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Re: [TowerTalk] N - clamp style connector

To: <>, <>
Subject: Re: [TowerTalk] N - clamp style connector
From: "Steve Katz" <>
Reply-to: "Tower and HF antenna construction topics." <>
Date: Wed, 10 Mar 2010 14:47:54 -0800
List-post: <">>
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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