HF frequencies wouldn't even work for 1/2G.
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A New Use for Shortwave Frequencies
- Thread starter DavidEduardo
- Start date
And it skips. And propagation changes at different times of the day and year. Stable and predictable propagation are essential for point-to-point or mobile usage.
The Air Force has used shortwave to blast megawatts of power into the ionosphere to create aurora in Alaska, with the help of the "Internet is a series of tubes" guy:
en.wikipedia.org
High-frequency Active Auroral Research Program - Wikipedia
That project ended years ago. The University of Alaska Fairbanks now operates the facility in a much different capacity than USAF/DOD. I've actually been there.
Totally yes, and much more available bandwidth to transfer much more data.
I worked with fiber-optic devices that had a bandwidth of 3 GHz 30 years ago. Not cheap, but they worked.
Better than 1200 baud, wouldn't you say?
I was going to say, "nothing is worse than 1200 baud" but then I remembered my first modem was only a fraction of that!
Sometimes latency matters more than bandwidth.
You can have a super high 30GHz bandwidth connection, but if that fancy connection has an average latency of ~500 milliseconds or more, it makes the connection feel quite slow, and for timing-critical things like financial transactions, such a high latency makes that connection useless.
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You can have a super high 30GHz bandwidth connection, but if that fancy connection has an average latency of ~500 milliseconds or more, it makes the connection feel quite slow, and for timing-critical things like financial transactions, such a high latency makes that connection useless.
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How would any of this be different from Bloomberg Terminal, which has existed for around 40 years? They might as well use carrier pigeons to transmit the orders.
The difference is: This would likely be slower.
300 baud with a place on top of the box to put the phone handset?
Bloomberg Terminal these days uses standard TCP/IP protocols (and probably some UDP in there too; I don't remember specifics).
Early 1980s: AP teletypes ran at 150. UPI could go up to 180 if you had an Exel dot-matrix printer.
I vaguely recall there was a stock information service in the 1980s that used FM subcarriers…I think it was called QuoTrader. I had the impression at the time it was data that would be fed into some sort of computer terminal. Can’t find anything about it now, probably different than the service the receiver in the video used.
As for that receiver in the video: I’ve used SCA demodulators in the past to explore what kind of services were offered, and in big markets there were quite a few using music, spoken word, and data. I will note that if you tuned the SCA receiver to an FM station that didn’t have any such services, you would instead hear distorted audio from the main channel, as was heard in the video.
I did most of this listening in the 1980s-90s…”Muzak” type services, ethnic broadcasters, reading for the blind, medical information for the healthcare fields, religious formats. And there were datacasters back then that used SCA, though at bitrates that would be laughably slow these days.
Keep in mind that the “41 kHz crystal” mentioned in the video could very likely be mixed with another frequency or oscillator that would produce a different frequency to be tuned.
Sprint won’t be using any spectrum now or in the future because Sprint no longer exists.
That was fast for radioteletype, which also used much slower rates. You would have to change the gears in the teletype machine for each speed, as well as adjust the receiver and demodulator.
Radioteletype - Wikipedia
Pretty much so. I haven’t checked in many years but I should dig out my old SCA receiver setup and see if anything is left here in Houston. I think KUHF might still have the reading service for the blind on a 67 kHz subcarrier (they also currently have that on their HD-4) but I would guess everything else is long gone.