"David Robbins" wrote in message ...
actually i would expect that a change in E/H would change the driving point
impedance and also the performance of the antenna. some possible examples
that show this effect are the changes in element sizes when modeling an
antenna printed on a dielectric circuit board material or sandwiched in a
dielectric media. the change in wire length due to insulation is another
example, the dielectric properties of the insulation change the E/H ratio
near the wire. some examples may be found in many electromagnetics texts,
look at things like dielectric waveguides, or dielectrics in waveguides,
wires in dielectric media. even the detailed calculation of fields within a
dielectric filled coaxial cable should show this effect, change the
dielectric and you change the characteristic impedance... a measurable
effect from changing the 'space impedence' between the wires.



Agreed, and emmersing a waterproof antenna into water will also
affect the input impedance.



Slick