I think you may be a bit confused about ALC, or I don't understand your
terminology.
In my world, "power down the radio" means it would be turned off.

ALC, when properly adjusted, is a control voltage that should limit the
power output of the transceiver to prevent overdriving and damaging the
amplifier. For Amplifiers that have relatively low drive needs for full
output, it can be helpful in extending the life of the tubes, as compared
to the reduced life effect of driving them beyond their dissipation rating.

I used to have an ameritron 811H (four tube version) and no longer have the
manual, but if I remember correctly, the setting method was to transmit a
known signal level into the amplifier and adjust the ALC control on the amp
until the power output of the amplifier dropped (just barely), thus setting
the level for protection. After it was properly set, cranking up the power
output on the transceiver had little effect when the amplifier was not in
standby mode.

A caveat though: Even though implementing ALC is a relatively good idea,
it is generally better to have really good operating habits and watch the
levels, rather than relying on the Amp to protect itself. I know there is
always the possibility of making a bonehead move (I'm sure we've all made
one now and then) but good operating habits first are the best defense
against overdriving an amplifier.

Thanks
--Rick AH7H

wrote:

I have a question for anyone who owns an Ameritron AL-811 amplifier.

I have connected the Relay and ALC connections to my rig and the
amplifer works great except for the ALC protection. I have confirmed
for 100% certain the radio is connected correctly.

When attempting to adjust the ALC limit on the rear of the amplifier as
suggested in the manual I am not noticing any effect on the rig. I
have driven the amplifier up to to 85W, and still do not notice and
reduction of power on the radio as indicated in the manual.

Perhaps I am missing something, but my understanding was when the power
into the Amp was over 70W and the rear ALC control was adjusted the
voltage from the Amp should kick in and power down the radio to avoid
distortion.

Any assistance would be greatly appreciated. Even if someone knows
which is MAX and MIN on the back panel ALC adj., that would be helpful
(i.e. clockwise or counter clockwise).

Thank-you...

Lloyd