[BULK] - Re: [TowerTalk] Replacing coax question

[Steve Katz]

An advantage of LMR-400 or any similarly constructed cable is that it's
double shielded, and literally 100% shielded by the inner foil shield.  That
hasn't anything to do with "loss," but is still a bonus in some
applications.  To achieve similar shielding with a flexible,
solid-dielectric cable also providing low loss and high power handling would
mean going to at least RG214/U (the double-shielded version of 213), or
better still, RG-218/U, which is bigger.  That's mostly what I use for "long
runs" up towers and around rotors.  Its average operating life in severe
weather, including the UV levels of the tropics, is 30 years. -WB2WIK/6

-----Original Message-----
From: Bob [mailto:rgshauger at myyellowstone.net]
Sent: Tuesday, October 12, 2004 11:16 AM
To: Tower (K8RI); Alan C. Zack
Cc: towertalk at contesting.com; kk9a at arrl.net
Subject: [BULK] - Re: [TowerTalk] Replacing coax question


It does seem that LMR-400 may be an overkill for 40 meters.  RG213 is very
durable and certainly suitable for this application.  Good luck.

Bob W7KD

----- Original Message ----- 
From: "Tower (K8RI)" <tower at rogerhalstead.com>
To: "Alan C. Zack" <k7acz at cox.net>
Cc: <towertalk at contesting.com>; <kk9a at arrl.net>
Sent: Tuesday, October 12, 2004 11:18 AM
Subject: Re: [TowerTalk] Replacing coax question


> Why not use a single piece of LMR-400 flex? It'd have still less loss
> and I believe it's cheaper than 213.
>
> As for splices, I use the flooded heat shrink and have not had any
> failures (leaks) so far.
> OTOH at 40 meters the loss between old fashioned RG-8 and even Heliax is
> hardly worth mentioning./
> /
> Roger Halstead (K8RI ARRL Life Member)
> Worlds Oldest Debonair (N833R S# CD-2)
> www.rogerhalstead.com
>
> Alan C. Zack wrote:
>
> > I agree.  Please correct me if I am wrong but I believe RG-213 is
> > flexible enough to use for the rotation loop at the beam as well as
> > where it would loop on the side of the tower when you crank it up or
> > down.  You could have one continuos coax run and not have the concern
> > of moisture getting into your splice points.
> >
> > kk9a at arrl.net wrote:
> >
> >> I would use a single piece of Belden 8267 RG-213 for this.  It's
> >> durable,
> >> there would be fewer connections and it would have less that 0.5 dB
> >> loss.
> >>
> >>
> >> ----- Original Message -----
> >> From: "Tom Martin" <tmartin at chartermi.net>
> >> To: <towertalk at contesting.com>
> >> Sent: Monday, October 11, 2004 18:36
> >> Subject: [TowerTalk] Replacing coax question
> >>
> >>
> >> I am replacing a 90' length of RG8 water damaged coax to my 40 meter
> >> beam.
> >> I have LMR 400 for the main run up the tower but want to use a RG8
> >> section
> >> for the rotator loop.  There are two ways to do this. First, a 14'
> >> section
> >> of RG8 from the feed point of the beam with one PL259 and one barrel
> >> connector to join the LMR.  Secondly, a 10' section of LMR and PL259
> >> to a
> >> barrel connector and a 4' section of RG8 for the loop to join the LMR
> >> that
> >> goes down 80' to the antenna relay box at the base of the tower.  This
> >> configuration would require 4 PL259's and two barrel connectors.  I
> >> want to
> >> avoid the many possible problem areas with the multiple connections.  I
> >> think that I have answered my own question but wasn't sure if adding
> >> that
> >> much RG8 to the run would offset the benefit of the LMR 400.  I
> >> suppose on
> >> 40 meters the loss would be negligible.  Am I correct?
> >>
> >> 73,
> >>
> >> Tom W8JWN
> >
> >
>
>
> _______________________________________________
>
> 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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> TowerTalk at 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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