Just to mention, as for cameras, I have used cheap old 8mm camcorders or ones that have a defect other than staying on and able to send the video. They last for years and the pic is the best. The audio beats anything. I run them to an old vcr or rf mod and then 300 feet with rg59 coax. I use a pinnacle pctv card to monitor and record to computer HD. You can get multichannel cards on ebay but the CCTV/ BNC plug type only allow one audio per 4 channels and you would have to do some adaptation for the cameras. I think pinnacle makes a 2 channel TV card or you can put more than one in the PC but the use 38% on my 2.6 GHZ PC while recording one channel. About 42GB / 24 hours on my setting.