[GreenKeys] oddball mark space frequencies

[Nick England]

Center frequency of 2295 kc with an 85 cps shift was one of the standard
channels in a 8 or 16 channel frequency-division multiplexed system a.k.a.
"tone pack" or VFCT (Voice Frequency Carrier Telegraphy). There were many
commercial as well as military systems that used this scheme. A block
diagram of the Navy's AN/UCC-1 is at
http://www.navy-radio.com/rtty/ucc1/ucc1-sys-31.JPG
and info on more of these systems is at
http://www.navy-radio.com/rtty-mux.htm

The item on eBay is 1/2 of a Northern Radio 152 dual tone keyer that has
the plug-in filter for 2252.5/2337/5 - FWIW a nice shiny complete Type 152
(but without filters) is also up on eBay.

cheers,
Nick K4NYW
www.navy-radio.com

On Thu, Feb 28, 2013 at 7:58 AM, Rokumon Cat <rokumoncat at yahoo.com> wrote:

> Hi,
>
> I was wondering what use would an audio pair of 2337.5/mark and
> 2252.5/space would be for AFSK?
>
> I found on the e-place a tone unit with this pair for my northern radio
> AFSK generator.
>
> I know that the recommended amateur frequencies are 2125/mark and
> 2275/space.
>
> Thanks once again!
>
> Joe
>
>
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