What is the maximum length of SVGA video cable that can be used from a PC to a TV?

Answer 1

The figure often quoted for maxmum length of a DVI cable is around 40 feet. However, the real distance is dependant on both the quality of cable and the quality of the signal source and the signal receiver. All three are important. Poor quality components can reduce the maximum length to as little as 10 - 15 feet. On the other hand, using low loss cable with good quality drivers and receivers can extend the distance significantly further. As no manufacturer of cable, DVI drivers or DVI receivers is willing to quote guaranteed figures, it's really a matter of trial and error. Personally, I have used a 70 feet cable length with DVI signals and had no problems. I might add that I used a very low loss cable for the job - and they don't come cheap.

Answer 2

Depends on the quality of the cable. Mainly the impedance (needs to be as close to 75 ohms as possible). My experience with SVGA cable to projected screen as large as 110 inch is as follows: thinner/cheaper cables should not exceed 10 ft. due to ghosting of colors and and black/white text. Higher quality cables (usually thicker as well), I have run to 25 ft. with minimal side effects; depending on the equipment on each end of course. An alternative is to use VGA to coax (BNC) adapter on each end and run good 75 ohm coax between them. I have gotten 60 ft. this way.

Answer 3

There are a number of factors that affect the signal quality of a VGA signal. The signal source (the VGA output) is often not designed to drive a long cable length. This can limit the line length to only a few feet. Similarly, the receiver needs to be designed to prevent the signal being reflected back along the cable to prevent ghost images appearing.

The cable itself is often the most important factor. For long cable lengths, the cable should include three co-ax cables to carry the image signals. Many VGA cables use an inferior internal cable lay-up and this will show itself with the image smearing on the display. For lengths more than 15 or 20 feet, it becomes important that the cable is of good quality and that the VGA output is capable of driving long lines. With good quality low loss co-ax cable, VGA can be run for well in excess of 100 feet without noticeable losses.