[Elecraft] FW: Proper installation of PL 259's

Wed Nov 13 01:01:56 EST 2013

Yeah, really?

I've been following this thread and can see we've barely scratched the surface of PL-259 assembly techniques. Where are the comments on brazing, laser welding, induction welding, and so forth? And how do you attach a PL-259 to hard line? And what about mods to use the PL-259/SO-239 pair as a high-voltage connector, by drilling out the center pin and feeding eight or ten inches of the insulated coax center conductor through the resulting holes? This was popular way back when real hams used real vacuum tubes with real high voltage in their "finals" instead of these newfangled transistor "tuner-less" finals running off of car-battery voltages.

Oh, wait! This is the Elecraft reflector! My KX3 (S/N 3931) works fine running off a car battery, if not perzactly real portable without the car attached. And did I not notice that it connects to the antenna using a (gasp!) BNC with a quarter-turn twist instead of the stalwart UHF that screws down oh-so-tight and can be waterproofed with only a few layers of assorted self-vulcanizing tape, spray on magic goo, shrink tubing and Scotch tape?

Just kidding! I bought a coax "kit" package from Amateur Radio Supplies a few months ago: 100' of "generic LMR-400" Made-in-the-USA DRF-400 coax; a bag of ten silver-plated, Teflon insulated, PL-259 connectors; 1" shrink tubing with "gooie inside" for same; a stripping tool; and a large-cable cutting tool. The stripping tool appears to be a waste of time and money as I can strip better with a sharp knife and a keen sense of touch, but maybe I'll get the hang of it eventually. The cable cutter is handy and appears well-made; about on par with the Crescent cable cutter before I loaned that out and got it back with nicks all over the cutting edges, despite warning the user not to cut anything except copper wire with it.

So, I dutifully followed all the instructions and attached a PL-259 to one end of the cable. But I haven't soldered it yet because I am still looking for my "real" soldering iron, with the fabric-covered cord, circa 1955, with which to solder the braid. A co-worker found exactly what I need on e-Bay for thirty bucks a few weeks ago and bought it for his work, bragging that the same thing sold for about $135 (new) from McMaster-Carr. Meanwhile, I'm looking at my propane torch and wondering about using that, with or without a soldering iron tip (which I have also misplaced) attached to the end. Or maybe I'll just borrow my co-worker's iron. Or maybe I can dig up the old tin-smith iron that Grandpa used to heat up with his gasoline blow torch... Sufficeint temperature AND thermal mass to maintain that temperature are important iron characteristics when soldering the braid on a PL-259.

I haven't assembled a PL-259 in over forty years, but it is just like riding a bicycle once you get the hang of it. Go in hot, go in fast, use eutectic 63/37 tin/lead rosin-cored Kester-brand solder, and don't "quench" it after soldering. Just let it sit undisturbed for a few minutes. I shudder every time I see a tech try to short-cut the cooling off period. This "quenching" practice leads to "cold" solder joints.

There has been some good advice and some bad advice in this thread, but that's typical of the Internet. YMMV. I really like the Max-Gain tutorial (http://www.mgs4u.com/Connector-PL-259-guide.htm)probably because that's pretty much the way I've always done it.

73 de AC8NS

Hop

----- Original Message ----- 
From: "Dr. William J. Schmidt, II" <bill at wjschmidt.com>
To: <elecraft at mailman.qth.net>
Sent: Tuesday, November 12, 2013 10:39 PM
Subject: [Elecraft] FW: Proper installation of PL 259's

> So far I've counted 96 posts on soldering connectors onto coax.  Really?
> 
> 
> Dr. William J. Schmidt - K9HZ / J68HZ/ 8P6HK/ ZF2HZ
> 
> Owner - Operator
> Big Signal Ranch
> Staunton, Illinois
> 
> email:  bill at wjschmidt.com
> 
> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net
> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Jim Brown
> Sent: Tuesday, November 12, 2013 3:51 PM
> To: elecraft at mailman.qth.net
> Subject: Re: [Elecraft] Proper installation of PL 259's
> 
> On 11/12/2013 8:42 AM, kd7gc wrote:
>> They are very expensive, some in excess of $100 each, but they have very
> low loss, and they are sealed well against WX.  When I order baluns or
> switches, I always specify that they must be made with 7/16 DINs, and I have
> never been disappointed with their performance.
> 
> I'm trying to understand, Alan, so could you please. define 
> "performance," and please tell us in what application, at what 
> frequency, and how you actually KNOW their performance.
> 
> Unless you're using them in critical small signal applications at UHF, 
> I'd call that a very poor allocation of financial resources.  I can 
> think of many better ways to spend $100.  The loss through a quality 
> PL259 or N connector is negligible in most real world applications, and 
> there are simple and effective methods of waterproofing them.
> 
> BTW -- the nicest male N connectors I've found for RG8/213-sized cable 
> are made by Andros Engineering, a machine shop owned by a ham.  They're 
> a 2-piece connector, with both center and shield rigidly assembled to 
> the same part to which you solder both center and shield, then screw the 
> outer shell onto it. Very easy to do, and zero possibility of shield 
> migration.
> 
> 73, Jim K9YC
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