[TenTec] TX EQ = -14 dB for PSK31

[Merle Bone]

Ron Castro (N6IE) said:
"Since PSK-31 works by shifting phase, the amplitude variations caused by ALC 
shouldn't have any significant effect on either the IMD or readability of 
this signal."
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Ron, we are going to have to disagree on this one. Anytime you introduce a nonlinearity into the system producing PSK31 signals you will generate unintended sidebands. You may do that by overdriving the audio stage or the PA , or you can do that by introducing any nonlinearity into the RF amplifiers, including the final stage.   Certainly, massively overdriving the signal, as you described, is one way to cause a problem. Of course, using speech processing - which introduces distortion into the signal, - will also cause serious sideband distortion and excessively wide signals. The problems caused by ALC making the final non-linear is probably a function of how much ALC action is invoked. But I think any distortion isn't helpful in this mode and creates a wide signal that isn't appreciated by other users. 

This is a pretty good presentation on PSK and tuning a rig (Worth looking at) http://kk7uq.com/html/download/IMD%20Presentation.pdf . I think you will always find that papers on this mode recommend low, or if possible, NO ALC action.
73. Merle - W0EWM