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Biggles · 1st Oct 2017, 1:38 pm

I'm quite a fan of AM. It is easier on the ear. FM is harsh, and as has been said, a lot of the time you can get away with defeating the squelch altogether on AM. The background noise is soft. The squelch even when enabled seems to have a smooth transition, although I dare say this could be down to receiver design. There was at least one PMR radio (Kyodo/Key KM150) which employed a delay circuit on the audio side to get rid of that horrible noisy squelch tail you get with FM. I seem to remember that AM was much favoured over FM with CB enthusiasts. I agree with them. Why change things if they work ok?
Alan.

1st Oct 2017, 1:38 pm	#24
Biggles Rest in Peace Join Date: Feb 2004 Location: Hexham, Northumberland, UK. Posts: 2,234	Re: Why is aeronautical VHF AM? I'm quite a fan of AM. It is easier on the ear. FM is harsh, and as has been said, a lot of the time you can get away with defeating the squelch altogether on AM. The background noise is soft. The squelch even when enabled seems to have a smooth transition, although I dare say this could be down to receiver design. There was at least one PMR radio (Kyodo/Key KM150) which employed a delay circuit on the audio side to get rid of that horrible noisy squelch tail you get with FM. I seem to remember that AM was much favoured over FM with CB enthusiasts. I agree with them. Why change things if they work ok? Alan.