portable-antennas - Delta loop 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
Antenna configuration
Configure antenna as:	△ Apex-up triangular loop ▽ Apex-down triangular loop
Antenna feed-point position
Feed-point position:
Antenna wire
Wire core:	mm diameter
Material:
Insulation:	thickness
Ins. type:	Corr. factor:
Antenna foot height AGL
Foot height:	m
Delta loop triangle height, as fraction of wavelength
Delta height:	λ m
Lower point height AGL
Point height:	m
Delta loop triangle height, as fraction of wavelength
Delta height:	λ m
Antenna apex angle (calculated)
Apex angle:	degrees

Antenna overview

Antenna sections lengths

Horizontal section height

Full
height

Delta loop 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 ...

portable-antennas.com

Antenna feed-point: ⬥

Show display hints:

Effect of coax- and system-losses on VSWR

When a coaxial cable is used to connect the antenna to a transmitter, the cable introduces signal loss, the magnitude of which can vary strongly with both frequency and antenna feed-point impedance.

The main blue VSWR curve for this antenna is calculated at the antenna feed-point. The optional green curve represents the VSWR "seen" at the transmitter after losses in the coaxial cable are taken into account.

At frequencies of antenna resonance, the blue and green curves usually coincide closely, since the coax contributes little additional attenuation at those frequencies. At frequencies away from resonance, however — often those corresponding to WARC bands — the feed-point impedance may become highly mismatched, producing very high VSWR values in the blue curve while the green curve shows substantially lower values.

This reduction in VSWR at the transmitter occurs because signal losses in the coaxial cable attenuate both the forward and reflected waves. As a result, the reflected signal returning to the transmitter is weaker, causing the transmitter-end VSWR to appear lower than the actual feed-point VSWR.

This effect can make some bands appear more "usable" from the transmitter's perspective, even though the antenna system may still be operating inefficiently at those frequencies.

The green curve represents the "flattening" of the VSWR caused by the coax. Additional losses elsewhere in the system can further reduce the transmitter-end VSWR - these may include:

ferrite heating and winding losses in baluns/ununs
common-mode currents suppression
coupling of RF energy into nearby ground and objects
matching network / antenna tuner losses

The magnitude of such losses, and their effect on actual radiated RF power, can only be estimated reliably through careful analysis of a particular antenna setup. In every-day portable operations, such losses can only be roughly estimated; however, comparisons can be made between commercially-produced EFHW and OCFD antennas for amateur radio use, and carefully-configured NEC models of those same antennas. Useful estimates can then be made of the efficiency of the commercial products by comparing their published VSWR curves, and the VSWR curves produced from the models.

Improved transmitter-end VSWR therefore does not necessarily imply improved radiation efficiency: in some cases, a significant proportion of the transmitted power may simply be lost: dissipated as heat within the antenna system. Read more...

Antenna: Configuration: Frequency: GenID:

Antenna
plane
0° - 180°

Azimuth:
Gain:
Beamwidth:	N/A
(At elevation angle: 133°)

Elevation:
Gain:
Beamwidth:	N/A
(At azimuth angle: 133°)

General parameters (at 7.000 MHz)

Outer ring:	5.23 dBi
VSWR:	2.06 : 1
Unun ratio:	49 : 1
Feed-point Z:	5125 - j1983 Ω
Transformed Z:	xxx

Show selected azimuth/elevation slices in 3D plot

How to use these diagrams » » »

Delta loop designer - reference

Various parameters and factors used in this application - these will be applied automatically

Antenna feed-point impedance - dependent on antenna geometry
Loop-length multiplication factor - dependent on antenna impedance and geometry

Delta loop length multiplication factors

Delta loop antennas are peculiar, in that the frequency of resonance is highly dependent on the configuration (point-up / point-down), also on the feed-point position, the delta height and antenna height AGL. In order to compensate for this, we introduce length-correction factors (charted here) to bring the resonant frequency close to the user-chosen frequency.

Changing the loop-configuration will re-load the chart with curves relevant to that configuration.

Chart of length correction factors by delta height, for
the apex-up loop configuration.

Antenna feed-point impedance

Average feed-point impedance as
a function of loop height AGL:

Chart of feed-point impedance as a function of
loop height AGL

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

You may choose an example from the list and import it into your "Favourites" list

Title	Band	Freq. kHz	Config.	Feed-Pt pos.	Wire Dia.	Lowest Ht.	Delta Ht.
Some title	20m	14250	ptup	qwave	1	1	1

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

#	Section Length	Full section coordinates
#	Section Length	x1	y1	x2	y2
1	1	1	1	1	1

Copy this CSV text and paste into your favorite spreadsheet program

Export antenna dimensions to file

Export format:
Antenna diagram:	Use original view Use current view
PDF options: Toggle all	Include radiation patterns Include VSWR chart Include currents diagram Include Smith chart If you include any of these options, make sure you refresh the required radiation patterns, charts and diagrams for your antenna before exporting.
Collecting data:	0 %

