But How Does the Michigan Mighty Mite REALLY Work?

Dean KK4DAS and I were talking to Mark, a new homebrewer.  After we sang the praises of the Michigan Mighty Mite,  Mark asked us a good question:  How does it really work? 

I guess the starting point for analysis is the Barkhausen criteria (that Pete N6QW taught us):  essentially you need enough feedback to overcome losses in the circuit, and this feedback has to be in phase with the signal at the input.  The MMM is clearly oscillating, so the question becomes, "How does this very simple circuit meet the Barkhausen criteria?" 

Here goes: 

Even though it is a very simple circuit, it is worthwhile to separate out the things that it has to do: 

1) It needs to set the AMOUNT of feedback.    This is done by the tap on L1.  Too low down on the coil, and it is too close to ground through the .05 uF capacitor (not enough feedback).  Too high on the coil and you get too much feedback.  This is like an inductive voltage divider. 

2)  It needs to make sure that this feedback is in phase with the input signal. Positive feedback. Q1 is an inverting amplifier.  So it supplies 180 degrees of phase shift. As the signal at the base goes more positive, the signal at the collector goes more negative, and vice versa.  But we need an additional 180 degree shift to bring the output signal in phase with the input signal.  Here is the key:   The crystal provides the other 180 degrees of phase shift.  See

https://www.allaboutcircuits.com/technical-articles/understanding-the-operation-of-quartz-crystal-oscillators/

I tested this:  A 3.579 MHz crystal does provide the needed phase shift:  It introduces a shift of about 190 degrees.  Check out this very cool picture. The two scope probes are looking at the input and the output of the 3.579 MHz crystal with 3.580 MHz frequency coming from my HP sig gen. 

Click on the picture for a better view.

3) It needs to filter out other signals -- the 365 pf variable cap resonates with L1 at around 3.579 MHz.  This results in maximum circulating current through L1 at this frequency. 

4) It needs to match impedance to the antenna.  L2 wound over L1 forms the secondary of a transformer and efficiently moves the energy from the MMM to the antenna.  Think about the gears on your bike. 

The 10k resistor biases the base of the transistor, keeping it on.   The 27  ohm resistors limits the current through the transistor, preventing it from burning up. Note:  the 27 and 10k resistors should NOT be connected directly to each other.  There is no dot in the schematic. This causes some confusion among builders. 

The .05 uF capacitor does two things:   It grounds the L1/365pf tank circuit for RF (but not for DC).   It is less than 1 ohm at 3.579 MHz.   And it helps reduce (smooth out) key clicks (very sudden on-off changes in the oscillation). 

Who is the IMSAI Guy?

I like his videos.  

https://www.youtube.com/watch?v=x3IPtBzxAgE

https://www.youtube.com/watch?v=Bgrubw6B_us&t=5s

W6UAB? 

Homebrew Transistors

Hang your heads in shame, my friends.  This dude is getting ready to homebrew his own transistors.  None of that store-bought stuff for him.  He is a few steps away from breaking free of the GLOBAL TRANSISTOR CARTEL that has been abusing us so-called "homebrewers" for so many years.   This guy really puts the home in homebrew. 

Plus he has a seriously cool shop enabling him to do some excellent metal and chemical work.  

Thanks to Hackaday for alerting us to this. 

https://hackaday.com/2023/08/22/start-your-semiconductor-fab-with-this-diy-tube-furnace/

15 Meter Homebrew SSB Rig As Heard in Mexico City

 19 August 2023. Ralph XE1RK recorded part of our QSO and played it back to me. Thanks Ralph!

I was running about 75 watts to a hex beam aimed Southwest.

Valveman -- The Story of Gerald Wells

Don't be deterred by the annoying test patterns at the start of this video.  Just skip past them.  The rest of the video is quite good.  Or you could just click on this link and avoid the first 83 seconds of test pattern:  https://youtu.be/Y8w6iwaAGJ4?t=83

Gerald Wells has been mentioned on this blog before, but I don't think we've ever presented the full documentary on this fellow.  Here it is.  Gerry is clearly one of us: a radio fiend, obsessed (as he admitted!) with wireless, a victim of THE KNACK.   

George WB5OYP of the Vienna Wireless Society got to meet Gerald Wells and visit his museum. George alerted me to this video.  Tony G4WIF also was able to visit Gerry and his museum. 

The documentary is full of interesting stuff, and is, in itself, a Knack Story.  Wells mentions the Crippens murder so well described by Eric Larson in "Thunderstruck."  It was this crime that brought radio to the center of public attention.  

