A 20-Hz-to-200-kHz magnetic flux probe for EMI surveys

A small magnetic flux probe is described. It exhibits a magnetometer-like response over the frequency range of 20 Hz to 200 kHz with an effective antenna height of 1 m. The E-field equivalent noise floor of this device is approximately 10 mu V/m square root Hz at 10 kHz. A switchable high-pass filter is included to allow the measurement of very low frequency fields in the presence of strong 50-400-Hz power-line fields. The distinguishing features of this probe are its method of winding and shielding. Both the theory of operation and practical construction are described.<
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