[Amps] World's worst coax connectors

[Paul Christensen]

>"Not to be outdone, the television industry has responded with its own bad standard, the type F coax "connector," which uses the unsupported inner wire of the coax as the pin of the male plug, and a shoddy arrangement to mate the shield."

Since the time of Horowitz's first print edition, the F type connector has evolved into a very reliable small-signal RF connector.  The mating inner connection has improved into a concentric fit around the coax inner conductor.  Back in the '70s, the inner connection typically relied on two small parallel metallic sleeves.  Shield connections were accomplished with a poor-fitting ring that was often clamped with slip-joint pliers.  That's the "shoddy arrangement to mate the shield' discussed by Horowitz.  Integrated-boot weatherproofing, use of gelled cables, and compression installation tools have all helped too. 

I'm mostly neutral toward RCA phono jacks.  Heathkit used an RCA phono jack on the back of the HW-101 transceiver to deliver 100W into an antenna.  After building one in high school, I recall my friends poking fun at it -- and also when I built a Heath SB-230 that used a phono jack on the RF input when a BNC would have probably been a better choice.  Provided the phono jack uses a ceramic insulator, and apart from potential cracking over time, I don't see much of an issue although I've never seen an RF-grade phono plug.  I think plugs with a phenolic insulator are all I've used.  

Even with the XLR-type connector, there's no guarantee that Pin 1 will mate before pins 2 and 3 100% of the time.  Yes, very close in time, but it's still possible for Pin1 to mate last unless Pin 1 is bonded to the XLR plug shell AND it's mated with a bonded jack.  Most preassembled XLR cables I've seen do not bond Pin 1 to the shell.  1/4" and 3.5 mm are poor designs as the signal pins typically rely on a single-point of contact.  They also don't guarantee a shield before signal connection.

Paul, W9AC