Q: Can I compute the free space field strength for a certain power at a given distance?
A: The free space field calculation is performed in TAP as part of field strength calculations in the Area Coverage, Single Point Field, and Microwave and UHF/VHF link budget calculations. You can use the Free Space Calculations item in the Utilities menu for a quick calculation of the free space values.
In the Utilities menu, click the Free Space Calculations item:
The Free Space Calculations form will be displayed:
Click the option button for the value you want to compute, such as the Calculate Field button:
The free space field value for the specified Effective Radiated Power (ERP) and distance is shown in the list.
You can also compute the required ERP for a specified field value. Click the Calculate ERP option button and enter the desired field, then click the Calculate ERP button again:
Likewise, you can compute the distance corresponding to a given ERP and field strength value:
You can also select the calculation based on isotropic or dipole antennas. When you click the antenna type, the current calculation will be recomputed:
Typically dipole antenna calculations are used for broadcast, land mobile, UHF-VHF links, etc., and isotropic calculations for microwave links. Be sure the calculation you use is appropriate for your application.
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