[TowerTalk] Hardline Fault

[Peter FORBES]

Roger,

The TDR might still show a "bump" where the inner and outer are separated by
such a small distance.

Worth trying.

Cheers

Peter  VK3QI

-----Original Message-----
From: towertalk-bounces at contesting.com
[mailto:towertalk-bounces at contesting.com] On Behalf Of Roger Parsons
Sent: Wednesday, 22 August 2012 9:13 AM
To: towertalk at contesting.com
Subject: [TowerTalk] Hardline Fault

For about 15 years I have been using CATV type flooded hardline lying on the
ground to feed my receiving antennas. It has worked very well, and until now
I have had no failures caused by biting animals. However, I recently found
that I had a short on one ~500' section. Easy, I thought
- to cause a short there must be a pretty big bite that has crushed the
outer into the inner - just follow the cable along until I find it. So I did
just that. Of course the cable had got buried under the forest floor most of
the way so I had to disturb it in order to check it. I found lots of small
bite marks, but no big ones. 


The problem is that when I got the far end and measured the resistance, the
short had disappeared - my moving the cable presumably moved the outer a few
microns away from the inner.


If I had been sensible and used a TDR to find the approximate location of
the short I would only have a small section of cable to check carefully.
I do not believe that a TDR would now find what can only be a very small
discontinuity somewhere along the length.

Now, I have no idea whatsoever how to find where the fault was, and 

can think of no way of avoiding it recurring just when the P5 finally gets
onto 160m other than replacing the whole length.

Anybody got any bright ideas?

73 Roger
VE3ZI
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