[Elecraft] Tips on setting transmit drive for PSK31

[Don Wilhelm]

Wes,

The capability operates within limits - it cannot be infinite.
However, the K3 (K2 as well) uses a control loop for power output 
control.  It senses the output power and adjusts the RF drive to 
compensate for differences in the power requested and the actual.
In SSB (and data modes) it operates on the peak values, so it will be 
related to the peak audio level rather than to the average.

The K2 has operated this way all its life, but the K3 has a more 
sophisticated detection mechanism, so control can be more precise than 
the K2.  It still takes a bit of output time for the power to settle 
down, and that fact has caused a bit of 'wonderment' among users - if 
the response is too fast, the power level will oscillate because of the 
required high gain in the control loop, so it take a couple dit times 
(or equal for SSB and Data modes) for the power to level out.  The 
control loop is reset with a band change, and a few other actions that I 
cannot recall right now.

73,
Don W3FPR


Wes Stewart wrote:
>
> Don,
>
> I'm curious about your statement that "the K3 will attempt to develop more power to maintain the power output level you have chosen" -
>
> Since PSK is an audio driven mode with a varying amplitude component,  linearity is very important.  What you are suggesting is that the K3 is highly non-linear and has infinite gain, i.e. it puts out X watts regardless of drive.
>
> I know that you don't mean that, so could you clarify?
>
> Wes  N7WS
>   
>