Here's an interesting Article. On something I have wanted to do, for several years. I tried making an Audio - Video Cable for sending Audio and an S-Video Signal. Over a Cat 6 Twisted Pair Cable. I use to be an Installer for a Telecommunications Company. And I had saved some 25ft Scrap Cable. That was going to be thrown away. This cable was used, in Telco's. For the installation of DSL Equipment, in Telco's. It is high quality Cable. With 32 or 42 Twisted Pairs. It worked, but the signal was noisy. The audio quality was Poor and the Video quality was even worse. I have always, wondered. Why it didn't work. Not, being an Electrical Engineer. I didn't know. Until, I found this Article, today. Check it out. This can be done and could save money over other methods...

Don

Increasing cable length in precision video applications | Electronics Open Source

Increasing cable length in precision video applications

Maurizio November 20, 2015 Electronics 1 Comment

Traditionally, the physical environment for transmitting video signals over long distances has been the shielded coax cable. Its quality and advantages are well known, and many times designers looking for off-the-shelf solutions do not know that long distance video transmission can be achieved with the same quality but for a much lower price.

1. Design

The solution described in this article proposes as the physical environment the use of a simple twisted pair cable; in addition to its lower price (compared to the shielded coaxial cable) it also features a much smaller weight, which sometimes can be a critical design criteria, especially for instance, in automotive environments, where cable weight account for the most percentage of the mass of a car.
Usually the regular configuration of a video transmitting system consists of an output amplifier (which either amplifies or acts as a simple repeater) mounted in the part of the system which generates video signal, connected via a shielded coax cable to the receiver part of the system. At the receiver, the signal is filtered, then amplified again, and fed to the display or perhaps to a video processing unit (Figure 1).

Figure 1: Usual configuration for transmitting video on coax cable

As stated above, using this configuration has a significant impact on both the price and the weight of the system. A much more advantageous solution, from these points of view, may be achieved through the use of a differential amplifier at the transmitting side, which would thus be able to confer a good degree of immunity to the video signal with respect to outside influences. The Video Driver is shown in Figure 2. It converts a single-ended input signal from a camera or DVD player into a differential signal that drives the twisted-pair line. The input receives an NTSC composite video signal with 1VPP amplitude, and the output drives the twisted-pair with a 2VPP differential signal. A 50Ω source resistor is in series with the outputs of both op-amps, matching the Video Driver output resistance to the twisted-pair characteristic impedance.

Read more...
http://dev.emcelettronica.com/increasing-cable-length-in-precision-video-applications