More Ancient Technology Keeping Space Missions Alive

 https://www.bbc.com/future/article/20230815-the-ancient-tech-keeping-space-missions-alive

Three cheers for software.  Really. 

Working Indonesia and Chile with new 15-10 Homebrew Transceiver

Conditions were good this morning, and the Radio Gods continue to favor homebrew rigs.  I got on 15 meters SSB with the new 15-10 dual bander and quickly worked YH0AD in Jakarta (about 10,000 miles).  A few minutes later I talked to YB2MVD; he was a bit further east on Java.  I shot a video of the QSO with YB2MVD.  He said I was 59.  

I then switched to 10 meter SSB (same rig) and worked CE4PS in Chile (5,000 miles).   

TRGHS. 

The antenna for all these contacts was my K4KIO Hex Beam.  I was running about 75 watts from the .1kW CCI amplifier. 

The Wizard of Kerala (India) -- Denny VU2DGR -- SDR and HDR

 

His signal was just booming in on 20 meter SSB yesterday evening.  It was one of the strongest signals I've heard from India.  I wasn't able to get through the pileup, but I heard mention of a homebrew station at his end...  Sure enough a look at his QRZ.com site shows that a LOT of solder has been melted in his shack.  Both SDR and HDR stuff.  Tube projects including an 807 amplifier made from "components collected from the scrapyard." And a homebrew 20 meter Moxon.  Check it out: 

https://www.qrz.com/db/VU2DGR 

FB Denny!

Kerala is on the southwest tip of India.  It is something of a hotbed of technological innovation.  My only Indian contact using my current series of homebrew dual-banders was with VU3TPW -- Renju is also in Kerala. 

You have heard of the International Geophysical Year (IGY). But have you heard of the IQSY?

 

International Quiet Sun Year.  1964-1965.  Yes, that was a thing.  

Voyager, Canopus, JPL, and 74xx Logic Chips from the early 1970s

"So somewhere out there in interstellar space beyond the boundary of the Solar System is a card frame full of 74 logic that’s been quietly keeping an eye on a star since the early 1970s, and the engineers from those far-off days at JPL are about to save the bacon of the current generation at NASA with their work. We hope that there are some old guys in Pasadena right now with a spring in their step."

https://hackaday.com/2023/07/31/just-how-is-voyager-2-going-to-sort-out-its-dish-then/

Understanding Maxwell's Equations (video)

And you should also look at the accompanying web site: 

https://www.maxwells-equations.com/m/index.php#maxwells

Writing about the equations, the author notes, "They are formidable to look at - so complicated that most electrical engineers and physicists don't even really know what they mean.  This leads to the reason for this website - an intuitive tutorial of Maxwell's Equations. I will avoid if at all possible the mathematical difficulties that arise, and instead describe what the equations mean. And don't be afraid - the math is so complicated that those who do understand complex vector calculus still cannot apply Maxwell's Equations in anything but the simplest scenarios. For this reason, intuitive knowledge of Maxwell's Equations is far superior than mathematical manipulation-based knowledge. To understand the world, you must understand what equations mean, and not just know mathematical constructs. I believe the accepted methods of teaching electromagnetics and Maxwell's Equations do not produce understanding. And with that, let's say something about these equations." 

Thanks to Armand WA1UQO for sending me the wonderful book about Faraday and Maxwell that put me -- once again -- on the path toward a deeper understanding of their work.  

https://www.amazon.com/Faraday-Maxwell-Electromagnetic-Field-Revolutionized/dp/1633886077/ref=sr_1_1?crid=1ZRPDYCCN9CGA&keywords=Faraday+and+Maxwell+Forbes+Mahon&qid=1690716355&s=books&sprefix=faraday+and+maxwell+forbes+mahon%2Cstripbooks%2C55&sr=1-1

Thanks also to Michael Rainey AA1TJ.  Several years ago he commented that he too wanted to get a better understanding of these equations. 

Phase Noise and the Radio Amateur

A weak signal disappears in the phase noise of the stronger signal.

The March 1988 QST provides a relatively clear explanation of what phase noise really is:

https://www.robkalmeijer.nl/techniek/electronica/radiotechniek/hambladen/qst/1988/03/page14/index.html

Highlights: 

Phase noise is an undesired variation in the phase of the signal. In this case, an oscilloscope shows that the time between zero crossings of the signal varies over time when compared to the zero crossings of an ideal sine wave. An exaggerated example of phase noise is shown above.

