Topband: My Inverted L

[Dave Novoa W4DN]

I built an Inverted L for160 meters following K2AV's  intructions for the 
FCP, using the Balun Designs' isolation tranformer.  It resonates around 
1813 kHz  (that's OK with me) but the SWR is 1.9:1 minimum, which my Yaesu 
Quadra amplifier does not like.   The feed point is at 8.5' high, 25' away 
from the tower. The antenna wire,  from DX Engineering, runs up to about 
67',  then slopes down to about 25'.  There is a 4 element 20-meter 
Cushcraft yagi about 3' above the apex of the wire on a 70' crank-up tower. 
What could be the problem that causes the high SWR?  Any advice is 
apreciated.
73,
Dave, W4DN