On Nov 15, 5:39*am, dave wrote:
D. Peter Maus wrote:

HF aero comms are not all USB. Some are. Most are still AM. This is due
to the ability of AM signals of very low level to be noticed while other
comms are taking place, facilitating discovery in an emergency when
conditions are less than ideal.

- VHF/UHF aero is AM; HF aero is SSB.
-*You can have half a dozen SSB transmitters
- all talking at once on the same frequency with
- much less harm than there'd be with several
- AM carriers.
-*I don't think intelligibility has anything to do with it.

Dave for both AM a/o SSB Voice Communications
'Intelligibility' is everything : First you got to hear
them and second you have to understand them too.
-to-communicate-

Same relative Power Output AM 100W or SSB 100PEP
most times the Receiving Station will Report the SSB as
having a Strong and more Listenable Voice Signal than
the AM. - nitt? ~ RHF