[aprssig] 1. DTMF on HF? (Robert Bruninga)

[K1LPI]

Try NBFM. If the bandwidth does not exceed 2.5 KHz or so it might be permitted on HF bands. I haven't checked but on 10m it certainly is. Using nbfm might also allow use of sub audible tones and maybe even DSS? Then switch modes as required.  Many hf radios have optional fm boards if not built in, and AR ports allow for mode switching under software control.

K1LPI
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