Quote Originally Posted by Marty Postma View Post
RF is really just a different plug for the same signal type as RCA composite...you won't see a difference between the two, but in my experience RF cables do seem to be more prone to signal interference from power lines etc.
Marty,

You are correct that both are RF signals. However, a "cable" signal traveling down RG Coax is very different from Composite Video.

The impedance is different between the Coax used in RG cable and the coax used as a shield in RCA or BNC type composite.

The "Radio Shack" type RCA cable is low quality with a lower resistance. The wires are stranded and very much more catering to voltage transmission than to RF transmission. (Basically crap but okay in small runs)

75 Ohm Video cable with BNC termination is specifically designed to transport the "video range" spectrum of RF signals. The tolerance of it is exceedingly higher than anything else. It also has much tighter twisted center wire, or solid copper.

Regular old RG6 type coax cable is solid core copper which means it is much better as a transmission medium for the modulating frequencies of VHF and UHF. In fact, it was designed specifically to transmit the ranges known as VHF. The shield diameter is larger that High quality 75 Ohm cable. The larger dia allows the sub harmonics to pass through the shield to eliminate ghosting sub harmonic reflections. Whereas in pro video cable, the shield is much tighter to enhance the filtering of electric fields and magnetic transients.

Another thing to mention is the nature of the difference between VHF and CVBS. Composite called CVBS (or Color, Video, Burst, Sync composition) is an RF signal where the scan rates are frequency and amplitude based. VHF however performs a frequency modulation of CVBS so that it can be encoded to a specific frequency channel for amplification and transmission.

Another way to think of it is that you need a tuner to use RF. RF has audio multiplexed with it.