[TowerTalk] Detailes On Installing PL-259s

[John Brosnahan]

I was surprised at the number of private responses asking for more details
and clarifications on my note on installing PL-259s.  I also noted that
my original posting had some minor problems, so I have decided to
write up the entire procedure in a bit more detail.  Hope it is of some
use.  If anything is still unclear let me know and I will revise my note.

73  John  W0UN

-----------------------------------

Installing PL-259s on RG-8 or RG-213


Requirements:

1)  Good quality coax with a high percentage of braid--96%.  Also note
        that good quality coax has better control on overall diameter of the
        jacket.  Some cheap brands have a jacket that is too thick and
        won't screw into the PL-259 properly.
2)  Good quality PL-259s, preferably silver plated with Teflon dielectric
3)  High temp soldering iron (800 degrees F) with a large heat capacity
        but with a tip that can be inserted in the soldering holes of the
PL-259
        (I use an old Weller WTCPL with a PTC8 (800 deg) but it is a little
        marginal on heat capacity)
4)  Very sharp knife such as a utility knife with replaceable blades
        and install a new blade
5)  High quality, small diameter solder such as Kester 0.031 inch diameter
        Sn63/Pb37 (or 60/40) with a 282 flux and a 66 core--the critical
        part is the 0.031 diameter
6)  A steel rule can be used for measurements but there is only one critical 
        dimension and it can be determined from the connector body itself
7)  Use decent cable cutters to cut coax to length.  Cutters with semicircle
        blades that slide past each other.   Radio Shack has some adequate
        ones for about $5.95.  The flat bladed cutters smash the end of the
        coax and take a lot of force.  Real cable cutters make a nice,
clean end 
        and require little force.


Procedure:

1)  Slide the outer shell over the coax first--nothing is worse than doing
a great
PL-259 installation and forgetting to put on the shell first!

2)  Measure 1 inch back from the end of the coax and, with the utility knife,
cut through the coax jacket, the braid, and most of the dielectric.  Try not
to nick the center conductors.  You don't need to cut all the way through
the dielectric, only 80 or 90% of the way.  If you hit the center you can feel
the drag of the knife increase.  The 1 inch dimension is not too critical
since
the center conductor will be trimmed later--just make sure it is at least 1
inch.

3)  Slide the 1 inch piece of jacket and braid off the cable.  Take the
dielectric
and bend it from side to side a bit to break the last bit of uncut material
and pull
the dielectric off.  This can get a bit tricky depending on the brand of
coax--
on some coaxes the dielectric is held to the center conductor better than on
other brands.  The dielectric wants to spiral since the center conductor is
stranded.  You can use either gas pipe pliers and unscrew the dielectric
or you can make a little gadget from sheet metal that has a slot in one end
just a bit bigger than the center conductor.  When the dielectric was bent
from side to side it forced a gap between the cut piece and the rest of the 
dielectric.  Insert the little tool into this gap and use it to pull off
the dielectric, allowing the dielectric to spin as it comes off.      

NOTE: When pulling off the dielectric (or any operation that involves a
pulling 
force against a length of coax) grab the main length of coax at least 18
inches 
away from the end.  If the coax is held too close to the end there is a
tendency 
to have the jacket and braid slide back from the end--exposing more of the 
dielectric.  When the jacket and braid are removed properly, the remaining
braid 
and jacket should remain flush to the end of the dielectric.

4)  Measure back 1/2 inch on the remaining jacket and very carefully
cut through the jacket in a circle around the coax without cutting into the 
braid.  This involves a certain amount of "feel" and "finesse".  With a 
sharp knife the jacket cuts like butter, but the braid has drag.  It takes 
a very light touch to cut the jacket without cutting into the braid.  How
tight the jacket is on the braid is a function of the manufacturer and the 
day on which the coax was made.  If the jacket is loose then just slide 
it off the braid without disturbing the braid.  If the jacket is held tightly 
onto the braid (ie, the process temp was higher and the jacket tended 
to melt into the braid a bit) then make a lengthwise cut in the 1/2 inch
piece of jacket so that the jacket can be peeled from the coax without
disturbing the braid.  The key part here is to remove the jacket but to
keep the braid intact so that it stays woven and tight to the dielectric.

5) Check again to make sure that the shell has already been placed on the
coax!!!   Screw the body of the PL-259 onto the end of the coax very carefully
in order to make sure that  a)  all 7 strands of the center conductor come
out 
the hole in the center pin and  b)  the braid is not disturbed.  The braid
should go past the solder holes in the connector body and the dielectric
should bottom out on the Teflon part of the PL-259.  Check to make sure
that each of the four holes has intact braid inside.  If things don't go
perfectly it is possible to rotate the connector body a bit until all of the
holes show full braid.  

6)  Using a hot soldering iron with a small tip, try to heat the braid in
one of
the solder holes without heating the PL-259 body until the braid is tinned in 
the hole and then start heating the shell so that it takes solder and add
just 
enough solder so that the inside of the hole is filled but no solder is on
the 
outside of the connector body.  This first hole is tough since the body is
cold--
the result may not be as pretty as one desires but this first hole can be
touched
up after the other holes are soldered and the connector body has gotten
warmer.  Proceed to the next hole and try to tin the braid before the solder
starts to melt onto the connector.  A good connection with have a nice
dimpled look to it--shinny and smooth, filling the hole but with no extra and
a bit of sunken look since the solder has wicked into the braid.

7)  Once the braid is soldered in all four holes, quickly slide the shell
over the body and partially screw it onto the threads of the body.  This will
help to heat sink the PL-259, cooling it down faster.  Note:  the center
conductor
has not yet been soldered.  It is left for last so that the hot air generated 
while soldering the braid can escape--otherwise you have a lot of bubbling
at that fourth hole when doing the braid.

8)  Using sharp cable cutters, cut off the center conductor flush to the
end of
the center pin on the PL-259.  Heat the center pin and center conductor
simultaneously and solder--allowing the solder to wick inside the center pin.
With finesse one can make a bit of a solder bubble on the end of the center
pin.  Try not to get solder on the outer part of the center pin.  If you
do, use
a rag to wipe it off while the solder is still in the liquid state.

With good cable and connectors and the right tools it is possible to
install PL-259s in only a few minutes.  Knowing how hard PL-259s have
been to install you can now sit back and admire the beauty of one done
properly!  It really does takes longer to describe that it takes to do the
work.

--de W0UN



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