[Elecraft] SWR Question

[Bob Fish]

Hi Guys,
I put up  Bobtail Curtain antenna for 20 meters for the CQ DX contest 
this afternoon. It is fed at the center vertical element. Here is the 
problem. It requires a matching network (tank circuit) at the feed 
point. So I took my MFJ-269 antenna analyzer out to the feedpoint and 
tuned the antenna. I got it to 1.1 to 1. I then went inside and found 
that I have a 3.9 to 1 swr measured both with the analyzer and the 
internal wattmeter on my K2. I have never measured feed point impedance 
before I always just tuned antennas by measuring SWR at the transmitter. 
Now, I feel like the guy in the old Chinese proverb with two 
wristwatches and never knowing what time it is!
I added some ferrite beads at the feedpoint to ensure that it isn't 
common mode currents on the outside of the coax sheild causing this. I 
always thought that SWR doesn't change along a transmission line. What 
is causing this I wonder, and should I just tune the antenna for lowest 
SWR at the transmitter regard less of feedpoint SWR?


Thanks in advance,

Bob  K6GGO