PURPOSE: To reduce the deviation of the effective gain of an antenna due to the way to place a portable radio equipment, by adopting a circularly polarized wave antenna as the antenna of a base station.

CONSTITUTION: Directional antennae with superior elliptically polarized wave ratio of transmission/reception shared circularly polarized wave antennae 3-1∼3-n are combined to obtain non-directional characteristics within a horizontal plane, and a land mobile communication system having almost a circular service zone 5 centering a base station 4, is constituted. The effective gain is reduced when the sleeve antenna of the portable radio equipment is inclined, but the deviation of the effective gain is scarcely generated when an elliptically polarized wave whose horizontal wave component is large and almost near to a circular polarized wave, is transmitted.