that made it was an Israeli firm called Vocaltech.   

Hi Bill,

Thanks for the recent emails and podcasts. I have attached a picture of my first radio - or at least what is left of it. I plundered it for parts down through the years as you can see. It is the build from the late Reverend George's "Making a Transistor Radio", the Ladybird book that really put the hook in me all those years back. I was probably only 11 when my late Grandmother and I went to Dublin by train (300 mile round trip) to Peats of Parnell Street to buy what components my pocket money could afford in order to build the first couple of stages of the radio, The wooden base was cut for me by a worker at a local furniture making factory here in Galway. He got a great laugh out of it when I told him I was going to build a radio - he kept putting the wooden blank up to his ear and joking: "I can't hear anything yet!". I will always remember it.

On another front I wanted to thank Pete and yourself for an entertaining and informative couple of podcasts. I made the leap a couple of months back and bought a set of boards for a uSDX (W2CBA version) but I may just use it as a receiver if I ever get around to building it. I don't know yet. The kit that Pete mentioned in episode #228 really got me excited. I expect you can imagine that my imagination is running riot at the moment.

Finally, I would be interested to hear about your take on half duplex VOIP apps such as Peanut. I realise that it is not 'real' radio to many but I have enjoyed several contacts with operators around the world with it and it has been quite satisfying. These ops that I have spoken with have often been infirm, elderly or have mobility issues. There are also a couple that are under HOA restrictions. One OM in particular lives in a retirement village and is a full-time carer for his wife. I think it is a good thing that they can still be involved in radio without all of the physical demands it might make on them or annoying their neighbours. It might, at least, it might be a worthwhile topic for discussion. Thanks again for an excellent Podcast. BTW, I am a bit of a guitar nut too - is that a Stratocaster that Pete is holding in the picture on the Soldersmoke Blog Page?

Right ho, time to put the kettle on. Tea is a vital component for operational efficiency in my radio world!


Tryg de EI7CLB

Wednesday, February 24, 2021

Quarantine Hodgepodge Rig -- Part 1 (Video)

More videos to follow.  I have added features, and a transmission mode.  Stay tuned.  

Tuesday, February 23, 2021

Awesome Video of Perseverance's Landing on Mars

When we watched the landing on February 18, Elisa kind of complained that they were using simulations -- like the rest of us, she has come to expect actual video of important events.  Well, now we have it.  Actual video of the parachute deployment, the decent, heat shield separation, dust from the Sky Crane rockets, the whole thing.   Wonderful!   See above. 

The full press conference is worth watching:

Here we learn that the placement of these cameras was inspired by the sports camera that enabled one of the NASA/JPL guys to watch his daughter's gymnastic back flip from her perspective.  As they discussed the images from the spacecraft,  I found myself thinking of my little Astrocam Estes rocket in the Dominican Republic, our kite-camera adventures in the Azores, and the key-chain video camera that Billy and I flew on a rocket in the Shenandoah Valley. 

We also learn that the parachute color pattern contains a hidden message... (see below for the solution, worked out by a fellow in France.) 

One of the JPL guys noted that we've all had a tough year, and he hopes that these images will bring some joy to people.  Indeed. 

And wow, there are microphones!  They show the mic in the press conference video, and they play audio of the sound of Martian wind. 

There was a nice shout out to Sojourner from 1997 (the year my son Billy was born).  

Someone cracked the code in the parachute coloration: 

and the JPL Coordinates

Monday, February 22, 2021

LA6NCA's German Military WWII Receivers, and a Luftwaffe Receiver with FAST QSY

Discussions of old military radio gear are dominated by talk of U.S. radios.   Yesterday in the comments section of the SWLing Post I found two interesting videos about German WWII equipment.  Above you can see LA6NCA's receivers.  Below there's a video of a Luftwaffe receiver with an amazing capacity for really rapid frequency change.  

Sunday, February 21, 2021

Bootleggers! Radio Criminality -- Some Jean Shepherd Stories

Thanks to Adam N0ZIB who alerted me to Shep's Cincinnati story about the stolen AM broadcast station.  I then found another YouTube video that had that story, but preceded by an even better tale of ham radio bootlegging.  

Adam found his story on this fantastic YouTube channel -- a collection of Shep stuff: 

Thanks Adam.  73  and EXCELSIOR! 
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