I have successfully installed a number of video
surveillance cameras up to 1200 feet from the
monitor/power supply using CAT-5 twisted-pair
Several suppliers offer small adapter
units to place at each end of the CAT-5 cable to
feed DC to the camera and receive video back to
the monitor. Check out
. The main problem with
CAT-5 is that its' DC resistance is
approximately 30 ohms/1000 feet. This means that
there is 30 ohms in the DC feed wire going TO
the camera and 30 ohms in the DC return.
It is possible to modify the adaptor modules
so that spare pairs of wire are paralleled in
order to cut the resistance in half.
solved the problem of excessive voltage drop by
using a power supply with a higher voltage
output and installing a simple little 3-terminal
regulator at the camera to drop any excessive
voltage back down to the required 12VDC.
Whatever you do, calculate the voltage drop
based on the total resistance in your CAT-5 run
and use a power supply that puts out 5 to 8
volts above that and let the 3-terminal
regulator drop the voltage at the camera site
back down to the required level.
video coming back from a 1200 foot run of CAT-5
cable is just a tad soft from high-frequency
roll-off, but is still at least as sharp as a
the video playback from a typical VHS video tape