A Very Early Radio-Controlled Device -- Using Spark and a Coherer, in Spain

Click on the picture for a better view -- check out the coherer and the tapper 

Hack-A-Day has an interesting story about Leonardo Torres Quevedo and his very early automated chess machine.  Torres Quevedo was a Spanish inventor active in the early years of the 20th century. 

The chess device was really interesting, but two things caught my eye about this fellow: 1) he lived and conducted some of his experiments in my old home of Bilbao, Spain and 2) he built a very early radio-control system that used -- in the receiver -- a coherer as the detector.  

There is a lot material on Torres Quevedo.  Here is just a sample of what is out there  

His book:  https://www.torresquevedo.org/revistas/index.php/BIB/issue/view/12/1.  Discussion of the Telekino device is on pages 109-127. 

The Branly Tube or Coherer: https://en.wikipedia.org/wiki/Coherer

https://en.wikipedia.org/wiki/Leonardo_Torres_Quevedo

https://www.researchgate.net/publication/2998424_Early_Developments_of_Wireless_Remote_Control_The_Telekino_of_Torres-Quevedo

https://cyberneticzoo.com/wp-content/uploads/2010/12/Telekine-Yuste.pdf

1903 article in Electron (Spain) about the Telekino and Coherers. https://hemerotecadigital.bne.es/hd/viewer?oid=0028654330&page=6

https://alpoma.net/tecob/?p=13766   This article contains the diagram of the device (see above).  You can see the coherer with its tapper.  

Here we see the Telekino installed in a boat in Bilbao harbor.

SolderSmoke Podcast #247 -- Hating on the IC-7300, Pete Goes FT-8 with a KWM-1, Bill's 15-10 Rig, MAILBAG

Bill's 15-10 Rig -- Click on image 

SolderSmoke Podcast #247 is available: 

Audio Podcast:  http://soldersmoke.com/soldersmoke247.mp3

Video:  (482) SolderSmoke 247 -- Hating on the IC-7300, Pete goes FT8 (with a KWM-1), Bill's 15-10 rig, Mailbag - YouTube

Bill’s Bench:

The 15-10 Dual Bander.

n  10 pole crystal filter at 25 MHz.

n  G3UUR, Dishal, AADE and all that..

n  Testing woes.  Looked bad.  But it was a bad test cable. Duh.

n  VFO (Colpitts) at around 3.5 MHz.

n  Buffer blues:  Bad J-310s.  Beware!  

n  Variable cap from a Heath Q Multiplier

n  A bit of a black art – competing goals. Freq coverage, etc.

n  BFO needed an amp to turn on the diodes in the balanced modulator

n  TIA amps.   SIX dual direction TIAs.  18 transistors.

n  On a pine board (like Frank Jones)

n  Will use the N6QW all discrete AF amp.

n  Maybe an RD16 in the final?

n  Will build a second one for the DR.

 Shameless Commerce:  Mostly DIY RF and the PSSST kit.  Todd K7TFC reports:  “The P3ST is on track for Lee Deforest's birthday release (August 26th). I'm going to send out another newsletter on July 4th, and I'll give some details on P3ST development.” Results of Todd’s Survey.

Pete’s Bench

n  FT-8 on the KWM-1!

n  Presentation to the ham club.

n  Why the Icom 7300 is the anti-thesis of homebrew.

MMAILBAG:

-- SPRAT 195  Summer 2023, in the mailbox.  A happy day at N2CQR

-- Armand WA1UQO sent a wonderful book about Faraday and Maxwell… And told me Jim K8OI was heading to our area.  I met Jim at the VWS Field Day event.  FB.  Thanks Armand.

-- Tony G4WIF sent Father’s Day greetings.

-- Alvin N5VZH asking about electrolytics for his 2-B.  Hayseed Hamfest!

-- John AC2RL replacements for the IBEW.  We need to start over!

-- Steve “Snort Rosin” Smith WB6TNL was in the area.  Sorry I missed him.

-- Joh DL6ID helping us to track down origins of a homebrew receiver Grayson saw in Berlin.

