On 2009-03-04 9:36 AM, David Gould G3UEG wrote:
> First thanks to those who helped a few weeks ago with my question
> about the significant differences between my model and reality for my
> 62ft vertical on 80m. The concensus was, go with what it is
> measuring at, and ignore the difference in the model.
>
> Last weekend I top loaded the vertical to bring it resonant on
> 160m, fed it through an UNUN and had a ball in the CQWW 160m SSB
> contest, making around 40 NA QSOs across 14 states, which surprised
> me, considering that conditions were not that good. I did not seem
> to be loosing very much compared top my previous 108ft vertical over
> better radials. (I must have magic soil!!!)
>
> EZNEC gives a table of currents along the antenna elements, is there
> a way to find the voltages? I would like to know the voltage at the
> top of the 62ft vertical for both 160m and 80m? I am considering
> putting either a trap or a relay to give me dual band, so I would
> like to know what ratings any components would need to have. (I
> have an aversion to traps and reactance in general because of the
> losses and the significant reduction in bandwidth as a
> result.) can't see anything in the help, but feel it should not be
> impossible. I may be missing something obvious...
>
>
Just place a 10 megohm or larger resistor where you are planning to put
the trap or relay. Use the Load Dat function in EZNEC to see the
voltage across the load. You can also easily model a trap in EZNEC to
see the dissipation in the loss resistance of the trap's inductor and
capacitor on both bands.
73, Terry N6RY
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