ben_indo 0 Posted May 24, 2006 Dear Forum; Should I use shielded twisted pair for CCTV transmission in area where power cables are near by ? or I just can just use a unshielded twisted pair ... Kindly give suggestions. Ben Share this post Link to post Share on other sites
rapid 0 Posted May 24, 2006 Always use unshielded twisted pair (UTP) cable. Each pair cannot have a foil shield or system will not function. An overall cable foil shield is ok. Good luck! Cheers......Rapid Share this post Link to post Share on other sites
ben_indo 0 Posted May 27, 2006 hi Rapid, Thanks for your info btw, do you know the reason behind why STP (with individual pair foil wrap) type not working ? I find that most literatures are not recommend shielded pair for CCTV application, I just don't know why, any idea ?, anyone ? Ben Share this post Link to post Share on other sites
shropna 0 Posted May 27, 2006 hi Rapid, Thanks for your info btw, do you know the reason behind why STP (with individual pair foil wrap) type not working ? I find that most literatures are not recommend shielded pair for CCTV application, I just don't know why, any idea ?, anyone ? Ben Bigger cable capacity. Share this post Link to post Share on other sites
rapid 0 Posted May 27, 2006 Hi ben_indo.....copied this from the NVT www.nvt.com website. Can shielded twisted pair be used? Some customers have successfully used shielded wire up to a few hundred feet. However NVT does not recommend it. Its high-frequency roll-off will severely degrade the distance performance. Use of an amplified receiver can compensate for some signal loss. Multi-pair wire (six pairs or more) can have an overall shield without degradation. Coax is an unbalanced method of transmission... UTP is a balanced method of transmission... Common Mode Rejection is the ability of a balanced input to reject the part of the incoming signal which has the same amplitude and phase on both input terminals, referenced to ground (The ability to respond to only differences at the input terminals). The original signal has a positive part on one termination and a negative part (opposite polarity) on the other. Any signal 'common' to both terminals will eventually get rejected, cancelled at the receiving end. The use of shielding would inhibit the effectiveness of CMR. Sorry to go technical on you. Share this post Link to post Share on other sites
AVCONSULTING 0 Posted May 27, 2006 Good advice Rapid, also love that Avatar. Share this post Link to post Share on other sites
rapid 0 Posted May 28, 2006 Gotta love Chief Wiggum. Share this post Link to post Share on other sites
ben_indo 0 Posted May 29, 2006 Dear Rapid; Thank you for your detailed replies; sometime or rather most of the time we need to go technical to satisfied curious minds. Ben Share this post Link to post Share on other sites
