If you regularly have need to calculate field strength / power / path loss
according to Friis transmission formula, you may find a little calculator I
have written to be handy.

The calculator is called FSC (for field strength calculator) and is a
Windows application, more specifically it requires the .NET Framework V2
which is installed on most recent computers, or can be downloaded from
Microsoft at no charge.

The calculator is described at http://www.vk1od.net/fsc and can be
downloaded and used at no charge.

Owen