10 Mar
2002
10 Mar
'02
9:51 a.m.
I agree with what you say here, even for the vintage
of the
transmitters. They were built in the 40's & 50's. It was
even fascinating to see how the technology worked. To modulate
a portion of the RF with low frequency (ranging from 30 to 90 hz)
there was two RF coupling loops with a specially designed fan
blade spinning between the loops. This changed the amplitude
of the RF coupled from one loop to the other.
Goniometer.
William Donzelli
aw288(a)osfn.org