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Author Topic: Installing PL-259 Connectors  (Read 2917 times)
WB4RA
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Posts: 4




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« on: December 02, 2017, 05:36:21 AM »

For years I have been installing my PL-259 connectors by folding back the braid then screwing the connector down over the braid and outer layer of the connector. This usually requires using pliers because it is so tight. Then carefully soldering the center connector.

Some people say this is OK some say no.

What say you?
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WB6BYU
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« Reply #1 on: December 02, 2017, 06:58:53 AM »

I've picked up a lot of coax and patch cords at hamfests, and the most common
problem is a poor shield connection at one or both ends.  Often the connector can
be rotated by hand, secured only by the center conductor.  Usually for such a cable
(at least for RG-8 \ RG-213) the shield was not soldered when the connector was
installed, though there are some cases of inadequate soldering.

While I can't always tell how the connector was installed originally, they often
have the braid broken off by fatigue at the end of the barrel.  My theory is that
screwing the connector over a doubled braid may damage enough individual
strands that eventually they all fail at that point due to repeated flexing,
possibly in applications where the cable hangs from one connector.  But I
don't know for sure whether that is the actual problem.


Perhaps the best way for you to answer the question for your particular
method of assembling connectors is to take one that has seen a lot of flexing
over the years and disassemble it.   How many strands of the folded braid
are still intact?  Are the strands still bright copper at the connections, or are
they dull brown, indicating a poor connection?  (If they are green you have
other problems.)

I'm a pragmatist - if it works for you, then there is no reason to change.
And I've certainly been known to do a lot of things "good enough for now"
over the years.  But when I put connectors on RG-8 / RG-213 that I want
to last through hard use, like frequent portable use or repeated flexing,
I tin the braid with a big iron, trim it to length with a tubing cutter, and
heat the whole connector body to get a solid solder joint.  Not that it can't
go bad if mistreated, but I've never found a bad shield connection that was
installed this way.
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WB4SPT
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Posts: 499




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« Reply #2 on: December 02, 2017, 07:09:06 AM »

If you can fold back a RG8 type braid and still screw on the shell, seems like lower than optimum shield coverage?   In any case, I prefer to tin all the exposed shield, single layer, cut shield to lenght with a tubing cutter, then dimension the center conductor, then screw on the shell, and heat the shell with a high capacity iron.  Tinning the entire exposed shield reduces the threat of loose wire shorts. 
Doesn't work this way with the RG58, 59 adapters though.  Sad
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K5LXP
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« Reply #3 on: December 02, 2017, 08:12:35 AM »

folding back the braid then screwing the connector down over the braid

I will do that depending on where it will be used.  For a cable assembly going on the tower or for a permanent install, I do them by the book.  But for a quick test, temporary installation or in the field this is a way to get a connector on the end and only requiring a light duty iron to solder the center conductor.  It's easy to recover the connector and reuse it by just unsoldering the center pin.

Mark K5LXP
Albuquerque, NM
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K6BRN
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Posts: 490




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« Reply #4 on: December 02, 2017, 08:35:21 AM »

Hi Burt:

This is almost a political argument amonst some hams... here is my 2 cents....

I've attached PL-259 connectors to RG-8 type coax three different ways over the years...

1.  Fold back the braid (after trimming), screw on the connector body over the shield, solder on the center conductor, then screw on the connector shell.  I usually put two layers of heat shrink over the junction between the base of the connector body and coax - just an extra touch.  I've never had one fail.  Mechanically, the coax is secured to the connector by the threads and very little stress is placed on the center conductor once it is soldered.  The coax shield is compressed between the threads of the connector body and coax jacket forming a very good compression fitting.  This approach works fine on ANY type of RG-8 style coax.

2.  Insert the coax into the connector body, with jacket stripped back and braid exposed for about 1/2 inch, solder the braid to the connector shell through the connector body holes, solder the center conductor, screw on the connector shell.  This approach works fine with RG-8, RG-213 and RG-214 but can easily damage the foam based dielectric of LMR-400 type coax.  I've noticed ZERO performance improvement/mismatch improvement with this method.  But I've used it quite a bit with RG-213/214.  In using it with LMR-400/UF, I usually succeed, but do check the cable with a Megaohmmeter afterwards just to be sure.  Several pre-made cables I've purchased that were made this way have been defective - damaged dielectric.  VERDICT:  Can work well on solid dielectric coax - risky on foam dielectric coax.

3.  Crimp connectors... every brand has different measurements for stripping, but once you have these down (and have the proper crimp tool), they go on very quickly with few defects.  This is by far the preferred approach of industrial, connectorized coax providers.  The only downside I've seen is that the retention strength of the coax in the connector is usually lower than 1 or 2 above.

