Abstract: The present invention relates to realize a tectonic activity monitoring equipment providing apparatus and method to detect a feeble electromagnetic wave occurred by the tectonic activity with a high signal-to-noise ratio (S/N) and to predict earthquake and volcano eruption. The apparatus and the method for monitoring tectonic activity of the present invention comprises electromagnetic wave sensors and one or more of amplifiers for amplifying signals detected by the sensors. And an observation frequency for detecting electromagnetic wave occurred from tectonic activity is set to a frequency between a few tens Hz and 1 kHz so as to eliminate the influence of noises of a strong radiation power less than a few tens Hz and tropical thunder noises of more than 1 kHz of higher order modes propagating between the earth and the ionosphere.

Abstract: In a transmitter and receiver system, a frequency converter doubles as a transmitter local oscillator, a receiver local oscillator, and a transmitter frequency converter.The present local oscillator is a semi-conductor oscillator such as a gunn diode or IMPAT diode, the DC power supply of which is converted to an intermediate frequency signal. The oscillator is stabilized by self injection locking by a cavity resonator connected to the output of the diode, thus the oscillating frequency is very stable. Some of the output power of the oscillator is separated for the receiving local oscillator through an isolator and an attenuator. The intermediate frequencies of a transmitter and receiver have a predetermined relationship.