"I do not expect the heating
factor to be involved if the proper cable materials are utilized, inherent
in a quality cable, and if the rated min. bend radius is adhered to."
What is the bending radius spec for BURY-FLEX cable?
I looked on the web site, but did not find it, maybe I missed it.
Thanks
John
Wa5zup
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Steve Davis -Davis RF
Co.
Sent: Sunday, July 20, 2008 9:12 AM
To: Jack Brindle
Cc: towertalk@contesting.com
Subject: Re: [TowerTalk] Paintg Traps-Coax issues-Respon fr DAVIS RF Co.
Hi Jack, Your discussion is not over technical as your points are well put
and fundamentally germane to the basics of coaxial design and function. The
only catch is that it appears that you are skeptical that all cable jacket
PVC's, and their PE dielectrics (both ref. RG-213 and many other similars)
will not hold up to heating by the sun and resulting ambient transferred
through the shield to the dielectric. There are many compounds of PVC
jacket and PE dielectric used in cable extrusion. Choosing the proper types
as I noted (or relying on the mfr.; distributor; or design engr), will
hold up very well in any sunlight scenario for many years. PVC compounds
certified at 60 deg. C., and UV resistant, are my requirement for outdoor
applications of our RG-213 and similar cable.
Your concerns are not uncommon and have been noticed in some of our
commercial inquiries where they have spec'd Teflon outer jackets when the
ambient would never reach in excess of 60 C, thus we've been able to save
them a lot of money by using the correct grade of PVC.
I agree completely with you ref. the electrical degradation due to center
cond. concentricity misalignment, IF there is enough ambient heat combined
with spiral exertion to cause this...however I do not expect the heating
factor to be involved if the proper cable materials are utilized, inherent
in a quality cable, and if the rated min. bend radius is adhered to.
73, Steve , K1PEK,
DAVIS RF Co.
Wire, Cable, RF Connectors and wire aerial parts. LMR, Heliax, Eupen
Commercial / Military / & Custom Cable Design
tel: 978-369-1738 Fax: 978-369-3484
www.davisRF.com
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