Hi All,
I recently picked up an Ameritron AL-811, nice little amp, but I have
problems on 10m. The 10m mod was supposedly done and I can see where the
bandswitch has been changed around. The amp will put out full power on 10
but has a very high SWR (5:1 or greater). The auto tuner must be on to
match it, and since the SWR is so far off the RX sensitivity drops quite a
bit (auto tuner works on RX). I tried adjusting the slug for 10m all the
way in or out, no difference, also checked all the way from 24-30mHz and the
input SWR is high all the way across and never dips anywhere. I also tried
several different length patchcords between the amp and radio and that does
not change anything. I am using a Heath Cantenna dummy load and my 10m ant
is resonant. All the other bands are less the 1.5:1.
I noticed a white wire going to ground on the 10m input coil, I'm not sure
if that is part of the 10m 'mod' or not. Someone suggested a bad tube, the
amp has full output and the SWR on the other bands are low so bad tubes
don't make sense to me - but who knows. I have tried to call ameritron but
I get no answer, maybe off a few days for Christmas - I'll keep trying
though. I am just wondering if this is a common problem with these, the old
SB-200 I have does the same thing on 10 - that's why I bought a newer amp...
Thanks and 73,
Kevin
KB9UPV
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