Posted on 09/17/2009 4:01:07 PM PDT by dalereed
Aircraft started out using AM radios, since FM hadn’t been invented yet, and it became a world-wide standard. It would be expensive to switch over everything at once, and not everyone would do it, so in the interest of safety, AM remains the standard. An advantage AM has over FM is it’s possible for a higher powered ground station to step over an airplane with a stuck microphone and still be heard. With FM, two transmitters at once distort each other and nothing can be heard. The disadvantage with AM is the sound quality is low-fi and staticky, but with practice it’s good enough.
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