Steve M wrote:
>Hi everybody,
>
>Assuming the same gauge, is a stranded conductor better than a solid
>conductor [less skin effect loss because of multiple conductor surfaces] at
>rf? How about at 60hz?
> Also can someone point out a good source for this info on the web? I've
>tried several google searchs with limited results and no answer to the
>stranded versus solid or tubing conductor.
> This subject is a current topic on another reflector. I'm seeing
>several guys say that stranded is better but I'm wondering if this is so
>then why don't amp builders use this technique?
> I'm thinking that stranded conductors by shorting against each other
>negate any advantage they might have at very low frequency and are actually
>worse at rf. Am I right, wrong, or clear off base?
You're pretty much right. The skin effect keeps the RF current on the
surface of the whole stranded bundle, so as each strand dives into the
braid the current has to hop across onto strands that are still on the
outside. There is not much force to keep good contact between individual
strands, so RF losses in braid are higher than in a smooth solid or
hollow conductor of the same outside cross-section. If the braid is even
slightly corroded, it's dead.
Litz uses individual insulated conductors so the crossover current path
is capacitive but predictable. Litz also uses a special weave (that is
unlike either braid or twisted rope) which gives each strand an equal
share of being on the outside of the bundle.
--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)
Editor, 'The VHF/UHF DX Book'
http://www.ifwtech.co.uk/g3sek
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