Just for Intruder....
Yes, there are HF radios that scan a preset range of frequencies, automatically looking for the best signal/noise ratio to communicate with, it's called ALE, Automatic Link Establishment.
If all the radios in the net have the same range selected, by prior arrangement, then they will all communicate on the same frequency, and that frequency will/can change as the signal/noise ratio changes.
Very neat really!
Cheers...FD...
