From: John Woodgate
Subject: Re: How to check for a 50 or 75 ohm connector
Date: Sun, 22 Dec 2002 10:38:02 +0000
Organization: JMWA Electronics Consultancy
Reply-To: John Woodgate
NNTP-Posting-Date: Sun, 22 Dec 2002 15:21:13 +0000 (UTC)
X-Newsreader: Turnpike (32) Version 4.01 <5Z8C9wtxbnpWyFnyfFzqmVF739>
I read in sci.electronics.design that Ian Walker
wrote (in <3keudKjAZXB+Ewcs@newbrain.demon.co.uk>) about 'How to check
for a 50 or 75 ohm connector', on Sun, 22 Dec 2002:
>It is an urban myth that the centre pins of 50 and75 ohm BNC connectors
>are different diameters, probably brought about by an optical illusion
>caused by the taper of the pin along with the knowledge that the inner
>to outer ratio must be greater for higher impedances. This overlooks
>that using a different dielectric will change the impedance, i.e. more
>air as in the case of 75 ohm BNC connectors.
No urban myth. I have both sorts of connector, marked with their
impedances, and the centre pins ARE of different diameters. It MAY be
possible to use the same size pin and different insulators, but I don't
have any examples of that.
Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk
Interested in professional sound reinforcement and distribution? Then go to
PLEASE do NOT copy news posts to me by E-MAIL!