"Beachcomber" wrote in message
...
On Sun, 10 Jun 2007 10:28:17 -0700, "Bob F"
wrote:


wrote in message
groups.com...
One TV in the house gets interference on the higher channels (50
and
up). This has been happening for over a week now. One minute
it's
fine, the next there is nothing but "snow," and static noise.
There
seems to be no cause of this, and it does not effect any of the
other
TVs, 2 of which have premium cable and 3 that have basic, just
like
the one with the problem. There was interference on a radio that
plugs into an outlet, but not with a radio that runs off
batteries,
even though they are in the same place. The radio problem,
however,
was bad about a week ago, but then the interference just stopped.
This TV problem goes on all day and night long. We have no new
appliances or anything like that. Any ideas?


Possible interference sources include aircraft and ground radar
(near
airports), cellular phone towers and cell phones (the new GSM band
phones are particulary nasty), abandoned antenna amps (possibly in
neighbors' houses) that may have been disconnected from RF cables,
but
are still powered up. Also power lines, (the intensity can vary
with
the current load throughout the day.)

Then there are the old fashioned sources of interference, electric
motors, vacuum cleaners, paper shredders, can openers, etc.

The timing and freqency can be clues to what is causing the problem.
For example, periodic interference every few seconds or so can be a
radar unit. Often these come on at the same time of the day.

A ham radio operator with a spectrum analyzer can help you track
this
stuff down if you are motivated enough.

AM Stations come in different varieties. Some of them switch power
or
change radiation patterns at specific times defined as local sunrise
or sunset. Weak stations usually come in only at night when the
ionosphere is hundreds of miles higher.

I wouldn't expect interference to have this effext.
"One minute it's fine, the next there is nothing but "snow," and
static noise"

Bob