[Elecraft] K2/100 low output power on 10-15 meters

[Mike and Alicia Fanning]

Hi all,
I have just finished building and testing my KPA100 kit, and the power  
output seems low (87-89 Watts) on 10, 12, and 15 meters.  Is this  
typical?  I have triple checked that the parts are installed properly  
in the 10-15m low pass filter stage, and everything looks good there.   
After verifying the LPF was okay, I went back and measured output  
power from the K2 without the KPA100 installed.  Here are the  
numbers.  The first column is the band in question, second is the  
transmit power without the KPA100 installed (barefoot), third is with  
the KPA100 installed but powered through the original low power DC  
input (amp installed but bypassed), and the fourth is with the KPA100  
installed and powered through the KPA100 high power DC input (amp  
installed and active).

10m    8W       7.5W    87W
12m    9.75W  9W       87W
15m    11.5W  10.5W  89W
17m    12W     11W     106W
20m    12W     11W     100W
30m    13W     11W     106W
40m    14W     11.5W  107W
80m    13.5W  11W     105W
160m  12.5W  12W     111W

When the KPA is hooked in but bypassed (column 3), why is the power  
output lowered?  Is it because of the second set of low pass filters  
(on the KPA100 board) coming in line?  I was surprised to see the  
transmit power level drop so much if this is the cause.

Are my barefoot numbers fairly typical?  Looks like the KPA is giving  
me pretty consistent gain, so do I need to be looking upstream  
somewhere in the original K2?  If so, why the big jump on the KPA100  
output between 15 and 17 meters?

Any thoughts or ideas appreciated.

Thanks and 73,
Mike Fanning, K4GU
K2 #5882