Hi,
I have a friend of mine who is setting up a projector in a church. He needs to run 150 ft of VGA cable in wall and is having a hard time doing so because of the size of the round cylinders (i think they are ferrites?) attached to the cabling near the VGA connectors. Are they necessary to keep interference out? Are they especially important over such a long run of cable? Any advice would be greatly appreciated.

Mike

Simply put... Yes and yes.

Others have also made their own VGA cable using two sets of Cat 5 cables. (8 wires per cable). The twists in the wire keep interference to a mininum. You can also buy ferrites to add afterward. Good thing about Cat 5 cable, it is easy to pull through walls (esp. exterior walls having insulation) and it comes in varieties such as "in wall" ratings which meet electrical building codes. You just need the cable, two VGA ends and some soldering experience.

cheers,
gs

GS, thanks for the response. He told me that he purchased a 150ft cable without the ferrites in place, would they (the company making the cable) sell a product without the ferrites knowing that it wouldn't work? Is it possible it is shielded in another way?

It is certainly shielded in another way, the main way, which is the shielding contained within the covering (or jacket) of the cable. The ferrites serve to shield interferences on the end of the cable before being transmitted the length of the cable. You can certainly test the cable before running it to see if their is interference to begin with... of course after the cable is run there may be intereferences (like from electrical lines in the wall) that you can't possibly test before hand. If you find interference after running the cable you can always try "snap on" ferrites to see if they help.

Funny how a cable of that length has no ferrites on it... almost all decent quality cables have them. Where did you/he get the cable from ? I know that monoprice.com carries a 100' cable (w/ ferrites) for $23, I think they will also make custom size cables...

gs