----- Original Message -----
From: "Jim Thomson" <jim.thom@telus.net>
To: <amps@contesting.com>
Sent: Wednesday, April 27, 2011 7:57 AM
Subject: [Amps] Power handling of an SMA
> Date: Tue, 26 Apr 2011 22:48:01 +0100
> From: Steve Thompson <g8gsq72@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.
** Tin the nickel ones first. I do a batch at a time of NOS Amphenols I
picked up back in the R-K days with a solder pot. Flux up, dip in pot and
bang hard to remove excess.
Is VGE still in business? I cant find a web site or phone #. I used to sell
those silver plated Teflon connectors by bags of 25 and 100 and those are
mostly whats on the 20+ year old jumpers here. Real easy to strip and reuse
with fresh coax.
Carl
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|