Can I use UTP cables instead of COAX for cable TV? Will soldering a coax connector to the UTP wire do it?

You can definitely use high performance twisted-pair cabling (UTP, STP, FTP and variants) as an alternative to coaxial cable as well as other line-level A/V cables including HDMI. Cost savings, if any, and performance will depend largely on the type, quality and quantity of twisted-pair cabling, including the type of active or passive hardware used at each end, as well as the application. Twisted-pair cable (incl. HDMI) is BALanced and coaxial cable is UNbalanced. Furthermore coaxial cable, such as RG-6, RG-59, etc., which is commonly used in residential applications, has a characteristic impedance of 75Ω whereas twisted-pair cable has a characteristic impedance of 100Ω. Substituting twisted-pair for typical coax-based video applications will require the use of a high quality passive (broadband) video balun, preferably with a frequency response that extends down to DC, or an active matching network. (The latter is sometimes referred to as an extender, “link,” or transceiver by some man ... more