MM wrote:

Dunno what to try now. I checked the plug where it goes into the amp
and it looks all right. Same with the wall plate, I've got it off the
wall and it's dangling there, but the connection seems well-made.

Typical of either damaged cable or a bad connection. Disassemble the
plug and wall plate and re-make the connections properly, and if that
doesn't cure it, you *could* get a proper aerial cable tester and find
out where the cable fault is, or you could just replace and re-run the
cable properly.

If it's the polythene and air insulated type, once the insulation gets
kinked, it can cause problems later. Foam insulated isn't so bad, but
damage can still linger. Foil shield is, IME, more fragile, too, and can
be a right pig to terminate correctly.

--
Tciao for Now!

John.