[Amps] Power handling of an SMA

[Jim Thomson]

Date: Tue, 26 Apr 2011 22:48:01 +0100
From: Steve Thompson <g8gsq72 at gmail.com>
Subject: Re: [Amps] Power handling of an SMA

I suspect a lot of issues with 259s arise from the variation in 
materials. I see lots with nylon and brown 'plastic' (bakelite or 
SRBP?) insulation which I wouldn't trust under stress or with age. 
  Then there's the problem with the braid connection and the cold 
soldered joints onto low grade plating. Even when that's ok, the 
coupling ring is prone to working loose given time, mechanical 
movement or thermal cycling etc. Most other connectors have some 
form of spring fingering that maintains contact even when the 
coupling nut isn't tight.

Where the non constant impedance isn't an issue, a good quality 
well assembled 259 will handle a lot of juice - but it's a trap 
waiting for the unwary.

Steve

## I have used Amphenol PL-259's  that were a bitch to solder the braid to..
through those 4 x little holes.   Think they were nickel plated.   The best types
appear to be Silver plated ones..with teflon dielectric.  I bought a bunch of Van-
Gordon PL-259's..and those are silver plated, including the outer shell.  Teflon
dielectric in the middle..and real easy to solder.    I also bought that stripper jig  from
DX eng  for stripping RG-231U.  [ DXE-UT-8213] Works superb.

 The pl-259 assy tool also works superb. ..and screws onto the
FRONT of the pl-259 connector.  [DXE-UT-80P] this allows precise threding of the PL-259 sleeve
onto the RG-213. It works very slick..and makes installing pl-259's a helluva lot easier, and faster, VS  using box
cutter's etc.  Check it out, well worth the price. 

For lopping coax, etc,  I used the [DXE-CNL-911   These are made  by chanellock. The blades are rounded..
and cut coax cleanly.  They don't crush the cable like regular side cutters do.   They will also cut cleanly... 4/0  AL
and also 2/0  CU  cable.   I did cut 2 ga  CU with it... when I did the  grnding sytem at base of tower.  It blows away
even the heavy duty side cutters. I took some scrap 213-U..and could easily cut it into 10 x 1"  long pieces in mere seconds...
with zero effort !    A 7 x yr old girl could do the same.  This tool was not available at my local
tool place !!   Channellock also makes a bigger version of this tool.    I also got the carry case for it all... which also holds
 a bunch of pl-259's, 88 tape, etc, etc. Handy, cuz  when it's time to install a PL-259.... just grab the carry case, and everything is right there. 

 Basic Coax Cable Prep Tool Kit - DXE-UT-KIT1-D  is what I bought last year... and includes the 2 x coax tools, chanellocks,
and carry case.   I wish this kit was around 35 yrs ago. http://www.dxengineering.com/Products.asp?ID=240&SecID=127&DeptID=36

later... Jim  VE7RF