This is a long article but a very interesting project. It uses HSMS-2850 Schottky detector diodes in a discriminator. He uses WE 1200 ohm sound powered headphones. He’s Canadian. https://electronbunker.ca/eb/FMCrystalSet.html
Archive for the ‘electronics history’ Category:
2024-03-22 The 555 Chip Under Microscope
The NE555 and some interesting information about it. A YouTube short by @Evilmonkeyzdesignz.
2024-03-15 Ferranti Argus “Hearing Aid” Computer
In the “Original Series” chapter this very interesting Wikipedia article talks about the “hearing aid computer” that used the OC-71 germanium transistors which were used in hearing aids and could go only up to 25kHz clock rate. That was quite slow – tube computers could clock at 500kHz. Later models used faster transistors and could
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2023-11-14 Amsec, Gary Lorenz, John Darjany – history of campus card
I finally found a bit of history about Gary Lorenz. He and I were high school friends. In 1972 he and John Darjany founded a company, Amsec, to make a “campus card system” for California Polytechnic University, Pomona. In 1974, Amsec was purchased by R.D. Products. A brief history of the campus card industry This
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2023-11-06 Reproduction Antique Radio Tubes and sets
I’ve been discussing the restoration of a hundred y.o. radio, and I thought about the retro light bulbs that look like incandescents but use LED filaments. Someone should make some old tubes that are actually using LEDs that look like the filaments, but just for decorative purposes. The glass envelope would look like the tube;
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2023-09-19 How Area Codes Were First Assigned By Telcos – Dr. Tyson
Well, Dr. Tyson got a few things not quite right. For one, he said that the area code numbers were chosen so that the most *people* would have do dial the least amount of digits. Well, that was just a side benefit. The central office equipment can’t have a dialer for every telephone, so they
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2023-07-16 26H20 Radar Repair At Ft. Monmouth, NJ
In 1966 I completed basic training and went to Ft. Monmouth, NJ for 10 months of Radar repair training. The last half of the course we got to work on the actual Radars in *that* barn-like building in the photo. I was on the graveyard shift. There were birds flying around up in the rafters
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2021-06-12 First Commercial Semiconductor Device
Q: What was the first commercially successful semiconductor device? Hint: It wasn’t germanium. https://en.m.wikipedia.org/wiki/Henry_Harrison_Chase_Dunwoody
