A few years ago I had a 2-camera CCTV system installed, with both
cameras fed through RF modulators so that I could view each on a
different channel on the TV. The "guts" of this setup was a complex of
cross-wiring in a project box:
- a pair of daisy-chained RF modulators
- power supplies to the cameras and modulators
- a capacitor
- another component which could have been a transistor (??!)

Due to problems with this setup, and overheating componentry, I have
dismantled it and tried to simplify it with the use of more standard
connectors into my video system. Before I begin, I wanted to check
that I had correctly understood the wiring of the existing cameras...

Each camera is linked to the junction box via a 4-core cable. Two of
these are for the power supply. The other two, I presumed, were video
and audio. I put some phono plugs on these two, and connected them to
the composite & audio inputs on my TV to check them out. The signal
appears to be almost non-existent, however - I can just about make out
the outline of an image on the screen, so I'm sure that I have the
video/audio cables correctly identified, but the signal is so weak as
to be un-usable.

Having no knowledge of CCTV systems, I was wondering whether anyone
could provide information on the video/audio output from them? Would
they usually need significant amplification before being fed into a
TV? In this case they are transmitting a signal over more than 40ft of
cable. The cameras themselves are very small, and presumably pretty
cheap.

Given the contents of the previous setup, there didn't appear to be
any obvious signal amplification, so I'm curious to know how it
worked!

Any advice would be very gratefully received...
TIA
Ian