Message-Id: <20031113184200.WMDK17368.imf20aec.mail.bellsouth.net@[68.212.98.27]>
Martin wrote:
>As for why aircraft use 400 HZ, you are all right but there is
>even one more reason. While I don't know why the exact number of
>400 Hertz, the biggest reason for using a higher frequency is the
>size of inductors such as what you have in motors and transformers.
<snip>
>I think that we'd get pretty tired of hearing that mosquito
>whine everywhere very quickly.
I get my share of aeronautical mobiles check in with me when I'm ncs
for the Maritime mobile service net and you always hear a hint of that
400 hz and its harmonics.
Also note that on hf a lot of the aero comms sound like there's a
little rf feedback into the audio. Harder to get a good ground up
there <grin>.
73 de nf5b
Richard Webb
Electric Spider Productions
"They that can give up essential liberty to obtain a little temporary
safety deserve neither liberty nor safety."
--- Benjamin Franklin, NOvember 1755 from the
Historical review of Pennsylvania