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Re: [TowerTalk] Coax Connectors

To: <>, "'Roger Kissel'" <>,<>
Subject: Re: [TowerTalk] Coax Connectors
From: "Dick Green WC1M" <>
Date: Thu, 4 Jan 2007 13:01:48 -0500
List-post: <>
To solder PL-259 connectors, I use a Weller temperature-controlled soldering
iron with a large flat blade tip. I've used a couple of different models,
but the one I have now has adjustable temperature control. Fixed or
adjustable, the important thing is that these irons maintain the tip at a
constant temperature. They have large power supplies that quickly pour a lot
of juice into the tip to raise the temperature very quickly, but don't
overheat the tip. I've also used a Solder-It butane soldering iron for
installing connectors outdoors. It works almost as well.

I use the following procedure. It's not original with me. I think you can
find pictures of the process somewhere on the web if you're good with

1. I use Amphenol silver-plated PL-259 connectors. Regardless of the method
used, silver-plated connectors make the job much easier. The regular plated
connectors just don't take solder very well. You have to heat them to the
point where the dielectric melts. Import silver-plated models are OK, but I
use Amphenol because the quality is first rate. I figure if a connector is
going to be in the air for many years, it's worth a few extra pennies to get
the best.

2. Always put the connector cover (the part with the threads) on the coax
first, facing the correct direction. This is so you don't accidentally
forget to do this. Nothing worse than soldering the second connector on,
only to realize that you forgot to slide the cover on first. If necessary,
tape the cover to the coax to keep it from sliding around. I use Cushcraft
coax booties (available from Texas Towers) for outdoor connections (I use
tape and vapor wrap over them, too.) If you use them, they have to go on
before the cover.

3. Using a very sharp utility knife, strip the coax jacket to about 1 1/8"
from the end. You can hold the connector body next to the coax, using it to
measure where to strip the jacket. Strip the jacket from a little beyond the
connector tip to the threads. Be careful not to nick the first 1/2" of braid
from the jacket.

4. Starting at the end of the jacket, quickly and *lightly* tin at least
1/2" of shield. Don't let the iron linger or you'll melt the dielectric
and/or jacket. If the dielectic melts, the connection will be no good. If
the jacket melts, you won't be able to screw the connector on. Also, don't
let the solder blob on the shield. The idea is to create a light, thin,
uniform coat.

5. Use a small tubing cutter (the kind plumbers use) to score the tinned
braid 3/8" from the jacket. I use a tiny one-handed cutter designed for
small pipe. Very gently tighten the cutter screw until the shield is just
barely cut through. Don't tighten it too much or you'll start cutting the
dielectric, which you don't want to do. I twirl the cutter around a couple
of times, then grab and wiggle the end of the coax to see if I'm through
yet. If not, I tighten the cutter a little more and go around again. When
it's ready, the tinned shield breaks at the cut when I wiggle it.

6. Using a pair of "nippy cutters", cut the braid from the circular cut to
the end of the coax and remove it. Starting from the jacket, this leaves you
with 3/8" of tinned braid, followed by about 3/4" of dielectric-enclosed
center conductor.

7. Using wire strippers, remove the dielectric from the center conductor
from about 1/16" beyond the braid. The little ridge of dielectric keeps the
braid from coming into contact with the connector body below the center pin.
On coax with a double shield (such as Bury-Flex), the little ridge will have
foil on it. Use a sharp utility knife to scrap it off.

8. Lightly tin the center conductor. Again, don't let the iron linger or
you'll melt the dielectric. With a stranded center conductor, the solder
should sink into the wire. Don't let solder blob on the center conductor or
it won't fit though the center pin.

9. The problem with PL-259 connectors is that the solder holes are not large
enough for the size soldering tip you need to quickly heat the connector
body. The solution is to slightly enlarge the holes. Using a reamer, enlarge
the solder holes in the connector body just enough for the tip of the iron
to fit in. You don't want to enlarge the holes too much or you'll weaken the
connector body. In fact, I enlarge the holes a little less than the size of
the tip, but enough of it fits through the hole to transfer heat to the

10. Slide the connector body over the center conductor, past the braid, and
screw it onto the jacket. Make sure it screws all the way down over the
jacket. There should not be any space between the connector and the jacket.
I usually have to use a rag to hold the connector and protect my hand.
You'll feel the connector bottom out when it's screwed all the way on, and a
small amount of center conductor will stick out the center pin.

11. Put the tip of the soldering iron in the first hole and heat the
connector body. Most of the tip should be contacting the connector body, not
the braid. You want to avoid heating the braid at this point because if it
gets too hot the dielectric will melt. It takes about 20 seconds to heat the
connector with my Weller iron. Be sure the tip of the iron is well-tinned.
If the tip isn't tinned, you won't get efficient heat transfer. When the
connector body is hot, rotate the tip of the iron so it also contacts the
braid, wait a second or two, and start feeding solder into the hole. If the
connector and braid are hot enough, the solder will sink into the hole
(i.e., you won't get a raised blob of solder.) Quickly move to the next
hole. This time, you don't need to heat the connector body -- it's already
hot enough. Just touch the tinned iron to the edge of the hole and braid,
then feed solder into the hole. You know the joint is hot enough when the
solder flows in, coating the braid and clearly connecting it to the edges of
the hole. When it's right, the solder is concave and you can see the threads
of the braid through the solder. Repeat with the last two holes.

