VGA cable run through wall to projector

[massive88]

Originally I ran two Cat 5 cables to field termination plugs in my wall and ceiling to patch a VGA signal from my home theater PC to my projector.  Which worked pretty good.

However, whenever I switch over to the satellite box for HD, the signal gets interference, with slow darker lines running across the screen.

Would running an actual VGA cable help with the interference?  I dont know enough about electronics, or the two cables to know if it would make a difference.  At first I was just floored to get it to work, and most of our watching on the projector was done through the PC, so I didnt mind.

Now we mostly watch the Satellite on the projector, and the intereference is bugging me.  Could something as simple as running the correct cable help?  And if so, where can you get bulk length of VGA, and how tough is it to connect to a field termination unit?

My jargon is also horribly off I imagine, I apologize.

[grantspain]

you need shielded cable

[fa001]

You could use a video balun. Check out this article:

http://www.muxlab.com/assets/files/articles/VGA_cabling_simplified.pdf


- Fred

[ahofle]

where can you get bulk length of VGA, and how tough is it to connect to a field termination unit?

http://www.monoprice.com/products/subdepartment.asp?c_id=102&cp_id=10201

[massive88]

where can you get bulk length of VGA, and how tough is it to connect to a field termination unit?

http://www.monoprice.com/products/subdepartment.asp?c_id=102&cp_id=10201

I actually first tried to run a 25' monoprice VGA cable.  However the tubing that is installed to run the cables is way too small for the plugs.  I cant pull them through.  I could try chopping the plugs off and attaching the cable to the feild termination units, but I am not sure how the wires would look if I did it, or if I could do it successfully.

[massive88]

You could use a video balun. Check out this article:

http://www.muxlab.com/assets/files/articles/VGA_cabling_simplified.pdf


- Fred

This is basically what I have done, only I just used Cat5 to wire two of these together to in wall faceplates.  I did this because in my apartment (before I had the house) I made a component to VGA cable to use with the same projector to hook up cable tv, so I knew the Cat5 could do the job over the 25' or so that I needed.

It is possible as suggested above, that I did not specifically get "shielded" cat 5 cable to do so, perhaps I should first try to rerun with a definite shielded product.

The picture is still good, and you dont even notice it on sports or other fast moving things, but it bugs me pretty bad when watching Conan or dramas where the screen sits still for extended periods of time.

[MonMotha]

The correct thing to do is grab yourself some RG-59, or (even better, but hard to work with) RG-6.  This is 75-ohm transmission line and is what VGA is based around.  This is readily available for cable television usage.

Terminate the signal lines into the RGB lines on the HD-15, and terminate the shield to the corresponding "shield return" pin directly below them on the middle line.  You can use normal wire for sync, but if you've got the coax, it doesn't hurt anything to use that.  You will likely have to solder short wires to both the center conductor and the shield to get them into the HD-15.

If you prefer, you can terminate each wire (you'll need 4 or 5, depending on if you use composite or separate sync) with BNCs and use a BNC/HD-15 breakout cable.  This is the more professional way to do it, but it requires more expensive tools (to crimp the BNCs) and more "stuff", so it's more expensive all around.  Make sure you use 75-ohm BNCs, not the (slightly more common outside of the A/V realm) 50-ohm BNCs.  They appear virtually identical upon a casual inspection.

With proper cable, 0.7Vpp analog video at up to UXGA (1600x1200, VGA style signalling) can be run for several dozen meters without any issue.  Just make sure both ends agree on the concept of "ground".  You may need to run a dedicated (and heavy gauge) ground line between both ends.  Consult an electrician before you do that as there are some issues associated with doing such a thing.  If you're in the same residence (this is not always true of commercial buildings), there should be no problem.

Using proper transmission line that is matched to the source and termination impedance will eliminate transmission line artifacts that can show up on sharp edges.  These artifacts would mostly look like "ghosting", similar to multipath interference on OTA NTSC signals.

For longer runs (>25m or so), consider using a balun and shielded CAT5 or CAT6 cable.  Note that you need the balun for these longer runs on twisted pair cable!  You will also have to use composite sync since there are only 4 pairs.

[incstlouis]

Have you considered using a Quick Disconnect Type of System like this:

http://www.showmecables.com/Rapid-Run-Audio-Video-Cables

[massive88]

Have you considered using a Quick Disconnect Type of System like this:

http://www.showmecables.com/Rapid-Run-Audio-Video-Cables

Im not sure what you are linking me to.

I basically have only 25 feet to cover, and my projector only has 15-pin VGA input.  My receiver could put out in any format though, currently Im using component to VGA to field termination terminals in the walls, which are connected by Cat5 cables.  The tube running from faceplate to faceplate is too small to allow me to run VGA cables with plugs or really even Ferrites on them.

I guess the real question is, if I buy a 25' VGA cable, and cut it open, will I just see 15 wires that I can then terminate in my plates?  When I was reading about VGA cables, it sounded like there was Coax and twisted pair lines, and I was too nervous to cut up a cable and check it out, when at the time my Cat5 solution was acceptable.