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Re: [TowerTalk] PL-259 question

To: towertalk@contesting.com
Subject: Re: [TowerTalk] PL-259 question
From: K8RI <K8RI-on-TowerTalk@tm.net>
Date: Fri, 16 Nov 2012 21:54:56 -0500
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
On 11/16/2012 5:54 PM, Dale Sanders wrote:
I use the PL259 everyday......just purchase from a reliable, local
electronics supply house and don't scrimp on the price of the connector.  An
antenna is only as good as it weakest connection and this is NOT a place to
worry about pricing.  The connectors I'm using are made by Emerson but I
still prefer the old Amphenol standards.  ....and make sure you use a large
soldering iron.  I use a Weller 200 - 300 watt iron and it heats quickly and
connects the thing without the long, slow, heating the deforms the position
of the center connector pin.



I go through a lot of UHF connectors. These are not a precision connector, they are not constant impedance connectors, nor are even the best ones expensive that fit RG-8 size and smaller cables. They are very expensive to fit the larger cables because there is so little demand.

I purchase them in lots of 25 or more where even the silver plated body and pin with Teflon insulators are less than $4.00 each for Amphenol PL-259s. I see those with phenolic listed as "old style".

Now I'm going to commit heresy! As these are not precision or constant impedance I'm only interested in quality. So far in the hundreds of connectors I've gone through, I've had almost as many Amphenol connectors fail as brand X, if I have a quality built brand X.

I purchase from several companies who have people on this reflector. I normally tell them I don't care who builds the connectors as long as they are of quality construction. I usually get silver with gold center connectors and Teflon insulation. It's my understanding that Phenolic will absorb some water but it's quite strong mechaqnically.

The system at times contains well over 100 connectors at one time. Each run may have from 20 mail and female connectors to about 14 with roughly 14 runs of various lengths for various antennas...when they are all up and functioning. Cables going up the tower have the shields grounded at the top and bottom of the tower. At least up through 6-meters these grounds are a double female connector through a bracket. Higher is the attempt the leave the coax unbroken with connectors at the ground points. IOW, I use a LOT of connectors because the loss exhibited in them is miniscule which is not the case for UHF and up.

One thing I have learned about connectors: no matter who builds them they all have weak spots, electrically and mechanically. My patch panel is a 4 X 10 X 10 NEMA box. I'm going to add another box on top of that one that will make it 10 X 10 X 10 to reduce the bending moment of the coax on the connectors at the front of the panel. This will greatly increase the radius of the bends and reduce the stress at the connector. If I can't find a box with front AND rear covers I'll just cut the back out of a 6 X 10 X 10. With guides for the plasma torch I can cut the back out in about 10 seconds (after taking 10 to 20 minutes to prepare). The plasma torch will cut so fast I can pretty much cut out the back without scorching the paint. At least I could if my hands were a little more steady. I could also do it on the milling machine, but that takes even longer to set up.

The point is I've not found any manufacturer to provide 100% reliable connectors without defects right out of the box/package.

73

Roger (K8RI)


73
Dale - WD4IFR

-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of John
Becker
Sent: Friday, November 16, 2012 2:46 PM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] PL-259 question

A little more clarification here relative to my inquiry:

I am only interested in the differences between the different Amphenol
PL-259 plugs. I won't consider using a generic plug from an unknown
supplier.

The plugs I have with either dark yellow or light yellow insulators are
marked 83-1SP. Amphenol's published data says these have silver plating on
both the body and the center pin.

I was incorrect in stating that I had some with blue insulators; they
actually are green and they are marked 83-1SP-1007. I haven't found any
description of this variety on Amphenol's website. These were very common at
Motorola before I retired. I wonder if they were a special Motorola-only
variation.

The plugs I have with Teflon insulators are marked 83-886. Amphenol's
published data says these have nickel plating on the body and silver plating
on the center pin.

There is a variation 83-886-2050 which is Teflon with silver plating on both
the body and the center pin, but I have never seen one of these.
R&L Electronics is selling them for $9.95 each. For comparison, they sell
the 83-1SP for $3.95.

Amphenol's UHF Connector brochure says the insulators used are PTFE
(Teflon), co-polymer of styrene, or mica-filled phenolic. It does NOT say
which insulator is used on each specific part number.

A couple of people have recommended the 83-1SP because the silver plated
shell is easier to solder than nickel plated varieties. I have also observed
this to be the case.

I have found no explanation from Amphenol as to why they use phenolic
insulators in some and PTFE in others. This is what I would like to
understand. Is there some application of a PL-259 where PTFE is
demonstratively superior to phenolic? Or is this just a marketing ploy to
justify a significantly higher price? I would guess that the difference in
material cost between phenolic and Teflon is very low in the quantities
Amphenol buys.

73, John, K9MM




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