[plug] TV interference (otopic)

[Denis Brown]

Hi, Darrell.

Points worth trying...

1. put a terminator on the unused tv outlet.  Ideally 75ohm if coax, 300
ohm if twin ribbon.
2. check the integrity of the connections in the whole tv antenna circuit
-- sounds to me like the shield connection has gone flaky on the run to
your computer room, so the cable run is acting like a very efficient
antenna.  This is most probable if the effect varies as you move the PC
around in the room -- interference stronger in one location than another.
This is most likely if you live near the coast -- lots of nice salt-laden
air to corrode things.
3. check for grounding of the case &/or power supply on your linux box and
monitor.  That would include a check on the power outlet itself.  If in
doubt, temporarily run an extension lead to your PC from another room's
outlet.  If the problem goes away I'd suspect a grounding issue in which
case it's electrician territory.  Especially the case in older houses.
Also check the ground connection to the waterpipe and grounding rod.
4. what happens with different monitor scan rates?  If they cause different
effects then try to get a large ferrite toroid and pass the monitor cable
through it once or twice to act as an RF trap.
5. could try the same ferrite toroid trick for keyboard and mouse cables
but I think my first question would be "has it always been like that or has
it happened recently?"  If recently, what's changed in the meantime --
keyboard, mouse, monitor, added a network card, etc?

Hope these help,
Denis