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Old December 3rd 05, 04:44 AM posted to rec.radio.amateur.antenna
dansawyeror
 
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Default how to model frequency response of a loaded vertical ?

All,

I am creating a 'scaled' model of a loaded vertical. The model is complete and
in place. However I immediately realized I had no idea of the 'theoretical'
response. How can I calculate the expected impedance response of a loaded
vertical? It a mid load construction,

the base in #10 solid copper 4 inchs,
the coil is .6 pitch, 1 inch diameter, 5 turns #12, measuring .72 uH,
and the top is 4 inch #12.

The antenna appears to resonate at about 112 MHz.

The instrumentation, a directional coupler measuring reflection is located at
the base, directly under the 'ground plane'. This allows measuring input and
reflected signal strength.

The question is: How can I plot the expected impedance from say 100 MHz to 130 MHz?

Thanks - Dan