[TowerTalk] Old coax questions.... OK? or NOT OK?

[John Simmons]

Please do not use this coax for any transmission line or high voltage 
purpose. It has been damaged by moisture!

I spent 27 years as a two-way tech, with hundreds of visits to tower 
sites. Weatherproofing coax connections is a science and there are lots 
of opinions. However, I've seen professionally weatherproofed 
connections with water ingress, including water actually pouring out of 
the shack end of the cable!

YMMV


-- 
73,
-de John "Curly" NI0K in rural Debs, MN USA
Hamshack Hotline: 6100000271
https://www.qrz.com/db/NI0K

john at kk9a.com wrote on 10/9/2022 9:51 AM:
> Well you probably got your money's worth out of that coax.  Without removing
> the coax it is probably hard to tell how much loss it has now. Of course
> changing coax is usually a pain unless the driven element is near the tower.
> Is the jacket OK, do you think there was water ingress from somewhere?  I
> have been using Belden 8267 RG213 for decades at various stations including
> P40A and I felt it was tough as nails but the stuff purchased in more recent
> years has not held up well at all. The jacket turns white, gets brittle and
> cracks after 5? years.  I just replaced all of the Belden coax leaders on my
> Rohn 65g tower with DX Engineering RG213 while upgrading or refurbishing the
> antennas.
>
> GL,
> John KK9A/4
>
>
> kq2m wrote:
>
> Hi,
>
> I used Davis Buryflex (RG213) on my 15 M yagis (they were put up in
> 1999) and I was replacing some connectors today when I noticed something
> disturbing.  On the PL259's on 3 of my 4 yagis;, there was a greenish
> hue.  I cut off the connector of one of them, looked inside, stripped
> off the dlelectric   and saw that the Center Conductor (CC) was blackish
> and that there was a whitish/greenish powder on top of the dielectric.
> The braid also had little flecks of black on it.  (I have not
> experienced any change in performance of the 15 yagi that had the
> discolored center connector.)
>
> Using a utility knife, I scraped off some of the black on the braid and
> it was shiny underneath..
>
> Then I cut off ~ 10' of the coax and again stripped it.
>
> The CC had less black on it and again scraping with the utility knife
> showed shiny copper underneath. The dielectric was white/green but not
> powdery - it was more like a thin paper covering.  What was very
> different was that the BRAID was completely clean and shiny.
>
> I soldered a new connector on and the yagi worked fine, the same as
> before.
>
> Questions:
> How problematic is the blackened CC?
> What is that whitish/green powdery stuff inside?
> How problematic are the flecks of black on the braid?
>
> The coax has been on the antennas for 23 years so I am probably at or
> near the expected life span of the coax.  Is the the coax breaking down
> and that is what I am seeing?
> Has there likely been any deterioration of performance?  If so is it
> substantial?
> Even if it is, replacing the coax is not an option right now.
>
> I would appreciate any thoughts/suggestions that you might have.
> Tnx & 73
>
>
> Bob, KQ2M
>
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