Cables and Connectors: They're More Important Than You Think (page 3)
BNC Connectors
Depending on who you talk to, BNC stands for Bayonet Nut Connector, Bayonet Naval Connector or British Nut Connector. Whatever it stands for, a BNC connection is the standard for pro video equipment.
It's that funny looking, twist-on connector that you see on a lot of professional grade video equipment. The BNC connector is found on composite video cables.
"It's one of the few connectors designed for constant impedance," says Sands.
This means that unlike other connectors, the BNC connector, as well as the cable, is rated at the right impedance for video.
"It's also a coaxial connection, so it maintains the shielding all the way through," adds Sands.
Its design allows the insulation and shielding of the coaxial cable to carry through the connector itself. This prevents breaks in shielding and assures a cleaner signal.
F Connectors
If you've got cable TV, you know what an F connector is. It's the screw threaded connector at the end of the coaxial cable that never threads on correctly when you're reaching behind the TV to hook it up. Like the BNC connector, this maintains the coaxial cable's shielding, making a very fine connection.
Cables with F connectors are usually for RF signals, i.e., the picture and Sound data together in one signal. This is a signal combo useful for viewing on a TV, but not ideal for dubbing and editing. When you copy or edit tapes, avoid using the poor-quality RF signal. Stick with composite or Y/C cabling.
S-video Connectors
Used in hi-band video systems (Hi8 and S-VHS), these connectors are round, multi-wire connectors. In video, the four wire system carries luminance and chroma signals separately, as well as their associated grounds.
RCA Connectors
"These are named after the firm that invented them," says Sands. "They vere invented for audio equipment and, as a friend of mine who works for RCA likes to say, 'There's a reason we invented them for audio.' These are fine for connecting a VHS deck to a TV or monitor for viewing, or as emergency back up in a pinch. But don't use them for serious video applications."
RCA connectors are common on consumer video cables because they are cheap. They don't match impedance and they don't carry shielding through the way that BNC connectors do. So they're more susceptible to noise and signal loss.
RCA connectors are pretty much the standard for unbalanced consumer audio. Good quality RCA connectors with high quality, shielded, unbalanced line can be a good choice for prosumer audio setups that don't use balanced line.