Combined azimuth + elevation patterns

Using combined azimuth + elevation patterns

The new combined azimuth and elevation patterns diagrams are fully interactive, allowing dynamic re-plotting of the patterns. You can choose any one of the following levels of interactivity:

No interaction
- the diagrams remain fixed at their default azimuth and elevation cuts.
Hover the mouse over the circular region in one diagram
- a green radial line and marker pair will appear in the diagram;
- the line and marker will follow the mouse around the diagram;
- angle and gain values at the mouse position are updated in the texts directly below the diagram.
Click within the circular region in one diagram
- the radial axis (the black line with numbers) is re-positioned to the selected angle;
- this new radial-axis position defines a new "slice" through the 3D radiation-patterns data;
- the other diagram is then re-plotted to reflect the new slice through the data;
- if the 3D radiation-pattern diagram is visible, then it too will be re-plotted to reflect the new slice through the data.
Click and drag within the circular region in one diagram
- the radial axis follows the mouse position in that diagram continuously;
- releasing the mouse fixes the radial axis at the selected angle;
- a new slice through the 3D radiation-patterns data is generated;
- the other diagram is then re-plotted to reflect the new slice through the data.
- if the 3D radiation-pattern diagram is visible, then it too will be re-plotted to reflect the new slice through the data.

All these different levels of interactivity are not just for show - they are designed to engage your curiosity about azimuth, elevation and 3D patterns and curves, and to help you learn about them.

By using the different levels of interactivity, you should gain a deeper insight into how each of the patterns and curves are intimately connected. Change one, and the other two are affected.

How deeply you venture into this, is entirely up to you: the tools are provided for you to use.

Choose ground type of land in the vicinity of the antenna:	Conductivity: S/m Dielectric const.: F/m
View radiation patterns:	Azimuth + Elevation Polarization patterns
	3D pattern Choose type: Classic 3D plot
Set ref. elevation angle:	Auto Choose:
Set ref. azimuth angle:	Auto 0° (inline) 90° (broadside)
Impedance transformer:	Using unun
View VSWR chart:	VSWR Check on: Principal band Bands range From: To:
Effect of coax on VSWR:	Include coax losses Coax length: Type: Effect of coax- and system-losses on VSWR When a coaxial cable is used to connect the antenna to a transmitter, the cable introduces signal loss, the magnitude of which can vary strongly with both frequency and antenna feed-point impedance. The main blue VSWR curve for this antenna is calculated at the antenna feed-point. The optional green curve represents the VSWR "seen" at the transmitter after losses in the coaxial cable are taken into account. At frequencies of antenna resonance, the blue and green curves usually coincide closely, since the coax contributes little additional attenuation at those frequencies. At frequencies away from resonance, however — often those corresponding to WARC bands — the feed-point impedance may become highly mismatched, producing very high VSWR values in the blue curve while the green curve shows substantially lower values. This reduction in VSWR at the transmitter occurs because signal losses in the coaxial cable attenuate both the forward and reflected waves. As a result, the reflected signal returning to the transmitter is weaker, causing the transmitter-end VSWR to appear lower than the actual feed-point VSWR. This effect can make some bands appear more "usable" from the transmitter's perspective, even though the antenna system may still be operating inefficiently at those frequencies. The green curve represents the "flattening" of the VSWR caused by the coax. Additional losses elsewhere in the system can further reduce the transmitter-end VSWR - these may include: ferrite heating and winding losses in baluns/ununs common-mode currents suppression coupling of RF energy into nearby ground and objects matching network / antenna tuner losses The magnitude of such losses, and their effect on actual radiated RF power, can only be estimated reliably through careful analysis of a particular antenna setup. In every-day portable operations, such losses can only be roughly estimated; however, comparisons can be made between commercially-produced EFHW and OCFD antennas for amateur radio use, and carefully-configured NEC models of those same antennas. Useful estimates can then be made of the efficiency of the commercial products by comparing their published VSWR curves, and the VSWR curves produced from the models. Improved transmitter-end VSWR therefore does not necessarily imply improved radiation efficiency: in some cases, a significant proportion of the transmitted power may simply be lost: dissipated as heat within the antenna system. Read more...
View currents diagram:	Antenna currents diagram
View Smith chart:	Smith chart
Antenna gains at 0° elevation:
Feed-point impedance:
Estimated bandwidth:

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TRX-end values
Freq:		MHz
R:		Ω
X:		Ω
VSWR:		: 1

Delta loop antenna designer

Antenna performance

Effect of coax- and system-losses on VSWR

Delta loop length multiplication factors

Antenna feed-point impedance

Using combined azimuth + elevation patterns