[Prev][Next][Index][Thread]
Re: Braided or Smooth Strap?
Hi Robert,
Good question....
<some snip>
> Have either of you considered 'why' bare coax outer braid is poor?
> Is it because the individual wires which are woven together do not
> 'talk' to each other contact wise at RF and what we end up with is,
> by the nature of the weave, a whole bunch of parallel conductors, ala
> litz wire, but measurably longer than the actual length of the
> finished cable. Such that a 10 foot section of coax in this series
> resistance concept, actually represents a 15 foot or so length which
> makes it measure poorer than a real 10 foot length of solid single
> wire? Or is it merely that the plastic which insulates and accurately
> positions the inner conductor conductor acts the same way as a
> spoiler that a plastic outer sheath can have. This should not be so,
> as the plastic employed inside the coax is the good stuff (polyethylene).
The current is attempting to stay on the outside surface of the
conductor and in doing so has to hop from strand to strand and hence
has to travel through a barrage of "connections". Braid would be
brilliant it it was insulated a la Litz! I have heard that braid was
chosen for coax to make the cable more flexible (oh dear!). Data on
various coaxes show that the solid outer types show lower losses.
Malcolm