[Elecraft] K3 power out vs commanded

[Mike Scott]

I spent some time measuring K3 power out vs. TUN PWR setting.

I used a 60 MHz scope for power measurement and a dummy load that measures
1.06 SWR with the 10X scope probe connected. I did all measurements on 40M
and I did these tests after conducting the power calibration procedure that
is part of the Elecraft K3 utility.

In general I found plus or minus 5% agreement with the Tune power setting
from 5 to 100 watts. With less than 5 watts power out the K3 seemed to have
greater errors with more output power than requested. Worse case was 0.1
watts commanded with 0.16 watts measured. At 100 watts I measured 95 watts
out, 5% low. I suspect +/- 5% is what I can measure with my equipment so I
find good agreement. The measurements were very repeatable and I saw no
evidence of power fluctuations on Tune power or later SSB tests.

I looked at PEP power out at two commanded power settings (100 watts and 30
watts). PEP was a tad low but it is now the same as CW tune (my TXG VCE is
+1 dB which I set based on these measurements). 

After looking at output in SSB I decided I could probably back my microphone
gain off a bit. Perhaps I was pressing the number of ALC bars more than I
needed to. There doesn't seem to be an advantage to pushing this.

Details are in this table, I hope it renders properly.

TUN	Measured	Error
0.1	0.16		58%
0.2	0.30		51%
0.3	0.46		52%
0.5	0.70		40%
1	1.2		16%
2	2.3		13%
5	5.1		1%
10	10.2		2%
12	12.1		1%
15	15.4		3%
20	19.8		-1%
30	30.3		1%
40	39.1		-2%
50	49.7		-1%
60	58.1		-3%
70	68.1		-3%
80	77.4		-3%
90	85.6		-5%
100	95.1		-5%

Mike Scott - AE6WA
Tarzana, CA (DM04 / near LA)
K3-100 #508/ KX1  #1311