[Elecraft] K1: KAT1 -- cannot reach 5.0W output when adjusting R1 after calibrating power

[KB3OKS - Mark]

I believe I solved my KAT1 power calibration this morning, so this is a
follow up post just in case anyone else ever runs into this problem and
searches this forum.

The solution was actually in re-checking my setting for the voltage null in
trimmer cap C9 in the step prior to power calibration. On the advice of a
friend of mine, I first decided to go way back to re-peaking the receive and
transmit of the K1-4 filter board (minus the KAT1 tuner) just to make sure I
wasn't selling myself short there. Things were still good, but I took my
time with those steps anyway just to make absolutely sure that the settings
of all the trimmer caps on the filter board were in their optimum positions.
If nothing else maybe I improved things just slightly from where they were.

Back at the KAT1 testing, I was still getting the same result with the RF
probe and setting of R1 -- turning R1 to its maximum travel was still only
showing about 3.8 watts out. So I backed up a step and re-checked the
setting of C9 for the voltage null. I felt good about it the first time I'd
gone through that step, but who knows ... maybe I didn't have as good a
connection as I thought with my probes at TP1 and the ground jumper.

In any case, power calibration this time around gave much better results. I
only had to turn R1 to about the 2 o'clock position (only a little farther
than it was already turned according to the instructions) to achieve 5.0
watts on the display. At its maximum, it was displaying about 8.5 watts!
That also matched up with my friend's description of his KAT1 testing.

So now I'm off to check the KAT1 with a real antenna. SWR with my dummy load
(clocking in at 49.5 Ohms) shows 1.0r ... so far so good.

Good luck to everyone else with their respective builds and testing in the
meantime. Looking forward to hearing and QSOing with all of you down the
log.

73,

Mark / KB3OKS


KB3OKS - Mark wrote:
> 
> [The problem:]
> The power out display on the K1 is now showing about 1.0. Adjusting R1
> even all the way to its max will only display 3.8 at the point where
> R1 is maxed out. I'm unable to reach 5.0. If I then exit tune mode and
> check my power out setting in the OUT menu setting, it's down around
> 1.0, plus or minus a few tenths.
> 

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