On Sun, 04 Jul 2004 22:17:17 -0700, jon wrote:

Hello-

I have an 8 or 9 year old Magnavox television that has a very
conditional problem. During the daytime, the picture is great, but when
it is dark outside, not just dark inside, the picture gets interferance
in the top 1/3 of the screen, in the shape of a thick black line that is
shaped like an arrowhead, that jumps from the left side of the screen to
the right. Anyone have a theory?

Thanx, Todd

Look for things that come ON at dusk...street lights, yard lights,
night lights, perimeter fences, etc.
The interefernce you describe appears to be 1/3 of a frame (180 Hz),
frame rate is near 60 Hz.
Amateur radio interference (ok, CBs n/ cabs too) would occur at an
audio rate, and would affect the entrie video and/or audio signal.