This is kinda redundant now that the digital switchover is nearly complete, but I did want to ask about the causes of 'ghosting' on my picture.
Attached you'll see an image I took with my capture card a couple of months before analogue was switched off. From what I understand, the ghosting on the right hand side is caused by the signal reflecting off something like a building (or even the ionosphere) and arriving at the aerial a split second later than the main signal. The ghosting on the left, on the other hand, is called pre-echo and is usually caused by the wires themselves acting as aerials. This signal arrives at the TV a split second BEFORE the signal from the aerial, and since it scans left to right, appears on the left of the image.
If any of you are knowledgeable about this kind of stuff, what do you think? Is it pre-echo, or a VERY late post-echo from the ionosphere? If it is pre-echo, the precise nature of the ghosts seems to suggest it's leaking in at one or two specific points on the system, rather than the whole wire…
Maybe the signal is 'ringing' in the wire?
The reason I post this is because it's MUCH easier to spot problems like this on an analogue signal than it is with a digital signal. The first you know about it on digital is when the picture starts to go blocky and flash 'no signal'. So far my digital TV has been working ok (in fact the signal is a little on the strong side), but could these issues cause problems for me later on?
Attached you'll see an image I took with my capture card a couple of months before analogue was switched off. From what I understand, the ghosting on the right hand side is caused by the signal reflecting off something like a building (or even the ionosphere) and arriving at the aerial a split second later than the main signal. The ghosting on the left, on the other hand, is called pre-echo and is usually caused by the wires themselves acting as aerials. This signal arrives at the TV a split second BEFORE the signal from the aerial, and since it scans left to right, appears on the left of the image.
If any of you are knowledgeable about this kind of stuff, what do you think? Is it pre-echo, or a VERY late post-echo from the ionosphere? If it is pre-echo, the precise nature of the ghosts seems to suggest it's leaking in at one or two specific points on the system, rather than the whole wire…
Maybe the signal is 'ringing' in the wire?
The reason I post this is because it's MUCH easier to spot problems like this on an analogue signal than it is with a digital signal. The first you know about it on digital is when the picture starts to go blocky and flash 'no signal'. So far my digital TV has been working ok (in fact the signal is a little on the strong side), but could these issues cause problems for me later on?
Attached Files
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