Specials - Dipoles-beam antenna

Design a directional wire beam antenna for one or more bands, consisting of an array of two angled inverted-vee dipoles, the apexes of which are arranged very close to each other at the center.  Each half of the array is a full-sized dipole antenna: to achieve directionality, one of the dipoles is loaded capacitively at the apex, effectively shortening its' legs electrically.  This dipole then becomes a "director" for the other, "driver", dipole, and the array radiates preferentially in that direction.  Some operators have arranged switchable capacitors and feed-point positions on each pair of arms of the array, such that the array can be quickly arranged to radiate in any one of four different directions.  Gains of 9dBi or greater can be achieved, and F/B ratios of 12dB or greater are possible, depending on height, apex-angle and frequency.

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  1. Use the controls on the left-hand side to configure your antenna - set the design frequency, antenna element lengths and angles, wire diameter, wire insulation if required, support height, etc.
  2. When you are happy with your configuration, press the "Show antenna" button to display your antenna in interactive 3D graphics mode in the area on the right-hand side. Each time you change your configuration, you should press the "Show antenna" button to register the changes to the app.
  3. After you have configured your antenna, you can then use the controls further down in the page to generate charts and diagrams to evaluate the antenna's performance - you will need to to access these controls.
    You can choose to view any combination of the available charts and diagrams: these include four radiation pattern types: azimuth, elevation, 3D and polarization patterns; other options include VSWR charts, an antenna currents diagram, and a Smith chart.

Antenna sections
No. of bands:
Section #1: kHz ( highest f )
Section #2: kHz
Section #3: kHz
Section #4: kHz
Section #5: kHz
Section #6: kHz ( lowest f )
Antenna wire
Wire core: mm diameter
Insulation: thickness   
Ins. type:   Corr. factor:
Antenna configuration
Pole height: m
Apex angle: °
Slope length: m
Rope extender: m
Foot length: m
Side length: m
Director capacitance multiplication factor
Mult. factor:
Antenna overview
  Antenna sections
Inner
#1 		#2 #3 #4 #5 #6
Freq. (kHz)
Length (m)
Total (m)
½ Length:   ½ Apex∠:   End height:   
 Dipoles-beam antenna designer
  1. Use the controls on the left-hand side to configure your antenna.
  2. When you are happy with your configuration, press the "Show antenna" button to display your antenna in interactive 3D graphics mode in this area.
  3. After you have configured your antenna, you can then use the controls further down in the page to generate charts and diagrams to evaluate the antenna's performance ...
Antenna feed-point: ⬥

Antenna performance

Here you can generate plots of radiation patterns, VSWR chart, antenna currents diagram and Smith chart for your antenna over a choice of ground types. By changing the physical dimensions of the antenna, and refreshing these plots, you can learn a lot about how such antennas will perform in the field.
Please note that radiation patterns are here modelled over flat ground - when the antenna is erected on a hill-top or mountain summit, the surrounding sloping ground will generally cause angles in the elevation radiation pattern to be lowered in the direction of the slope: the steeper the slope, the lower the effective elevation take-off angle will be, and the better the chances of making long-distance contacts.

Choose antenna section:
Check harmonics?: kHz  Info
Choose ground type of
land in the vicinity
of the antenna: 		   Conductivity: S/m    Dielectric const.: F/m
View radiation patterns:    Set elevation angle for azimuth plot:     Info
  Set azimuth angle for elevation plot:     Info
  Chart patterns for:     at spacing
  Info
View VSWR chart:
Impedance curves scales:   
View currents diagram
View Smith chart:
Antenna gains
at 0° elevation:
Antenna impedance:
Frequency range: