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I've got a few NTSC security cameras I'd like to set up around the perimeter of the house. They output standard NTSC video and require 12V for power. I was hoping to power them and take video off the same cable, but I haven't been able to figure out a slick way to do it yet. Structured cable isn't all that expensive but if I could stick with standard RG59 or RG136 I think that'd be best.

Unfortunately it's not like injecting power into RF signals; NTSC video sits around 1Vp-p and has high frequency components to it so it's not as simple as just using a DC blocking cap. Has anyone done something like this before and what kind of success have you had?

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    \$\begingroup\$ I think you have misspoke. 1Vp-p and high frequency components isn't a reason to not use a DC blocking cap. What is a reason is a DC offset that changes slowly with time and is needed by the receiver to get some information. \$\endgroup\$ – Kellenjb Jan 2 '11 at 20:12
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How did you get your Nintendo to display on a TV without baseband inputs? You used an RF modulator.

So set up an RF modulator at the camera, then the normal DC block capacitor will work.

It shouldn't be too hard to find an NTSC demodulator for the other end.

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  • \$\begingroup\$ Hmm, so I'd end up powering the modulator and the camera from the power injected on the coax... not a bad idea... \$\endgroup\$ – akohlsmith Jan 3 '11 at 2:47

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