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Re: LMR-400 Variants?



John and the multitudes,

Many years ago when I first started using the cable with the larger center
conductors, I did not know about the special center pin for the Type N
connectors.  I had a small drill press and a set of numbered bits and
just drilled out the hole so make it fit the conductor.  I don't remember
the number of the bit but if you have a set and a drill press, you can
find it experimentally in a few minutes.  Some of those pins are probably
still in use some where around the shack after all these years.

I had the water problem with 9913 the very first time I used it.  After
several months, I found the SWR had gone to pot. Suspecting water, I
removed the connectors from both ends and "cobbled" an air line to my air
compressor. Imagine my amazement  when I hit it with about 100 pounds of
pressure and the water squirted out of the cable like a water hose!!  I
just let the comperessor run for several hours and put the cable back in
service where it stayed for many years.

The problem came from a poor job of sealing the antenna end of the cable.
I was using it on a homebrew helix and just didn't get a good seal around
the feed point. It is extremely important to get a good seal at the
antenna end but DO NOT seal the end in the shack.  If this is done
properly, you can get years of good service out of 9913.  However, there
are much more flexible cables available with just as good loss
characteristics these days.  So I don't use 9913 any more but I keep a
supply of the larger pins available since the other cables also use them.
I usually see them at ham fests.  They are inexpensive so lay in a stock.

73...Jim...W5VZF.



Dr. Jim Akers
Dept. of Electrical
and Computer Engineering
Miss. State Univ.


On Thu, 22 Jul 2004, KC6UQH wrote:

> John,
> LMR 400, 400Ultra Flex, Belden 8214, & Belden 9913 all use the larger center
> conductor except the Belden products center condoctor is all copper. Belden
> 9913 is also known to make vast quanities of water in its hollow dielectric
> if exposed to the cold sky!
> Art, KC6UQH
>
> ----- Original Message -----
> From: "John B. Stephensen" <kd6ozh@verizon.net>
> To: "Bill Acito W1PA" <w1pa@hotmail.com>; <amsat-bb@AMSAT.Org>
> Sent: Thursday, July 22, 2004 1:51 PM
> Subject: Re: [amsat-bb] LMR-400 Variants?
>
>
> > The copper-plated aluminum center conductor in LMR-400 is much larger than
> any
> > other RG-8 variant. You will have to buy connectors specifically made for
> > LMR-400. RF Industries and Amphenol make suitable connectors and HRO may
> still
> > stock them. My catalogs and cables are 300 miles away so I can't give you
> part
> > numbers.
> >
> > 73,
> >
> > John
> > KD6OZH
> >
> > ----- Original Message -----
> > From: "Bill Acito W1PA" <w1pa@hotmail.com>
> > To: <amsat-bb@AMSAT.Org>
> > Sent: Thursday, 22 July, 2004 15:51 UTC
> > Subject: [amsat-bb] LMR-400 Variants?
> >
> >
> > > I have a length of LMR-400, and picked up some plenum crimp N-connectors
> > > (all on ebay)... the pins of the connectors do not fit over the solid
> center
> > > wire of the LMR-400.
> > >
> > > Besides the flex version, are there different versions of LMR-400? Are
> there
> > > different versions of N-connectors (these were advertised specifically
> for
> > > LMR-400)?
> > >
> > > Bill
> > > W1PA
> > > ----
> > > Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
> > > Not an AMSAT member? Join now to support the amateur satellite program!
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> > ----
> > Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
> > Not an AMSAT member? Join now to support the amateur satellite program!
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> ----
> Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
> Not an AMSAT member? Join now to support the amateur satellite program!
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----
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