Mike,

You would need to put an swr meter between the radio and amp.  If your 
radio has an internal swr meter that your XYL can read, that will work 
too.    Tune the amp for that band and  output of the amp should go to a 
  low swr load.   A dummy load would be best, but if you have to use the 
antenna, make sure it is tuned up  right.   At low power, key the amp 
and  check the swr between radio and amp.  This will tell you what the 
output of the radio is  seeing when the amp is keyed.

Did this problem just start, or are you just getting around to checking 
all bands?


73, Steve KW3A


On 4/4/2014 9:52 PM, Michael Ryan wrote:
> 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
>
>
>