[GreenKeys] Very Slow Shift Frequency keying?

[jim at k6ccc.org]

From: "steve bennett via GreenKeys" <greenkeys at mailman.qth.net>

> Ever heard of this?]


Yes.  Different purpose.  Decades ago a large electric utility I worked for could send data to interruptable customers for electrical load management using FSK on a 50KW AM station.  As I recall it was +/- 10 Hz.  Had to be that narrow to stay within the frequency limits of an AM broadcast station.

73
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Jim Walls - K6CCC
jim at k6ccc.org