Calibrating the Antennas

We address the procedure of a ‘through’ antenna and receiver calibration in this chapter. Electric and magnetic channels are calibrated individually, and we separately describe the relevant sets of devices. The necessary formulas are given to describe a calibrating capacitor, the gnome and radiating antennas, Helmholz rings, and the accuracy of calibration. Procedures are addressed of calibration at the field-site. A regular calibration is desirable of the receiver channels together with the field sensors. Such a procedure exploits the known ‘standard’ field applied to the antennas. Calibration is usually performed between the measurement sessions, and its results are stored and used in the data processing. We explain why the accurate calibration is hard to do at the field-site, so that root mean square error of the procedure is about 10 %. Attention is given also to the symmetry of angular patterns of magnetic field sensors.