Freespace is a small tool that calculates the range of a freespace radio link. With the software Freespace you can calculate the range of a freespace radio-link. The results of 'Freespace' are most accurate for radio-links from and to satellites but are also useful to get an estimate of the range of a ground-based radio-link.

For these links the results can be seen as the maximum possible range. The ground-based range can be longer when special atmospheric conditions are present (sporadic-E, ducts, aurora etc.) or shorter when there are obstacles in the way.

The program works well for satellite paths, between antennas that can see each other and between mountain tops. To consider the extra attenuation with radio-paths over plain ground you should subtract at least 6dB (1/4 of power in Watts) from the power level of your transmitter in order to get a true result.
If there are any obstacles in the path, things become very complicated and the results of the program are very unaccurate. When you select a parabolic dish antenna the efficiency of the antenna is assumed to be 55 %.

When you try to calculate a very long ground radio-path you have to consider the curvature of the earth. In this case, the program can not be used.

The program works well for satellite paths, between antennas that can 'see' each other and between mountain tops.

To consider the extra attenuation with radio-paths over plain ground you should subtract at least 6dB (1/4 of power in Watts) from the power level of your transmitter in order to get a true result. If there are any obstacles in the path, things become very complicated and the results of the program are very unaccurate.

The license of this software is Freeware, you can free download and free use this calculator software.