[GreenKeys] Brecom system

[KFIam640@aol.com]

In a message dated 4/23/03 13:44:22 PM Pacific Daylight Time, bstrang@iac.ne=
t=20
writes:

>=20
> Someone was just telling me about the "Brecom"
> system developed in or around WW2.  It involved
> hidden FSK keying on clear-channel am broadcast
> stations in Cincinnati (WLW) , St. Louis, Des
> Moines, Salt Lake City, San Francisco, Los
> Angeles, Dallas, New Orleans, Atlanta, New York,
> and Pittsburgh.
>=20
> They keyed the carrier of these stations by two
> cycles at 30wpm.  It was unnoticeable by regular
> listeners.  This chain of stations was a backup if
> national telephone communications failed.  It
> apparently wasn't needed for the design purpose,
> but they kept chatter on the system to maintain
> readiness.  Apparently used model 15 machines, but
> my informant wasn't certain.
>=20
> Anyone have more information on this?
>=20
>=20
>=20
>=20

I just received word from a long time KFI retiree with the following comment=
s=20
about the KFI FSK system.

Marvin Collins, W6OQI
retired Chief Engineer, KFI Los Angeles

The Navy was using KFI's 640kc audio modulated carrier, to frequency modulat=
e=20
a tty carrier with a Navy code group to ships at sea.=A0=20
=A0
It was not much of a problem that the Navy's frequency modulated square wave=
=20
contained amplitude modulated KFI program.=A0 KFI listener's receivers didn'=
t=20
define their band width enough to demodulate the FM
=A0
Marvin;=A0 When working at the KFI 50 kw,=A0 I saw the tty equipment parked=20=
in=20
the input room. While this was off or shut down,(KFI not sending tty)=A0 I s=
aw=20
the deviation monitor (input bay in transmitter room) slowly swing exactly 5=
=20
cycles + - with dwell enough to create a square wave of our carrier.=A0 I wa=
s=20
told not to worry and not to talk about it.=A0 We were cooperating with a Na=
vy=20
project.=A0 KFI was chosen because of our good signal over the ocean.
=A0
We, (I didn't ) could print out the coded information, but it was still in a=
=20
letter code group!
=A0
Marvin, your understanding about this project is right, and from what you=20
sent, I can't add anything to it.



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