> This in turn is why air traffic still use AM where you can hear both overlapping transmissions at once (possibly garbled if carrier wave was off), and react accordingly rather than being unaware that it happened.
I’m not convinced this is the reason. The carrier wave is always off by a little. While you’re transmitting you hear nothing anyway. And when two parties are transmitting simultaneously, any third parties just hear very loud screeching. A 0.001% difference in carrier frequency would be more than enough to cause this effect in a VHF radio. Notably, this exact problem was a major contributing cause to the worst accident in aviation history. Using FM would have prevented it.
I’m not convinced this is the reason. The carrier wave is always off by a little. While you’re transmitting you hear nothing anyway. And when two parties are transmitting simultaneously, any third parties just hear very loud screeching. A 0.001% difference in carrier frequency would be more than enough to cause this effect in a VHF radio. Notably, this exact problem was a major contributing cause to the worst accident in aviation history. Using FM would have prevented it.
https://archive.ph/2013.02.01-162840/http://www.salon.com/20...