RadioWORKS
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RadioWORKS is a tool for calculating various items related to radio waves. It enables you to calculate the wavelength and proper antenna length for any given frequency, and also includes an "Inverse Square Ratio" calculator, useful for estimating how a proposed power change will affect your usable range -or- how a proposed distance change will affect your power requirments. Very useful for getting quick information about antenna lengths, making range predictions, etc.
RadioWORKS is made available as FREEWARE. It contains no viruses, adware, spyware, back doors, or trojans.