[Elecraft] K2, ATU & WM-2 wattmeter

[TIM LOGAN]

Hi folks -
I believe my OHR QRP watt meter is accurate, but it does not coordinate
with my K2 power out readings though. For example, if I tune on 40m and
the K2 power out shows 5.1, my external watt meter might show 7.1. If
the K2 is setup at 10w it about knocks the needle off the OHR meter.

I have the ext meter between the ATU and the antenna and am using the
ATU in either Auto or POUT mode. What am I missing here? Are these two
sources reading the same power? Both the K2 and the OHR meter are
reading power that exits from the ATU aren't they? Or is the K2 reading
power at some different point?  Thanks for the clarity. Regards, Tim
Logan KB7OEX