robert99d Posted May 4, 2004 Posted May 4, 2004 hello all can i use alarm cable to wire cctv cameras(power and video) or what about tv coax? thanks Robert
ian.cant Posted May 4, 2004 Posted May 4, 2004 The realistic answer is no! While you will be able to send a video signal down either cable the results will be poor. Depending on the length of alarm cable, the amount of interference the cable will pick up will vary mainly because it isnt shielded. The tv coax will be more successful as it is a similar cable with simillar construction, however it is slightly different. Mainly TV coax is 50 ohms and CCTV cable needs to be 75ohms. Also you will have problems trying to fit BNC connector to it as it will be a different size. Joining the cable with connector block will induce interference into the signal. Use the right equipment to do the job, you wouldnt use a knife as a screwdriver would you?
robert99d Posted May 4, 2004 Author Posted May 4, 2004 thankyou so am i right in thinking i need RG59 coax for the video? and i can use alarm cable for the power what about audio? also how would you wire up one of these to the coax http://www.maplin.co.uk/products/module.as...3617&Products=2
Guest dale Posted May 4, 2004 Posted May 4, 2004 Yep use RG59 for video, and alarm cable for the power and the sound (as the sound will be seperate to the video). To wire these up I would put about 20 cm of high definition interconnect cable into a phono adapter (this is how most of them come when pre-wired) then have that go into a phono to BNC converter then straight down the RG59 to a BNC connector at the other end that goes into the VCR/DVR. Defenition wont be lost using only a small ammount of high definition cable. Dont try soldering the RG59 straight onto the board, its near impossible...(yep been there done that!). Also dont try putting a BNC connector onto the interconnect cable, its not a round cable so it just wont go on, no matter how hard you try!
neil.c Posted May 5, 2004 Posted May 5, 2004 Are you sure TV coax is 50 Ohm Ian, I thought it was 75. I thought that RF cable such as RG 174, RG178 and RG213 were 50 Ohms.
ian.cant Posted May 6, 2004 Posted May 6, 2004 You could well be right Neil, i aint an expert on what cable is what in terms od ohmic value rated, i am however fairly confident that you wont fit a BNC connector onto the end of domestic tv coaxial. Also i am fairly confident that there is a design difference between the two types of coaxial cable which make them unsuitable for use in the other application.
secure4 Posted September 23, 2004 Posted September 23, 2004 TV Coax is fine for black and white cameras however its **** for CCTV really, and your right you cant fit a BNC on to the end of it. How do I know? I upgraded the cameras fitted by a large national company for a guy and becuase they installed black and white cams, they went the cheap option and installed standard coax, worst of all they then soldered the ends to about 3 inchs of rg59 so making the signal even worse. Cant get any decent colour out of one of the new cameras, and these are at the guys gatewhouse, the cabel runs for about 200 yards underground so replacing them will be a nightmare! Some companaies / installers just dont think of the future upgrades. Regards. Mark secure4.me.uk digital cctv
Guest Posted October 1, 2004 Posted October 1, 2004 RG59 and TV-cable are same kind of cables. Only difference is physical size and attenuation. This attenuation shouldn't matter under 500m cable lenghts. And there are BNC connectors for both cables. Though BNC - connectors are rarely used with TV - cables which means that they are more expensive. When continuing coaxial cable you have to know what you do. If you don't, you will create extra attenuation (easily 3-5dB). In coaxial cable it is very important to maintain that spesific distance between the wire in the middle and the shielding. Diameter of the middlewire and the distance from its core to the surrounding wire specifies the impedance of the cable.
Guest bryan1656 Posted October 25, 2004 Posted October 25, 2004 Correct me if I am wrong, here, but my understaning is that RG59 is a larger guage with single foil and braided shielding, while RG6 is smaller diameter solid copper core, but is quad shielded (two foil/two braided) to reduce interference. I can't recall which is the one usually seen on television cable (??) but I want to say it is the RG59 (at least in the US), unless you are looking at at higher end multimedia, where you are likely to see RG6. (and it is usually RG6 that is used for high-speed cable modems). F connectors come in both sizes, but do they terminate in the same size? The one end would have to be slightly differnt due to the different core guage, but will both screw on to the same television set? (I should know this, but it escapes me at the moment.) I've also seen the BNC connectors in both RG59 and RG6. (as well as RCA) at any rate... What are some of the pros and cons for each type according to use? I'm sort of looking at this as parellel to Cat5 vs. Cat5e vs. Cat6 on a netwrok install. Sometimes you can't justify the expense of a higher grade cable, but other times, you'd be doing a poor job if you didn't run the good stuff. Or if this is a stupid question, don't be shy in telling me... I don't wear my feelings on my mouse!
ian.cant Posted October 25, 2004 Posted October 25, 2004 RG 59 doesnt have a foil around the braided shield.....not here anyway lol! Generally speaking i would use coax for most small camera installs but if i had cable runs in excess of 100 mtrs then i would consider cat5 and video baluns, especially if i had a few cameras at the same location and even more so if they were functionals. The key i have found is to use quality baluns such as NVT's kit. If you have acess to a network and it is where you need it then rock on!
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