crosseyed66 0 Posted February 16, 2010 I have an instulation where there is alreasy some shilded cat5 run that tested out fine using a Omni Microtest Scanner and I was wondering if I could use the shielded cable that is existing or if I had to replace it with unshielded cable? I always read that the baluns are for unshielded cable, just not sure if you do not need to use shielded or if you can not. Thanks in advance for your advice. Share this post Link to post Share on other sites
Soundy 1 Posted February 17, 2010 Shielded cable will be fine... the benefit of baluns is simply that they DON'T REQUIRE shielded cable, because it substantially more expensive. Share this post Link to post Share on other sites
crosseyed66 0 Posted February 17, 2010 That's what I thought, I am running my power in the wire with the video (should have mentioned that in first post) and was not sure if that could cause and problems inside of the shielded cable or not. I work fo an IT company and we are getting into the security end of the business sort of the opposite way of most. We have 17 years or network experience and have been installing cameras on for our network customers for years. Have been the IT partner for several other "Security Companys" over the years where they called us in to do what they could not. They have since gone out of business and we have been expanding and 2 years ago decided to do more on the security side from "A-Z". So for us we would have been more likely to set up a campus wide system than the small stand alone DVR with 8-10 cameras. Just a different learning curve. Share this post Link to post Share on other sites
hardwired 0 Posted February 17, 2010 At least two manufacturers say no... here's from Nitek's FAQ page. Q: Can shielded twisted pair be used? A: NITEK does not recommend the use of individually shielded twisted pair cable. Individually shielded pairs have a capacitance much greater than the recommended nominal value of 17pF/ft, which severely degrades the video signal, drastically reducing operating distance.In some cases use of an amplified receiver can compensate for some of the signal loss, however use of individually shielded pairs should be avoided. Multi-pair wire (six pairs or more) with an overall shield can be used without signal degradation. And from NVT: 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. Share this post Link to post Share on other sites
Soundy 1 Posted February 17, 2010 At least two manufacturers say no... here's from Nitek's FAQ page. Q: Can shielded twisted pair be used? A: NITEK does not recommend the use of individually shielded twisted pair cable. Individually shielded pairs have a capacitance much greater than the recommended nominal value of 17pF/ft, which severely degrades the video signal, drastically reducing operating distance.In some cases use of an amplified receiver can compensate for some of the signal loss, however use of individually shielded pairs should be avoided. Multi-pair wire (six pairs or more) with an overall shield can be used without signal degradation. And from NVT: 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. Given that last bit, I don't see why there'd be a huge difference with four pairs with an overall shield. Look at it this way: the STP is already in place. So try it - worst case, it doesn't work and you have to pull something new, or go to active baluns. Got nothing to lose by trying it! Share this post Link to post Share on other sites
hardwired 0 Posted February 17, 2010 I agree, why not try it. I think the note about using 6 or more pairs has to do with the distance from the shield to an individual pair, which affects capacitance, and the high-frequency attenuation. So, CAT5, at four pairs, is at least partway there in that regard. Share this post Link to post Share on other sites
