> -----Original Message-----
> From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
> Behalf Of Joe Isabella
>
> Yep -- my 950SDX is no different. If you just use the power adjusment, it
> actually lowers the entire power envelope and you gain nothing. The key
> is having the 100W (150W, in my case) PEP headroom while keeping the
> carrier reduced to a level that allows it to be fully modulated without
> exceeding final amp's headroom. Low-level AM is a whole different ani-
> mule than real plate modulation!! I've never messed with screen or series
> modulation, though.
>
> And then, driving an amp with AM is a whole 'nother can of worms, too.
> You MUST tune it with the highest PEP level you have from the rig. If you
> tune it just with your unmodulated AM carrier, it'll be mis-tuned and
> you'll splatter like crazy. Easiest way with a solid-state, low-level rig
> is to use fast CW pulses at max output (just like what you would do for
> SSB), then adjust the rig's AM carrier for the desired level (20-25W max
> for a 100W rig).
>
> Joe, N3JI
When tuning up the amp for AM service you should tune it up just as you
would for SSB. As Joe says, using a keyer or just tuning for maximum output
with full drive.
Then reduce the carrier level for 1/4 output power on the AMPLIFIER. Don't
touch any tuning on the amp again!
This is assuming that the amp takes the full 100 watts drive from the
exciter for full output power of the amp.
If it does not, then adjust drive and amplifier tuning for maximum power out
as you would tune for ssb operation. Then reduce carrier output for 1/4
power out of amp not the exciter.
73
Gary K4FMX
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