The Watson-Watt technique is especially suitable for lower frequencies in the range where the AX320D is designed to predominantly operate.
Using this antenna, the WD-7200 control unit compares amplitude differences between electronically switched loop antennas (contained within
the AX320D weather-proof radome) against a vertical, omnidirectional reference antenna (usually referred to as the "sense antenna").
On HF frequencies, the antenna is particularly effective for ground-wave propagating signals, such as low-power man-portable transmitters
("manpacks") at typical distances of several kilometers, depending on the type of terrain and the transmitted power.
The AX320D antenna is designed to receive vertically polarized signals in the 2 to 280 MHz frequency range. All power and control signals
to the antenna are provided through one multi-conductor control cable via the standard WD-7200 control unit. The received signal with
encoded bearing information is routed to the receiver through a RF coaxial cable. The AX320D is fully compatible with the existing standard
WD-7200 control unit and does not require any other add-ons or modifications for operation - simply plug it in and "DF on HF".