Antenna Design
Learn to model your own antenna designs.

# MMANA Antenna Modeling Program Tutorial, Part 5

A Quick Halfwave-Dipole Modeling Example

A Quick Halfwave-Dipole Modeling Example
To see how the geometry screen is used, check the lambda box in theupper-right-hand corner of the program window. That will change the element-length unit-of-measure from the meters program default to wavelength, so we can quickly model a halfwave dipole without having to calculate its length in meters. Notice when you check that box that the spreadsheet column labels change from containing (m) to containing (wl) as a reminder that element dimensions are to be specified in wavelength, rather than in meters, as shown below: MMANA geometry screen with the lambda element length option selected

Antenna Frequency
We could model a halfwave dipole for any frequency, but the purpose of this demonstration leave the frequency set to the 14.050 MHz MMANA default frequency.

X and Y Element Directions
Antenna elements can be described in terms of Y and Y directions. X and Y are any two arbitrary directions in azimuth that are orthogonal (at right angles) to each other. For example, we could arbitrarily decide that the X direction runs east and west and that the Y direction runs north and south. However, it isn't necessary that an antenna description be aligned with compass points. We could decide that the X direction is the direction between two oak trees that are going to support an antenna wire and that the Y direction is the azimuth direction that will be at right-angles to that wire.

Z Element Direction
The Z element direction is always the direction that is normal to earth (in other words, orthogonal to a line that is tangent to earth or vertical to the local earth surface).

Describe the Halfwave Dipole Numerically
The No, X1, Y1, Z1, X2, Y2, Z2, R and Seg labels across top of the empty spreadsheet fields have the following meanings:

Geometry-Screen Column Labels
LabelLabel Meaning
NoThe "No" column will contain antenna element numbers. MMANA automatically numbers each antenna element described to provide a means of element identification.
X1One end of an antenna element that runs in the X direction
Y1One end of an antenna element that runs in the Y direction
Z1One end of an antenna element that runs in the Z direction
X2The other end of an antenna element that runs in the X direction
Y2The other end of an antenna element that runs in the Y direction
Z2The other end of an antenna element that runs in the Z direction
RThe radius of an antenna element.
SegA code number that specifies how the antenna element is to be segmented when calculating antenna characteristics (more about this later).