[Amps] MLA-2500 question

[Steve Thompson]

Ian White, G3SEK wrote:
> Roger Parsons wrote:
>> Neither of my MLA2500s has a reflected power
>> monitoring position - other versions may have. I think
>> that the purpose of the trimmer is to try and make the
>> flat across the frequency range.
>
> As Steve said, it's intended to be a 'bridge balance' or directivity
> adjustment, to make the forward power indications independent of load
> mismatch.
I looked out the circuit - that's the case for the '2500. There's no reverse
power output from the bridge, so I think the only way to adjust the trimmer
accurately is to hook it up to a dummy load and run power backwards through
it. I imagine there's many where the trimmer has been tweaked, then it's pot
luck as to what it reads.

Steve