[AMRadio] Grandpa's Radio ?

[Donald Chester]

>Why does the FAA still use AM? Our aviation industry depends on AM to keep
>our people safe and we have the best safety record in the world. AM should
>be eliminated as some would say ? HUMM.

Because of the capture effect of FM.  They don't want a strong signal from 
one aircraft to completely block a slightly weaker signal from another.  
With AM, despite the QRM, both signals would be heard at the same time, 
letting air traffic controllers know there was a second plane.  With SSB, 
there is too much liklihood one station may be too far off frequency to be 
audible at a critical moment.

I have also heard it said that the doppler shift from a jet aircraft running 
at full speed is enough to make SSB inaudible due to frequency error.  Not 
sure if this it true.  Anyone know from experience?

Don k4kyv

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