This exact problem of the center pin pulling back was terrible problem when
Doc, K8RR had his large contest station in Columbus, Ohio. All of his phasing
and feedlines were "N" type and
the majority had center conductor pull backs in cold weather.
The newer "captivated" center pin N connectors cure the problem. They are
somewhat more expensive, but they solve the pin "floating" problem.
I am using good silver plated teflon PL-259's and SO239's. No problems with
connector failure so far.
Be very careful using any SO239 that is not an Amphenol connector. I had
terrible loss problems and intermittent issues with SO239s that were sent to me
by ICE. Their off shore female UHF
(SO239) connectors would not allow the center pins to seat all the way and the
PL259 center pins were not "grabbed" by the connector either. It was amazing
how things worked so much better
when I changed out over 50 of their SO239 connectors.
73!
Tim K3LR
Peter Sundberg wrote:
> I have done away with N-connectors in my VHF EME array as they are failing
> during cold winter days. The problem is that at low temperatures (I live at
> 65.4N...) the center conductor of the coax gets shorter and the center pin
> of the N-male is pulled out of the socket hence making poor contact. A
> split second of 2kw RF vaporizes the center pin..
> After having multiple failures during cold winters I now use PL259/SO239 of
> good quality at the relay and as for the driven elements and powerdividers
> I have soldered the coax direct and done away with connectors.
>
> I dont think these problems will occur in places where the temperature
> swing is somewhat less than -40C -> +35C....
>
> 73/Peter SM2CEW
> www.qsl.net/sm2cew
>
>
> At 15:04 2003-09-05 , you wrote:
> >It is well known among vhf/uhf operators that N connectors will survive
> twice
> >legal power through 432mhz with reasonable vswr. Even at 1296mhz they
> survive
> >full legal power with low vswr.
> >
> >As others have mentioned, they will fail at any frequency under fault
> >conditions. Heck, I even managed to smoke a 7-16 Din connector when the
> shield let
> >loose on a 1296mhz PA output connection. The screen trip circuit would have
> >saved it if I had realized that the fault was external to the PA . You
> live and
> >(hopefully) you learn!
> >
> >73/k5gw
> >_______________________________________________
> >
> >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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> >
>
> _______________________________________________
>
> 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.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> 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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