The approach detailed probably works pretty well at HF, and not as well at
VHF-UHF because the impedance discontinuity introduced by the PL259 is now
made even longer by the method prescribed. Also, if you can thread the
PL259 body onto the braid-over-jacket combination, you're likely damaging
the braid by cutting strands, since the PL259 dimensions are maintained by
design specifically to tightly thread onto the outer jacket of .405" O.D.
cable *without* the braid being present. Also, by not filling the body
solder holes in the PL259 body, and also by not tightly threading the
connector body directly onto the jacket as intended, you've voided a lot of
the weatherproof features of the connector design. (A PL259 properly
installed onto properly toleranced RG cable is quite weatherproof -- in many
cases, more so than a type N, especially when UG21 connectors intended for
RG214 are actually used with RG213 -- a very common application -- which
leaves a pretty big gap inside the rear nut of the connector.) I have
demonstrated many times that a PL259 properly installed (threaded on and
fully soldered, including the four body solder holes) onto properly
dimensioned RG213/U is so weatherproof that it can be considered water tight
at one atmosphere, tested by complete immersion in a seawater tank while
making dynamic measurements on the cable in-circuit. Many times! In fact,
I did this at the Dayton Hamvention in 1982, at the outdoor swap meet with
about a hundred hams watching in disbelief. It's an easily repeatable test.
No heatshrink required. The results might not be very good at several
atmospheres, but at sea level, I can make it work. Thus, my take on this is
there's really no reason to install PL259's any differently than they way
they were originally designed to install. It's a good, solid way that
doesn't damage or overheat anything if the proper tools are used (which of
course includes the use of a large thermal mass soldering tool, not a
pencil, not a flame, and not an instant-heat gun). -WB2WIK/6
"Success is the ability to go from failure to failure with no loss of
enthusiasm." -Winston Churchill
> -----Original Message-----
> From: Bill VanAlstyne [SMTP:w5wvo@cybermesa.net]
> Sent: Thursday, April 29, 2004 11:32 AM
> To: _Mailing List Tower-Talk
> Subject: [BULK] - [TowerTalk] Alternate method, PL-259 on RG-8-type
> coax
>
> I read through an extensive, several-years-old archived thread the other
> day, -- somewhere, maybe on QRZ.com -- on UHF vs. N-type connectors. While
> the recent discussion of UHF connector loss at various frequencies has
> been
> very enlightening, the caveat "high-quality, properly installed" is always
> stated or implied.
>
> One of the things I read in the aforementioned thread was from a guy who
> believed that the PL-259 connector is much better installed in a manner
> that
> differs significantly from the "standard" method. I'm wondering what the
> group here thinks of this idea. This is paraphrasing from memory:
>
> "Slip the connector sleeve ring and a length of heat-shrink 2-3" long over
> the coax. Strip the outer jacket and center dielectric using the same
> dimensions as for the "standard" method, but don't trim the shield braid.
> Instead, pull the shield braid inside-out back over the outer jacket.
> Screw
> the connector body over the prepared cable end such that the braid is
> compressed between the connector threads and the jacket of the cable. This
> will be hard and will require hand tools, but keep screwing it on until
> you
> can just see the braid through the solder holes. You stop there. You don't
> solder it through the solder holes, but rather around the rear edge of the
> connector body. Then trim off the excess braid and apply the heat-shrink
> over the connector body and the cable behind it. Solder the center
> conductor
> and trim off any excess length. Then thread on the sleeve ring."
>
> That's it. I don't recall that the guy said exactly WHY he thought this
> was
> a better method, but after thinking about it, I'm not sure I like it. The
> good point is that it would result in less deformation of the dielectric
> material by soldering heat. But the shield connection seems problematical
> to
> me. While compression of the braid against the inside of the connector
> body
> would make a good unsoldered shield connection (assuming you were using
> good-quality silver plated connectors), that connection would degrade over
> time, as the connector is not weather-resistant like the N-type. Soldering
> it as proposed in his method, on the other hand, would effectively relieve
> the beneficial pressure of the braid against the inside of the connector
> body by melting the jacket material. Of course soldering would provide its
> own permanent electrical connection to the shield, but only at the back
> edge
> of the body. Because of the squirrelly back-looped path of the shield to
> the
> connector body attachment point, it seems to me that this method would
> create even more of an impedance hump that the "standard" method. (Though
> at
> HF, as discussed here earlier, it probably wouldn't matter a hill of beans
> one way or the other.)
>
> But I could be completely off the wall here. What do y'all think of his
> method?
>
> Bill / W5WVO
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
> Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with
> any questions and ask for Sherman, W2FLA.
>
> _______________________________________________
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> http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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