Howdy all..........As it seems there's a lot of fine TV (and other!) techs
on here I thought I'd ask a question thats been bugging me for years. On
my 22+ year old RCA I've noticed for years a faint, approx 2-1/2" wide
horizontal "bar" in the background....just as if the picture was
at-a-different-depth while the bar slowly scrolls up the screen. Picture
isn't otherwise distorted and, most times is not very noticeable. I just
receive off-the-air here......3 signals strong and 2 fringe with the
antenna input usually routed through a VCR. I've tried in the past to
determine whether the bars were interference being received via the power
line or the antenna by selectively disconnecting the VCR and unplugging it
etc......removing and unplugging any active antennas......and finally by
routing the antenna direct to the set (via one 50:300 balun) and tripping
all the circuit breakers in the house except the one supplying the
TV.....and then trying a different circuit for even that. Seeing no
difference......and noting the bars on more than one channel, I've often
thought the problem was likely a distortion in either the horizontal or
vertical retrace circuits......no schematic and I seldom have worked on
TV's in my 30+ years around radio and electronics. This Christmas I bought
a new Toshiba 14AF44 as a second TV for the wife and was surprised to find
the exact same abnomality showing up in it's picture.......no more or no
less than on my old RCA. Trying to figure out a common denominator here
for the problem........I've scoped the house power via a transformer and
don't see any strange features.......I've had dozens of LF, MF, HF, VHF and
up receivers here over the years and have not noticed anything consistent
interference problems......nor noted during the hundreds of hours I've had
my old FM modulation scope on during bench work. Antennas and feedlines
have varied over the years from simple whips and "rabbit ears" to yagis and
dipoles. There is no power company high-lines in our vicinity nor any
industry (I live approx 22 km from the nearest city). There is an ATC
radar site at 4km south......3 TV transmitters and at least one broadcast
FM transmitter 4 - 9 km south of here for consistent "other" signals.


Any ideas on what this might be appreciated.........curiousity has
returned.



Gord