-- Grayson KJ7UM was in Europe visiting his wife’s relatives.  But I think he is back in the USA.

-- Walter KA4KXX sent a QRP HB family portrait. 

-- Wouter ZS1KE sent info on surface mount soldering.

-- George Zaff KJ6VU Ham Radio Workbench – re-runs! Recommended audio processor.  Let me know how it sounds. 

-- Michael AA1TJ   Great to hear from him. 

-- Alan Wolke W2AEW on the toroids  he used in Diode Ring video.  Thanks Alan!

-- Dean KK4DAS, AI and SWR meter project  And new lexicon word:  Hamsplaining. 

-- Bob N7SUR --  Let me know we are semifinalists in the Hack-A-Day prize!  

The 15 - 10 rig from above -- Click on image

Australia and Apollo 11 -- Honeysuckle Creek

Trevor reminded me that Parkes ("The Dish") was not the only Australian antenna at work during Apollo 11.  This very nice video gives a more complete description of what happened.  

I saw one piece of Collins gear.  And some of Curious Marc's HP frequency counters.  

More on the Honeysuckle Creek Tracking Station here: https://honeysucklecreek.net/

The Carrington Event and the Current Solar Cycle (Solar Max "Sooner and Stronger")

 

From the article: 

"Sunspot activity has increased dramatically in early 2023, with sunspot numbers far exceeding NASA's predictions each month — though nothing as big as Carrington’s sunspots have been seen yet. Still, the profusion of sunspots and other solar weather suggests that the next solar maximum will arrive sooner and stronger than NASA previously predicted. Whether the incoming maximum brings with it a Carrington-level storm is a matter of pure chance — but scientists will keep watching for spotty signs on the sun, just in case."

https://www.yahoo.com/lifestyle/see-monster-sunspot-launched-carrington-120000667.html

Part III: Curious Marc Repairs an All-Discrete Freq Counter: DO NOT ATTEMPT REPAIR OF CAVITY RESONATOR

I love all the "DO NOT ATTEMPT" warnings.  Wow, even HP got so skittish about this stuff.  Marc has a great sense of humor and notes that, "no cavity resonators were harmed in the production of this video."   I like the description of the mixers and the photo of the mixer antennas. 

Another Podcast -- "Lamp Talk"

 

This is a blast (!) from the past.   A SolderSmoke listener sent this to us in 2006.   

So hey,  be careful with the high voltage!  

Another Model Rocket that Lands like SpaceX -- With a Great Description of the Flight Computer, Software, and Design

Wow, I have to give the devil his due:  this is NOT something that could be accomplished with my beloved discrete (not discreet!) transistors. 

As someone who spent a lot of time as a kid shooting Estes model rockets into the sky, this project really caught my attention.   (My simple rockets used parachutes, "streamers,"  or nothing at all to land.)  This guy uses onboard computers, software, and retractable landing gear.  Very cool.  

Thanks to Jenny List and Hack-A-Day for alerting us to this.  

Part 2: CuriousMarc Fixes an All-Discrete Counter -- "Like an IC, but in discrete form."

Marc nicely sums up this project with this line:  "It's an IC but in discrete form!"  On the same theme, he later says, "Who needs a logic analyzer when you can do a visual debug with neon bulbs?" 

Very cool.  Lots of troubleshooting and repair lessons in this video: 

-- Again we see the benefits of paper manuals.  (Todd K7TFC commented astutely on this under yesterday's post.)

-- 2N2222s to the rescue.  

-- A surprisingly large number of bad transistors (6?) found.  Why did they go bad? 

-- Marc repeatedly says, "Let me poke around."  Poking around is often important.  Mark fixes the reset line after poking around.  He is not sure HOW he has fixed it, but he has... by poking around.  Sometimes this happens.  Thank God for small favors. 

-- Marc has some fancy HP board extenders.  I am jealous.  

-- He also has a cool de-soldering tool.  More jealousy.  Want one. 

