CAT5E TV connection

gwenfo · 06-11-2008, 17:53

Grateful for any help anyone can offer to help this new member solve an irritating problem.

I have made up and installed a CAT5E cable between two rooms. The cable connects at each end to a Madnat box that converts Cat5E to SCART. At one end of the link I have a Pioneer digital HDD/DVD recorder and at the other a 32" Sony LCD TV. The picture and sound transmitted to the TV are very clear but ... the picture is spoiled by a rolling white horizontal bar and its black shadow (or vice versa!) rising gently up the screen.

I have tried using a different LCD TV - same problem.

I have tried placing the TV close to the the DVDR connected by a short off- the-shelf CAT5 cable - problem goes away.

I suspect, therefore, that my made up cable is picking up some sort of interference. It does run quite close to some speaker cables but I have disconnected the amp that drives them to no avail. It's always possible that there are some mains cables fairly close to the run but I don't know of any thing closer than about 6 or 8 inches.

Does anyone know of a filter that I can fit in line or some other device/solution to the problem?

Clearly I'd like to avoid having to re-run a different cable?

Many thanks in anticipation (and desperation and FRUSTRATION!!!),

Graham

Graham M · 06-11-2008, 18:14

Your best bet if you think it's by interference would be a run of STP earthed at ONE END, your first port of call is to check that your connections are all tight and there are no shorts

gwenfo · 06-11-2008, 18:34

Many thanks for quick response. Afraid you'll have to expand STP for me (pretty sure its not Sellotape!). Only reason I use the term interference is because the effect interferes with the picture. I did see a reference elsewhere to scrolling (horizontal or vertical - not clear which ) being due to DC interference but it also wasn't clear whether that only applies to CRT TVs.

I'm guessing my problem is some sort of pick-up from adjacent cabling but I have no specific evidence. How would the STP (whatever it is) have to be run: alongside a short or long length of the Cat5? Connected at one end to an adjacent radiator perhaps? I'd be a bit reluctant to connect it to mains earthing!!

I should have mentioned in my post that I have connected a Cat 5 loop tester to the cable and that shows all strands to be properly connected.

Regards,

Graham

haydnwalker · 06-11-2008, 18:35

I second the STP approach. Obviously UTP is picking up some interference so shielded should help aleviate the issue

Kiryu · 06-11-2008, 19:21

a simple fix i once read on a website was to cover the UTP cable with the thermal pipe insulators (the stuff you wrap around the outside of hot water pipes and refrigirant pipes).

it works well and a very easy fix instead of trying to earth STP.

Thanks

Please see this thread Courtesy of DSL Reports