[Elecraft] High SWR on 20 meters

[Bill Carpenter]

I've been enjoying my K2/100 a lot but was never happy with the SWR bridge 
alignment which I did per the manual.  I found a great procedure here on the 
list that uses Caddock power resistors from Mouser as 25 and 100 ohm dummy 
loads.  I got everything aligned and all seems fine except for high SWR on 
20 meters.  It's fine on my dummy load (1-1) but both my beam and vertical 
read at around 2-1 which cuts back my power.  Both these antennas are nearly 
flat at the frequency I used as measured on every other SWR meter I have and 
my MFJ analyzer.   I feel reasonably certain that my power calibration is OK 
though I don't have a Bird or equivalent so I used the power meter in my Ten 
Tec tuner.
Any ideas?  Why only on 20 meters?

Thanks!

Bill NZ0T