No antenna is a perfect point omni emitter, the weird non spherical shapes like doughnuts is the antennas gain, almost are antennas are somewhat directional, th

No antenna is a perfect point omni emitter, the weird non spherical shapes like doughnuts is the antennas gain, almost are antennas are somewhat directional, the shape is a plot of the measured radiation around the antenna. You take advantage of the fact that it radiates more to the sides than up and down and orient that so it putting more power to the horizon rather than up into space (for terrestrial transmission). The term gain is just referring to the antennas directionality relative to a perfect spherical omni radiator that doesn't exist.