Comment by _moof
25 days ago
HF radio. Highly depdendent on space weather, but generally I can communicate around the world with only 100 watts and a long wire.
Be aware though that transmitting on any radio is like turning on a giant, extremely bright light bulb directly above your antenna. Anyone with basic radio know-how will be able to hear you and locate you.
I had to think for a second to realize that HF means lower frequency than VHF, not high frequency in an absolute sense.
It's very silly that "high frequency" is among the lowest frequencies, and that we wound up with Very, Ultra, Super, Extremely, and Tremendously High Frequencies!
I thought you had to be joking, but... https://en.wikipedia.org/wiki/Tremendously_high_frequency
And here I was thinking that GregTech's "Ludicrous Voltage" sounded out of place...
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It's because when the term was first used, newer electronics to generate those frequencies had only recently become available.
The HF band is 3-30 MHz. Maritime navigation was operating on 500kHz (.5MHz) for most of the 20th century because that was what Marconi's alternators used at the beginning of the system. These machines produced the carrier frequency mechanically by rotating a disc with lots of tiny magnets on it at high speed.
https://en.wikipedia.org/wiki/Alexanderson_alternator
Reminds me of High Speed USB.
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Back in ye olden days, HF was really high! What we'd consider today to be near useless due to limited bandwidth and insane antenna requirements were once the primary frequencies for communications.
I wondered if that was the case! 28 MHz must've seemed pretty high at the time. :)