SolderSmoke Podcast #224: Mars. Spurs. Bikes. SDR. NanoVNA. Antuino. MAILBAG

SolderSmoke Podcast #224 is available:

http://soldersmoke.com/soldersmoke224.mp3

1 August 2020

--The launch of Perseverance Mars probe with Ingenuity helicopter.

--China’s Tian Wen 1 on its way – radio amateur Daniel Estevez EA4GPZ is listening to it! 

--Sci Fi Books:  Mars Trilogy by Kim Stanley Robinson.  No skip on Mars :-(

--We have some sunspots!  SFI now 72 and the Sunspot number is 23. 

Bill's bench: 

--Conquering Ceramic Spurs in Q-31   Roofing filter -- sort of 

--NE602 for a Q-75 converter – Gilbert Cell. 

--Measuring low power levels out of NE602.  Antuino better than 'scope . 

--NanoVNA   Really cool stuff.  SDR in there. 

--Building a 455 kc LC filter from QF-1 rubble. Using LTSPICE, Elsie... 

--Reviving my bicycle AM radio – The “All Japanese 6”

--Understanding L Network impedance matching. 

--Bill’s new resistor kit from Mouser. Thanks to Drew N7DA. 

SHAMELESS COMMERCE:  PATREON, AMAZON SEARCH.  THANKS

Pete's Bench: 

--Lockdown Special 

--BPF work on SDR Rig

--I U W I H 

Mailbag:

VK3HN Summit Prowler 7

VK2EMU “The Stranger”

SM0P  HB uBITX in Dubai

AE7KI  Worked him in VK from London

ON6UU  EA3GCY’s 4020 rig

KA4KXX A Simpler Mighty Mite

W9KKQ M19 DMR

KD4PBJ Radio Schenectady

W3BBO 12AU7 Regen

KE5HPY Another 12AU7 regen

N5VZH Ne602 Converter

KY3R Wall Art

G4WIF  Spectrum Analyzer in your pocket

W2AEW  Talks to UK Club

KK0S Sent 455 Kc IF cans

KL0S Making 9Mhz filters

VU2ESE  Diving into simple SDR schemes

Dean KK4DAS  Amateur Radio Astronomy

D-Lab Re-Caps a Drake 2-B (Very Economically)

A bit ugly, but it gets you there!   I like it. 

Thanks to John KE5ETX for alerting us to this video. 

A 75 Meter AM Quarantine Converter for the Q-31 Receiver (video)

A while back Fred KC5RT sent me a nice collection of parts, including some 6 MHz crystals.  I had been thinking of making a converter to put ahead of my Q-31 receiver.  When Fred's 6 MHz rocks arrived, I knew that The Radio Gods Had Spoken (TRGHS).  

I found some NE602 chips in the junk box.   I used an Altoid-sized box for the case.  The toroids are from W8DIZ.  I use trimmer caps from KC5RT to resonate the input and output circuits.  

Hooray!  Now I can listen to 75 Meter AM on the Q-31.  I may have to build a transmitter to go with this contraption.  

Thanks again Fred. 

Paul Taylor's Quarantine "Summit Prowler 7" and some Radio Archaeology

Paul Taylor VK3HN has really outdone himself in this video (above) and blog post. He describes coming across a somewhat mysterious homebrew SSB exciter with some cryptic markings on it. Paul eventually figures them out.  We still don't know who the builder VK3WAC was -- can anyone find him in their logbooks? 

As Paul goes through the description of the transceiver he built around the mystery exciter, he mentions a number of hombew heroes including Farhan VU2ESE, Peter DK7IH, Eamon EI9GQ (I have to get his book!), and Don W6JL.  Also,  our beloved SSDRA book plays a prominent role in the story. 

Paul's video is really beautiful -- at one point the camera pans the landscape and we see kangaroos in the field.  It is also refreshing  -- as we suffer in the heat of the northern hemisphere summer -- to see Paul and his friends out on the summits in their winter coats and hats.  

It looks to me as if Paul built this rig during the current emergency, so I will list it as a Quarantine rig.  Every dark cloud has a silver lining, and Paul's rig has added a bit of silver to the dark COVID cloud.  Thanks Paul. 

https://vk3hn.wordpress.com/2020/07/26/something-old-something-new-a-four-band-5w-50w-ssb-cw-transceiver-summit-prowler-7/

Alan Wolke W2AEW on IMD, NanoVNA and more (presentation to UK club)

This video is another reminder of how lucky we are to have Alan Wolke W2AEW as a fellow radio amateur, and as a teacher and mentor. 

In this video, Alan is talking to the Denby Dale Amateur Radio Society in Yorkshire, UK. 

The first part of his talk is about IMD products, the importance of 3rd order products, and the benefits of attenuation. 

The second part of the talk (after a few questions) is a look at the NanoVNA, which Alan cites as the "Toy or Tool of the Year."   

