Might be a bit 'blunt', excuse me for that, but IMHO ALC-feedback
from an Amp into an Exciter/TRX is just about the very last thing
I would consider to make an TRX/Amp combination 'work'.

It's a backward feedback loop with all kinds of implications
included!

I'd rather set the DUOs RF output level such that the Final Amplifier
is running within it's desired linear amplification range/IMD range.

You do not need a high-spec SDR for checking the quality of your
transmitted signal. A simple RTL-stick will do, as long as you'll keep
it's RF input level (monitoring your TRX signal) within the units
dynamic range.

You'll then literally 'see' (waterfall) any changes of TRX drive power
into the Amp and what this does to the quality of your transmitted
RF signal.

I have done this kind of 'exercise' on the air with quite a couple of
my local club mates and they all were quite surprised in the end
about what they've sent-out before and after this exercise.
'After' = a non-offensive RF signal transmitted w/o losing any
signal strength at the receivers side.

Klaus, DK3QN

Am 04.11.2019 um 17:59 schrieb Tony EI8JK:

Thanks for that Iain.
Not really the answer I had hoped for ;-)
What I wanted was an ALC connection to run/control a non-Elad linear.
I thought that was a non runner though, so not unexpected.
Regards & 73
Tony...

On 04/11/2019 16:50, MM6IXE wrote:

Hi Tony

you are correct on both accounts, No alc meter, and yes u would need to adjust windows drive .

I asked the same question couple weeks ago, and was given a workaround for wsjtx, 

if u go back a few pages on forum, you will find the question from me
andbthe answer from Neil

regards

Iain