[GreenKeys] 850 shift history - AN/FGC-1

[Jim Haynes]

On Fri, 8 Oct 2021, Nick England wrote:

>       On Fri, October 8, 2021 2:53 pm, Nick England wrote:
>       > Well, I found my FGC-1 manual but it is later than the 1943
>       > The one I have is August 1952 TM 11-356 which supersedes the
>       1943 edition
>       > and is typeset in typical TM fashion. One interesting addition
>       is that
>       > when
>       > radio frequencies in the 70-kc to 500-kc range are used, a
>       frequency shift
>       > of 170 cps is used which necessitates replacement of the M and

Yeah, I didn't know that.

There is a paper somewhere about transmitting FSK at VLF, points out that 
the antenna is rather sharply resonant, so they experimented with 
switching in a reactance electronically to make the antenna resonate
as the frequency shifted.