Wisconsin Test Facility Transmitting Antenna Pattern and Steering Measurements

During August and September 1971, the New London Laboratory, Naval Underwater Systems Center, performed pattern and steering measurements on the Wisconsin Test Facility (WTF) antennas. The pattern measurements were made at 13 locations in Minnesota and Wisconsin (covering approximately 120° of arc), while the far-field steering tests were taken in Maine and North Carolina. To be certain that the receiving sites were acceptable, several components of the received magnetic field were measured at each site and plotted on a normalized cosine curve. The 45- and 75-Hz pattern measurements were made at a range of approximately 300 km, while the steering measurements were performed at 1.7 Mm. The principal results from the pattern and steering measurements were 1) the east-west (EW) antenna pattern is skewed clockwise; 2) the north-south (NS) antenna pattern is skewed counterclockwise; and 3) the effective conductivity under the EW antenna is greater than the effective conductivity under the NS antenna.