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Antennas

 

File: Dipolentstehung.gif

Electromagnetic Radiation
 
 The magnetic field lines are in red
 The electric field lines are in blue
 
 The inductance and capacitance (together with the implied excitation energy) comprise a tuned circuit. This dynamic representation above depicts electromagnetic radiation illustrating how the plates of a capacitor relate to the elements of a dipole antenna.  Not shown is the wave nature of the radiation fields and their 90
relationship to each other.
 


The electric and magnetic energy in an electromagnetic wave are in phase with each other and polarized at ninety degrees to each other with the electric field being vertically polarized, and the magnetic field horizontal in these graphic examples.  

Below are shown the vertical electric field (blue) and the horizontal magnetic field (red) with their magnitudes varying sinusoidally with time on the X axis. 
 
 

 


Above is a dynamic illustration of the magnetic and electric fields shown in the static image above it (albit with the colors reversed).
 



Above is another dynamic illustration of the magnetic and electric fields of an electromagnetic wave.


 



The above picture shows how several quantities on and near a half-wave dipole vary in the course of time. These quantities are indicated by different colors, as follows:

Currents: indicated by blue lines, with length proportional to the magnitude.

Charges: indicated by cyan and magenta square around the wire on which the charge is "sitting". The size of the square represents the magnitude, the color the sign: cyan for positive, magenta for negative charge.

Electric field vectors: indicated by red lines.

Magnetic field vectors: indicated by green lines.

The dipole antenna itself is on the Y axis, in the bottom left corner of the picture.  The electric and magnetic field strength has only been calculated in the first quadrant of the YZ plane.  Because of symmetry, extending the calculation to other quadrant positions would not add anything significant to visualizing the fields.  Although this is not immediately obvious from the picture, the electric field vectors lie in the YZ plane, while the magnetic field is perpendicular to that plane.
 

 

From this page you can view the antennas currently in use at station KJ6YVT by clicking on the links on the right menu below.

The SWR plots on the antenna pages were created with the LP-Plot utility program kindly provided by Larry Phipps, manufacturer of the LP-100A digital vector wattmeter. 

 

 


 
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Antennea

bullet  Parallel Four-band Dipole
 
bullet  Butternut HF9V 80-6 Meter 9-Band Vertical
 
bullet  Hex-Beam
 
bullet  Remote Antenna Selector
 
bullet  Remote Antenna Relay Box
 
bullet  Understanding Antennas For The Non-Technical Ham
 
 
Hits: [an error occurred while processing this directive] Date of last edit: March 01, 2015 10:07:54 -0800
Copyright: L. Dighera, 2012; All Rights Reserved: LDighera@att.net