A multi-directional antenna connected with a digital television broadcast
signal receiver is arranged not to move one full turn instantaneously in
response to an abrupt drop down in the intensity of a received signal
thus to avoid any downward overshooting of the intensity of the received
signal and eliminate any useless direction searching time while remains
favorably controlled to face in the direction where the intensity of the
received signal is at optimum. More specifically, the maximum of the
intensity of a received signal at each channel is measured and the
threshold is set to a level lower than the maximum. When the intensity of
a received signal has dropped down from the threshold, the antenna
remains not turned within a predetermined period of marginal time. The
antenna is moved one full turn only when the intensity drops down from
the threshold and stays continuously over the predetermined period of
marginal time. Then, the maximum of the intensity of the received signal
is modified and stored for future use.