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#1
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Double Tvision
A friend's TV has a ghost image. She lives in the New Forest and tells me
that all TVs in the area are the same because of poor reception. She has a booster in the aerial system. Is the ghost image due to poor reception or actually something else (which is my feeling)? What else can be done about it? I can't believe in this day and age that someone should have to put up with a ghost image. Rob Graham |
#2
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What you are describing is called "Multipath Distortion". Thats where an
antenna system picks up a TV picture as well as a slightly delayed, weaker signal coming from reflections of the TV signal off of buildings. The ghost will be to the right of the main image and will usually be faint. NTSC TV broadcasts the picture with AM modulation, so the ghost is added into the picture. Audio is FM radio, and the TV will lock into the stronger TV signal - thats why ghosting only affects the image and not the sound. Now, if this only happens on one particular station, or other stations also have it but look different, then it probably really is multipath distortion. However, if it occurs on all TV stations and looks the same, then I would suspect a problem with the amplifier or cabling. If a cable is improperly terminated (bad cable, connectors, etc.) then you can get those reflections in the cable itself. Assuming that she has her own antenna, amplifier, and cabling, and the ghosting is the same on her neighbour's TV, then its definately Multipath Distortion. The only solution: Get a highly direction TV antenna and an antenna rotator (available at Radio Shack!) and she can rotate the antenna to point directly at the transmitting antenna, reducing or eliminating the ghosting. BTW Ghosting and antenna rotators were common in the days when everyone had their own antenna. Cable systems started out at the community level and used seperate antennas pointing to each TV transmitter, and a combining power amplifier for distribution to the local community. The advantage was stronger TV signals with much less noise. We have been spoiled! "Robin Graham" wrote in message ... A friend's TV has a ghost image. She lives in the New Forest and tells me that all TVs in the area are the same because of poor reception. She has a booster in the aerial system. Is the ghost image due to poor reception or actually something else (which is my feeling)? What else can be done about it? I can't believe in this day and age that someone should have to put up with a ghost image. Rob Graham |
#3
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"Dana Raymond" wrote in message t.cable.rogers.com... What you are describing is called "Multipath Distortion". Thats where an antenna system picks up a TV picture as well as a slightly delayed, weaker signal coming from reflections of the TV signal off of buildings. The ghost will be to the right of the main image and will usually be faint. NTSC TV broadcasts the picture with AM modulation, so the ghost is added into the picture. Audio is FM radio, and the TV will lock into the stronger TV signal - thats why ghosting only affects the image and not the sound. Now, if this only happens on one particular station, or other stations also have it but look different, then it probably really is multipath distortion. However, if it occurs on all TV stations and looks the same, then I would suspect a problem with the amplifier or cabling. If a cable is improperly terminated (bad cable, connectors, etc.) then you can get those reflections in the cable itself. Assuming that she has her own antenna, amplifier, and cabling, and the ghosting is the same on her neighbour's TV, then its definately Multipath Distortion. The only solution: Get a highly direction TV antenna and an antenna rotator (available at Radio Shack!) and she can rotate the antenna to point directly at the transmitting antenna, reducing or eliminating the ghosting. BTW Ghosting and antenna rotators were common in the days when everyone had their own antenna. Cable systems started out at the community level and used seperate antennas pointing to each TV transmitter, and a combining power amplifier for distribution to the local community. The advantage was stronger TV signals with much less noise. We have been spoiled! "Robin Graham" wrote in message ... A friend's TV has a ghost image. She lives in the New Forest and tells me that all TVs in the area are the same because of poor reception. She has a booster in the aerial system. Is the ghost image due to poor reception or actually something else (which is my feeling)? What else can be done about it? I can't believe in this day and age that someone should have to put up with a ghost image. Rob Graham Thanks, Dana. I've forwarded your reply to her. Rob |
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