On 2019-06-06 09:37, Noel Petit via AMSAT-BB wrote:
the other reason to stick with AM is that you can hear if other stations are trying to break in. FM has capture and blocks all but the strongest station. AM can superimpose multiple signals and hear if emergency calls may be made. Additionally, in the '30's FM was nearly impossible to generate reliably. AM doesn't depend on the transmitter's stability (to an extent).
On linear transponder satellites (https://www.amsat.org/two-way-satellites/), you _can_ hear other stations doubling.
AM is wasteful of power, as others have commented, and has no place on a power-limited satellite. The carrier, containing no information, consumes 2/3rds of the transmitted power. The rest of the power is split between two sidebands carrying the exact same information. (https://www.tutorialspoint.com/analog_communication/analog_communication_amp...)
I disagree strongly with your assertion that FM was "nearly impossible" to generate. (https://en.wikipedia.org/wiki/Armstrong_phase_modulator)
--- Zach N0ZGO