PL-259
I have seen nearly a hundred websites, YouTube videos, and even manufacturer's instructions, for installing the good old PL-259. I'm going to comment on a lot of the content I have seen, the tools that have been made available, and the techniques shown by others. I will then also show a step by step pictorial on how to install a connector, basically how I have been doing them for years myself!
When it comes to the PL-259 I prefer the solder on variety. Crimp on connectors are usually cheaply constructed, have a poor fit to the SO-239 due to the center pin being under or even oversized, and the crimping tool required to install them is out of the budget of most hams. If you're installing a few connectors a year tops then investing in a crimping tool is simply not economical. If you put on dozens or hundreds per year then by all means go for it, but then you also have to deal with fitment and quality issues on a regular basis as well.
Connector Selection:
There are a lot of choices when it comes to the PL-259.
Silver plated body and tip.
Silver plated body, gold plated tip.
Gold plated body and gold plated tip.
Cheap connectors that are chrome plated.
Let me first say that I prefer one of the first two, I generally use the type with a silver plated body and a silver plated tip. But recently came across a deal on a large batch of silver plated body with gold plated tip, and they work great as well. The main issue here is solder ability! But you also want ones with a good Teflon center insulator. How many of you have bought PL-259's from Radio Shack and melted the coax before the solder will flow into the braid holes? I know I have! All of the PL-259's out there seem to be Brass, and then plated with various metals. The cheapest of which seem to have chrome plating, which is hard to get a nice result soldering. I've seen many of them with file marks around the holes for the braid in an attempt to remove enough of the plating to get a good solder joint to the underlying brass! And now there are even tools that have been created to circumvent soldering it, I will touch on that shortly as well. The thing here is the connector will last for years and years of service, I have had them literally outlast the coax, but you need to spend a little money here and buy good connectors! Silver plated PL-259's can be had for about $2-3 depending on where you buy them from and what brand they are. I have actually had very good luck with the cheaper $2 variety that have no brand name on them at all, most are simply stamped Made In USA on the shield and that's it. They are silver plated, heat up very quickly and wick up the solder very nicely.
Tools:
There are two categories here, preparation, and installation.
When it comes to prep tools I have tried many, and returned or sold them all. The coax prep tools available are ok at best. Most of them use razor type blades that dull quickly, are a pain to replace, and just not worth the cost. The biggest pain is you usually can make the first cut with one of these, through the jacket, braid, and center dielectric, only a few times before the blade no longer makes a clean cut through the braid. So what do I use? A plain old utility knife with a new blade, though that new blade will last for a dozen or so connectors before I need to replace it. There are a lot of arguments here; the so-called "experts" claim that this step cannot be done correctly with a utility knife as u will knick the center conductor. After doing dozens of connectors, if not nearly a hundred or more, I can tell you that it does take a little practice and a feel for the knife blade but its easily do-able. I will explain my method in detail shortly, but it's easy guys!
Installation tools abound! I have seen a lot of things available for this. Everything from a special tool to screw the body onto RG-8U size coax, to a crimper made to circumvent having to solder the braid holes. I have had a few rare occasions where I was installing onto some RG-8U size coax and the outer jacket was thicker, especially on direct burial type coax, and it required a pliers to help get it started and onto the coax, but most can be done by hand. As for the PL-259 crimper, I shudder seeing that tool. Many are probably already familiar with the K4AVU Coax Crimper. It's a device intended for crimping a standard solder on PL-259 around the braid hole area to make a mechanical connection to the braid by pinching it tightly to the coax. I recently had an opportunity to try one of these devices and I have some reservations against its use.
