Saturday, January 11, 2014

How I Do My PL259s

(1) First is to wrap about 3-4 turns of electrical tape right where the insulation of the shield will be cut.  This forms a backstop  for the PL259 to apply pressure while screwing the assembly.

(2) Cut open the insulation over the shield as shown below:

(3) I then spread the shield wires apart from the center dielectric and wrap a piece of tape around the dielectric only about 2 turns.  This will thicken the joint For a tIght crimp when the PL259 is screwed on later. When this is correctly done, there is a half inch of braid of shield inside the PL259 jammed up against the screw threads.  This is shown below:

(4) Now cut the dielectric off at the of the electric tape wrap and tin the copper center conductor.  Tightly wrap the shield conductors against the black tape.

(5) Insert a 3 inch piece of thick heat shrink.  This will be used to later shrink around the bottom part of the assembly.

(6) Screw the PL259 assembly over the prepared and folded up shield wires.  The center conductor should poke through a bit.  This will be cut off later.

(7) Trim the shield wires back so they are about 1/8 inch long.  Solder the center conductor to the PL259. 

(8)  Solder the shield wires to the shield of the PL259 all the way around. When the shield is soldered some of the solder will wick up through underneath the PL259 because of capillary action,

(9) Finally, wrap the heat shrink about 3/8 of an inch on the PL259.  Make a test assembly and make sure the PL259 can be unscrewed off an SO239 or similar connector.

Now we have a redundant crimp and soldered connection on the shield.  The heat shrink will give it some additional stiffness against flexing.  Stress is the enemy of soldered joints and that is why a good crimp is important.  This joint should continue to function even if the solder joint is to break.  However, with every strand of the shield soldered to the PL259 - this is not very likely.  

Note that this method has been challenged by others as being inferior.  I have only 3 years of experience as a ham but I am a very experienced engineer and builder.  I stand by my contention that this is a superior way to do it.  I also offer this internet article from a ham who has been doing something similar for 45 years without having a joint fail.  I doubt I will live another 45 years to prove this as I am already 56.  The internet article is by K3DAV

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