[TowerTalk] Hardline Fault

[Roger Parsons]

Further to my messages of last week, I have now tried again. The RigExpert TDR
gave some sort of results, but was not really terrribly useful. Its built in display just
does not have the definition to work out the position of the fault - it would have
been fine on a hard fault such as a short or open. Bringing it back into the shack
and downloading onto a PC produced a much better picture. However, much as
I had feared, there were many small discontinuities faithfully displayed.

(I should mention that the cable in question is over 2500' from the shack across very
rough and rocky terrain. There would have been too much chance for me to break
my VNWA and/or laptop if I had tried to take them with me.)

In the end, low tech has done the trick. I carefully examined the cable again, and found
there were a number of places where a tooth of about 2mm diameter had pierced the
outer sheath and compressed the aluminium shield without breaking through. I believe
that this would compress the dielectric and obviously produce a discontinuity which
would be seen by the TDR, but could not cause a direct short between inner and outer.
There was just one place where the tooth had actually broken through the outer shield
and exposed the inner conductor. The inner and outer were very close together and
could certainly have been shorted before I moved the cable. So I fixed that, and I am
fairly confident that my problems are over until the next sabre toothed unicorn attacks!

Thanks to all for their suggestions.

73 Roger
VE3ZI