In the search of an inexpensive BNC/F to RJ-45 Balun, I came across the Impact Acoustics BNC/F to RJ-45 Balun. It seemed too good to be true, at a price of under $10 each (you need 2 per camera), but I picked up a few to try and I am extremely surprised.

They use one pair of the RJ-45 connector (the brown/brown white pair) but you could easily pass multiple signals over one cable if needed.

I purchased mine from CablesToGo here

Features:

• Multiple signals over a single 4-pair cable
• Video over UTP cable
• Male and female RCA or BNC connectors available (with RCA Connectors they are almost 5X the cost of BNC)
• RJ-45 output for easy connection into existing wall plates
• IDC output for easy connection without tools and multiple signals over a single 4-pair cable
• Transmit video up to 1500 feet with little visible degradation

The following images were taken using a Hunt CCD Camera 580 Lines resolution and a cheap capture card.

30 feet of standard RG-59 cable, direct connection from camera to capture card.	50 feet of Ethernet cable with baluns and a 1 foot BNC cable at each end.