Questions tagged [hf]

The frequency range 3-30 MHz. HF radio waves often propagate by bouncing off the ionosphere, allowing communication between continents. This tag may also be used for questions about the 160 meter band (1.8 MHz), which while not HF is often referred to as such due to its similar propagation.

Radio frequencies are commonly divided into ranges by frequency. Here are some of the ranges:

  • Medium Frequency (MF), 300 kHz - 3 MHz
  • High Frequency (HF), 3 - 30 MHz
  • Very High Frequency (VHF), 30 - 300 MHz

HF frequencies have been used since the very earliest days of radio, and the HF bands remain very popular in amateur radio. HF radio signals often bounce off the ionosphere, allowing communication far beyond line-of-sight ranges; ham radio contacts between continents are common.

More information about HF is available at Wikipedia.

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Highest Q loading Coils

The loading coils for electrically short MF and HF antennas that I have seen over the decades are all air cored. Ferrites have got better but air has not .Clearly a ferrite cored coil would be smaller but would it have lower losses? How would say a…
Autistic
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Can we build an open source firmware for the X1M qrp transceiver

There is a chinese transceiver the X1M, look at x1m.wikia.com and on google. That is basically an SDR but no one has worked to build open firmware for it yet. i think we have a great chance to build something awesome from a cheap and solid chinese…