Multiple Earth Curvature Values in HDPath™
Q: How can I show the effects of different effective earth curvature values on a single profile?
A: With TAP6.0.2255 or later and a Maintenance Subscription date of August 31, 2008, or later, you can draw a profile showing multiple effective earth curvature values.
Note that all values in this example are for demonstration purposes only. You should determine appropriate settings for your application.
For example, suppose you have a path profile drawn with 4/3 (1.333) effective earth curvature:
The reference line at the bottom of the profile gives an indication of the effect of the curvature value used.
You can enter a different earth curvature value, such as 2/3 (0.666) and draw the profile with that value:
With the new feature, you can enter multiple curvature values (separated by spaces) and display all values on a single profile plot:
(Note that a curvature setting of 0 (zero) represents a “flat earth” or infinite curvature plot.)
The multiple values for effective earth curvature only apply to the graphical path profile. Other functions (such as computing the field strength at the receive location, antenna elevation settings, or link budget calculations) use only the first value listed for the effective earth curvature.
You also have the option of adjusting the line of sight to indicate earth curvature, using the “Bend Line of Sight” checkbox.
With this option, the line of sight and accompanying Fresnel zone is adjusted downward along the path, instead of adjusting the terrain upward along the path. The effect is the same, showing the same clearance between the terrain and the line of sight and Fresnel zone at any point along the path.
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Copyright 2008 by SoftWright LLC