Mike, you might try using a different length of coax between the transiever 
and the input of the amp.  Some people have to use a small tuner in that 
line.  I don't know anything about that amp but it is possible there is some 
tuned input components that have changed value for that band.  G l  73



ED K7UC
-----Original Message----- 
From: Michael Ryan
Sent: Friday, April 04, 2014 7:52 PM
To: [log in to unmask]
Subject: 20m reduced output

Hi all:

I run an Ameritron al811h and when I use a 20w tune up drive level, with the 
amp controls preset as instructed, I only get 60w out.
I have to turn the plate and load along way counter clockwise to get 80w 
out. I noticed that my load pointer was past the 2 mark. I also got my XYL 
to read my grid and plate while I keyed the amp while advancing my 102s 
drive and it took about 45w to grid to 150 and the plate to 450. Something's 
not right. On 15m I get 500 and on 40/80 I get 600 all with 50 of drive. 
With 75 of drive I get over 600 on 15 and 740 on 40/80. I don't see how one 
of my tubes are bad with numbers like that. 20m? 240 with 75. I was 
suggested to check the SWR between the rig and amp but dunno how.

73:
Mike VO1AX