Topband: Rather use N-type (was Re: The answer to PL-259

[Jim Thomson]

Date: Sat, 8 Dec 2018 18:43:36 -0500
From: <john at kk9a.com>
To: <topband at contesting.com>
Cc: <k3lr at k3lr.com>
Subject: Re: Topband: Rather use N-type (was Re: The answer to PL-259

<A BNC connector has a ?.050 pin and when mated properly an N connector has a
<.120 center pin.

<John KK9A

##  front end of a BNC is the same diam and taper as a type N.   The back end of a type
N is bigger, to handle the larger center conductor  of  213 U etc. 

##  There is NO RF flowing on the pin on any of these connectors !   The RF flows on the
outside of the mating female... that the  pin is inserted into.   All the pin is doing, is mating the
hollow  female  to the back end cylinder, that the center conductor terminates to.   The back end  portion
is the same  OD as the female...the 2 are butted together.   Mean while the  pin is buried inside, invisible..with  no RF on it. 

##  while you may well get away with using a BNC, with small coax, like  RG-400,  RG-142,  RG-303,
and  RG-59 etc, on 160m,  with 1.5 kw....  I would not use the BNC on the upper bands  with high power. 
The V stand off is not there.    I  would not flood the inside of a type N  with dielectric grease.  With  1.5 kw
and high swr, etc, the V breakdown  through the grease, could easily cause issues, then u get carbon tracks etc.
A tiny bit of grease on the center pin..and a tiny bit on the threads is fine, and works good.  

Jim   VE7RF