First of all let's discuss the connection it produces. By crimping the connector down against the braid you're compressing it tightly against the center dielectric, nothing else! Since the center dielectric has some give to it a flexing connection is made where everything is held fairly tight but still allowed to move due to the give in the dielectric. If you look at crimp on type connectors the difference is apparent. The body of the connector has a nipple off the back end of it that slides over the dielectric underneath the braid, and then you crimp a ferrule over the braid. This gives you a solid connection because there is metal on either side of the braid, think of it as clamp with the braid in-between. However, when you use the Coax Crimper as shown above it doesn't have that other side of the clamp to provide the connection.
The next problem is the way it modifies the connector. PL-259's in general are a pretty thin brass. Crimping them in this way weakens the already weakest part of the connector. There is very little metal here due to the holes. Reading some online reviews one problem that has come up after time is they will crack around the connector between the holes from stress on that area. I didn't experience that myself, but I did experience the connector cracking above or below the flat area that the braid holes are in, it would separate from the rest of the body of the connector after crimping it with this tool. In my opinion it was a nice try in engineering a solution, the tool itself is very well made and would undoubtedly last a long time, but the connectors are simply not up to the challenge. The only way I could think of making this work is to design a metal ferrule that could be slipped over the center dielectric under the coax shield, yet still be thin enough to allow the connector to still be slipped over it and strong enough to stand up to being crimped against, then you could do this with less force and the connector wouldn't have to deformed as far. It would also provide a better mechanical connection having that ferrule as a backing to the shield.
When it comes to soldering there are many choices out there. The center conductor doesn't take a giant iron, a good quality pencil style or temperature controlled station will do. The main thing here is you want to be able to quickly heat it, apply solder, and allow to cool. The longer you have to apply heat the better the chance you will do damage to either the connectors center insulation or the coax center dielectric. When it comes to soldering the barrel to the shield through the holes you want to be able to solder it quickly, again the longer you apply heat the better chance you have of melting the center dielectric or even the outer jacket where the barrel is screwed onto it. This is not a case of how hot the iron is, but rather its size. It's all about thermal transfer here; if you have a hot iron with a small tip the cool barrel will quickly cool down the tip once it's applied. The iron needs to be of sufficient wattage and size (thermal mass) to overcome this. I use a Hakko 936 temperature controlled station with a large chisel tip, I have no problems whatsoever with this setup. I will explain another method for doing this later on that I use for both outdoor and cold weather installation.
Installation:
Now it's time to get down to business!
Installing a connector on RG-8U size coax is simple. The first thing you need to do is remove that outer shield and slide it over the cable, you will hate yourself later if you forget this step, and I think we have all done it at least once! If you want to install heat shrink tubing over the back end of the connector, to give it a more professional look or to help with sealing it for outdoor use then slide that over first and then the shield. A quick note on this, I have used the heat shrink tubing that has a coating of hot melt glue inside of it for this purpose, it really seals up the back end of the connector against water intrusion, but the rest of the connector still needs to be sealed if used outdoors. More on that later...
Next is to make some cuts. First you want to remove 3/4" of the outer jacket, braid, and center dielectric. Again being careful not to knick the center conductor. I have been asked many times why that's important. There are probably as many explanations for this out there as there is for how to install the connector. Some say it can affect the impedance of the connection, others say it creates a stress point where the center conductor can break if flexed. I tend to agree with the latter more than anything.
Next step is to remove 3/8" of the outer jacket, being careful to avoid cutting the braid. If any of the braid is hanging past the end of the center dielectric after this step take a wire cutter of your choice and snip them flush.
Now you want to screw on the barrel of the connector. A lot of the guides out there claim you need to tin the braid or the center before doing so. I never have and never will. This is just adding additional heat that isn't needed when it comes to the braid. All too many have melted the center dielectric by taking this step and tinning the braid. If you have good quality coax this isn't needed as it will wick up the solder just fine through the holes when soldering the connector.
