whenever i have any kind of a problem like this i always try three
things first, in order ..

1) wrap the signal and power cables multiple turns around a ferrite
rod, then ...
2) if problem persists, try another (better) ground, then ...
3) if problem persists, re-route signal cables so they aren't following
beside other wires, especially a/c power wires or wires from electric
motors ...

then once i've satisfied those superstitions i try to actually figure
out what is going wrong, what the real trouble is .. lol

if i had to guess i'd say it's the inverter ...

b393capt wrote:
I am getting a humming sound in my boat TV, new installation, maybe
someone has solved this before.
[snip]