I learned a lot from both portions of the presentation.  I now find myself wanting an H4 model of the NanoVNA (bigger screen).  Or maybe even an F model.   Thanks to Alan, I now know what S21 and S11 means. 

Thank you Alan, and thanks to the Denby Dale ARS.  

73  Bill 
  

ANOTHER 12AU7 REGEN! W3BBO's Quarantine Receiver

Hi Bill,

I was really impressed with Chuck KE5HPY’s 12AU7 Quarantine Regen!  A very nice build and my hat is off to him!  It caught my eye, as I also built a 12AU7 regen during this period, my first “Hollow-State” unit in sometime. 

It would be interesting to find out what other construction projects fellow hams have involved themselves with during this trying time.

Keep melting solder!

73 de Bob W3BBO

  

Radio Schenectady

A while back I posted a picture (see below) of the shortwave dial of an old receiver used by my wife's grandfather.  I noted the odd  presence of 'Schenectady"  among the exotic foreign locations on the dial.  Pete immediately connected the dots by noting that Schenectady was the home of General Electric.  This week Chris Waldrup KD4PBJ sent us a great web site describing the shortwave stations in Schenectady.  Check out the tube that runs 100 kw AM (Big Bertha).  

https://www.radioworld.com/news-and-business/schenectady-shortwave-transmitters-1941

Chris also sent information about BIG AM broadcast band stations: 

In addition to Schenectady being home to  GE it is the city of license to clear channel AM 50 kW WGY 810.  WGY was started by GE so if the radio was GE it was probably a way to promote their station at the time. I heard mention of Rochester too and that would be for 1180 WHAM another 50 kW clear.  Both WGY and WHAM are still there going strong banging out their 50 kW.

And Pete reminded us of KDKA, describing its long-lasting impact on one of his ears:  

Let us not forget KDKA in Pittsburgh at 1020 which I think is no longer clear channel. I used to listen to KDKA on my crystal set when I went to bed at night. My bed had an exposed bed-spring which was my antenna. To this day there is a slight kink in one of my ears where my Brush headphones rested –I am a side sleeper.

KE5HPY's 12AU7 Quarantine Regen -- FB!

Bill and Pete:

Thanks for upping the frequency of your podcasts.  Each one is a welcome note to break-up the COVID monotony.

Following on to Bill’s 31m rx, I am pleased to have a new regen on the air and performing well.  This started as the 12AU7 Hartley circuit found on the web; however, the original circuit needed some further work IMO.  I made a number of modifications – outboard 30 MHz LPF (to remove our local Spanish FM station), inductive antenna link, variable cap for antenna coupling adjustment, up to 24V on the plate, extra by-passing, NE5532 audio section vs LM386 and a switched cap for a lower “band”.  It’s still a starved triode oscillator/audio amp and it has that regen presence.  Best DX is Singapore (BBC) and Madagascar although it’s ideal for easy listening on 19-60m to Romania, Greece, Cuban music, Spain, etc.  As Bill said, there is still plenty worth listening to on a homebrew AM rx.  40, 30 and 20m copy OK, but bandspread is tricky! Adjusting regen is good for +/- 1 kHz, kind of a poor man’s BFO adjustment.   I heard a TI station calling CQ on 20m and called him back on my Icom for a QSO. 

By the way, this rx has some serious vintage mojo – Hammarlund varicap, National coil form, Millen dial and an RCA tube.  The all-star team plays great together! It’s a kick seeing the filament glow while putting RF through recycled parts made decades ago.

73,

Chuck

KE5HPY

A Quarantine Mighty Mite

'Tis a thing of beauty. 

Bill/Pete:

    I just decided here over the COVID period to head back to basics here and build a Michigan Mighty Mite with a Color burst crystal I had here. And wouldn't you know it, it works!  Here's a couple of pictures, it's not pretty at all. Needs to be mounted on something. 

Don KC9ZMY

Knack Story -- Tom WX2J

RTTY Model 15

Hello Bill,

Greetings from a fellow ham in Northern Virginia. I have enjoyed the SolderSmoke podcast for a few years now, and I just heard your recent presentation to the Vienna Wireless Society. We have a lot in common so it is about time I reach out to make your acquaintance.

I was born in NYC and grew up in Northern NJ. I was first licensed in 1969 as a high school student (51 years ago! Goodness!). My novice callsign was WN2JFX, and I progressed from Novice and then to General and Advanced as WB2JFX, and then eventually to Extra (in about 1990 -- while the 20 WPM code requirement still existed). At that point I put in for a 2X1 callsign and received WX2J, which is a nice twist on my original call.

