Originally they are a kind of strengthening from thestuff being bent too
much is what I was told. One used to find it also in some long audio cables.
It was often spiralled around or ran straight through the middle as I
recall.

Brian

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This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
wrote in message
...
Just curious- I dug up and I am re-using some old 4 core steel wire
reinforced cable. The core colours are red, black, blue and yellow, IIRC.
What I'm puzzled by is a small diameter white tube that runs within the SWR,
which appears to contain a fibrous, non metallic material.

What might the fibres in the white tube be and for what purpose? They don't
quite look like fibre optic material, but that's all I can think of.

Cheers.

Terry.