portable-antennas - Vertical antenna designer

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.
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.
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 scroll down in the page 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.

Set antenna color: Show person-height plane

Principal band
Band:
Frequency:	kHz
Nom. length :	m Corrected length: m
Wvl-fraction :	λ
Antenna configuration
Configure as:
Antenna wire
Wire core:	mm diameter
Insulation:	thickness
Ins. type:	Corr. factor:
Support pole
Height:	m
Main vertical section
Length:	m
Base height:	m
Radials - for 1/4-wave and 5/8-wave vertical antenna variants
No. of radials:
Radials length:	λ = m
Radials angle:	° from horizontal
Counterpoise - for 1/2-wave vertical antenna variant
Length:	λ = m

Antenna overview

Support
height

Main vertical section

Radials / Counterpoise

Length

Top
height

Bottom
height

No.

Length

Angle

Tip
ht.

Vertical antenna designer

Use the controls on the left-hand side to configure your antenna.
When you are happy with your configuration, press the "Show antenna" button to display your antenna in interactive 3D graphics mode in this area.
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: ⬥

Show display hints:

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 - generally speaking, when an antenna is erected on a hill-top or mountain summit, surrounding sloping ground will often cause angles in the elevation radiation pattern to be lowered in the direction of the slope.
This is not, however, the case with vertical antennas, since the vertically-polarized waves radiated by the antenna are emitted horizontally, such that reflections from the ground will be minimal, with the resulting elevation radiation pattern being largely unaffected by downward-sloping ground.
A more profound effect on the take-off angle from vertical antennas arises from the conductivity of the ground immediately surrounding the antenna: the higher the ground conductivity, the lower will be the take-off angle. Try it!

Export antenna dimensions to file

Export format:
CSV options:	Text delimiter:
CSV options:	Column separator:

Vertical antenna designer - correction factors reference

Length-correction factor used in this application - this will be applied automatically

Radials angle impedances - how feed-point impedance varies with radials angle
End-effect multiplication factor - dependent on wire diameter and frequency
Half-wave vertical impedances - 1/2-wave vertical impedances by counterpoise length

Radials angle impedances

Both the 1/4-wave ground-plane (GP), and the 5/8-wave, vertical antennas will need a system of radials attached at the feed-point.

How many radials are to be used is left to the builder to establish - sometimes a single radial will suffice to "get a signal out", although a minimum of 3 or 4 will give excellent results.

Sloping the radials downward from the feed-point will alter the feed-point impedance - how much will depend on the angle, as can be readily determined from the accompanying chart.

In general, the 5/8-wave vertical has a higher feed-point impedance than the 1/4-wave vertical for a given number of radials and radials angle.

Data for the chart derived empirically for 1/4-wave and 5/8-wave vertical antennas using the NEC v4.2 engine. Chart for illustrative purposes only - actual values for a particular antenna will depend on its' configuration.

End effect multiplication factor

Wavelength / wire diameter ratio, λ/d:

End-effect multiplication factor :

Half-wave vertical impedances

The 1/2-wave vertical antenna, unlike its' 1/4-wave and 5/8-wave cousins, presents a high impedance at the feed-point, typically around 1300 Ω to 2000 Ω.

The reactive part of this impedance is often high also: a counterpoise is attached at the feed-point to minimize this reactive component.

Many antenna builders agree that the optimum counterpoise length, to bring the reactive component close to zero, is 1/20λ (0.05λ) - the accompanying chart shows this very clearly.

Save antenna configuration

Give your antenna configuration a meaningful title...

Title:

Manage saved antenna configurations

Your saved antenna configurations:

Click on
an antenna
configuration
to select it

Double-click
to load a
configuration

Coordinates of each section can be used to model this antenna in a separate program

Main antenna characteristics
Band	Frequency (kHz)	Units	Wire diam.	Antenna length	Base height	No. of radials	Radials angle
a	b	c	e	d	f	g	h

Antenna sections
Section		Segment start			Segment end
Segment	Length	x	y	z	x	y	z
Vertical	1	1	1	1	1	1	1

Copy this CSV text and paste into your favorite spreadsheet program

Vertical antenna designer

Choose ground type of land in the vicinity of the antenna:	Conductivity: S/m Dielectric const.: F/m
View radiation patterns:	Azimuth Set elevation angle for azimuth plot: Auto Choose: Elevation Set azimuth angle for elevation plot: Auto Choose: 3D Polarization patterns
View VSWR chart:	VSWR
Display impedance curves:	Using unun
Impedance curves scales:	Shared Independent:
View currents diagram:	Antenna currents diagram
View Smith chart:	Smith chart
Antenna gains at 0° elevation:
Antenna impedance:
Frequency range: