I had a brief experience using the AL-811A, which is pretty close
to the 811H. I would guess your input slugs need to be touched up
for the portion of the band in which you operate. In my case, the
amp came from an OM who was mostly SSB-- he had adjusted the tuned input
slugs to work well in the SSB portion of the band. I had to re-adjust as
I am a CW op -- you should be able to get the VSWR at maximum output
down to 1.5:1 or less -- mine was fine on all bands except 10M -- for
some reason it would not fall below 1.8:1 on the CW portion of ten.
As a fix, I just put a small manual ATU inline between the rig and
the amp, a trick I learned with my first amp, the Clipperton L.
73 and GL.
BV/N0IAT in Taipei Taiwan R.O.C.
CQ-Contest on WWW: http://www.contesting.com/_cq-contest/
Administrative requests: cq-contest-REQUEST@contesting.com