[1000mp] Braid or strap for ground wire...big question.

[Tom Rauch]

> You may want to check the details about braided wire.
> The matter is skin effect. As frequency increases, current
> flows closer to the surface only, regardless of the wire
> diameter. In braided wire, having many wires in the
> 'bundle' reduces the impedance.

There is an inductance reduction with width or diameter, but it 
applies generally to the overall conductor width and not how thinly 
the conductor is "sliced".

> Braid is better than single wire. Flat straps are also very good
> because of large surface area and less skin effect problems.
> This is the same reason why some RF coils use Litz wire which
> is several insulated wires formed into one - just like a rope.

Litz wire is effective only because it reduces eddy currents in the 
wire when used in transformers and multi-layer coils, not because of 
wire resistance or unit inductance of the wire. As a matter of fact, 
Litz wire has noticeably more resistance-per-foot than solid wire of 
the same diameter at every frequency, from dc to whatever.

The benefit of insulated strands is in preventing or reducing 
circulating currents where the wire cross section acts like a big 
copper plate with eddy currents, and the advantage only occurs in 
multilayer coils and at lower frequencies (normally below 1 MHz). A 
solenoid coil or straight conductor using litz wire always has lower 
Q and more loss than an identical coil wound with solid wire the same 
size, material, and insulation type.73, Tom W8JI
W8JI@contesting.com