I was looking at this again and I realized that there was more to it than I thought. Who was the "doctor" who was filling in for their regular doctor?
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Wednesday, January 4, 2023
Sunday, January 1, 2023
Happy New Year and Straight Key Night from HI7/N2CQR
HNY from HI7! In keeping with SolderSmoke tradition, I recorded the above greeting. If you look over my right shoulder, or in the picture below, you can see the apartment building we will be moving into (at least for the winter months) later this year. There will be a small shack on the top level. And yes, a telescope.
This morning I fired up the uBITX on 20 CW and made two Straight Key Night contacts. My key is the straightest of the straight -- a homewbrew thing made from an old hack-saw blade, copper tape, brass screws, scrap wood, and duct tape. Picture below.
73 to all! HNY and good luck in 2023!
Saturday, December 31, 2022
Wednesday, December 28, 2022
Tuesday, December 27, 2022
Monday, December 26, 2022
A Blast from the Past: TR on Homebrewing (sort of)
"It is not the critic who counts; not the ham who points out how the homebrewer stumbles, or where the builder of rigs could have built them better. The credit belongs to the ham who is actually at the workbench, whose hands are scarred by solder and metal and glue; who strives valiantly; who errs, whose amp oscillates again and again, because there is no effort without error and shortcoming; but who does actually strive to build his rigs; who knows great enthusiasms, the great devotions; who spends himself in a worthy cause; who at the best knows in the end the triumph of homebrew achievement, and who at the worst, if he fails, at least fails while daring greatly, so that his place shall never be with those cold and timid operators who neither know victory nor defeat.”
Sunday, December 25, 2022
Some Direct Conversion Receiver History
Here is the article by Wes Hayward and Dick Bingham that started it all:
https://worldradiohistory.com/Archive-DX/QST/60s/QST-1968-11.pdf
page 15
Here's a discussion by Wes of the original project:
https://www.n5dux.com/ham/files/pdf/Direct%20Conversion%20Receivers%20History%20-%20W7ZOI.pdf
Here is an article about DC receiver in phasing rigs by Gary Breed K9AY:
https://worldradiohistory.com/Archive-DX/QST/80s/QST-1988-01.pdf
page 16
Roy Lewallen W7EL's Optimized transceiver (with a direct conversion receiver):
https://worldradiohistory.com/Archive-DX/QST/80s/QST-1980-08.pdf
page 14
Jerry KI4IO on Building a DC Receiver
https://groups.io/g/qrptech/message/17
Michael Black wrote on March 5, 2014 at 3:54 PM
Isn't it a bit dated?
When "direct conversion" receivers came along in 1968 (the concept existed before, just not the name), it was to build simple receivers. They took over from regens (which of course for the purpose of CW and SSB, were "direct conversion"), and kind of bumped simple superheterodyne receivers out of the magazines.
And they were easy to build, so long as the meaning of the dots were standard, but good performance was elusive. Endless articles about better mixers or more front end selectivity, and still the same basic results The Heathkit HW-7 comes along, and endless mods to that, but still no perfection.
Slowly the move was back to simple superhets, especially with some of the early seventies ICs intended for radio, and then ladder filters came along (actually they came early at least by 1974 from the UK and/or France, but while they got mention in North America early-ish, it took some years before the KVG filters were pushed aside and ladder filters got the spotlight).
And then wham, in the mid-eighties someone caught on. The problem with direct conversion receivers wasn't the mixer (well not once it was a balanced mixer) or lack of front-end selectivity, it was the matter of properly terminating the mixer. The problems that had been there all along were gone. And direct conversion receivers started their climb to being complicated receivers.
I guess it was that receiver by Gary Breed in QST circa 1986 with diode balanced mixers and termination that changed things. A new concept, but not really, I remember an article in QST in 1974 where a DBM diode mixer for VHF was properly terminated, and yet the concept went no further until a decade later.
Actually, I think there is a tiny bit about mixer termination in "Solid State Design for the Radio Amateur" but it never went so far as to say "this is what we need".
Or perhaps that tiny transceiver by Roy Llewellyn in QST was the first, I cant' remember. It certainly used a diode mixer with termination for the receiver.
