Using TV modulator is the only way to transmit multiple cameras thru one coaxial cable. Please check our web page http://www.apeccctv.com/apecdirect/products/MOD500.html. Each channel is modulated and demodulate at the other end with each channel tune to an individual channel. Take a look at it and if you have any question, you can email me to edward@apeccctv.com, and I will be happy to answer your question. Cost with other accessories will be about 110.00 per channel.