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!
And here I was thinking that GregTech's "Ludicrous Voltage" sounded out of place...
> The time derivative of acceleration is called jerk, and the time derivative of jerk is called jounce. One published paper whimsically named the fourth, fifth, and sixth derivatives of "snap", "crackle", and "pop" after the cartoon characters on boxes of Rice Krispies breakfast cereal.
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.