As always the 3D radiation pattern is complex. If the sensor antenna rotates, the signal picked up by the receiving antenna will be modulated by this rotation. To improve the situation you can use two receiving dipoles or other antennas, one polarized vertically, the other horizontally. Best to use also two receivers and sum their outputs after detectors.
What is the transmitted signal? if it is like an AM or FM fast logic, then the slow sensor motation may be no problem. Best is to run a trial and adjust the receiving system for a good response.