-- Marc's understanding of how the HP engineers had to put one of the flip-flops "on the edge of stability," and how his 'scope probe was capable of disturbing this stability. 

-- Remember that those Nixies are TUBES with enough voltage on them to really zap you.  So be careful in there.  This is an especially dangerous mix of transistor tech and tube tech.  With transistors you can work on them with the rig fired up.  With tubes, well, you have to be careful.

Part III tomorrow. 

CuriousMarc Repairs an old DISCRETE COMPONENT HP Frequency Counter

I really liked this repair video from CuriousMarc (aka AJ6JV).  This counter pre-dates the use of integrated circuits -- it is all discrete transistors.  Near the end, Marc mentions how this made this repair "like debugging a big integrated circuit, but with access to each transistor -- this made it quite satisfying."  I hear ya Marc -- with big ICs maybe all you would get to do would be to swap out a single IC.  There would not be much of a challenge there.  

With the older, discrete circuitry you get a good view of how Marc troubleshoots -- how he finds the precise points where the device is failing.  Note his use of the old HP paper manuals. I know this is an old guy thing, but I think the paper manuals (as opposed to the online versions)  just make the process easier.  Note too that Marc at one point had to go back to microfiche. 

The transistor tester Mark used was very cool. 

The whole physical structure of the HP device is very similar to my NYC HP8640B.  Thanks again Steve Silverman and Dave Bamford. 

I will look at Parts II and III of this series soon.  

Sam WN5C Builds a Michigan Mighty Mite and Takes it to Lake Thunderbird

 

Sam WN5C built a Michigan Mighty Mite and then went the extra mile by putting it on the air from a field location.  And what a great name this location has for a QRP operation:  Lake Thunderbird. 

Sam wrote up his experiences for K4SWL's QRPer blog: 

https://qrper.com/2023/05/guest-post-lake-thunderbird-k-2792-with-a-homebrew-transmitter/  

Below is a picture of the rig.  NOTE THE LOW-PASS FILTER.  FB OM. We wouldn't want that rig tearing up the electromagnetic spectrum. 

Looking ahead, Sam writes: 

Next step is a DC receiver (maybe the high school receiver?) and then a more substantial transmitter married together, I think. This is all incredibly fun.

Thanks Sam! 

Nine Homebrew Transceivers by Walter KA4KXX (and some QRP and QRO RC planes)

 

Our friend Walter KA4KXX in Orlando recently sent us this really cool "family photo" of his homebrew rigs.  Be sure to see the key that explains the photo (below) FB Walter.  Thanks too for the model airplane pictures. (Click on the images for better viewing.) 

Walter wrote: 

I recently realized that I am now operating nine homebrew transceivers, which would fit nicely in an “aerial” photograph, so I grabbed my stepladder and everything did fit well in the frame.  Six of them come from the BITX side of the family, with #1 and #7 direct conversion and #9 a single conversion superhet but using the NE602.  More basic information is included in the sketch.

I tried a Si5351 VFO once in the dual-band rig #4, but by the time I built the QRP Labs kit with so much closely-spaced soldering, and then added sufficient filtering and amplification to properly drive a 50 ohm load, I was exhausted!

These nine were created during the past eight years, and were preceded by eight more transceivers that I can document, but those have all been disassembled, with many of the parts being used in these later rigs.  I build my transceivers to be operated often, and since 20 Meters has been hot lately, for example, my POTA Hunter log shows over 300 CW and SSB contacts in 2023 alone, so rig numbers 7 - 9 have been earning their keep lately.

In summary I have created a lifetime total of seventeen transceivers so far, and although I am nowhere near the fifty-plus tally of Pete N6QW, I did spend a lot of years instead homebrewing many radio-controlled model airplanes of my own design.  Two photos show one example that I flew in the 2011 Blue Max Scale R/C Contest at the Fantasy of Flight Museum in Polk City, Florida against some stiff QRO competition.

—Walter KA4KXX

How they Make Raspberry Pi 4 Single Board Computers

So, if the Raspberry Pi is a key part of your new "homebrew" rig, how much of the rig did YOU actually build?