[Elecraft] K3: Still unable to set power correctly - clarification

[Dave, G4AON]

There seems to be ambiguity as to what this problem is and its effect.

Several months ago, I and others noted difficulty setting power levels 
on data modes. This was looked at by Lyle and Wayne with an improvement 
but it still is an issue right up to the latest beta firmware (2.76). 
This problem has little to do with the K3 pre-set power level as dialled 
in with the PWR control.

Many of us have very accurate peak reading external power meters and 
oscilloscopes to set peak power levels with - and know what power we 
initially set. What happens is the ALC is fairly loose in operation with 
a long time constant, while this may produce a clean signal when running 
near full power on SSB, the peak power levels at less than full output 
vary considerably. Not only is this a pain on data modes such as PSK31 
where you are (a) not needing high power and (b) trying to produce very 
low IMD products, but also when driving a linear which requires less 
than 100W of drive.

Here in the UK the power limit is 400 Watts, driving my Acom 1000 linear 
with typically 20 ~ 25 Watts of carrier will give 400 Watts measured on 
an LP-100 power meter. However, during the course of an SSB QSO the 
power output on peaks runs anywhere from 200 Watts to 600 Watts and that 
is not good. Checking my K3 at 20 to 30 Watts output into a dummy load 
also produces this variability.

We have been told the K3 ALC produces a cleaner signal than many other 
transceivers with "tight" ALC control, I don't doubt the signal is 
cleaner than many, however the problem of adhering to a legal power 
limit still remains... Clean signal or not.

73 Dave, G4AON
K3/100 #80