[TowerTalk] Clamp Type UHF/PL-259 Connector (Epilogue)

Paul Christensen w9ac at arrl.net
Fri Feb 11 10:12:36 PST 2011


A few weeks ago, Ian, GM3SEK suggested looking into a clamp-type UHF/PL-259 
connector (not crimp) that offered easy assembly and a weather-resistant 
backing for outdoor installations.  The only soldering required is for the 
inner conductor.

I ordered a dozen connectors through Newark Electronics and the shipment 
arrived today.  I had a RG-214 jumper that needed shortening so I tried the 
new connectors this morning.

http://www.newark.com/jsp/search/productdetail.jsp?SKU=94M6035

These connectors are specific to the larger RG-213/214 and LMR400 class of 
cables.  However Multicomp offers a smaller clamp-style connector for RG-58.

Cable prep for the Multicomp clamp UHF connector could hardly be easier. 
When Ian said it was a one cut prep with no special tools required, he meant 
it.  I used a ChannelLock cable cutter (seen on the bench) but a utility 
knife could also be used to make the single cut.  I simply took the cable 
cutter to rotate a single cut at one time through the jacket, braid, 
dielectric, and stopped at the inner conductor.  The jacket, braid, and 
dielectric are spun off in one twist and discarded.  Next, a flanged 
metallic and non-metallic bushing are inserted onto the end of the cable. 
The result looks like this:

http://72.52.250.47/images/PL-259-1.jpg

You can see I first installed the connector on a section of discarded LMR400 
for a trial.  Notice the end clamp and red non-metallic bushing on the 
cable.  The connector inner pin must be milled out just a bit to accommodate 
the LMR400's solid inner conductor.  I inserted a 7/64 drill bit and twisted 
until the opening widened.  This step is not required with the RG cables and 
may not be necessary with other LMR400 variants like UF.

After completing the connector, I wanted to disassemble it to determine 
difficulty.  It was a super-easy to remove just by re-heating the inner 
conductor and unscrewing the end clamp.  Next, I re-used the same connector 
on my RG-214 jumper.  Here's the end result:

http://72.52.250.47/images/PL-259-2.jpg

The end clamp screws into the body using two adjustable open-ended 
wrenches -- similar to installing an "N" type connector.  The cable at the 
clamp end is fully sealed and the connector body absolutely does not rotate.

A few comments:

1) This connector is weather-resistant between the nut and connector body. 
Unlike an "N" type, the threaded shell does not form a seal onto the mating 
SO-239.  That's primarily a limitation of the 'teeth' design used on the 
SO-239.

2) Unlike a soldered UHF connector, one can visually inspect the work before 
inserting the cable into body of the connector until satisfied that the prep 
is good before soldering the inner conductor.  Even then, removal only 
requires re-heating the inner conductor.  Try that with a soldered PL-259 on 
RG-213/LMR400 cable.   Yes, I know there are those who claim they can 
visually inspect and remove a soldered PL-259 by pounding the connector's 
dielectric out of the shell with a nut driver.  You decide whether that's 
the proper use of the connector and right tool for the job;

3) These connectors are not inexpensive but I will now use them for outdoor 
use, while continuing to use crimp connectors indoors.  However, since these 
connectors are easily re-used, the initial cost may be offset by economizing 
on re-use in some instances rather than the purchase of new UHF connectors.

Paul, W9AC




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