On 28 Mar 2005 11:52:23 -0800, "Brian Kelly" wrote:

So two questions in this regard: Is there a way to measure the Vf of a
wire without having to resort to using 2" Heliax to feed a dipole and
without a lab full of HP and GR test equipment? Second, assuming the
Vf becomes known how does one handle it during the modeling process?
Model the antenna wire lengths at an upward-shifted frequency based on
the Vf?

Hi Brian,

1. Drive the design with power instead of low level excitation;

2. Remove half the transmission line muffling of results by using a
field strength meter to find resonance (another reason for power);

3. Find the Vf (as you put it) by derivation against a wire model
(through the difference in lengths of bare wire model resonance to
real wire resonance);

4. Use the new EZNEC which allows you to employ insulation over wire
and adjusting the thickness to conform with results found
experimentally with real wire at actual length;

5. Assign these insulation properties to all future designs in the
modeler.

73's
Richard Clark, KB7QHC