Now that the barrel is on the coax I like to take my VOM set to the continuity setting and make a quick check that there is no short between the center and the braid. Why? Because despite good preparation there is always a possibility that a small piece of braid wire got in there and shorted it out, or the connector was faulty to begin with. I had one instance where I put the connector on and the VOM showed a short, took it back off and the coax looked fine, checked the connector while off the coax and it still showed a short! Looking down in the connector from the back end showed a metal shaving that was across the center to the shield, a small dental pick was used to remove it and all was well. You want to find problems like this before you solder it all on!
I like to start with soldering the center conductor. I use a Hakko 936 temperature controlled soldering station as mentioned previously. This takes very little time to accomplish.
Next is the part that all too many people have troubles with. By using a chisel shaped tip you can lay it across the hole leaving a small gap through which to apply the solder. This traps the melted solder underneath the tip in the hole and against the braid. Give it a little time and it will wick into the braid, and then just repeat for the other three holes. The first one is always the hardest as you're initially heating the barrel and most of the heat applied is being taken away from the connection you're trying to make. Be patient! Also, you will notice that while doing this I have the connector suspended in the air, you don't want the connector laying against something, and not just for the obvious reason of melting or burning something, but also to allow the connector to heat up quicker since it's not resting against something that would be taking away the heat your putting into it!
That's it! Soldered and ready to go. Slide the shield forward and screw it onto the connector. Use caution here however, the connector is still going to be hot, or allow it some time to cool first. If you're going to apply heat shrink tubing to the back end of the connector you might want to allow it to cool for a minute or two or the heat shrink will start shrinking as your trying to put it over the connector from it still being hot.
As I mentioned earlier there is another method for soldering the barrel to the shield if you're in a situation where you do not have a sufficient iron to do so, or if you're outside. Outside installation can be a challenge, cooler temps or a bit of a breeze can quickly cool the connector while you're trying to heat it enough to solder it on. In these situations I have been able to do it two ways. One is with a butane soldering iron, they are harder to control temperature wise, but if you follow the same precautions here, work quickly, don't apply heat for too long, you can do just as good as if you were working at your bench. The second method I have used is to apply a large glob of solder to each hole with a pencil iron or butane iron and then use the butane torch to quickly heat around each hole until the solder wicks into the braid, this works really well in cold weather! The connector and the coax are cold, and there is very little risk of melting the center dielectric or jacket by overheating as you're usually only able to heat enough of each hole, one at a time, and the braid below it to flow the solder. I have done this in the middle of the winter here in the Midwest and you can usually handle the connector seconds after soldering, it just cools that fast! As with anything practice and patience makes for good connections!
Sealing:
Let's take a moment to talk about sealing up a PL-259 when used outdoors. A PL-259 exposed is water intrusion waiting to happen when it's in a location that is exposed completely to the weather, even when up inside the mounting tube of some popular dual band vertical antennas this can be a problem as well. I like to take a two step approach to sealing these. First is a couple layers of tightly wrapped butyl tape, some call it Self-Amalgamating Tape as well, this plus a couple layers of 3M Super 33+ as a UV barrier for the butyl makes a connection that will last for years! Most of the Butyl tapes that I have used are not 100% UV resistant, so the layers of electricians tape over the top of it helps prevent breakdown. A couple years ago I moved all of my antennas from one location to another, when I installed my first tower, after cutting the Butyl tape down one side it came off in a perfect molded shell, with the knurled portion of the connector being a perfect mirror image. The connector looked brand new as if just installed! This is very impressive stuff, and FAR better than the coax seal products sold, it has no adhesive to dry out and rolls of it can sit on the shelf for years. If you're going to use one of those other products beware, they stick to everything, it's hard to remove and clean up, and it discolors the connector after being on there for a year or two. With the Butyl if you need to replace/repair an antenna it's just, slit, remove, and disconnect. Then rewrap when you reconnect. It can actually be cheaper than the coaxial seal or other mastic type products, rolls of it can be had for merely a few dollars if you shop around!
Conclusion:
There you have it, my take on installing the PL-259. As always opinions vary, but a link is provided below if you feel you need to email me!
This site was last updated 01/25/10