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[TowerTalk] True or Not True?

To: <>
Subject: [TowerTalk] True or Not True?
From: (2)
Date: Mon, 3 Sep 2001 11:10:54 -0700
>I think most of the NEC based programs calculate the current distribution
>along the length of the antenna's linear elements. The far field pattern 
>of the
>antenna can then be derived by integrating the field contributions of each
>elemental portion of that distribution. The equations given in Kraus's
>"Electromagnetics" 2nd edition express the E and H fields in the far field
>in terms of the current distribution only. His text does mention that the
>E field depends on both current and charge distribution, but that only the
>current distribution needs to be considered in the far field.
>A 1/2 wave dipole can be thought of as a bunch of short linear dipoles
>placed end-to-end with the current in each short dipole element proportional
>to the magnitude of the dipoles familiar half sinusoidal current 
>distribution at that point along the length of the antenna.  The short dipole 
>near the
>center of this array will of course contribute more to the overall radiation 
>than the ones near the ends since the current will be larger in the elements
>near the center than that of those near the ends.
>If I had the choice between having the ends of my dipole high with the center
>low versus having the center high and the ends low, I would choose the latter
//  It takes volts and amperes to make the E-field and it takes volts and 
amperes make the H-field.  Eliminate one and EM radiation is none.  I 
used to get involved in 40m daytime shootouts between Las Vegas and L.A.  
The consistent winner was a flat-top dipole.  

cheers, Mike>
>----- Original Message -----
>From: "2" <>
>To: "Ron Lile" <>; "at towertalk" <>; 
>"1topband mailing-list" <>
>Sent: Sunday, September 02, 2001 9:18 PM
>Subject: Re: [TowerTalk] True or Not True?
>> >
>> >Several papers have been published lately that attempt to explain the 
>> >of radiation from a dipole.
>> >
>> >The papers are saying that the primary radiation on a dipole come from the
>> >middle (the high current point) AND the ends.
>> >
>> //  I used to think that the radiation mostly came from the current
>> portion of an antenna.  However, the University of California currently
>> teaches that all parts contribute equally.  Electro Magnetic radiation -
>> a.k.a. photons - consist of an electrostatic E-field and a perpindicular,
>> electromagnetic H-field.  The higher-voltage ends contributes most to the
>> E-field and the higher-current center contributes most to the H-field.
>> --  Congrats Ron Lile, KØRL, you were the only one who agrees with the
>> University of California.
>> cheers
>> >The papers have been publish in the Journal for the Antennas and 
>> >Society of the IEEE. I need to look them up again in the library. They are
>> >recent issues.
>> >
>> >Ron , K0RL
>> >
>> >
>> >----- Original Message -----
>> >From: 2 <>
>> >To: at towertalk <>; 1topband mailing-list
>> ><>
>> >Sent: Sunday, September 02, 2001 9:39 AM
>> >Subject: [TowerTalk] True or Not True?
>> >
>> >
>> >>
>> >> Does radiation come mainly from the high-current portion of an antenna --
>> >> i.e., for a half-wave, from the center?
>> >>
>> >> -  R. L. Measures, 805.386.3734,AG6K, ... ...

-  R. L. Measures, 805.386.3734,AG6K,  

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