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