Phase noise on an oscillator signal has exactly the same effect as frequency modulating the oscillator with noise.

Whenever a carrier is passed through a mixer, the phase noise of the oscillator driving that mixer is added to the carrier.

Phase noise on a transmitted signal causes effects identical to phase noise generated in a receiver.

Any signal that reaches a mixer in the receiver is modulated by the phase noise in the local oscillator driving that mixer. As such, the signal appears to have at least as much phase noise as the local oscillator. Thus, sufficiently strong signals off the receiving frequency can degrade receiver sensitivity by raising the noise floor at the receiving frequency. Receiver dynamic range is reduced as the noise floor rises.

With a frequency-shift-keyed or- a phase-shift-keyed signal, the close-in phase noise limits the maximum bit error rate that the system can achieve. Both of these effects can be quantified once the communications system is defined. With an SSB voice signal, the effects are much harder to predict, but excessive phase noise does degrade SSB signal intelligibility to some extent.

--------------------------------

Receiver guru Rob Sherwood provides some very useful historical background on his web site:

http://www.sherweng.com/documents/TermsExplainedSherwoodTableofReceiverPerformance-RevF.pdf

Phase Noise: Old radios (Collins, Drake, Hammarlund, National) used a VFO or PTO and crystal oscillators to tune the bands. Any noise in the local oscillator (LO) chain was minimal. When synthesized radios came along in the 70s, the LO had noise on it. It is caused by phase jitter in the circuit, and puts significant noise sidebands on the LO. This can mix with a strong signal outside the passband of the radio and put noise on top of the weak signal you are trying to copy. This is a significant problem in some cases: You have a neighboring ham close by, during Field Day when there are multiple transmitters at the same site, and certainly in a multi-multi contest station. You would like the number to be better that 130 dBc / Hz at 10 kHz. A non-synthesized radio, such as a Drake or Collins, has so little local oscillator noise the measurements were made closer-in between 2 and 5 kHz.   

-------------------------------------

Experimental Methods in RF Design (EMRFD) has this to say about phase noise:

"The local oscillator is a critical part of any communications system. Modern transceiver performance is often compromised by LO systems that suffer from excess phase noise, effectively limiting the receiver dynamic range. While quiet oscillators, those with low phase noise, can be built using traditional methods, these circuits often lack the thermal stability of a synthesizer.... Frequency synthesis is not, however, the answer to all the LO problems presented to the experimenter.  Some PLL synthesizers are burdened by excessive phase noise. Those using DDS, while quieter, emit spurious outputs, often in profusion.  Both use an excess of digital circuitry that can often corrupt a receiver environment."  page 4.1

   

"At first glance, phase noise sounds like an esoteric detail that probably has little impact on practical communications.  This is generally true." page 4.12 

--------------------------------------

Hans Summers G0UPL analyzed and measured the phase noise of the Si5351a chip: 

http://qrp-labs.com/qcxp/phasenoise.html

------------------------------------

DC4KU appears to be using the crystal filter method used by Hans: 

https://dc4ku.darc.de/Transmitter-Sideband-Noise_DC4KU.pdf

------------------------------------

Martien PA3AKE has done a lot of great work on this topic.  See: 

https://martein.home.xs4all.nl/pa3ake/hmode/dds_pmnoise_intro.html

-----------------------------------

Dean KK4DAS commented on the phase noise video of the IMSAI guy: 

Watching the video I was reminded of Segal's law roughly paraphrased as follows.:

A man with one spectrum analyzer knows his phase noise. A man with two is unsure.

First Contacts with 15-10 Rig -- Two Atlantic Crossings

 

I was just testing it, working (as usual at this stage) on final amplifier stability.   Then I heard ON5WO calling CQ.   I could not resist.  I worked him, but had to use a test lead to manually key the .1 kW amplifier.  Minutes later I worked OH6RM.  He very diplomatically said that I had "highly unusual audio."  This was probably due to earlier efforts to shift the carrier oscillator to improve carrier suppression. (I will fix this.)  

I will continue to work on the rig; It should look a bit better when I am done.  But hey, it works!  It has already crossed the Atlantic. Twice!  

"Onda Corta" ("Shortwave") -- A Short Film about Ham Radio in Venezuela (Please ID the Boatanchors!)

https://youtu.be/J1QlKykhR2M?t=583

I have it cued up to 9:43 -- at that point Ramon is in his ham shack.  

