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Re: [TowerTalk] Radiation angle

To: <towertalk@contesting.com>
Subject: Re: [TowerTalk] Radiation angle
From: "AD5VJ Bob" <rtnmi@sbcglobal.net>
Date: Thu, 8 Dec 2005 19:13:47 -0600
List-post: <mailto:towertalk@contesting.com>
Hi Jim:

Thanks for the reply you led me to this program since I
cant afford the other one right now:

Looks like this might work for now at least

EMMCAP 

Modeling of wire structures

1.      Wire structures can be modeled by combining
different types of wires:

q       Straight wires.
q       Circular and elliptic arcs.
q       Circular, elliptic and rectangular loops.
q       Several kinds of tapered helices with arbitrary
orientations.
q       Parabolic wires.
q       Hyperbolic wires.
q       Archimedian, logarithmic and tapered spirals.
q       Catenary wires.

2.      All wires can be loaded or excited at any
position.
3.      The structure can also have finite conductivities.





> -----Original Message-----
> From: towertalk-bounces@contesting.com 
> [mailto:towertalk-bounces@contesting.com] On Behalf Of
Jim Lux
> Sent: Thursday, December 08, 2005 6:29 PM
> To: AD5VJ Bob; towertalk@contesting.com
> Subject: Re: [TowerTalk] Radiation angle
> 
> 
> At 03:44 PM 12/8/2005, AD5VJ  Bob wrote:
> >Does anyone know all the factors that affect the angle
of radiation 
> >from a horizontal dipole.
> >
> >Height being one of course, but are there others that
> >raise or lower the angle and /or broaden or narrow the
pattern.
> >
> >Has anyone ever really done a study on this?
> 
> 
> Not to be glib, but the answer is yes, hundreds and
hundreds 
> of people have 
> studied this. Such studies, from both a theoretical and
experimental 
> standpoint, form the basis for such useful programs as
NEC.
> 
> Now that computers are fast enough, it's really
interesting 
> to put a simple 
> horizontal dipole model into a decent code that renders
the 
> pattern, and 
> try changing things, like the lengths of the wires, the 
> position of the 
> feedline, whether it droops, putting in other things
near it. 
> Modeling a 
> dipole over real ground takes a few seconds on a
moderately 
> fast Pentium A 
> couple or three hours of fooling around can be quite
interesting.
> 
>   I just ran a single dipole using NEC4 (using the 4NEC2

> front end) over 
> Sommerfield Norton ground, and it took 2 seconds all
told to 
> run the model 
> and display the 3D pattern on a 3.6 GHz Pentium.
> 
> A modeling program makes it easy to systematically
change 
> something to get 
> a good intuitive feel for what will happen.  As you move
the 
> dipole up, you 
> can see the lobes changing.  Actually, now that it comes
up, 
> I wonder how 
> hard it would be to render an animation of something
like this.
> 
> 
> 
> 
> 
> _______________________________________________
> 
> See: http://www.mscomputer.com  for "Self Supporting
Towers", 
> "Wireless Weather Stations", and lot's more.  Call Toll
Free, 
> 1-800-333-9041 with any questions and ask for Sherman,
W2FLA.
> 
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com 
> http://lists.contesting.com/mailman/listinfo/towertalk
> 


_______________________________________________

See: http://www.mscomputer.com  for "Self Supporting Towers", "Wireless Weather 
Stations", and lot's more.  Call Toll Free, 1-800-333-9041 with any questions 
and ask for Sherman, W2FLA.

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