Thread: Newbie, VGA Cable FAQ

Originally Posted by rmason

So where is the FAQ on VGA Cables? Need to know such goodies as:
1) How long can you run a cable without it effecting Quality
2) Where is a good source to get Quality cables
3) Is there a better technology than VGA for small touchscreen monitors
4) Any "best practices" when it comes to running the cables in a vehicle?

Not a FAQ but here goes:
1) 0 (zero) feet. As soon as the cable exits the case, you get interference. Now, how far before you really see a "bad" picture. That depends on lots of things and can't be predicted. I run 15ft of VGA cable in my car. The picture is definitely worse then just the 5ft cable attached to the monitor, but I'm happy. I've seen/heard of people running much much longer with well built cables (you can break out each conductor in a VGA cable to it's own high-quality RG6 cable, some think it's overkill, but others swear it'll let your run 100 feet.

2) That's tough. The home theater PC guys over at AVS Forums have tackled this and have lots of opinions. Someone there once recommended bettercables.com, keep in mind these get REALLY expensive quickly, their "Silver Serpent VGA Cable" is $140 for 15 feet. Hey, you said quality. In general, the "which cable is better" question degrades into "is monster cable worth the money". That is, lots of opinions, not a lot of facts.

3) Yes. I can think of two:
- DVI, just like the DVI connector on your desktop LCD screen. You need a DVI out on the video card and a DVI in on the screen.
- LVDS, read this. I think the max is 15 meters. But, this is harder then it looks.

4) Keep the data cable as far from power cables as possible (anything cable in your car that powers something is a power cable), I ran my VGA and USB down one side of the car where nothing else was, the power for the LCD down the other.

i run a 25 foot vga cable bought off of ebay and i have no display issues in the car.

Originally Posted by Sonicxtacy02

i run a 25 foot vga cable bought off of ebay and i have no display issues in the car.

None? If you compare your display plugged directly into the carPC vs. using your extension cable (even out of the car), you can't tell the difference? My point was that there is always some degredation, it's just how much you car and how much you want to spend to try and fix it.

nope there's really no difference at all that i can see. I mean yes there's always some degradation but not enough to make a difference whether or not an extension of that length should be used.

Originally Posted by Sonicxtacy02

nope there's really no difference at all that i can see. I mean yes there's always some degradation but not enough to make a difference whether or not an extension of that length should be used.

I bought some cheapy generic 10' VGA extension cable and I definitely saw my lilli get fuzzy between directly connected and going thru the 10'. It wasn't enough to stop me from using it, but I really should look at upgrading the extension cable.

Some advice:
Don't buy the cable unless it specifies that it's shielded, and make sure it has the "lump" in the cable near each connector. That lump is a ferrite, and it will help reduce EMI and improve signal quality.

Here's one for $40 that's ferrited and double shielded:
http://www.cablestogo.com/product.as...2810&sku=28003

Originally Posted by kbyrd

None? If you compare your display plugged directly into the carPC vs. using your extension cable (even out of the car), you can't tell the difference? My point was that there is always some degredation, it's just how much you car and how much you want to spend to try and fix it.

I am using a cable that is similar to the one linked (above). It is a 50ft extension running to a XGA projector. There may be interferance but if there is I dont see it in the picture. There is no noticeable difference (in this installation) between a 2ft from the pc or a 50 ft (properly shielded/ferreted) cable.

Now notice I said in this installation (in my living room). I would think in a car there would be alot more electrical things to interfere with the signal (alternator, battery, audio cables, amps, speakers etc).

As always YMMV

c-ya
Chris