And that set the stage for Rick Campbell's various receivers, all counting on termination of the mixer.
The ideas can often be there, but not applied because technology doesn't allow it yet, or just not looking that far beyond this month's construction article.
Michael
Saturday, December 17, 2022
Kludge. Rhymes with Fudge. On PBS!
At about 12:26 in this video, David Brooks uses the word "kludge" on the Public Broadcasting System. He pronounces it CORRECTLY! (But then he and the host question whether it is a real word.)
Friday, December 16, 2022
Did Marconi Cross the Atlantic with a Coherer? No.
Jagadish Chandra Bose
A while back I posted the re-mastered version of the excellent "Secret Live of Machines" episode on radio. Among other amazing things, Tim and Rex build a spark radio transmitter and a receiver that uses a coherer and a tapper. They even set up a demonstration and sent signals from the pier to the shore. Very cool.
I shared this with George WB5OYP of the Vienna Wireless Society because he had been looking carefully at the gear that Marconi allegedly used to make that first transatlantic contact. George wondered if Marconi could have really done this with a coherer as his detector; he was -- for good reason -- skeptical. Could a glass tube filled with metal filings really detect radio waves sent from across the mighty Atlantic?
Marconi claimed that he did it with a coherer as the detector:
On December 12, 1901, Marconi attempted to send the first radio signals across the Atlantic Ocean, in spite of predictions that the radio waves would be lost as the earth curved over that long distance. He set up a specially designed wireless receiver in Newfoundland, Canada, using a coherer (a glass tube filled with iron filings) to conduct radio waves, and balloons to lift the antenna as high as possible. The signals were sent in Morse code from Poldhu, Cornwall, in England. Marconi later wrote about the experience:
"Shortly before midday I placed the single earphone to my ear and started listening. The receiver on the table before me was very crude -- a few coils and condensers and a coherer -- no valves, no amplifiers, not even a crystal. But I was at last on the point of putting the correctness of all my beliefs to test. The answer came at 12: 30 when I heard, faintly but distinctly, pip-pip-pip. I handed the phone to Kemp: "Can you hear anything?" I asked. "Yes," he said. "The letter S." He could hear it. I knew then that all my anticipations had been justified. The electric waves sent out into space from Poldhu had traversed the Atlantic -- the distance, enormous as it seemed then, of 1,700 miles -- unimpeded by the curvature of the earth. The result meant much more to me than the mere successful realization of an experiment. As Sir Oliver Lodge has stated, it was an epoch in history. I now felt for the first time absolutely certain that the day would come when mankind would be able to send messages without wires not only across the Atlantic but between the farthermost ends of the earth."
https://www.pbs.org/wgbh/aso/databank/entries/dt01ma.html
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I mentioned this in SolderSmoke Podcast #242. This resulted in a very interesting message from Steve AB4I:
The reason that I am writing is to comment on the coherer and Marconi's transatlantic test. One of my research interests in my doctoral studies was the development and evolution of early radio detectors. Marconi did not use a coherer for the successful transatlantic tests, but secretly used a detector and telephone receiver that had been invented by the Indian polymath Jagadish Chandra Bose of Calcutta. Bose's iron-mercury-iron detector was sensitive to a wide range of wavelengths and he used the detector in his 60-GHz millimeter wave and experiments. Bose presented his results to the Royal Society in London in 1899 and his paper was published in the Proceedings of the Royal Society the same year. Marconi came by the mysterious mercury coherer detector through a friend in the Italian Navy who constructed the device from Bose's paper in the Proceedings in an effort to improve the performance of the Marconi equipment aboard . The Bose detector was superior to anything that Marconi had and was key to the success of the transatlantic tests and for Marconi's subsequent successes. Marconi then filed a patent for the detector in his own name in 1902, even though it was not his invention.
A lot of nasty business went on in the early days of wireless. The scandal around the "Italian Navy coherer" raged for years, but eventually the role of Bose was revealed. The popular view of Marconi as radio inventor extraordinaire is idealistic, because he did not actually invent anything, but he was very good at dragging laboratory hardware into the real world to serve practical ends. In every case, crucial parts of Marconi's patents were stolen or copied from other sources and successfully defended through aggressive litigation, deep financial backing, and extensive public relations through advertising and newspaper interviews. Marconi absolutely deserves recognition for his successes in the development of practical wireless communications although he is not noted for his ethics. Marconi's reputation is a bit tarnished nowadays, but that of Jagadish Chandra Bose has blossomed and he is now acknowledged for his epochal work that was fully a half-century before his time.
