63. A vertical 1/2 dipole antenna is used as a ground-to-air, over-the-horizon communication antenna at the VHF band (f = 200 MHz). The antenna is elevated at a height h

(measured from its center/feed point) above ground (assume the ground is flat, smooth, and perfect electric conductor extending to infinity). In order to avoid interference with other simultaneously operating communication systems, it is desired to place a null in the far-field amplitude pat-tern of the antenna system at an angle of 60° from the vertical.% Determine the three smallest physical/nontrivial heights (in meters at 200 MHz) above theground at which the antenna can be placed to meet the desired pattern specifications.