On 11/2/2018 8:29 AM, jimlux wrote:
Tungsten is 3 times the resistivity of copper, and results in about a 5%
Whenever skin effect is involved, the RF resisitivity
is proportional to the SQUARE ROOT of the DC resistivity.
Therefore, the RF resistance of tungsten is only SQRT(3) or 1.8
times as much as copper.
Another example, aluminum has 58% more DC resistance than copper
but only 26% more RF resistance. These numbers happen to neatly
translate into 4 wire gauges and 2 wire gauges respectively.
For example, 4 gauge aluminum wire has the same resistance at RF
as 6 gauge copper wire.
This calculation doesn't apply to magnetic alloys like nickel, iron, or
stainless, because the permeability affects only the RF resistance,
so there is no simple relationship.
73
Rick N6RK
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