Cable Building

Karl gave me a hand putting together a new cable to feed the projector. The project went really well, we both needed long VGA cables and did his a few weeks ago. If you do a google search for “RGBHV over shielded cat5” you should hit some relevant information. (Note: the google answers hit looks really bogus as they are talking about sending video vs. doing a long VGA run)

Here is what we used:
Shielded cat5 cable. This is 4 twisted pairs (8 wires) + a drain wire that is un-insulated.
DSub15 VGA connector with metal case.
RG59 BNC connectors
Heatshrink etc,.. to make it pretty.

HD-15 pin Cat 5 color
1. Red + Orange
2. Green + Green
3. Blue + Blue
4.
5.
6. Red - (aka GND) Orange stripe
7. Green - (GND) Green stripe
8. Blue - (GND) Blue stripe
9.
10. Ground (GND) shield wire.
11.
12.
13. H sync Brown
14. V sync Brown stripe
15.

For Karl’s projector (my old ECP actually) he needed both H and V sync. So as you can see, we double up the shield wire as a ground for the H and V sync signals. This just means you need to splice on a Y-split at the BNC end. The Ampro only has a 4-wire hookup, so we were able to leave the shield wire alone – soldering it to the metal VGA connector “hood” and leaving it unconnected at the BNC end — this also let us use the brown stripe wire as the ground for the combined sync signal which runs on the H sync line.

Since we are not using any shielding at the BNC end, we tried to keep the pairs twisted and kept the distance they were fanned out to a minimum (6 inches or so). We used coloured heat shrink to identify the connectors which turned out really slick. For my cable I also got some 1/4 inch nylon sleeve from TakeFiveAudio to make it black for the bit that runs across the ceiling as the cable itself is blue.

This new cable replaced the VGA break-out + BNC extensions I was using. The BNC extensions were pretty hacked up, and were using a steel core RG6 cable as well. I didn’t see any real cable artifacts in my image previously, and the new cable seems to be flawless. For Karl there was a more dramatic difference as he had a very poor VGA extension + VGA break-out cable — this was giving him a visible ghost in his image which went away with the new cable.

Cost was under $40 for each assembled cable. Everything was easy enough to find locally, the cat5 being the most difficult and that only took 4 phonecalls to a few network cable installers until I found one nearby who had some shielded cat5 that he’d sell small quantities of.

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