Re: NEC-LIST: Modelling a balanced dipole with stub

Good day Corte.

I am not quite sure what you want. However, there are many illustrations
showing a "fat" dipole created using multiple wires anchored onto a ring
structure to spred the wires out. I have also seen dipoles created from
multiple wires lying in a single plane. These wires are spread out to form
essentially a "strip" dipole with a lowish length to width ration. I have a
feeling that ther may have been a patent on this last approach.

Best regards,
Duncan Baker.
----- Original Message -----
From: "CORTE Massimiliano" <Massimiliano.Corte_at_vodafoneomnitel.it>
To: <nec-list_at_gweep.ca>
Cc: <bluemax69it_at_libero.it>
Sent: Wednesday, April 16, 2003 11:17 AM
Subject: NEC-LIST: Modelling a balanced dipole with stub

> Hello,
>
> I would like to know how to model the most used broadcast dipole
> (wideband).
>
> The antenna has a simple vertical dipole connected with a shunted
> transmission line stub (short circuited by one side).
>
> In the real antenna the transmission line is made using wires as the
> antenna dipole.
>
>
>
> This is a draw of the antenna:
>
>
>
>
>
> |
>
> |
>
> |
>
> _______|
>
> |_______X
>
> |
>
> |
>
> |
>
> |
>
>
>
>
>
> In the ASCII draw X is the generator.
>
>
>
> With NEC this antenna can be modelled in three different ways:
>
> 1) The dipole with the shunt short-circuited stub modelled as a
> transmission line (TL card)
>
> 2) The dipole with the shunt short-circuited stub modelled as
> wires (horizontal U shape)
>
> 3) The dipole with the shunt short-circuited stub modelled as
> wires with, in parallel, a shorted transmission line (TL)
>
>
>
> The radiation patterns are similar but the third case is the best for
> matching the impedance (50 Ohm).
>
>
>
> I would like to know which one is the more realistic model, specially
> regarding the antenna impedance (putting the generator where there is
> the X character in the draw) that, considering the three cases, is
> completely different.
>
>
>
> Thanks.
>
>
>
> Best regards,
>
> Massimiliano.
> --
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>

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