Choosing the right kind of coax connector.

There are some things to keep in mind when buying PL-259 or SO-239 coax connectors. If the material holding the center pin is white or clear, DON'T BUY IT! I have found that these materials will not tolerate much heat from soldering. They will  melt and come out of the barrel. The best type are connectors that are either brown or baby-poo yellow. These stand up to heat very well and can even be reused. I try to buy Amphenol brand coax connectors if possible. I think they are the best. Beware of buying coax connectors at hamfests. I have seen some that are factory rejects and some of the center pins are undersized. This causes problems in getting the center conductor of the RG-8 coax to fit.
If I ever need to cut off a coax connector from a cable, I try to leave at least an inch of coax sticking out the back side of it so I can grab it with a pliers while heating up the center pin and outside of the barrel with a propane torch. I have a small torch head that is on the end of a rubber hose and it has a sleeve that you turn to turn on the gas. The other end has a cap that fastens to the propane cylinder. It was rather expensive to buy, but very handy. You can regulate the amount of heat more precisely than with a standard torch head.
Once I get the old piece of coax out, I set it aside to cool for a while. When it is safe to touch, I take a Swedish file and file the area around the 4 holes in the barrel so it is shiny brass. This also gets rid of burned soldering flux. I also use the same file to clean the inside of the barrel of solder fragments and any wire whiskers that may be still sticking to the inside. Once this is all done, the connector is reusable.

Soldering Coax Connectors for RG8X.

Here is an almost fool-proof way of soldering a coax connector for RG8X coax. First, strip off 1 1/8" of insulation from the coax as in this picture.








Now, separate the strands of braid into 2 groups and twist them together as shown.








Now, slide the RG8X reducer up to the separated braids, then clip the braid ends so that they don't hang down past the threads on the reducer.








Now, strip the insulation from the center conductor just above the reducer, then twist the strands together. Take the soldering gun and "tin" the end of the conductor to keep the strands together.









Now, prepare the barrel of the connector for soldering by filing away the plating around the 4 holes in the middle of the barrel. I have found that the plating interferes with good solder flow. You will be filling these holes with solder later.










Next, we slide the barrel over the coax end and screw the reducer on, watching that the center conductor goes thru the center tube. I use a channel-lock pliers to screw the reducer on.











You will see that the two strands of braid are over two of the holes in the barrel and the center conductor sticks out from the end of the center tube. Trim the excess wire off flush with the end of the center conductor tube. Now, it is ready to solder.











Now, we can solder the center conductor to the tip.











Next, we solder the 4 holes in the middle of the barrel. The technique for doing this is to position the connector so the center pin is facing either to your left or right. Then get the iron good and hot. Touch the tip of the iron at the top edge of one of the holes, then feed solder to the tip, dragging it over the hole until the hole fills up with solder. It is important that these holes be soldered shut because I have found that small amounts of RF can leak out, causing RFI in the ham shack.











Now, all that is left is to slide the threaded sleeve up over the coax and screw it onto the barrel. Of course, be sure to check the connector out with a multimeter first to be sure there is no short circuit between the center pin and the barrel of the connector.