[SOLVED] Airoplane two way radio modulation

[BarNash]

Hi all

so I was told , that because of DOPPLER airplanes use AM or SSB modulated two way radio .
Is it true , if yes is it because that DOPPLER issue ?

Thanks
Elico

 

[davenn]

hi there Elico

I haven't heard that, but from my personal radio activities over the years, I do know that Doppler affects AM, FM and SSB

Dave

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OK google tells me this .....

Modulation[edit]

Aircraft communications radio operations worldwide use amplitude modulation, predominantly A3E double sideband with full carrier on VHF and UHF, and J3E single sideband with suppressed carrier on HF. Besides being simple, power-efficient and compatible with legacy equipment, AM and SSB permit stronger stations to override weaker or interfering stations, and don't suffer from the capture effect found in FM. Even if a pilot is transmitting, a control tower can "talk over" that transmission and other aircraft will hear a somewhat garbled mixture of both transmissions, rather than just one or the other. Even if both transmissions are received with identical signal strength, a heterodyne will be heard where no such indication of blockage would be evident in an FM system.[12]


nothing to do with Doppler, everything to do with signal efficiency and multiple signal interaction
and that I can agree with

Dave