daubs8 Posted August 26, 2008 Share Posted August 26, 2008 QED are claiming this quality picture over 500m coax. Any thoughts? http://www.qed-online.co.uk/a87/Worlds-bes...ticle_info.html Ta. Link to comment Share on other sites More sharing options...
james.wilson Posted August 26, 2008 Share Posted August 26, 2008 i thought the RG and the 59 bit was the type of cable. Its not just about pure dc resistance to get more disatnce but the lower the resistance the better gernally as long as capacitance isnt too high. Do they say this will work with any camera or only that one? Im suspecting either a non std video signal or some form of amplifier or lift. ie we have sites doing over 700m on coax but they do need amplification. As another question why would you want to anyway? when you could utp it? Anything other than small stuff we now utp as std. securitywarehouse Security Supplies from Security Warehouse Trade Members please contact us for your TSI vetted trade discount. Link to comment Share on other sites More sharing options...
kensplace Posted August 26, 2008 Share Posted August 26, 2008 I could not really tell much about the quality from that clip, if they want to show of the cables quality why not show two examples side by side, one with rivals cable, and one with their cable both hooked up to a signal generator at one end, and a scope at the other end so you can see the actual degredation or not.... Plus its all in a roll, in real world applications the cable would be unrolled and exposed to 500meters of potential interference sources..... Link to comment Share on other sites More sharing options...
SUBS Posted August 27, 2008 Share Posted August 27, 2008 As far as I know, all full spec RG59 has a 20awg solid copper core and 95% braid, and Capacitance of about 16 pf per foot So theres nothing special there. Cant tell much from that picture, its a single, static camera. wonder what the amplitude of the signalis at the monitor end. and how your average mux would cope with it. I've seen reasonable pictures over long lengths of RG59, but would be so much better with CT125 or something like that. Link to comment Share on other sites More sharing options...
ilkie Posted August 28, 2008 Share Posted August 28, 2008 As far as I know, all full spec RG59 has a 20awg solid copper core and 95% braid, and Capacitance of about 16 pf per foot So theres nothing special there.Cant tell much from that picture, its a single, static camera. wonder what the amplitude of the signalis at the monitor end. and how your average mux would cope with it. I've seen reasonable pictures over long lengths of RG59, but would be so much better with CT125 or something like that. Just thought I would comment that the key issue with cable performance in the avialable bandwidth per 100m at say 5MHz The composite video output from the average CCTV camera covers a bandwidth ranging from 5Hz to many MHz, the upper frequency is primarily determined by the resolution of the camera and whether it is monochrome or colour. For each 100 lines of resolution, a bandwidth of 1 MHz approx is required, therefore a camera with 600 lines resolution gives out a video signal with a bandwidth of approx 6MHz As the losses of the high frequency components are very high on coax cables usually used in CCTV systems, for instance, using the common co-axial cables URM70 or RG59, 50% of the signal at 5MHz is lost in 200 meters of cable! Typically, good quality URM70 will have a loss of 3.3dB per 100m and RG59 2.25dB per 100m (all measured at 5Mhz). So in practical terms around 200 - 250m is the maximum that can be used without significant degrading of the images of today's high resolution cameras using this type of coax. The above figures ignores losses due to joints, connectors and poor cable installation. Of course launch amplifiers, and cable equalisers can extend the usable range but needs specialist equipement to set up. I have not yet been able to get the bandwidth figures for the new cable, but 500m implies a loss of around 1dB per 100m, a figure normally associated with CT167, a hose pipe sized coax! Ilkie Link to comment Share on other sites More sharing options...
james.wilson Posted August 28, 2008 Share Posted August 28, 2008 just what i was thinking honest i know rg was about 250m but to be fair i have never installed a run that long without a dome with an amp or a telemetry transmitter and if it was a static i would definetly go utp and active, so im really unsure as to the benefit of this.... unless im missing something really glaring obvious securitywarehouse Security Supplies from Security Warehouse Trade Members please contact us for your TSI vetted trade discount. Link to comment Share on other sites More sharing options...
camerabloke Posted August 28, 2008 Share Posted August 28, 2008 i think the most ive had with RG59 is 600 meters, it was a struggle though Eucam Security Systems 0845 4630 746 www.eucam.co.uk Link to comment Share on other sites More sharing options...
Securitycomp Posted October 16, 2008 Share Posted October 16, 2008 With no external interferances i'm sure its possible......but i would upgrade to ct125 just for peace of mind Link to comment Share on other sites More sharing options...
techyguy Posted October 17, 2008 Share Posted October 17, 2008 I'd be tempted to get QED to send over a manufacturers spec on the cable and see what distance is guaranteed. I'd be surprised if the manufacturers spec gives more than 300m for RG59. Link to comment Share on other sites More sharing options...
TimPickles Posted November 11, 2008 Share Posted November 11, 2008 CT125 is a good idea. Remember that from day one - the cable integrity and quality can only degrade. You also have one guge aerial for any EMF that is kicking around - or could be kicking around in the future. Best to go UTP and balun, or suck it and see with CT125. Tim Security Centre Grand Cayman xxxx CT125 is a good idea. Remember that from day one - the cable integrity and quality can only degrade. You also have one guge aerial for any EMF that is kicking around - or could be kicking around in the future. Best to go UTP and balun, or suck it and see with CT125. Tim Security Centre Grand Cayman xxxx Link to comment Share on other sites More sharing options...
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