Re: LF: Is it expected for antenna phase to change with varying power levels?

[DK7FC <selberdenken@posteo.de>]

Hello Chris,

Congrats to your working circuit.

Am 16.05.2018 17:38, schrieb Chris Wilson:
> Hello Stefan, Yes the waveforms look perfect, only a minor phase shift
> from 12V supply to 55V.
Maybe there is a transformer between antenna and the phase meter that 
starts to saturate at QRO?
Some nonlineatity, that's my own idea. It could also happen in the 
variometer circuit, if you use the wrong cores. But it shouldn't.
>   But the vario circuit seems ultra sensitive, a
> sniff of wind moving the antenna around sees the motor constantly
> correcting. As does changing voltage to the amp considerably, so it
> changes from "QRP" to QRO. Am I right in thinking adding another two
> BAT42 diodes or whatever they are in each leg of the last opamp will
> calm it down a bit?
In the original schematic there is a potentiometer ( 1 MOhm) for 
adjusting the sensitivity.
73, Stefan