[amsat-bb] Telling the difference between 50-ohm and 75-ohm N connectors

Zach Metzinger zmetzing at pobox.com
Sat Jul 25 18:50:33 UTC 2020


I just ran across this tidbit[1]:

> Q: How can I tell the difference between a 50 and 75 Ohm N connector?
> A: You can tell the difference by the center pin. A 50 Ohm connector has a pointed pin. A 75 Ohm has a rounded pin.
I've always looked at the center conductor to shield (not ferrule) 
distance to make sure I had a 50-ohm version. I don't have any 75-ohm 
versions lying about the shack. Can anyone else confirm this?

I recall, back in my RF engineer days, that we had a whole box of 75-ohm 
N connectors which were marked with bright red paint. Woe to the junior 
engineer who coupled the 50-ohm and 75-ohm version, which would bend the 
center spring fingers on the female connector apart permanently.

One can also kill a female N connector by mating it with a male PL-259. 
I have not done this myself, but I knew someone who did this twice on 
his fancy new antenna analyzer and wondering why everything was such a 
poor match. :-)

[1] https://www.showmecables.com/n-male-crimp-connector-lmr-400-belden-9913

--- Zach
N0ZGO


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