I was fanatically active in my early years in ham radio. My Elmer (George, K2VVI, SK) set me up with a DX-40, and my parents provided a brand new Hallicrafters S-120 (you could copy the whole 40 meter band without changing the frequency!). I think I Worked all States as a Novice and learned that the human brain is the most amazing audio filter on the market. When I made General, George lent me an old Hallicrafters SX-25, and then I was really in good shape. Besides CW, I was also very interested in RTTY. I had my own Model 15 leaking oil in the basement and had a blast watching the magic of that thing printing messages out of thin air. I have always been a home-brewer, and one of the first serious things I built was a two- or three-tube RTTY demodulator from the Handbook. Aluminum chassis, chassis punches, tube sockets -- the whole works. I have no idea what the real inductance was of the inductors that went into the filters but somehow if the signals were strong enough, and on 850 Hz shift, it could actually demodulate signals. I probably still have that thing around here somewhere.

Another local ham bequeathed me his entire collection of 73 magazines - 10+ years starting with the first issue (~1960). I read them from cover to cover so many times I probably have them memorized. I became a real fan of Wayne Green, W2NSD, who was always ornery and controversial but a very interesting guy. I met him at a hamfest many years later and we had a great chat.

In any case I wanted to mention some other things that resonate with me as I listen to your podcast. As a kid growing up in the shadow of NYC in those years, you can bet that the Jean Shepherd broadcast was a regular part of our life. My dad used to listen to it every night -- 10:15 p.m. I believe, on WOR -- and we both used to greatly enjoy his stories of lighting up the fuse panel and nearly blowing up the house as he and his old man were playing with radios, etc. It was a common theme in our house too when my ham radio signal would blast into the TV set or I dangled new antenna wires off the house and out of the trees -- "You're going to blow this house up!" I studied electrical engineering in college and was commissioned in the Air Force upon graduation. I served a 20-year career in the Air Force and stayed somewhat active in ham radio. I was licensed and operated out of Okinawa (KA6TF) and England (G5ERE) during tours of duty in the early 1980s. Always an HF guy, in about 1982, in Japan, I bought myself a new Icom IC-720A, and this is still my primary rig. I was an early adopter of PK-232 and did some extensive building and experimenting with it. Sadly though, in the last 25+ years, my ham radio experience has mostly been vicarious as my work and family obligations have just not left much time for ham radio. I do have a G5RV wire antenna strung up but very rarely jump on the air -- sometimes during contests.

In high school we made a field trip to ARRL HQ in Newington, CT. While there we did all the things people do on such a visit, but one of the high points for me was meeting Doug DeMaw. I can just hear how Shepherd would describe it -- "I turned the corner and there he was! In person! The high priest of homebrewing! Doug DeMaw. In the flesh!" Cue the kazoo. I actually also met Shepherd at a book signing (Wanda Hickey's Night of Golden Memories?). I remember presenting him with a computer-printed banner of his callsign -- K2ORS -- produced by one of the few functioning computer programs I had written in high school. I also heard him on the HF bands one night -- I think he was in Florida -- and actually made contact with him, if barely being able to exchange callsigns can count as a contact.

Well, more than you wanted to know. I just wanted to let you know that I enjoy your podcast and can personally relate to very much of what you say. Although I am steeped in Hardware Defined Radio, I am also a software guy so I expect that my future includes SDR. I hope you and Pete are able to continue the podcast for a long time to come because I need the full HDR-SDR spectrum to be covered -- hi.

73,

Tom Fuhrman, WX2J

Overcoming the Complexity of the Michigan Mighty Mite: Walter's Sunrise Net Special

From Walter KA4KXX
June 21, 2020

Michigan Mighty-Mite:  Why So Complicated?

The April 2020 issue of QRP Quarterly magazine featured an article by Bob Rosier K4OCE which included a schematic for a “Ten Minute Transmitter” by G4RAW (SK), which apparently first appeared in SPRAT 82 in 1996. 
It is even simpler than the Michigan Mighty Mite, so this transmitter can truly be built on a solderless breadboard in about 15 minutes, because a complex coil is not required.  
The only tuning needed was for me to establish the correct value of the output series capacitor. 
This rig allowed me to check-in to the Sunrise Net (see details in blue text on my QRZ page) today on my very first attempt, and landed me a 549 signal report from 250 miles away.
The first photo shows the transmitter connected to a Transmit/Receive Switch mounted in an Altoids box. In the Transmit position the antenna is disconnected from my 1979 Heathkit HR-1680 receiver, which then coincidentally supplies a sidetone at an ideal volume level.  That little black pushbutton which can be seen in the second photo serves as my key, and works just fine for a five-minute daily QNI on the Sunrise Net.
Of course, part of the secret is having a crystal exactly on the Net frequency, and I have a few left, free to whomever in the Eastern U.S. is interested in building one of these simple Sunrise Net Special Transmitters and participating in our Net. 

SSB Transceivers of the 1960s --- Videos by Mike WU2D

I liked both these videos.  Mike WU2D really does a great job.  He covers a LOT of technology and theory in two videos.  Thanks Mike!