You most likely will have a problem if you use a long video cable. The problem is referred to as line loss. The longer the cable the greater the loss of signal.
We cannot definitively state the length at which line loss will begin to have a detrimental affect on the signal, because we do not know the construction of the video extension cable being used. However, if you are using a cable 50 feet long, there will be degradation of the video signal. This is usually╩manifested as ghosting, smeary video, or transparent lines running through the screen. A long video cable will not damage the display or the computer. Therefore, if you find the distortion acceptable, there is no reason why he cannot use the display with a long video cable.
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