Lots of good stuff in there! 

Please ID the rigs/parts you see and list them in the comments below. 

This version has subtitles in English.  I like it -- a nice story.  And the whole film is only about 15 minutes. 

Going Down the Phase Noise Rabbit Hole with the IMSAI Guy (VIDEO) -- Is there a better way?

Chimera:  2.

a thing that is hoped or wished for but in fact is illusory or impossible to achieve.

(from the Oxford English Language Dictionary). 

Phase Noise.  We know what it is, but how do you measure it?  Pete N6QW and I went through this back when people were casting phase noise aspersions at (Pete's!) beloved Si5351.   More recently phase noise hate  has been focused on (my?) beloved Franklin oscillator.  When I asked a very technically proficient and guy at the VWS club if he could measure phase noise, I was surprised when he honestly said that he could not. 

And now we have the IMSAI guy saying, essentially, the same thing.  Wow, if the VWS guy and the IMSAI guy -- with all the spectrum analyzers at their disposal -- have trouble measuring phase noise, what hope do we ordinary hams have?  I mean, at best most of us have just an oscilloscope, a NanoVNA,  and a TinySA.  

Look, I know that phase noise is real and in certain circumstances, it is important.   But sometimes I suspect that its measurement is also a bit of a technical chimera:  If,  for whatever reason,  there is a circuit that you don't like, you can claim that the phase noise of that circuit is bad.  Or horrible. I think we see this sometimes with the Franklin oscillator.  Very few hams will be able to measure it and dispute the assertion that the phase noise is bad.    

For a perhaps painful walk down SoldeSmoke's "Phase Noise Memory Lane"  go here: 

https://soldersmoke.blogspot.com/search?q=Phase+Noise

Thanks to the IMSAI guy for a great video.   But let me ask:   Is there a better, simpler way to measure phase noise?  One that will avoid chimerical results and that could be used by hams with sort of standard ('scope, sig gen, NanoVNA, TinySA) test gear? 

The Super Islander Mark IV -- A Cuban DSB Transceiver Made From CFL Lightbulb Parts

Trevor Woods also sent us this report from Arnie Coro.  It is not clear to me what difference (if any) there is between the Super Islander Mark IV and the Jaguey Five (described yesterday).  But the bit about using parts from old CFL bulbs is interesting.  This was something championed by Michael Rainey AA1TJ several years ago.  See: https://soldersmoke.blogspot.com/2009/01/soldersmoke-98.html  

and:

https://www.qsotoday.com/transcripts/aa1tj

April 2010:

Today, I will be answering a question sent by listener Bruno from Croatia... Bruno picks up our English language programs via Internet, but he is now also listening on short wave too. He sent a nice e-mail message asking me about the latest version of the Super Islander amateur radio transceiver, because he wants to build one.

Well amigo Bruno, the Super Islander Mark IV is now on the air, and results are very encouraging considering that it is a 40 meters band transceiver built using recycled electronic components.

The Mark IV uses a totally different approach to the receiver design, and it adds two solid state audio filters.

Amazing as this may sound, some of the electronic components used to make the Super Islander Mark IV transceiver came from the circuit boards of broken or damaged Compact Fluorescent Light Bulbs... and that means that there is virtually an endless supply of those parts.

Here is now amigo Bruno, and amigos listening to the program at this moment, a brief description of the Super Islander's Mark IV receiver module.

It starts with a simple resistive signal attenuator that feeds a dual tuned bandpass input filter.

The filter has a limited bandwidth , chosen so as to limit response to out of band signals... The filter is followed by a cascode transistor radio frequency amplifier stage, that feeds a broadband four diodes product detector.

Low level audio from the product detector goes to the audio filtering and amplifying module, made with discrete transistors, of which several of them are also recycled from the Compact Fluorescent Light Bulbs circuit boards...

This version of the Super Islander, the Mark IV , is radically different from any previous ones, as we have now switched over to a totally low cost solid state design , that can be easily reproduced because it uses very common electronic components and straightforward , easy to adjust circuits.

In our upcoming mid week edition I will describe the VFO, or variable frequency oscillator and the transmitter module of this unique low cost amateur radio transceiver, the Super Islander Mark IV... about the lowest possible cost transceiver that will make possible regular two way ham radio contacts on the 40 meters band using either voice or radiotelegraphy modes.

The Jaguey Five -- The Solid State Cuban DSB Rig -- Circuit Description

Obviously we need a picture of a Jaguey transceiver. 

