Abstract: A calibrator circuit for a self-contained device for vertification of open field test site accuracy. This device generates a broadband width of discrete frequencies from 10 MHz to 1000 MHz which is then radiated into space. The circuit contains a power supply subcircuit, an oscillator subcircuit which generates an output signal rich in harmonics, an antenna radiating element and a balun network to couple the output from the oscillator subcircuit to the antenna element.