the toss

The only difference between a 12Vdc & 24Vac is a (usually seperate) power supply board in the camera to drop the 24Vac down to 12Vdc. This is the most likely part to fail. By bypassing this board you will salvage the camera and be able to use it on 12Vdc only. Open up the camera & identify the main incoming power cable. This will terminate on the power supply board. There will be another pair of wires leaving this board to supply 12Vdc to the camera. Cut & join these wires to each other taking care of polarity. I have found about 80% of dual voltage cameras are able to be salvaged this way. It may not recover the IR depending on the IR power configuration but with a bit of poking around this should be overcome.

That is what I do & give my customers an extra years warranty if they accept this option

It is also likely that the BNC o/p is 75^ while the RJ socket is 100^

Where are these imaginary video inputs if you don't have a camera , a DVR or any connectors

Some cameras has twisted pair output in camera. Its camera "design problem", not a cable Yep. If you want extend distance from analog camera, you will use twisted pair or fiber optic, but not coax Say also, that fiber is designed for day light transmission from Austrlia to night Europe, but not for CCTV ???????

As the others have said , be VERY careful with wireless. Two immediate problems come to mind. They may be wireless but they are not powerless. You wil need to supply power to them. Secondly if you are putting cameras on the eves of a two storey building you will need a cherrypicker or some other sort of elevated work platform. Any maintenance/repair will require that same equipment . These are not cheap to hire. Make sure whoever needs to know realises that repairs/maintenance will include these costs.

As with RG6 , twisted pair is not the best to use, It can be extremely convinient to use & give good results but again it is not designed for this purpose. Its characteristic impedance is 100^ (120^) and requires impedance matching devices to operate (baluns) . The use of each balun will result in an insertion loss of up to 1.5db. This may offset any advantage over long runs. I guess it boils down to - TV guys will always want to use RG6 Comms/IT guys will always want to use Cat5/6 Electricians probably want a way to use 2/E CCTV guys will always want to do it right & use RG59 Do farmers want to use barbed wire?

100m is not a very long run. You get both HF & LF interference from Fluoro lights. You get short term HF interference from the striking of the starter & ionisation of the tube. This interference can affect devices at quite some distance but is only short term. The other is LF interference from mains voltage in the ballast transformer & light cabling. This is proportional to current which is quite low in Fluoros so its range is not great but it is long term , being present while ever the light is on. You shouldn't need to do anything more than space your coax as far as possible ( at least 12") and not run parallel with any mains cabling

I have posted many times trying to convince people about the hazards of using RG6 cable for CCTV and yours is a perfect example. I don't know what your technical background is but read up on the shielding capabilities of RG6 vs RG59. Everyone thinks that RG6 is the bees knees because it has quad shield & is a modern innovation. For digital TV there is no argument that its performance is superior to RG59. This is the first clue. It is designed to stop interference at RF as it's prime purpose is to transport RF signal from your anntena to your TV. Look at the specs and you will see that its shielding capabilities are very poor below about 50Mhz. What is the baseband frequency of CCTV, it is around 5.5Mhz.This is where RG59 comes into use. RG59 shields best at frequencies below about 50Mhz. RG59 was designed for a time when there was nothing that could utilise frequencies of hundreds of Mhz and it did the job well and has years of refinement. In a low noise environment RG6 can (and does) work ok but you need to understand the dangers (as you have discovered). I would like to know what prompted you to use RG6 thinking it would solve your problem.

I my experience the most vulnerable part of any DVR or camera is via the power supply. I give my customers an extra year warranty if they have ( or I supply ) a UPS as extra protection. I dont use it so much to provide backup power but it has that as a benefit

Installng it will be the same regardless of product quality. Installing it yourself will let you learn about your system and how it works. You may make mistakes but that is part of the learning process. I have seen some excellent DIY installations & some piss poor professional installations. For entry level systems I work on these criteria. Picture quality , ease of use , cost and (nearly) most important warranty. I use an entry level 4 ch kit here that comes with everything and carries a 4 yr warranty for $500

There will be if you don't house those connections. A bit of rain with a bit of wind and they will get wet.

BNC is not a cable type , it is the connector. I'm guessig you meant to say that it is not using normal coax (RG59) but the mini coax with the RCA connectors. If that is the case then there is the FIRST thing to address.

That's correct

almost certainly the red & black will be power ( 12Vdc or 24Vac) while the white will be the video signal ( together with the black earth )

Buy thiem at any audio/video shop. Normally used for connecting xbox/dvd/wii etc to your TV

It wasn't a smart ass answer. I have never seen a high quality camera come with unterminated leads and your question demonstrates why. One quick way to destroy a cameras reputation would be to have people doing crappy terminations. I use cameras in that price range nearly every day of the week , it is nothing special. In fact it is less than special. 12V dc , 1/3" sensor and even with heater /fan only consumes 3W. Seems like it has reached new heights in efficiency. If you know all about baluns then you would know that using two back to back for no other reason than providing a method of termination is rediculous. Insertion loss for a balun can be as high as 2dB

Dyou know what a balun is and what it is used for ? That sounds like a quick way to destroy your signal quality. Like I inferred in the last reply , don't ask how the "pros" do it cause they dont do it.

They can work but are unreliable and a constant source of problems.

A proffessional camera would come with either a built in BNC connector or one already terminated on a flying lead.

I have read (but am yet to see it) that there has been a huge improvement in cmos cameras over recent years. I don't think this is one of them

I don't think much of that.

There is so much more to take into account than impedance. The bottom line is - RG6 has lower HF losses than RG59 ( it is desugned for RF frequencies ) RG6 has lower DC losses than RG59 ( it uses heavier guage copper ) RG6 can be harder to run due to physical properties RG6 is more vulnerable to low frequency noise ( <50Mhz ) CCTV baseband signals are 5.5 - 6.5 Mhz So - if your runs are more than about 250m and are in a low noise environment and are easy to lay then RG6 will probably be ok. I hold by the premise that RG6 is designed for RF signals & RG59 is designed for baseband signals.

just do it properly and use RG59

I don't know why people think that just because a pole is earthed then anything attatched to the pole will be immune from lightning. One way to think of it is a dam bursting. MOST of the water will take the path of least resistance but some will find an alternative route to flow. So with lightning most of the energy will go directly to earth via the pole. But as with any conductor it is not perfect and that energy isn't going to line up and wait its turn to get to earth. Everything on that pole will assume the lightning strike voltage and initially that will involve current flow. Read up on lightning strike voltage gradients. A good insulator may give some protection in the event of a close strike but in the event of a direct hit anything on that pole is cactus.