I have a cable TV hookup and my reception is excellent on most channels. However, some of the local channels have faint ghosts, no matter how I move the coax cable feed. The UHF stations have a different cable number than their broadcast number and there are no ghosts on them. But the VHF channels use the same cable numbers as the broadcast numbers (for example, channel 8 broadcast is 8 cable) and faint ghosts show up on them. If I disconnect the coax completely I can still get a faint picture on the TV, which means the local broadcast signal is so strong it is picked up by the connecter where you screw in the coax cable. Does anyone know how to shield or trap the cable connection to eliminate these faint ghosts?

I would have the cable company check it out. It could be that the coax cable is not properly grounded.

Since you say that you are connected to the tv through the coax cable then make sure that there is no internal tv antenna also connected to the antenna input.

Is there a cable box? If there is can you directly connect it through the aux inputs.

Thanks for the suggestions. Someone else suggested the use of double-shielded cable described at:

http://www.monstercable.com/productPage.asp?pin=240

Trying to visualize your system. Does it amount to the fact that you view some channels via RCA cables going into the back of the TV (I thinks that's equivalent to the SCART cables that we use in Europe) and some channels that come in from an aerial on the roof?

If so, is it the ones viewed via the RCA (audio/video) connections that have the ghost images in the background? If that is the case, unplug the lead that goes into the aerial socket at the back of the TV. Do the ghostly figures go away?

Tellywellies, there is no aerial in my system. All the channels I receive are delivered by the cable. The problem I am asking about (this post) is faint ghosting on the three cable channels that are local stations (i.e., most of the channels on the cable are out-of-town stations but three channels on the cable are local stations with broadcast signals in my area). If I disconnect the coax cable from the TV completely I can still get a faint picture on the TV, which means the local broadcast signal is so strong in my neighborhood it is picked up by the connecter on the back of the TV where you screw in the coax cable.

Another suggestion I received suggested the ghosting might be caused by mismatched impedances.

The reason I mentioned the two different inputs to TV was that it rung a bell to something I had with my own set-up years ago. The TV was receiving signals from both a loop-through of the roof aerial (coming in via a satellite box and distribution amplifier) and the AV connections (SCART/RCA). This gave the ghosting you describe.

I went through the measures you are trying to no avail. Then, while I was watching a program that came via the television AV sockets, I just happened to unplug the aerial lead that arrived via the amplifier and box. The ghost images of people wandering around in the background disappeared.

I think I overcame the problem by putting an attenuator in the aerial lead. This cut the RF signal from the aerial system down enough to stop it interfering with the AV signal coming from the satellite receiver. In the end. I put the trouble down to being something to do with the TV. Perhaps there was a way that signals arriving into the TV from two sources could interfere with each other, even though that shouldn't really happen because only one or the other is selected at any one time.

Anyway, that's why the situation you have rung a bell and probably why I got the wrong end of the stick

Lets try a different theory. It is possible that something called cross-modulation is occurring. This can happen if the signal is too strong. You could try cutting the signal down a bit to see what happens. This can be quickly tried by pulling the coax connector out of the back of the TV and holding it very near (almost touching) the socket. See if that has any bearing on the ghost images. Try holding the plug at marginally different distances, just to give an idea of whether cutting the signal strength down a little might provide a cure. If you feel that does help, it is possible to get a device called an attenuator to use in series with the coax lead. They come in various strengths and are measured in dB's (decibels). Something like a 3 or 6dB attenuator might be needed if this is where the problem lies.

It could be that the signal needs reducing where it comes into the house. In this case, it would be a job for the cable company.

It's all a hit and miss I'm afraid and the advice may not be on the mark. However, it is something that can be looked into.

EDIT: Are you able to link your cable box up to the TV using audio/video leads only (RCA)? This way, the only coax connection is to the cable box. The signal is then fed to the TV by way of the AV leads. You just select AV on your TV (if detection isn't automatic). I wonder what would happen under those circumstances.

A prime suspect just occurred to me. I have two TVs in my apartment and I use a passive signal splitter to divide the cable signal into two feeds. This probably decreases the strength of the cable signal compared to the broadcast signal the cable screw connector on the back of the TV is picking up. Maybe I should instead get an active splitter that amplifies the signal. Comments?

What happens if you remove (bypass) the splitter and run just one TV. Any ghosts?

That's my next test. I first have to get the coax connector that connects two male connectors.

Another option occurred to me: Replace the present splitter (probably a cheap Radio Shack model) with a good-quality Monster splitter.

Quote:

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I have two TVs in my apartment and I use a passive signal splitter to divide the cable signal into two feeds.

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That was our issue when we had that problem. (Forgot all about it till you mentioned it, otherwise I would have said something sooner... ) Hopefully that's all that's wrong with yours?
We also had too many shorter cables conneted together and got signal leakage at the connections which caused poor pictures as well. Once we changed to one long cable, that problem disappeared.

A good splitter should stop one television affecting the other. If you do get and improvement from bypassing the existing splitter, you could try a different one. Most are inexpensive anyway. Passive splitters give a signal loss to each TV but if you have enough signal to start with then that doesn't matter. As long as you are getting a noise-free picture on both TVs (not at all 'snowy' or grainy) then I don't think you'd need a powered or amplified splitter.

If the pictures on both TVs are grainy then perhaps a powered amplifier/splitter might help. However, these can give too much signal output and overload the first stage of the TV tuner, so making the picture grainy and lined. It can also cause that 'cross-modulation' effect mentioned earlier. With both of these situations you find yourself putting attenuators in the coax line to cut the signal back down a bit.

Still a bit difficult to know if altering this area of the set-up will affect the ghosts though. Just to be certain, you do mean that images are actually moving around in the background? Not just that there are outlines to the right of objects or people? I wish I could see the effect.

A knowledgeable friend said a frequent weak cable signal culprit is the drop (cable line from pole to house). Mine is at least 20 years old and there are squirrels in my neighborhood. I had to have my telephone line replaced a few years ago (because of static on the line).

The culprit turned out to be the drop line from the pole to the house. I live in a neighborhood with a lot of squirrels, and the cable repairman said there were gnaw marks all over my old drop. He said wherever the braided shield was broken the broadcast signal in the air would be picked up and get on the line. Thanks to everyone who made suggestions.