Amateur Radio short hand from High Frequency.
High frequency (HF) is the ITU designation[1] for the range of radio frequencyelectromagnetic waves (radio waves) between 3 and 30 megahertz (MHz).
https://en.wikipedia.org/wiki/High_frequency
HF
Amateur Radio short hand from High Frequency.
High frequency (HF) is the ITU designation[1] for the range of radio frequencyelectromagnetic waves (radio waves) between 3 and 30 megahertz (MHz).
https://en.wikipedia.org/wiki/High_frequency