Induction Loop Antennas for Geomagnetic Field Variation Measurements

This report rescribes the design considerations, construction techniques, and testing procedures followed in the preparation of large induction antennas for geomagnetic field measurements. The design was to provide a maximum amplitde, undistorted voltage response to magnetic flux density changes at frequencies below 5.0 c/s. The selected two-meter diameter antennas had between 8000 and 32,000 turns of fine copper wire with 0.127 mm diameter. Effects of some permutations in wire size and winding configuration are described. Details are given concerning the procedure for determining the antenna constants and calibrated response.