I have a customer with two fixed outdoor cameras,both cameras are sharing one cat 5 for video and one cat 5 for power. Both cables are less than 100Ft. both cameras are rolling before I replace the cable what troubling steps can I run to narrow my trouble down?

on the dvr end......use the 2 baluns on a test cable to check that they work.........then use thos eto install on one camera run........

is the cable indoors? is it run near any AC voltage wires?

I will check the cable for twist are a possible EI.And try your first test.

Are they 12VDC or 24VAC? Do they both run off the same power supply?

I've seen ground loops cause weird problems with 12VDC cameras using a common power supply.

They are 12v are two cameras are on one power supply and the two that are rolling on another.

Try putting the two rolling ones each on its own power supply.

Thanks for help if will give it a try today will post outcome.

Try powering the DVR and the cameras from the same AC outlet.

In theory, that shouldn't matter, as the power tranformers isolate the cameras from the DVR power ground. unless, of course, the camera chasis is attached to an earth ground...

I think Its worth a try.

I've had situations were cameras was powered locally using Isolated Transformers and still had image distortion and looping.