[Elecraft] K3 FSD-D (RTTY) power-control bug fixed

[Don Wilhelm]

The K3 power control is a closed loop system, and the loop gain will 
vary a bit with variations in the K3 RF chain gain.

While it would be ideal if the control loop could be critically damped 
for all K3s, I don't think that is practical because of component 
tolerances giving rise to variations in the RF TX gain.

IMHO it is better to make the loop gain be a bit overdamped than to 
allow it to be underdamped which would permit power spikes which drive 
some modern amplifiers 'wild'.

Yes, too much overdamping is not good - unfortunately the response time 
varies with the mode.  Hopefully a compromise can be found that will 
satisfy all K3s.

73,
Don W3FPR

On 2/8/2014 7:49 PM, Joe Subich, W4TV wrote:
>
> > Meanwhile it lags a little in this mode, which is hopefully just a
> > minor inconvenience.
>
> It's more than a little lag <G> - particularly on those occasions the 
> lower level is nearly 3 dB low to start.  I'm looking forward to the 
> next one.  Perhaps the update rate should be adaptive - fast for the
> first couple seconds of a transmission and then slowing down after the
> power has had a chance to stabilize ...
>
> 73,
>
>    ... Joe, W4TV
>