Wednesday, December 05, 2007

F

I use these constantly. It was invented by Eric Winston at Jerrold Electronics. It was in the in the 1950’s while they were developing cable television. The F connector is a type of RF connector. There's one at each end of the cable connecting your cable box to your television. there's probably another split off and connecting to the cable modem that is proving the Internet access that permits you to read this.

Eric was a mechanical engineer, he has a few dozen coax-related patents for feeder lines, bushings, and other paraphernalia. He worked with Len Ecker an RF engineer. Len's role in the invention is downplayed, but it seems impossible that he was not involved. Today it's a standard for several applications, most commonly for TV signals. The most commonly used are RG6 and RG59. It's cheap, and has a decent 75-ohm impedance match up to 1 GHz. Popular F-connectors today have integrated compression technology and dialectic to reduce water entry, lengthening it's functional life. It's also hard to screw up. Even a novice can learn how to crimp a fitting, and most "mistakes" will not fully obstruct function. More Here.

The reason it's so cheap in terms of comparable connectors is that it uses the center wire of the coaxial cable as the pin of the male connector. That does have a downside. Water entry in that case causes oxidation directly to the center wire increasing resistance. They also make screw on F-connectors that actually thread onto the sheath of the coax. These are for plebeians. Don't use them, it only encourages radio shack to dumb down consumers. More here.
Coaxial cable is much older than cable TV so we can at least rest easy that the F-connector is superior to the C52 fitting it largely replaced.In application, a coaxial cable is stripped to expose a length of the copper center wire, a segment of the dielectric, and a length of the grounding mesh. the mesh should be spread out and then pushed back against the sheath to ensure good grounding. This stripped cable is pushed into the fitting. The copper should protrude just beyond the fitting, the dielectric should fill the void up to but not into the threaded portion. Then crimp, or compress.. whichever fitting it it. I also like to smear a smidgen of dielectric paste into the threads to reduce water entry.

Jerrold Electronics did not invent cable TV. That honor goes to John Walson. They were however pioneers in the cable TV industry. Jerrold was founded in 1950 by Milton Jerrold Shapp. The company was sold to General Instrument in 1967, but Jerrold kept the brand name which he continued to use on hardware into the 1990s. General Instrument merged with Motorola in 1999. More on that here. Shapp became incredibly wealthy on the massive growth of CATV which was due in part to the simple home installation of the F-connector. He was so popular in Pennsylvania he actually parlayed the success of Jerrold into a democratic two runs for governor. He won the second time and served 1971 - 1979. More on that here.