MMANA Antenna Modeling Program Tutorial, Part 5A 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
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:
|No||The "No" column will contain antenna element numbers. MMANA automatically numbers each antenna element described to provide a means of element identification.|
|X1||One end of an antenna element that runs in the X direction|
|Y1||One end of an antenna element that runs in the Y direction|
|Z1||One end of an antenna element that runs in the Z direction|
|X2||The other end of an antenna element that runs in the X direction|
|Y2||The other end of an antenna element that runs in the Y direction|
|Z2||The other end of an antenna element that runs in the Z direction|
|R||The radius of an antenna element.|
|Seg||A code number that specifies how the antenna element is to be segmented when calculating antenna characteristics (more about this later).|
- MMANA Antenna Modeling Program Tutorial, Part 6 (More to follow)
- MMANA Antenna Modeling Program Tutorial Starting Page
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