On Mon, 18 Aug 2003 11:28:40 -0700, Roy Lewallen
wrote:

. . .
An antenna is a structure that transforms Radiation Resistance into
the Impedance of free space, as shown, and by definition. Both use
identical MKS units, both are identical characteristics.

Sorry, that's a demonstrably absurd assertion.

Hi Roy,

although the feedpoint impedance is an impedance with the units of ohms,
and the impedance of a plane wave in free space also has the units of ohms,
they're not the same thing.

So, how do the "ohms" of free space differ from the "ohms" of a
quarter wave monopole's Radiation Resistance?

The demonstrables you offer do not enlighten us in what physical
constants these unique terms of your usage diverge from those in the
MKS system. As I pointed out in my posting, whatever derivation for
the characteristic Z of free space is, it must ultimately devolve to
the identical expression for the common Ohm.

I would offer by way of caution that the expression
Zc = (µ0 / e0)^0.5
where µ0 is expressed in Henrys per meter and
where e0 is expressed in Farads per meter;
that that, too, arrives at the same Ohms employed by carbon resistors
and Radiation Resistance.

This is much like trying to compare miles per gallon and kilometers
per liter. When push comes to shove, the reduction to MKS will reveal
that the same container of gas will get you down the same stretch of
asphalt the same distance no matter what mix of terms you substitute
for liquid volume and length. This goes to include offbeat
descriptive terms like miles per liter; kilometers per gallon; or
furlongs per hogshead for that identical container of gas. Solutions
of proportionality are not unique physical constants.

73's
Richard Clark, KB7QHC