# Cctv security system interference



## airbearlittleroc (Aug 1, 2009)

I have purchased a fairly high end nine camera color security system with 9 Sony high resolution cameras and a v-sync dvr. The system was purchased from DVRMASTER.COM. The cable they sent is RG 59 U 95% copper, I am receiving diagonal bars in the cameras something like: //////. I believe the interference is coming from one or both AM RADIO towers one on 1150 Mhz and the other on 1340 Mhz...about one-half of a quarter mile away. Both camera and dvr ends have BNC connectors. DVRMASTER has no suggestions. Another site suggested RF filters or RF traps and referred me to: elect-spec. com. I have left phone messages, faxed and e-mailed them but have received no reply since about last Wednesday. Does anyone have any suggestions? THANK YOU IN ADVANCE FOR ANY HELP. airbearlittleroc


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## JohnWill (Oct 19, 2002)

RG-59U is pretty lousy quality cable, I'd go with a higher quality cable. I'd recommend RG-6 cable.


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## airbearlittleroc (Aug 1, 2009)

Thanks for that info about the coax. Problem is it's already installed and would be a MAJOR project to re-do. So that's why I'm trying to come up with filters. Any ideas on that? airbearlittleroc


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## JohnWill (Oct 19, 2002)

I don't know of any filter that would be effective.

I'd start by checking grounding for all the cameras. 

A question:

If you take one camera and connect it with a short cable near the controller, do you still get the interference? If it's really the AM radio stations, perhaps a notch filter might help, though it would likely have to be on each incoming line. Proper grounding of the units would go a long way to solving any interference issues.


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## airbearlittleroc (Aug 1, 2009)

JohnWill: Thank you for the reply. I will get with our computer guy who installed the system, and give him a copy of this. The cameras do not have an independent ground. How do we do this? Also, what is a notch filter?
We could start with the two cameras that have the worst interference and see if that filter helps. I think he did try putting the camera near the dvr with a short cable but I will double check. THANK YOU! AIRBEAR


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## JohnWill (Oct 19, 2002)

See the description here: What is a notch filter?

Here's a page on addressing RF interference: http://www.kyes.com/antenna/interference/tvibook.html


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