Hi Jeff, hi Alan,
sri for being so late with the response.

I use 54µH air coils

Jeff, here are two 54µH ring core coils in use. they did and do a good job
up to 1kW output.

What is it like a lower power levels ??

Alan, it was all the same, 10W or 800W.

what if there is insulator leakage

to find the defect I connected a aerial dummy to the end of the feeder (80m
long) in the first step: all the same! second ?accidentally- step: I manually
moved the phasemeter somewhat ? surprise: sines like they have to be on the
screen!
I am ashamed to tell you that inside the phasemeter (homebrew) a ?naked- wire
touched the case.

thanks for the hints and best regards
Uwe/dj8wx