Say you have a projector in the roof, but can’t (or just don’t want to) run a long VGA cable from it to your media box. If you already have Cat 5 conduit in the house, you can use these VGA extenders to send an RGB signal over very cheap Cat 5 cable.

For those who don’t know, a standard 15 pin VGA connector sends red, green and blue signals, along with vertical and horizontal information through its pins. A lot of pins aren’t used or aren’t connected, which is why some cables that appear to be missing some still work.

Electrically, there’s very little stopping you from converting the 15 pins on the end of a VGA lead. As a classic example, professional CRT display leads start with a VGA connector and end with BNC plugs. A more common and modern example is the ubiquitous DVI to VGA converter. The difference with using Cat 5 to do the job is that not only is the video signal being transmitted over very cheap and thin cable, it’s travelling over a long distance.

Using inexpensive Cat 5 cable to send video sounds like a good idea (it’s being successfully used in many other applications) however in this case sending video didn’t work as well as we were hoping. Due to the lack of insulation around a Cat 5 cable, a lot of noise is picked up, and depending on the distance you cover between the sender and receiver, a lot of the signal’s gain is lost. The two models have to compensate somehow, which is how they differ from each other.

The cheaper VE-120 compensates by adding a certain amount of gain to the signal at the transmitter end, depending on the length (and by extension the resistance) of the cable run. On the transmitter, you can select between long and short cable lengths, but the actual lengths that correspond to the switch positions aren’t listed in the included documentation. There’s a monitor passthrough so you can both watch the signal locally and on whatever happens to be plugged into the receiving end, and two AC adapters are included, one for the transmitter and one for the receiver.

You should get an acceptable image over 80 meters at resolutions of 1600 x 1200, although lower resolutions, shorter cable runs and low refresh rates give you a far better looking image. We didn’t have a lot of success with text, which could limit the unit’s appeal. The main problem that we had with the unit (both of them actually, but more so with the VE-120) is that colours are washed out.

The more expensive VE-150 has a 16 position distance selector on the receiver that works its way up from 0 to 150 meters in 10m increments. The output quality is far better because of the control this gives you over the signal. The fuzzy edges of text were less of a concern and although the image still looked underwhelming it was passable, unlike the VE-120, which looked as though it had been through a washing machine.

If image quality matters to you, you should get some high quality VGA cable and a line driver to go with it. But if all you want is to send a video signal over a long distance on the cheap without much concern for image quality, these are worth a look. Just don’t get too excited.