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![]() "Cecil Moore" wrote in message ... Richard Fry wrote: TV Ghosting (quotes below) To elaborate, the visibility of a ghost image in analog TV systems is related to the magnitude, phase and time displacement of the RF reflection that produced it as compared to the original, or non-reflected waveform. The round-trip transit time from the TV tx output to the mismatch in its antenna system will determine the time displacement of the ghost, at the rate of 1 microsecond of displacement per ~490 feet of distance between the tx and the reflection plane (vp = 0.997c). Richard, you know you are going against the conventional wisdom on this newsgroup. Ghosting cannot exist during steady-state so if ghosting exists it simply means that you are still in the transient state and the steady-state doesn't exist (yet). -- 73, Cecil http://www.qsl.net/w5dxp Looking for the smiley face. It is probably fair to say that in the *general case* there is no steady reflection in video transmission, unless the round trip delay is N horizontal lines. BTW, weirdest case I saw came when the dog chewed through the cable. Now I was seeing the main signal coming from the cable, plus a ghost that was picked up directly from the transmitter. The ghost was to the left and above the main signal. Tam/WB2TT |
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