Brian - K6BRN
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K0UA
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Posts: 1461




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« Reply #5 on: December 02, 2017, 08:56:34 AM »

I used to do these type of quick "work arounds", but gave up on it. I used to fold the braid under the rg58 and rg59 adaptors, but no more.  I had too much trouble with this method.  I put them on now as the manufacture suggests in their instructions.  Sure it takes a bit longer, but I believe it makes a stronger installation. 
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AC5UP
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« Reply #6 on: December 02, 2017, 09:18:01 AM »

3.  Crimp connectors... every brand has different measurements for stripping, but once you have these down (and have the proper crimp tool), they go on very quickly with few defects.  This is by far the preferred approach of industrial, connectorized coax providers.  The only downside I've seen is that the retention strength of the coax in the connector is usually lower than 1 or 2 above.

+1
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K5LXP
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« Reply #7 on: December 02, 2017, 11:37:06 AM »

the retention strength of the coax in the connector is usually lower than 1 or 2 above.

Not if you crimp it right.  The conductor should break before it pulls out.

Mark K5LXP
Albuquerque, NM

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K6BRN
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Posts: 490




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« Reply #8 on: December 02, 2017, 02:43:12 PM »

Mark (K5LXP):

Send me a jumper you've crimped and we'll do a pull test.  I could use a nice 3-footer.

BTW: 

Quote
Not if you crimp it right.  The conductor should break before it pulls out.

Of course the center conductor will break on a crimped connector, before it pulls out - it pretty much has to.  Same as on a soldered connector.  It's the jacket connection that is generally weaker.

Don't bother arguing - I'm ALWAYS right.  (well, usually.)  (umm... most of the time) (normally)

So... when are you sending out the jumper?

Brian - K6BRN
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WB4SPT
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Posts: 499




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« Reply #9 on: December 02, 2017, 03:06:59 PM »

Is there a crimp PL259 with the shield crimped on a LMR400 or even a RG8?  That would be a pull test.  And, I don't expect much of that.  I've seen lots of RG58 crimped OK, though.
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AC5UP
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« Reply #10 on: December 02, 2017, 03:18:03 PM »

Gents:

We do realize the 'pull test' concept is a straw man argument...  Because, in the world of real professionals, the word is:  " You don't pull a cable by the connector! "

Connectors are invariably the most fragile part of a cable assembly whether crimped, clamped, soldered or stir fried.  You're pulling a cable?  Grab the cable a foot or so from the connector and pull.  If a connector fails post-install due to stress or vibration that's considered an installation error.  Properly dressed wiring has enough slack, mechanical support and strain relief to live long and prosper despite its environment.

Given the ubiquity of crimped connectors in high-value aeronautics I'd say the pull test argument is moot.   Tongue
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WB6BYU
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« Reply #11 on: December 02, 2017, 04:19:54 PM »

Quote from: AC5UP

Because, in the world of real professionals, the word is:  " You don't pull a cable by the connector! "



Which, of course, includes hanging the cable off a dipole without proper strain relief.


I do remember one ham relating the story about the moment he recognized why connector
installation could be important.  A couple teen-age hams were installing an antenna on the
roof of an apartment building when they accidentally locked themselves out.  "Not a problem",
one says, since the coax drops down to the balcony several stories below.  They secured the
top end of the RG-8 and he proceeded to rappel down the coax to the balcony.

The moment of realization came when he got about 2/3 of the way down and felt the splice
in the cable (two PL-259s and a barrel) against his leg.  A bit late to wonder about how well
he had soldered the connectors...


Anyway, he survived to tell the story, though the last part of his descent was a bit more
expeditious than the first in an effort to minimize the stress on the splice (or to get closer
to his target before it let go.)  But he said that he always made sure his connectors were
installed carefully after that.
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K6REA
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« Reply #12 on: December 02, 2017, 05:38:12 PM »

I never solder the braid on any size coax.

Works fine for the last 50 years.

kevin rea
lancaster, calif.
K6REA
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K6BRN
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Posts: 490




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« Reply #13 on: December 02, 2017, 07:11:42 PM »

Nelson (AC5UP):

I forgive your profound innocence.  (waves hands in an impressive arc....)

Because those with actual experience know that unplanned and unexpected stress happens frequently on coax connectors (and coax), during installation and sometimes in use, making pull strength very important.

Quote
Which, of course, includes hanging the cable off a dipole without proper strain relief

Lots of hams do this.

So, listen to WB6BYU, grasshopper.  For in his words are truth and wisdom.  (except for the rappelling down the coax part, later in his post - don't do that  Smiley)

Brian - K6BRN
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K6BRN
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Posts: 490




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« Reply #14 on: December 02, 2017, 07:16:58 PM »

David (WB4SPT):

Yes, there are PL-259 crimp connectors for RG-8 (RG-213, 214, LMR-400, etc.)

They look like this (and I have a few):

https://www.showmecables.com/uhf-male-crimp-connector-lmr-400-crimp-pin?gclid=EAIaIQobChMIqbf6ifDs1wIViop-Ch1YfgyxEAQYASABEgJ7qPD_BwE

Brian - K6BRN
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