It modifies the pattern of a DF antenna to provide a null in only one direction✓Correct answer
It increases the sensitivity of a DF antenna array
It allows DF antennas to receive signals at different vertical angles
It provides diversity reception that cancels multipath signals
Explanation
A sense antenna supplies an omnidirectional signal of the right amplitude and phase to be added to the loop's bidirectional output. The two combine on one side and cancel on the other, turning the figure-eight into a cardioid with just one null, so the bearing is no longer ambiguous.