"Bill" wrote in message
...
In message
-septemb
er.org, Tim writes

I would hazard a guess that the likeliest cause is a poor connection in
the
plug that's that's going to the amp. I'd take it apart and make sure that
the screen isn't shorting with the central conductor.

Tim


Another favourite problem is pin of the plug, assuming a Belling Lee plug
rather than an F. Quite often for speed the installer will not solder the
coax inner to the pin of the plug, maybe he will have crudely crimped it
with a pair of side cutters, most likely not though. This can lead to
problems years down the line with corrosion isolating the coax inner from
the pin. Any slight movement could have remade the connection. Although
the pin and inner may not have been making contact there could have been
enough capacitance for a signal to get across, but not strong enough to
give a good picture.

I never solder those things, and I expect the tiniest amount of capacitance
will do the job. Actually, I often only have to hold the plug near the RF
socket on a TV, and I start to get a picture, on an analogue set at least.

(In fact, I'm just done a test on a digital TV, disconnecting the RF lead at
a joint: if the outer screen is in contact, I start to get a picture when
the inner core is 2 or 3 mm away from the centre pin! So the signal can jump
an air gap of a tenth of an inch, and from one point to another, while an
unsoldered wire will have a 1 or 2cm length in a hollow tube so a greater
capacitive effect)

--
Bartc