How do I access my CCTV system on my TV sets around the house.

This is an easy thing to do as all you have to do is modulate the composite video output of the Digital Video Recorder (DVR) onto a clear channel and inject it into the TV system. However you do need a basic understanding of RF TV system.

An RF TV system has many TV signals all existing at the same time in the same system as they are all at different frequencies. One of the nice things about Coax systems is that they have enough bandwidth to do this. Therefore all your TV signals are being squirted all around your house all the time on the same cable. When you select a TV channel from the TV set you are simply picking out a single channel and viewing it on the screen. As I mentioned each signal must be on a different frequency to coexist with the other channels at the same time. The frequencies available for TV are channels 21-69. All the channels used for the analogue and digital terrestrial TV service are specified by Ofcom and cannot be changed. Also you have to take into account that if a signal is on channel 30 then channels 29 and 31 cannot be used as the signal will "bleed" over the adjacent channels. The process of taking a video signal such as a composite video feed and modulating it onto a channel is called modulation. The process of taking this signal and turning it back into a composite type video feed is called demodulation. All TV sets have demodulators built into them. A TV tuner is a demodulator as it tunes into a channel and displays the contents.

With our CCTV system we need to use a modulator to modulate the composite video feed onto a free channel in the RF TV network that is not going to interfere with any of the terrestrial TV broadcast signals. This is the difficult part. You can use this website to work out what transmission tower you are connected to http://www.ukfree.tv/mapsofsignal.php

You can then use this website to see what analogue and digital channels are already being used and therefore find channels that should be spare
http://www.ofcom.org.uk/static/reception_advice/index.asp.html

You should then be able to find a clear channel that you can set your modulator to which will not affect any of the broadcast channels. The coaxial output of the modulator connects via a coax cable to the CCTV input on the TV amp in your house. If your TV amp does not have a CCTV input you can loop the TV aerial cable through the modulator to mix in the CCTV signal before going into the TV amp.