Topband: EZNEC Shunt Feed Model Gain
RadioIR at charter.net
Wed Aug 19 07:31:13 PDT 2009
k8gg at voyager.net wrote:
> When I model it as a shunt fed tower, base grounded, with 50 feet of 1.6 inch OD pipe about 27 inches
> from the center of the tower as the shunt feed rod, the gain drops to about 0 (zero) dbi.
Modeling a gamma match for a tower is almost impossible to do in NEC2.
It can't handle a junction of wires that have large differences in
diameters. Check to see if the program is making errors. If you are
using EZNEC, set all resistive components to zero, wire loss to zero,
and set the ground to perfect. Run a 3D gain plot and check the
"Average Gain" on the main window. This will be the amount of error the
program is making. No you can't just add that amount to the answer.
Read the help file for more info.
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