[TowerTalk] KF4BWG

[Richard (Rick) Karlquist]

On 4/18/2019 5:46 PM, David Gilbert wrote:
> 
> I was more concerned about the proximity effect in the horse fence 
> scenario ... 1.5 inches wide with eighteen 7 mil wires.  I suspect that 

If you have a solid metal ribbon, skin effect causes
the current to crowd to the outer edges.  With a ribbon
cable, the current will flow mainly in the outermost
wires and underutilize the interior conductors.
The horse fence wires are closely spaced enough to
have substantial proximity effect.

You can fix this by wrapping the ribbon cable
lengthwise around a plastic hose so the conductors
are arranged in a circle.  Now there are no "edges"
upon which current can concentrate.  It's probably
simpler to just wrap aluminum tape around the hose.

A "cage" element with as little as 3 conductors
spaced as an equilateral triangle will approach a
metallic tube in bandwidth performance.  It will
work better than a 3 conductor "fan" design (all
in one plane).

Rick N6RK