[Elecraft] K2 power anomalies

[Julian, G4ILO]

I just completed assembling a DL1 which I got because of the potential to 
get some accurate power measurements by attaching a DMM to it, and thereby 
to more accurately calibrate the KAT2. While doing various tests I found a 
couple of anomalies:

It appears that the K2 takes no notice of the Po28 option set in the 
seconadry menu. Although the numbers in the display stop increasing when 
they reach the value set when you rotate the knob on the front panel, the 
actual power out is the same whether this option is selected or not. With 
the control fully clockwise the power out from my K2 is typically 11.9W as 
reported by the KAT2 in CalP mode, regardless of the Po28 setting.

Does the voltage / power graph shown on the DL1 instruction sheet hold true 
across the whole frequency range the DL1 is specced for (0 - 225MHz), or 
even the whole HF bands? If so, my K2 is delivering considerably less power 
than I thought on the highest bands, as is my 6m transverter. This problem 
is not evident using my other homebrew power meter. For example, on 40m at 
5.0W by the K2 display I am reading 11.5V on the DL1 test points. On 10m 
when the K2 is reading 7.6W I am getting only 11.1V across the test points. 
At maximum output 11.9W according to the K2 I am only getting 12.6V across 
the test points, which if true would mean that at full output my K2 is 
putting out little more than 5W according to the graph. My homebrew power 
meter does not show this significant fall-off in power compared to the K2's 
own readings.

Unfortunately I don't have access to an accurate, calibrated power meter 
which was the reason for getting the DL1 in the first place.

73
--
Julian, G4ILO. (RSGB, ARRL, G-QRP, K2 #392)
G4ILO's Shack: http://www.qsl.net/g4ilo