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Old December 7th 08, 09:23 PM posted to rec.radio.amateur.antenna,rec.radio.amateur.homebrew
Tim Wescott Tim Wescott is offline
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Default "Dual crimp" coax connectors?

On Sun, 07 Dec 2008 12:48:14 -0800, SparkyGuy wrote:

Halfway down this page (it's a PDF doc):

http://www.cablesandconnectors.com/PIX/CC-040.pdf

the TNC and BNC connectors are advertised as "dual-crimp". What does
this mean? "Dual" as in center in crimp and outer shield ferrule crimp?

As opposed to what? Single-crimp? That would be connectors that use the
center, solid conductor as the center pin and then crimp the shield
ferrule? Or...?

Newly (did you guess?) into small coax connectors and trying to get the
terminology straight...

Thanks.


The common BNC "crimp" connectors have you solder the center pin to the
center conductor of the cable, then assemble the outer with a crimp.


It works quite well in my experience, but I have yet to do this without
distorting the center insulator and having to trim it with an X-acto
knife to get it to fit, and I'm sure that in a critical application (like
TNC in the GHz) that I'd be creating an unpredictable impedance bump with
my hacking. This is bad enough with cables that have solid dielectric; I
can only imagine the pain it would be with foam. In a production
environment I'd almost certainly want to spring for the necessary crimp
tool to crimp the inner, if the quality were there.

(This is opposed to BNC connectors where you thread in a plug to capture
the outer conductor between the outer shell and a rubber insert. It also
works well, but it is bulky and the connectors cost more. And you're
still asked to solder the center pin on, with all of the accompanying
center insulator distortion issues).

--
Tim Wescott
Control systems and communications consulting
http://www.wescottdesign.com

Need to learn how to apply control theory in your embedded system?
"Applied Control Theory for Embedded Systems" by Tim Wescott
Elsevier/Newnes, http://www.wescottdesign.com/actfes/actfes.html