[Elecraft] K2 and the KPA100 Power Fluxuates?

[Michael Harris]

G'day Folks,

> It's 5W output the AMP, not out of the K2!  Probably a few mW out of the
K2
> itself.

Not so.

I raised this question when I first built my KPA100.  On my unit at a set
20W output the power fluctuates between 17 - 22W.  This makes it very
difficult to set the SWR bridge pots for example in the KAT100.

The problem eases a little as the PA heats up but never goes away.  I find
it's a little more stable at a demanded 30W.  I feel the ALC is probably too
aggressive and would be a suitable subject for study and a possible firmware
upgrade or what have you.

It is a real niggle.

Regards,

Mike VP8NO (IOTA SA-002)
GQRP 10148
QRP-Canada #57
K2/100 #1400


> At 11:54 AM 6/11/03, Harry Yingst wrote:
> >hmmmmmmmmm
> >
> >5 watts is a Big difference when feeding an amp
> >(150 watt fluctuation on the output of the amp for a 5 watt variance).
> >
> >Any way to settle it down?
> >
> >
> >
> >
> >--- Tom Hammond <n0ss@earthlink.net> wrote:
> > > Harry:
> > >
> > > At 09:26 AM 6/11/03, Harry Yingst wrote:
> > > >I got the KPA100 all finished up and installed last night 100+ watts
> > > >out on all bands.
> > > >
> > > >The KPA100 went together without a hitch.
> > > >
> > > >The only thing I noticed is that the output power fluctuates with a
> > > >steady carrier (Bounces around, not just a steady rise, ie: in tune
> > > >mode, etc).
> > > >
> > > >I recall seeing something about this as being normal behavior.
> > > >
> > > >Any thoughts?
> > >
> > > You SHOULD expect to see a SMALL amount of fluctuation (maybe 5W or
> > > so, at
> > > higher power levels) as the ALC attempts to maintain the requested
> > > power. I
> > > think the 'adjustments' are made about 1/sec.
>