Broadcast Signal Ghosting Over Cable

Discussion in 'Beginners, General Questions' started by Steve Armstrong, Feb 2, 2004.

  1. Steve Armstrong

    Steve Armstrong Auditioning

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    Does anyone know how to filter out Broadcasts that Ghost over Cable SIgnals? I'm a basic Cable subscriber with no Box and since the Local Stations are broadcast on the same channels as the Cable channels for the same stations I get serious Ghosting and disruption on all my VHS stations. Does anyone know of a way to clear this up without having to rent a Box from the cable company?
     
  2. Bob McElfresh

    Bob McElfresh Producer

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    Hi Steve. Welcome to HTF!

    Have you done something to mix the cable signals and the "Local Stations" at the back of the TV?

    If you just joined them together at the back of your Television, this is very, very bad. You may be injecting the antenna signals INTO the CATV system and messing with the service for all your neighbors.

    Radio Shack sells some A/B/C selector switches for a few bucks. Run the CATV signal into 1 side, the Antenna feed into the other (The Shack sells converters from 2-wire to coax) and the output goes to your television. The beauty is the A/B switch isolates both inputs from each other.

    Hope this helps.
     
  3. Wayne A. Pflughaupt

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    Steve,

    Bob is on the right track – somehow a broadcast signal is being “injected” into your CATV signal stream, and a cable box will not solve this problem. The only way this can happen is that something, somewhere is acting as an antenna. It could be a loose, unterminated cable somewhere (connected via a splitter).

    As Bob noted, whatever it is could “pollute” your neighbor’s service. But alternately, it could be one of your neighbor’s polluting yours.

    I’d say trace the cable feed from the source to the TV and eliminate any signal split-offs that are not being used. If you can verify that all cabling is good and intact, then call the cable company and let them deal with it. If they try to tell you a cable box will solve the problem, make them show that to be a fact before you financially commit to one.

    Regards,
    Wayne A. Pflughaupt
     
  4. Jim Rakowiecki

    Jim Rakowiecki Stunt Coordinator

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    You have a condition known in the cable world as ingress. There is a leak someowhere in the cable system. The more splices, the more cuts the worse it's going to be. Fitting especially crimped on fittings are can also cause ghosting. The crimped fittings are usually put on wrong, often times the braiding is left long acting as an antennae or the shielding has been pulled away from the cable.
    This is one of the reasons the industry has moved away ffrom crimped fittings.
    Also look for open splitter ports and avoid bargain splitters.
    The problem may not be in your house at all, it may be out in the cable system. A chewed wire, cracked hardline etc could cause this problem. If you can't nail it down ride the cable companies butt until the fix it. You should get everything you pay for. If the only answer the tech can come up with is "you need a box" he is lying to you and he is lazy and perhaps incompetent. Get his boss's phone number, kick him out of you house and tell the supervisor to send someone that knows what he's doing.
     
  5. Bob McElfresh

    Bob McElfresh Producer

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    So Steve: exactly how do you have your television hooked up?
     
  6. PaulcM

    PaulcM Auditioning

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    wow a question i have knowledge of. ingress can be caused by a multitude of problems. loose connectors, poorly attached connectors, damaged cable, unterminated splitter ports (why u would have this situation puzzles me), cheap cable (lack of shielding - i.e. typical of cables that come boxed with vcr's), push-on connectors, living in close proximity of a tower, and your TV. ingress caused by a problem between the tap and tv will not affect your neighbors. problems in the plant will affect everyone downstream from that point. ingress will not migrate upstream. cable co.'s use a simple leakage detector to find the problem. which is nothing more than a receiver tuned to the freq. of a cable channel. if signal is getting into the cable then signal is getting out of the cable, which the FCC takes a very dim view of, since it can potentially affect aeronautical freq's which can cause loss of communication. (it's been documented) and yes, sometimes the only fix is to put a box on the tv. if your tv tuner is not shielded well it will pick up local signals. by using a converter box which outputs on ch. 3/4 you can pick a channel that doesn't have a signal on it. cable boxes are shielded very well from outside interference. disconnect the cable from your tv, and tune to a local channel 2-13. are your getting a picture? it could be the shielding in your tv. got a vcr? tune channels thru that tuner. ingress go away? its your tv. homes that are prewired with cheap cable are a witch to fix. (all cable isn't created equal). bottom line - make sure all connections are tight. and then call the cable co. it can be fixed! but sometimes people don't want to hear the solution. lastly-not every catv employee is a jerk. be polite, but insistent. that will go farther than kicking someone out of your house. i personally will bend over backwards for someone that treats me with respect which is the direct opposite for someone that doesn't.
     
  7. Bob McElfresh

    Bob McElfresh Producer

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    Hi Paul. Welcome to HTF!

    Your experience with CATV, cables and connectors is welcome.


    For YEARS I used a 1-to-4 splitter without putting resistor caps on un-used outputs. Only when I installed a ChannelPlus amp/splitter did I learn about these. In model homes for plans that are pre-wired, I have never seen the outlets in the various rooms with a terminator plug. Please help us educate our members.

    CATV TERMINATORS

    These are little "caps" that sell at Radio Shack for about $1 for a set of two. If you have a CATV cable that goes into a splitter, every output should go to a television or CATV box. If you just have a wire or an un-connected output, the signal can flow down the wire, hit the end and reflect back. This can cause a "Ghosting" on the televisions that are connected.

    The solution: one of these little termination caps on the un-used output of your splitter, or on the un-used CATV jacks in every room. The resistor in the cap basically "eats" the signal so it does not reflect back into the wire.
     
  8. PaulcM

    PaulcM Auditioning

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    i guess i'm real big on using the correct splitter for the application. i mean only activate the outlets that are in use. an example would be a home prewired for 10 outlets. if you only have 4 tv's use a 4-way, there's no reason to fire up the rest. the more ports on a splitter the less signal passing to each port. manufactorers make 2,3,4,8 splitters so there are situations to terminate ports. i just try to avoid where possible. i have been in the catv industry since '82. i have have done everything from digging ditches to my present job - sweep tech. ingress is something i fight on a daily basis. thanks for the welcome by the way.
     

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