A mobile communication base station determines the oncoming direction of a radio
wave with a simple arrangement and transmits a narrow angle beam in this direction.
Received signals from a pair of wide angle beam antennae 21-1 and
21-2 having an equal configuration and a common orientation and which
are located close to each other are fed to a direction finder receiver 22 and
a communication receiver 15. By utilizing the fact that the both received
signals have a coincident amplitude, a phase difference between the received signals
is detected. The oncoming direction of the received radio wave (or the direction
of a mobile station) is determined on the basis of the phase difference. A beam
switcher 12 is controlled so as to connect a transmitter 13 to a
narrow angle beam antenna (one of 11-1 to 11-4) which
is directed in the oncoming direction thus determined.
