400 Hz is easier to turn back into DC using much smaller capacitors in the
power supplies.  Think about the resulting waveform after full wave
rectification of 60 Hz vs.,. 400 Hz.  there are much deeper valleys to fill
in the 60 Hz waveform.

73,, KY2D

Jim Kutsch
Jacksonville, FL

----- Original Message -----
From: "shawn klein" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Friday, November 07, 2003 17:38
Subject: Re: OT - Line Voltages, Frequency in History


Definitely an interesting topic. It's funny, I hadn't
read this thread till today, but yesterday I was just
musing on how interesting radio must have sounded in
the spark gap erra with DC and various freqs of AC
being used. I wonder why the military and aviation
decided to use 400 HZ, and you probably know that the
phone system uses 25 HZ AC ring current. Just think,
if everybody'd stuck to DC we wouldn't have to deal
with 60 HZ RFI. On the other hand, getting
inadvertently zapped by 120 volts DC might be a bit
more dangerous, I once heard, because your muscles
would contract and not let you let go. It's doubtfull
that the high voltage power line cancer scare would
have occurred.