"Made in Jaguey Grande" 

Trevor Woods found this report from Arnie Coro (SK) CO2KK: 

February 2009: 

Here is now item three in detail: It was quite a long time ago, when I heard about a nice project sponsored by IARU, the International Amateur Radio Union, that was promoting the design of a kit, a simple single band transceiver kit that could be sent in a small air mail parcel to radio clubs in Third World nations which could then deliver them to would-be radio amateurs, and help them build and align the radios... But, unfortunately I lost track of the project, and as many of our listeners may realize there is still a great need of such a project... Past efforts along this line have had some problems, among them the mistaken approach of using of very sophisticated electronic components that in case of a breakdown would be impossible to replace locally; and also, all attempts seemed to try to make the transceiver an ultra- or near-ultra-miniature radio, something that won't help at all with beginners...

So, when I recenlty received an e-mail from Canada, asking what I thought about reviving this great idea, our Canadian amigo asked what we had already done here in Cuba, with our JAGUEY double side band plus CW 10 watt transceiver that went up to REVISION NUMBER 5. , This was the last upgrade, done about three or four years ago, and we named it the Jaguey FIVE, as it generates 5 watts of CW... The Jaguey FIVE was a low parts count, not miniature, easy to build single band transceiver that used readily available components, instead of sophisticated state of the art parts...

In order to please the friend who wrote about this topic, here is a brief, on the air, description of our Jaguey FIVE and by the way, Jaguey is the name of a town, actually it is Jaguey Grande, or big Jaguey, and the Jaguey is a beautiful tropical tree... The original Jaguey transceiver originated in that Matanzas province town in 1982,

The receiver part starts with a simple yet effective RF attenuator, then it feeds a bandpass
filter made of two tuned circuits... we use shielded IF transformers from old TV sets 4.5 megaHertz audio chains... A simple bipolar NPN small signal transistor grounded base amplifier feeds a homebrew double balanced mixer... and we "discovered" quote, unquote, that the antenna balun transformers used in TV sets, the 300 to 75 ohms baluns, had a ferrite core with two holes that makes a wonderful broadband transformer for the double balanced mixer...

We use computer diodes removed from defunct ISA old computer cards and motherboards and developed a very simple test jig to match the diodes... The double balanced mixer is fed on the other port from a simple three transistor oscillator, of which we have two versions, one using three NPN bipolar transistors and the other one using an FET oscillator followed by two bipolars... at the output of the mixer we have AUDIO, as this is a direct conversion receiver, amigos!!!

Now we amplify the audio using discrete components and again we have two versions of audio filters, one with bipolar NPN transistors and the other using a very common operational amplifier IC... The audio power output stage also is available to the builder in two versions, one using discrete components and the other using an integrated circuit audio amplifier that is locally available here in Cuba and produces a booming 2 watts of audio, with a lot of gain and rather low noise! This is the audio IC used by the most popular TV set in use here in Cuba, so we were able to obtain them from the TV repair shops at low cost.

Well, that's why I will describe as a flexible design... again, no attempt is made to make the Jaguey single band amateur transceiver a miniature rig, as miniaturization is definitely not for beginners!!! And following up this description of the receive section of the Jaguey, in our upcoming mid-week edition of Dxers Unlimited, I will describe the transmitter section of the rig,that shares the same variable frequency oscillator with the receiver.... I think that a new more up to date version of the Jaguey transceiver could very well be made available in kit form, with large-sized and easy to assemble circuit boards. The old Version 5 uses three circuit boards, one for the receiver, one for the VFO and one for the transmitter, so the newcomer can assemble just the receiver and start listening to amateur radio communications before having his or her own ham license!!!

You are listening to the weekend edition of Dxers Unlimited coming to you from Havana on the air and on the web at our Dxers Unlimited blog.

----------------------

A video of Jaguey Grande, Cuba: https://www.youtube.com/watch?v=krblz_5o6jU

Earlier posts about the Jaguey on the SolderSmoke blog: https://soldersmoke.blogspot.com/search?q=Jaguey

Homebrew in Namibia -- Joe Noci V51JN -- -- The Wizard of Sawkopmund

 

Here at SolderSmoke I like to highlight the homebrew adventures of far-flung radio builders.  Joe V51JN melts solder in an especially exotic location:  on the edge of the Namib desert.   He is in a very interesting place:  https://en.wikipedia.org/wiki/Swakopmund

Here is Joe's QRZ.com page: https://www.qrz.com/db/V51JN

Joe recently posted on the Amateur QRP Radio Facebook group: 

I am not on the air much - here in Swakopmund ( Namibia) we have quite bad RFI from mains borne RF control signals for geysers, pumps, etc and 40M is unuseable, 30M almost usable and 20M sort of useable.. Complaint to CRAN - Our Radio Ministry - achieve nothing...So I do mobile out in the desert in the 4X4 when I can! I enjoy building radios - here are some photos - first is a 5watt 7MHz to 21MHz all band SSB rig - all homebrew, inc crystal filters, etc. PA is a push-pull LDMOS amp, 5W PEP.

