[GreenKeys] 10cps shift

[Brooke Clarke]

Hi:

The BR Chirp system uses a similar technology for the order wire 
message.  As the transmitter is sweeping from 2 to 30 MHz at 100 kHz per 
second it's also being FSK modulated.  
http://www.prc68.com/I/RCS-5A.shtml#Cc
They made some (prototype only?) Chirpcom HF man pack radios that would 
inter operate with the order wire message format.  Since the short (40 
character max) message was transmitted on all frequencies between 2 and 
30 MHz it was pretty much sure to find an optimum frequency.

I wonder if the AM broadcast FSK system is still in place?

Have Fun,

Brooke Clarke
http://www.PRC68.com


George B. Hutchison wrote:
> GreenKeyers&  Nick - - -
>
> The Defense Department at one time had an arrangement with a group of
> broadcast stations around the country where those affiliated stations
> were carrying clear text traffic by shifting their carriers ten
> cycles at a data rate of 60 WPM.
>
> A few that I know of were WABC in New York, KFI in Los Angeles, and
> KNBR in San Francisco.
>
> KNBR keying was controlled out of Hamilton Field AFB, North of San
> Fran.
>
> The equipment and technology was produced by Barry Research.
>
> Rich McClung, WA6KNW, San Jose, Calif,. now works for TCI/BR, who
> absorbed Barry Research, the "/BR" denoting this. I think Rich does
> have some manuals on the equipment.
>
> There was a thread about this on GreenKeys some years back, and you
> might want to rummage through the site's archives to see all that was
> mentioned on this topic.
>
> George - W7TTY
>
>
>
>
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