[RFI] Tough to solve TVI problem

kelly at thejohnsons.ws kelly at thejohnsons.ws
Fri Jun 6 10:19:31 EDT 2003

I've gotten several e-mails with various suggestions.  Thanks everyone for
the suggestions.  I will keep experimenting.  In response to requests for
additional information, here it is for everyone to ponder:

1) The interference only affects the video, not the audio.  All that happens is 
that the color picture changes to black-and-white.  I lose the color.  There
are no obvious lines, herringbones, etc.

2) The interference occurs even when playing a DVD connected to the
S-Video input (ie. not using the RF downconverter section of the tv)

3) I get no interference when there is no signal connected, but that seems
expected since the interference symptom is to change a color picture to
black-and-white.  It's rather difficult to see this with no signal connected
since the screen is already black.

4) I am feeding my dipoles with coax and no balun.  The coax lines are at least 
20 or 25 feet away from the tv.

5) There is a large amount of HF noise coming OUT of the TV, especially in
2 or 3 key places (near the speaker grills and one corner of the picture
tube).  I explained this to a TV tech. and he insisted this was normal.
Normal?  S9 broadband HF noise when using an RF sniffer next to the tv?
That doesn't sound normal to me.  He claimed it was normal HV circuit noise.

Kelly Johnson

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