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Re: [TowerTalk] N - clamp style connector

Subject: Re: [TowerTalk] N - clamp style connector
Reply-to: "Tower and HF antenna construction topics." <>
Date: Wed, 10 Mar 2010 18:01:52 EST
List-post: <">>
Steve, your info is very timely as I encountered that very problem today  
while building a 70cm 2 way power divider with RG213/u.
Do you have a solution for the loose fitting nut?
Gerald K5GW
In a message dated 3/10/2010 4:46:45 P.M. Central Standard Time, writes:

As  someone who's actually set up assembly lines to install Type N
military  connectors for USAF contracts (20+ years ago!), I might add one
of the  biggest problems hams have is misapplication of connector vs.
coax.   Even a skilled expert who's assembled thousands of N connectors
on cables  is going to be highly challenged if the right materials aren't
presented to  him.

As an example, I see a lot of hams using the UG-21D/U connectors  from
the Amphenol "RFX" series (82-202-RFX or equivalent).  You might  note
those are intended for "RG8, RG9, RG213, RG214" cables.  Well,  this is
downright impossible.  RG8 and RG213 are single shielded and  smaller in
O.D. than RG9 and RG214 which are double-shielded.  For a  "clamp"
connector, how can a single design work for cables having either  one or
two shields, and having two different O.D.s?   Impossible.

So what Amphenol did, in their infinite wisdom, was make  the connector
suitable for double shielded cable with a larger O.D., and  figured
somehow we'd make that work for the other stuff.  It really  doesn't.

If you use one of these connectors (or hundreds of varieties  like them)
you'll find that on single braided cable like RG213, or 9913 or  LMR400
etc, the clamp does not clamp tightly (it clamps loosely, even with  the
nut fully tightened) and there's a gap between the jacket of the  cable
and the hole in the rear nut.  That's 'cause the cable's not  right for
the connector.

Now use the same connector, but with  RG214/U, having two braids and the
proper O.D.  What a  difference!  The clamp clamps very tightly, before
the nut is fully  threaded into the connector body, and the hole in the
rear nut just barely  passes the cable -- after assembly, there is no
visible gap there at  all.


-----Original Message-----
[]  On Behalf Of w4lde
Sent: Wednesday, March 10, 2010 2:37 PM
Subject: Re: [TowerTalk] N - clamp style  connector

Thanks to all that replied, I remember that I never had  soldered the 
shield and thought that was the correct method.

I will  also as many have suggested use some heat shrink for stability as

well  as helping with water intrusion.  Was planning on #33 or #88 tape  
plus some fusion style tape to help with the final  connections.

Again thanks to everyone for your comments.

73  de

On 3/10/2010 3:18 PM,  wrote:
> Ron, the clamping ring for N connectors is nickel plated. You  will
turn the
>   coax to charcoal before successfully  soldering the shield to it.
> One of the major failure modes  with N connectors is having the shield
> loose due to pulling  and twisting the cable. A short piece of heat
> tubing   over the clamping end of the connector and a couple inches of
>  coax will  provide excellent reinforcement and improved  reliability.
> The recommended connector installation procedure  has worked very well
for a
>   lot of  years.
> 73,
> Gerald  K5GW
> In a message dated 3/10/2010  12:00:01 P.M. Central Standard Time,
>  writes:
> Just  getting ready to install some a new beam  and  coax plus N style
> male  connectors on a new  tower.  It's been awhile since I last used
> (N  style)  and have reviewed via the WEB and the ARRL handbook
> recommended   installation methods and find two different methods with
> respect to  the  barrel and shield connection.
> The barrel I am  referring to is the small  piece were the shield is
> folded back  over and then compressed and held in  place by a O-ring,
> washer  and screw in clamp.
> The ARRL handbook  does not call for  any solder of the shield to the
> barrel peace but on one  ham web  sites recommends that the shield be
> soldered to the barrel  insert  piece and then assembled the same way
> the non  soldered.  If I  remember and it has been some time since  I
> N type but I believe I did  not solder the shield but  relied on the
> compression and clamp fittings to  make good  contact from the shield
> the N fitting.
>  Would  appreciate your opinion, to SOLDER or NOT to  SOLDER.
> 73 de
> Ron  W4LDE
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