12. Let the connector cool a bit. Then solder the center conductor to the
center pin. This will take much less heat and time than the holes. First
make sure the tip of the iron is well-tinned. All you need to do is touch
the iron to the center conductor just above the pin, let it heat for a
second or two, touch the iron to the center pin (the thin silver heats
fast), and feed solder into the point where the center conductor emerges
from the top of the center pin. Hold the connector slightly above horizontal
so that the solder flows down into the center pin. Don't use too much solder
or it may flow all the way down the pin, shorting it to the connector shell
or braid. Use just enough to ensure that the upper 1/8" or so of the center
conductor is well-soldered to the center pin.

13. Let the connector cool completely. This takes longer than you think, and
you'll burn yourself badly if you touch it too soon.

14. Using cable cutters, snip off any excess center conductor sticking out
of the pin. Test whether the center pin will fit into an SO-239 connector.
If there's excess solder on the outside of the pin, it won't fit. If this is
the case, you can gently scrape or file the solder off the pin.

15. Check the connector with an ohmmeter. Make sure you have zero ohms from
the center pin to the center conductor and zero ohms from the braid to the
connector body. Then make sure you have infinite resistance between the two.

16. When both connectors are on, connect a small dummy load to one end and
use your transmitter or an SWR analyzer to make sure the SWR is flat across
the entire spectrum for which the coax will be used. An ounce of

Yes, it's elaborate, but it really works.

73, Dick WC1M

> -----Original Message-----
> From: Mike Clarson [] 
> Sent: Thursday, January 04, 2007 10:36 AM
> To: 'Roger Kissel';
> Subject: Re: [TowerTalk] Coax Connectors
> I always solder standard PL-259's. Must have done several 
> hundred over the years, and only recall screwing up maybe 
> half dozen. All types of cable, foam, Teflon, including RG-8, 
> 213, 214, 58, 59, 8x, LMR-400,8214, 9913 and Buryflex. Most 
> were with a Weller 8200 Gun, but I have used something as 
> small as a 25 watt Hexacon (my favorite) Iron. It was tough 
> with the iron.
> Lately I have used one of those butane irons. Seems to work 
> the best--plenty of heat and gets into the holes. I solder 
> because it works well, that is how the connector was 
> designed, I do not find it difficult and many are used in 
> Duplex systems (repeaters etc) where a dissimilar metal 
> connection such as you describe, can generate noise. I do 
> like your method over soldering on the outside of the 
> connector as I like the strain relief threading the jacket 
> into the connector provides. Much better than most crimp on 
> connectors. I suspect trying to thread jacket and two braids (like on
> RG-214) into a PL-259 is almost impossible. 
> A technique I use is that when starting the soldering, I just 
> blob some into the first hole and quickly move on to the next 
> hole and continue around the connector. By the time I get 
> back to the first hole, the whole body is hot enough to let 
> the solder flow properly. Keep changing holes until solder 
> flows into the braid. Then, let it cool completely before 
> moving the connector. --Mike, WV2ZOW
> -----Original Message-----
> From:
> [] On Behalf Of Roger Kissel
> Sent: Thursday, January 04, 2007 9:20 AM
> To:
> Subject: [TowerTalk] Coax Connectors
> Hi All
> I'm curious about coax connectors and how YOU assemble yours.
> Of course, we all would like to use Type Ns for the impedance 
> uniformity, in
> comparison to the old fashioned PL-259s.
> What I'm wondering is:
> Do you solder the braid into the connector body when you 
> mount a PL259 onto a piece of RG-8 or RG-213 ?
> If you do, TELL US WHY YOU SOLDER IT.  Then tell us how 
> successful you are with your solder job.
> I have never successfully soldered the braid because I have 
> never had an iron that would heat the body hot enough to flow 
> the solder without melting the dielectric. And then these 
> people who use a 50 watt iron so they can get
> inside those holes are, in my opinion, fooling themselves.
> I fan the braid back over the outer jacket and screw the body 
> over it, capturing it with a fairly good mechanical 
> connection. However, sometimes, the jacket is too stiff/thick 
> and/or the braid is too bulky so I have to remove some of the 
> braid to be able to do the screw-job.
> Then, of course, I solder the center pin and am good to go.
> BTW HF and PL-259s are synonymous. I don't know any SERIOUS 
> ham who would 
> use a 259 for UHF.   Uhhh, why do they call a PL259 a "UHF 
> connector" ?!?
> 73
> RoGrrr


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