As for the coherer, we still do not have a full understanding of how the thing actually works. The cohesion effect of small particles clumping together in the presence of a static charge has been known from antiquity as evidenced by dust bunnies under beds through the ages. There were coherer-like lightning arrestors used on telegraph lines just after the American Civil War and in 1879 David Hughes found that a carbon microphone with loose contacts could detect arcing in nearby equipment and from considerable distances too. He was told that the phenomenon was nothing new and he just missed the discovery of radio waves. Thanks to some monumentally bad advice we now speak of Hertzian Waves instead of Hughian Waves. Branly made a detailed study of resistance changes in metal particles and is generally acknowledged as the inventor of the coherer detector. Oliver Lodge coined the name 'coherer' and demonstrated the detection of Hertzian waves in 1894 a few months after Hertz's death. Lodge wrote a tribute to Hertz, which was to inspire the young Marconi to begin his own experiments with Hertzian waves.
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Hack-A-Day looked at all this back in 2016:
Here are the key passages: One improvement invented by Bose in 1899 was the iron-mercury-iron coherer, with a pool of mercury in a small metal cup. A film of insulating oil covered the mercury, and an iron disc penetrated the oil but did not make contact with the liquid mercury. RF energy would break down the insulating oil and conduct, with the advantage of not needing a decoherer to reset the system.
Bose’s improved coherer design would miraculously appear in Marconi’s transatlantic wireless receiver two years later. The circumstances are somewhat shady – Marconi’s story about how he came up with the design varied over time, and there were reports that Bose’s circuit designs were stolen from a London hotel room while he was presenting his work. In any case, Bose was not interested in commercializing his invention, which Marconi would go on to patent himself.
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Here is a lot more background on Dr. Bose:
http://www.cse.iitm.ac.in/~murthy/sirjcbose.pdf
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I think the more we learn about Marconi, the less admirable he seems.
Wednesday, December 14, 2022
Faust Gonsett and the SB-33 in 1963
Click on the images for better views
When this ad appeared in 73 Magazine in February 1963 I was 4 years old, living on Manhattan Island. Pete N6QW was in the Navy, heading to Midway Island.
Pete writes:
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This ad has a tremendous impact on the foundations of our hobby. The SBE-33 was pure genius in its design and implementation.
- It is a hybrid rig using Germanium transistors –the transistor was only 15 years old
- The Mechanical band switching showed the strong use of mechanical assemblies
- The small size was simply amazing
- The Bi-lateral circuitry predates any Bitx circuits.
- The urban legend was that a team of illuminati were involved in its design (Don Stoner is one name that pops up)
- The Japanese were a quick study and the FTdx100 in 1967 is a result, only better.
- Many are still around in shacks. I have three
Gonset was well known for innovative designs – the Gooney Box is another example. Look at all of his compact mobile equipment.
The next point – the final owner of SBE was Raytheon thusly the next generation of SDR Radio Equipment for the US Air Force can trace its pedigree to the SBE-33.
This was the appliance box of 1963. I saw my 1st SBE-33 (August 1963) when likely you were in the 2nd Grade and I was headed off to Midway island.
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I have an SBE-33 that N6QW sent me. Thanks again Pete!
Also, I'd like to note that W6VR had a very cool name. Faust Gonsett. I just sounds like the name of a real radio guy. Google says this of the given name Faust:
"Faust as a boy's name is of Latin origin, and the meaning of Faust is 'fortunate, enjoying good luck.' Indeed.
Tuesday, December 13, 2022
Save the Antenna!
SolderSmoke fans have an interest in saving this antenna because it is the site of one of the most amazing RF troubleshooting stories of all time: Wilson and Penzias were trying to track down some noise. At one point they thought it might be the result of bird droppings. Uh, no, it was really the result of the Big Bang! Please sign the petition:
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