[Antennaware] EZnec - coils, traps, baluns, coax, laddreline ?

Jim Miller KG0KP JimMiller at STL-OnLine.Net
Sat Mar 14 18:59:16 PDT 2009

OK, request for ideas to get online with the EZnec.  I can do dipoles, 
verticals, place the wires for beams, etc. BUT I ahve no idea about 
including loading coils, traps, or feedlines.  Looking for the easiest, 
quickest way to get the basics.

My thoughts are to look at a model with coils placed away from the feedppint 
in a dipole.  Anybody have something SIMPLE that I could look at?

Same with a trap?

Same with a capacitor?

"Standard" dipole fed with ladderline?

"Standard" dipole fed with coax?

"Standard" dipole fed with coax and a balun?

Just simple examples.

THANKS, guys.
73, de Jim KG0KP

----- Original Message ----- 
From: "Terry Conboy" <n6ry at arrl.net>
To: "David Gould" <dave at g3ueg.co.uk>
Cc: <antennaware at contesting.com>
Sent: Saturday, March 14, 2009 11:06 AM
Subject: Re: [Antennaware] Voltages along an antenna

> 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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