Might be something with that section of the amp, just put a swr meter 
between the rig and amp and see what the swr is. I forget how that amp 
works, I just got up, I don't know if there's a coil for each band or what 
but it sounds like the swr on that band is off. I take it 15 and 10 meters 
are where they should be?
----- Original Message ----- 
From: "Ed Malmgren" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Friday, April 04, 2014 11:18 PM
Subject: Re: 20m reduced output


> 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