[GreenKeys] 10Hz RTTY

[Sheldon Daitch]

Many years ago, it appears that Voice of America may have experimented with small shift frequency shift keying on the HF transmitters, but it certainly was gone by 1979, when I started working at Greenville VOA.

I think it might have been an attempt to run RTTY on the existing HF transmitters vice dedicated HF communications transmitters, . Many of the Greenville transmitters were HF feeders to overseas transmitter sites and any of the HF receivers used at the receiver sites associated with these transmitter sites used exalted carrier receiving techniques and these receivers used AFC circuits to keep the receivers exactly on frequency.

If the carrier frequency was being shifted to accommodate RTTY, it is very likely the AFC circuits in these receivers would not track the shifts and cause major problems for the receivers and of course, audio quality for the transmitters overseas.

73Sheldon
WA4MZZ


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