[Elecraft] K2 power efficiency

[Bob - AG5Q]

I took some data on the DC power input and  power output to a dummy load for
my K2 (#2856):

5W power level:

Display Pout = 5.0  W
Measured power out = 5.2 W
DC current in = 1.60 A in CW tune mode
DC current for rcvr = 0.2 A
DC voltage = 11.1V (displayed value, after the input diode)
DC Power into xmtr = (1.60 - 0.2)*11.1 = 15.5 W

Overall CW xmtr efficiency = 34%

 ====================
10W power level:

Display Pout = 9.70  W
Measured power out = 9.7 W
DC current in = 2.0 A in CW tune mode
DC current for rcvr = 0.2 A
DC voltage = 11.0V
DC Power into xmtr = (2.0 - 0.2)*11.0 = 19.8 W

Overall CW xmtr efficiency = 49%

The pre-driver and driver take about 0.2A dc bias, so if we subtract that
from the
displayed current, the efficiency for the PA stage (Q7,Q8) increases to 39%
at 5W and 55% at 10W.

I have not modified T4 for higher efficiency at 5W.
I'm not using battery power, so the overall efficiency is not critical for
me, but I'm
just curious if this is typical results?

When the heatsink is removed to access components on the bottom of the RF
board,
how much power can you safely run for testing purposes?

73/ Bob - AG5Q