[WARC] antenna modeling result.

[Clare Jarvis]

On Monday 21 May 2007 22:59, Leslie Hittner wrote:
Here are some answers.  More answers will follow this evening.



> Clare,
>
> Sounding more interesting every time you discuss it. I have some
> questions:
>
> What is the half-power beam width on 80, 40, and 20 meters (main
> lobes)?
>
> What are the reactive components of the impedance on each of
> those bands?
>
> Is that 250 feet on a leg?   Yes
>
> How does the gain/beam width of thge main lobe vary with the
> angle between the legs?  I do not know.  These antennas vary wildly with 
length of leg and angle.   The angle between legs is 55 degrees.  I used the 
antenna book chart for this angle.     Each leg is approx 3 wave lengths, so
55 degrees is recommended.
>
> How does the impedance vary on, say, 80 meters with a change in
> angle?    See the answer above.   My guess is that the angle will have to be
somewhere around 80 degrees.  I think this angle would make the antenna 
difficult to use for 20 Meters, but won't know for sure until I model it.   I 
could bring my laptop over some eveinging and we can work on it together.


>
> -Les
>
> ----- Original Message -----
> From: "Clare Jarvis" <clarej at hbci.com>
> To: "Winona Amateur Radio Club general discussion"
> <warc at lists.w0ne.org>
> Sent: Monday, May 21, 2007 10:08 PM
> Subject: [WARC] antenna modeling result.
>
> > I have modeled a v-beam that uses aprox 500 feet of wire but
>
> has 7.93dBd of
>
> > gain at 14.22 MHz.   The front to back ratio is 1:1 and the
>
> take off angel is
>
> > 20 degrees.   If anybody is interested I can show nice plots
>
> of gains and
>
> > take-off angles.
> >
> > BTW this model has significant gain on both 40 and 80 meters
>
> but is quite
>
> > reactive.  If someone would like to work on how to feed it on
>
> these other
>
> > bands then we should be able to lighjt up both the left and
>
> right coast on
>
> > three bands.   This antenna should be easy to erect.
> >
> > 73 Clare
> > _______________________________________________
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>
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