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Intercom camera replacement

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Greetings all! I'll do a brief intro here. I'm a cable technician with experience in RF and telephony so the CCTV world is unfamiliar to me. I'm used to copper-clad steel conductors and aluminum braids and that copper RG59 is "bad" and causes problems with digital phone. Our policy is to replace any RG59 whatsoever, which makes sense from an RF perspective. However as I become familiar with baseband video I can see that copper braids and RG59 do indeed have a secure place in telecom.


I live in a condo building with a front door camera built into the intercom system. It's a simple PC board with a CCD and lens on it that someone sandwiched into a wallplate, and then screwed into the aluminum face of the intercom. Pretty hack, but it works. One problem is the lens is exposed and people walking in will sometimes monkey with it, throwing the focus off. Since I work in telecom I was approached by the building management to fix it even though it's not our company's responsibility. I focused the camera successfully and thought to myself, "I can make this better." Thus began my first venture into CCTV.


Years ago I worked contract security for the railway and was involved with facilitating a CCTV upgrade at one of the yards, so I had an idea what a professional company would charge to install a new camera. I went to a local firm known for good prices and was quoted over $120 for a replacement color camera. I checked eBay and found a Sony 1/3" CCD 480 line unit for some $33 with free shipping out of China, so I opted for the latter. Should be here sometime this week.


Now, the current installation is set up as follows. The garbage room on the main floor is where all of the CATV equipment is mounted, including the channel remover (the building opted for channel 9), modulator, and power supply for the camera. The power supply is my main concern at the moment as it's pushing 12V 200mA through about 100+ feet of 22/24ga alarm wire through the crawl space to the front door. The leads of the power supply wire have been cut off and beaned to a pair each of the alarm wire presumably to increase the current carrying capacity, though I'm not happy with this. The video cable is copper RG59 with a BNC connector at the camera end and a Gilbert Corning compression fitting (my company's standard) at the modulator, so that should be fine. The camera I bought calls for 120mA so am I correct in thinking this rather substandard electrical supply should be replaced?


Since I'm doing this more as a favor to the management company, cost is the primary issue. I'll be billing the company for materials and nominal labor, but I want to use as much of the existing equipment as possible to keep the costs down. I planned to replace the alarm wire power cord with something better, not sure what yet. Probably depends on what two-conductor wire Princess Auto has in bulk; I'm not concerned about size since it's going through a crawl space so it doesn't have to be small. I'd also considered going with a 13.8V power supply instead to account for voltage drop but with a larger diameter conductor I don't think that'll be necessary.


Thanks if you've read up to this point! Anything askew with what I have planned thus far? I figure that aside from fabricating a better mount for the camera (with plexi to protect the lens) it should be fairly straightforward. Thanks in advance!

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If you're doing this more as a favor than a paid job, why not just swap the camera and secure it first and see if you have any problems with it? If the current system is working except for the occasional fooling around with the lens, keep it. Make a suggestion that they might want to amp up the power supply in the future or tell them the newer camera may over tax the current power supply so changing it is better. Remember....you're the last one touching the system......anything else goes wrong and they're coming to you.

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Clarify also where you stand on what happens if the thing breaks in the future.


You dont want them to bill you for a replacement camera if the chinese cam fails in a few months (or even if it turns out to be so bad you need to spend more to buy another cam, are they going to pay for both or will you end up shouldering the cost?)


Also find out the stance on insurance/liability etc, if something goes wrong, you dont want them suing you (unless your covered)


btw - it almost certainly wont be a sony cam, even if advertised as one. The chinese tend to advertise a cam as a sony cam if it has some sony components (chipset, ccd or both) in it. There is a also world of quality difference between a good cctv cam, and the stuff is sold on ebay in that price range from china... It may be ok though (assuming it lasts!) for a door type cam, only way is to try it I guess.

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