[Elecraft] K2: KAT2 Calibration Results, typical?

[M. Linden]

Hi folks,

  I've finally had time to recalibrate my K2's KAT2 automatic antenna
tuner module using 25 and 100 Ohm loads on 40m. Please take a look at
my results and let me know if this is typical or if you think I have a
problem.

	     	25 Ω (2.0:1)	50 Ω (1.0:1)	100 Ω (2.0:1)
1900 kHz	2.1:1		1.0:1		1.9:1
3700 kHz	2.1:1		1.0:1		1.9:1
7150 kHz	2.0:1		1.0:1		2.0:1
10125 kHz	1.9:1		1.0:1		2.0:1
14172 kHz	1.8:1		1.0:1		2.2:1
18110 kHz	1.6:1		1.0:1		2.3:1
21200 kHz	1.5:1		1.0:1		2.4:1
24900 kHz	1.4:1		1.1:1		2.5:1
28500 kHz	1.4:1		1.2:1		2.6:1

	KAT2 - CALP (Watts)	OHR WM-2 (Watts)
1900 kHz	5.5			6.0
3700 kHz	6.0			6.0
7150 kHz	3.9			4.0
10125 kHz	5.2			5.0
14172 kHz	5.2			4.9
18110 kHz	5.5			5.0
21200 kHz	5.5			4.9
24900 kHz	5.0			4.3
28500 kHz	5.0			4.1

  Given the VSWR numbers, I thought that performing the 25/100 Ohm
calibration on 20m or 30m might give me better overall results. To the
contrary, the overall results were much worse than performing the
calibration on 40m -- 40m seems to be the sweet spot for CALS.

  Likewise, attempts to improve on the overall forward power
calibration (make 10m a bit better and 160m a bit worse) only yielded
results that were worse overall. As with CALS, 40m also seems to be the
sweet spot for CALP.

  Note that my OHR WM-2 Wattmeter was calibrated with lab equipment at
40m. Also, my 25 Ohm and 100 Ohm loads were checked with my MFJ SWR
Analyzer.

  Any comments would be appreciated!

Michael N9BDF, K2 #4137