I just finished talking to the Mediacom Cable TV Co. Tech Service and they
are going to send a technician with some detection gear. They want to get
it fixed because of FCC requirements and also to satisfy the customer.

Defective cables is a common problem that the Cable TV and Wideband
Internet
Companies are interested in.

Mediacom Co. here has been a pretty good company to deal with. My Wideband
Cable Internet connection has also been very good.

Yes, so good that I'd cancel them for their outages if it were not so
impressive when it IS working. Never thought that they might be sending the
color burst frequency down the cable as well as the programming. I've ALWAYS
disliked TV programming so much (other than a few exceptions) that I've
refused to study the technology. When one of mine breaks it's either to the
dump or to some repair shop.

Wish you well in getting rid of it. At 14.307, I'd get a nosebleed if I got
that high in the band. At 3579, I don't do that mode anymore. (Ernie ALWAYS
said, "If God had meant for man to talk with his fingers, She would have put
lips on them")

Regards
W4ZCB

The signal on the cable goes to a phase-locked-loop in the TV rcvr. This
keeps the TV picture synchronized.

Bill W0IYH


"Harold E. Johnson" wrote in message
news:I9v7e.14366$Bb3.12702@attbi_s22...

I just finished talking to the Mediacom Cable TV Co. Tech Service and
they
are going to send a technician with some detection gear. They want to
get
it fixed because of FCC requirements and also to satisfy the customer.

Defective cables is a common problem that the Cable TV and Wideband
Internet
Companies are interested in.

Mediacom Co. here has been a pretty good company to deal with. My
Wideband
Cable Internet connection has also been very good.

Yes, so good that I'd cancel them for their outages if it were not so
impressive when it IS working. Never thought that they might be sending
the
color burst frequency down the cable as well as the programming. I've
ALWAYS
disliked TV programming so much (other than a few exceptions) that I've
refused to study the technology. When one of mine breaks it's either to
the
dump or to some repair shop.

Wish you well in getting rid of it. At 14.307, I'd get a nosebleed if I
got
that high in the band. At 3579, I don't do that mode anymore. (Ernie
ALWAYS
said, "If God had meant for man to talk with his fingers, She would have
put
lips on them")

Regards
W4ZCB

William E. Sabin wrote:
The signal on the cable goes to a phase-locked-loop in the TV rcvr. This
keeps the TV picture synchronized.

I won't say it doesn't happen, but I'd be surprised if your cable
operator is transmitting a 14.318 (or 3.579) signal down the cable.
(that doesn't mean they don't have a leak that needs fixing!)

Roughly 15,700 times a second, a brief burst (about 8-11 cycles) of a
3.579MHz reference signal modulates the TV RF carrier. This burst is
used to synchronize the color circuits. Left-to-right and top-to-bottom
scanning is synchronized with other pulses that modulate the same carrier.

So, for example, on a channel 2 station (RF carrier at 55.25MHz), the
synchronizing burst would create a sideband at 55.25 + 3.58 = 58.83MHz.
(it would also create a lower sideband around 52MHz but a filter in
the transmitter lops off most of the lower sideband, around 54.25MHz.)
No 3.58 signal is transmitted.

That's how an over-the-air station would work. But cable differs only
in that the output of the transmitter is connected to a combiner and
then to the cable to your house.

(and, of course, the transmitter is a LOT less powerful!)
--
Doug Smith W9WI
Pleasant View (Nashville), TN EM66
http://www.w9wi.com