Thanks to Doug KB8M for alerting me to this amazing work. 

Martein's Bandpass Filters - PA3AKE

Above you can see the really nice 15 meter filter that I built using data provided by Martein PA3AKE. 

https://martein.home.xs4all.nl/pa3ake/hmode/bpf_all.html 

Before I built Martein's filter, my bandpass had been inadequate.  Looking at the signals coming out of the diode ring mixer in my 15-10 rig, I realized that when I was on 15, there would also be an output on 10.  And vice-versa.  These outputs would have to be knocked down by the bandpass filters.  I had been using simple dual tuned circuit filters. But when I looked at the filter shapes of these filters in NanoVNA, I could see that On 15 the 10 meter signal was only down about 20 db.  And on 10 the 15 MHz output was also down only by about 20 db.  That's not enough.  Take a look: 

Before,  with the dual tuned circuit filter

After with Martein's Filter 21.5 Mhz

AFTER with Martien's filter 21.1 MHz

While the earlier filter had provided only about 20 db of attenuation at 28 MHz, Martein's filter provided at least 68 db of attenuation.  That is really nice.  And the passband is nearly flat at 1 db attenuation. 

I built mine using some of the guidance provided on Martiens site.  I did use T80-10 toroids (I got them from kitsandparts.com).  And I did not use copper clad boards.  

One of the charming features if Martein's filters is the total lack of trimmer caps:  Martein recommends tuning the filters by simple squeezing the coils (to increase inductance and decrease frequency) or by spreading out the turns a bit (to decease inductance and increase frequency).  I did the later when NanoVNA showed that I didn't quite have all of the 15 meter phone band on the flat portion of the curve. 

I also like the way Martein provides the values for BP filters for all of the HF ham bands.  Very useful. 

Next I will build one for 10 meters.  And I will probably go back to my Mythbuster and 17-12 rigs and build Martein's filters for these rigs.  

Thanks Martein! 

Progress Report Video on my 15-10 Meter Homebrew SSB Transceiver

The receiver is mostly done on my 15-10 rig, and I am following Farhan's BITX20 advice: "pause at this point and listen to the receiver that you have built." In the video I mention a problem with out-of-band signals. I was hearing shortwave broadcast signals (Brother Stair!) and even strong 20 meter CW signals. I thought the problem may have been with the bandpass filters, but after thinking about it I focused on the diplexer coming out of the product detector. I put a simple diplexer (from W7EL's Optimized Transceiver) in there and the problem disappeared. I still plan on beefing up the Bandpass Filters -- the dual tuned circuits I have been using are, I think, inadequate. I needed some more space on the wood board so I installed a sort of "back porch" -- you can see it in the video. I will build a power amplifier (RD6 or RD16) and a mic amp. Soon I will be on 15 and 10 with this rig. On this one, I am going the full "radical fundamentalist homebrewer" route: no ICs, no manufactured PC boards, no VFOs from old Yaesus.

The TEK 465 'Scope Used to Create Pong and the Apple II

Wow, this is almost enough to make me take another shot at repairing my TEK 465.  

 

Quetzal-1 -- The Guatemalan CubeSat

 

Wow, here's another piece of tech news from a place in which I have some experience.  Yesterday I posted about the Telekino developed and tested in Bilbao early in the 20th century -- today's post is about a much more recent effort in Guatemala: this one  to launch a small satellite, a CubeSat. 

Details here:   https://www.uvg.edu.gt/cubesat-en/

Hack-A-Day reports that the Guatemalan University recently open-sourced all their data on the satellite: https://hackaday.com/2023/07/04/quetzal-1-satellite-goes-open-source/   The Hack-A-Day comments are, as usual, harsh and critical, filled with the assumption that the commenters could have done better.  

But hey, three cheers for Quetzal 1 and the Guatemalan satellite builders!  

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.