An electrostatic overvoltage protection device for use in remotely mountable weatherproof bi-directional, half-duplex switching amplifier system designed to provide maximum range for low power half-duplex radios such as Spread Spectrum radio transceivers in which a conductor is connected between the signal input and a source of reference potential having a length selected to be one quarter of the wavelength of a preselected desired signal band frequency and is one of a trace on a circuit board and wire.