Now I AM glad My Belden 9913 is inside 2" PVC pipe... if NOT for the
water .... well now for the SUN... Hi Hi..
The depletion of the Ozone layer over Australia really makes a
difference.... The Sun's UV rays destroy everything [out in the Sun] in a
short period of time.... Many items for use outdoors are Now being made
from UV protected material !!!
I ran My old RG-213 inside 1" black poly pipe used in garden watering
systems over here.... mainly for the purpose of stopping Our Large Parrots
from biting into the coax... they did bite into the Poly pipe though...
which un-waterproofed the poly pipe... and probably kept moisture inside
the pipe... but the LIGHTNING probably dried out all the moisture Hi Hi...
I was told by the VK Belden agent that 9913 is designed to be used in the
open air..... when its wet from Rain.. the Sun dries it out... His thoughts
were mainly - on keeping the moisture out by the heat from the Sun - and
Condensation??
I continue to use the Black Poly pipe from the top of the tower to the Gamma
Match on the Antennas....
again mainly to stop the large parrots from chewing on the coaxial cable....
Now also to stop the Sun's UV rays.. Hi Hi...
73
Lee VK2LEE
----- Original Message -----
From: "Steve Katz" <stevek@jmr.com>
To: "'Tom Frenaye'" <frenaye@direcway.com>; <towertalk@contesting.com>
Sent: Tuesday, December 03, 2002 3:10 AM
Subject: RE: [Towertalk] coax losses over time
>
>
>
>
> > I've seen lots of printed references to the fact that coax losses
increase
> > over time but have never seen any "hard" data. Are there any real
> > studies of coax deterioration? Makes sense that it would deteriorate
> > more quickly outside, in the sun, or buried, than inside, for example.
> >
> > //While some (like Pres, W8UG) do claim that coax degrades in dry/dark
> > storage, if that's the case, it must take an awfully long time. I've
> > measured every characteristic that's measurable on very old cables like
> > RG8/U (original MIL-C-17 product manufactured in 1959 and still carrying
> > its DoD contract tags) that were stored (dry/dark) for 40+ years and
they
> > were the same as what we'd expect of newly manufactured cable of the
same
> > type. Possibly some of the newer chemistry used in low-loss cellular
> > dielectric cables deteriorates faster.
> >
> >
> > I assume that the primary cause of deterioration is the dielectric
> > material, correct? How does CATV hardline compare to something like
RG-8
> > foam, for example?
> >
> > //In my experience, which I think it quite a lot, CATV hardline lasts
> > forever, or until it takes in water, whichever occurs first. I've never
> > seen hardline go "bad" just by age alone. But the cellular dielectric
can
> > absorb water, and when it does, the cable degrades quickly -- to the
> > extent that the signals carried are sufficiently attenuated to draw the
> > attention of users and the concern of the service providers, and the
> > cable's replaced. I've seen this happen in just a couple of years, with
> > buried cables having the distribution amp literally immersed in water
> > after heavy rainfall.
> >
> > Or, is it all so variable that it makes more sense just to measure the
> > loss on each one. (i.e., no rules of thumb apply)
> >
> > //The only "experiment" I've ever done is accelerated life testing using
> > 150W U.V. lamps shining directly on cables. We monitored illumination
> > (similar to direct sunlight in the tropics, but 24 hours a day and not
> > reduced by humidity) and thermal rise (negligible) vs. attenuation at 10
> > MHz, 100 MHz and 1000 MHz. The Type IIA and Type IIIA cables fared
best,
> > with small change after 1000 hours. The Type I cables, and almost
> > anything having a soft jacket and cellular dielectric, mostly drifted to
> > >+100% change in attenuation over 1000 hours, but only negligible change
> > in impedance, so a standard "SWR" measurement would not reveal any
> > problem. In fact, due to the higher cable loss, "SWR" would likely
> > measure *better* with age, rather than worse, if the measurement is made
> > at the generator end of the line. 1000 hours of tropical intensity
> > sunlight would be only about three months at the equator, but might be
> > years at 40 degrees latitude. -WB2WIK/6
> >
> >
> > =====
> > e-mail: frenaye@pcnet.com
> > Tom Frenaye, K1KI, P O Box J, West Suffield CT 06093 Phone: 860-668-5444
> >
> >
> > _______________________________________________
> > AN Wireless Self Supporting Towers at discounted prices,
> > See http://www.mscomputer.com
> >
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> _______________________________________________
> AN Wireless Self Supporting Towers at discounted prices,
> See http://www.mscomputer.com
>
> Wireless Weather Stations now $349.95. Call Toll Free,
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