Siamese Cables up to 150ft Premade Cable and 500 or 1000 Feet Reels Available! 
Premade Waterproof 100 Foot Siamese Cable -Available for 12 Volt DC or 24 Volt AC Cameras! WDBNC

WDBNC100 :Waterproof Cable - 100 foot Length -Very Flexable. BNC Male connectors on each end with a DC Connector for Power (this part is obviously not waterproof). Great for running power and video for you Security Camera.