Tom Donaly wrote:
According to
one of Cecil's sources, Balanis, the current distribution on such
a wire resembles a triangle.

It only resembles a triangle. It is actually part of a
cosine waveform. From cos(80) to cos(90), the cosine
function is close to a straight line but it is *NOT*
a straight line. Assuming the current distribution is
a triangular is only an approximation with a known error.
The current distribution acutally remains a cosine function
but assuming a straight line simplifies the math and doesn't
cause an unacceptably large error.

It is akin to the approximation that A = sin(A) when
A is very small. It is *ONLY* an approximation with limited
accuracy.

cos(80)=0.17365, cos(85)=0.08716, cos(90)=0

0.17365/2 = 0.08682 which is an error of 0.4% when one assumes
a triangular function.
--
73, Cecil http://www.qsl.net/w5dxp