[Elecraft] K3 output power unstable

[Kamal Sirageldin]

Bjorn,

I notice the same thing with my K3 S/N 775, V2.38.   For me, the problem
appears to be in SSB mode, and not CW.  For example, if I adjust the power
output of my K3 by a very small amount i.e. say from 50w to 52w output, it
will initially transmit much more power than 52w  – driving my amplifier way
past the limit for a second or two before settling back down.  It seems to
me that it also does not necessary settle on the right power output.

The problem also happens when you switch bands.  The transmitter power
output will initially be very high (i.e. closer to 100W) and then appears to
require some ‘settling’ time to go back to the power that it is actually set
for when transmitting on SSB after a band change.  I do not have my K3 setup
for a different  power output on each band.  But, I know my amp, and know
the results of using other transceivers with it.  There is something
definitely wrong with the (my) K3 power output management on SSB.   I do not
use external ALC.  The amp is an Acom 2000A.  

73,
Kam  N3KS
Ksira at corpten.com

Bjorn wrote:
> 
> I am right now in the middle of the SAC contest when I notice that the K3
> has a problems keeping output power stable. I noticed some excessive high
> output from the amp when investigating I found that my K3 set to drive the
> amp with between 20-30 watt output depending on band, delivers
> substancially
> more. Ouptut power pulsate between nothing and full power, delivering more
> than 100 watts in bursts into the amp (designed for 30W input).
> 
> The problem is easiest to reproduce on 80 meters, but I am sure I saw the
> power wobble a few seconds b4 stabilizing on higher bands to. Even when
> the
> radio has cooled down to a PA temp of 34C the problem is there.
> 
> I think I read somthing about a similar prioblem somewhere, would
> apreciate
> any leads that I might help to narrow down and eliminate the problem.
> 
> 73 de Björn /SM0MDG (SE0X in SAC)
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Bjorn,

I posted about this very problem a couple of months ago but had virtually no
feedback so it's interesting to hear of someone else being affected. As you
say the power would drop quite suddenly then come back up; when running an
amp it once went right up to ~100w even though set for about 35w - it
tripped the amp....

Seems to do this on phone too but cw is easiest to see when it's happening.
To be honest it has hardly happened to me at all recently and I wonder if
you have the latest firmware installed. I did contact Elecraft support and I
seem to remember they said it was an AlC control software problem and to
keep downloading the latest firmware which would eventually sort it, and as
I say it seems much better now here. However the other day I was on phone
and the power was all over the place; it then started giving me TXG Error
messages and I had to do the 5 and 50 watt power output config from start to
finish which seemed to fix it.

Good luck in the contest - family duties here else I would be giving away
some points for you....

73, 

Stewart Rolfe, GW0ETF (K3 145)