the fins and through the vents 22 thereby generating a whirring noise in other words wind currents pass through the upwind vent openings oriented toward the wind arrow w and into the inner chamber 44 of the rotor 11 and then pass out of the chamber 44 through the downwind vent openings oriented away from the wind arrow w this wind current air flow in combination with rotation of the repeller body 11 is believed to be the source of the whirring noise observed during prototype testing referring now to fig5 there is shown a second embodiment of the invention wherein the same numeral part designations have been used to indicate structural elements identical with those shown in fig1 4 in the modified or second embodiment shown in fig5 the rotary connection between the rotor body 11 and the top of the pole 12 is significantly different from that shown in fig3 in the second embodiment a lag bolt generally designated 50 has a head 51 engaging the outer surface of head section 28 and a threaded shaft 54 that passes through the head section 28 and is secured thereto by a pair of anchor arms 52 u2014 52 the lag bolt 50 is of conventional design wherein the arms 52 u2014 52 are initially folded so as to pass through an aperture 53 in the center of the head section 28 and then the arms 52 u2014 52 are expanded against the underside of the head.