Confirmation of Geminid meteor parameters via simultaneous 3-point radio observations of meteor head echoes using VHF ham radio waves and low-powered ham devices

Abstract

Two Geminid meteor head echoes were detected simultaneously at three points on December 13, 2021, by installing amateur radio receivers within approximately 20 km east from the transmitting station that was continuously transmitting at 10W. The meteor echo of the VHF ham wave was received using the USB format, and the waveform was imaged after frequency analysis. The transmission wave of the meteor head echo is reflected at the head portion of the meteor. The Doppler frequency was confirmed by subjecting the meteoroid to Doppler effect according to its observed velocity. These two meteors have been successfully observed at multiple points optically by the network of meteor researchers in Japan, and several meteor optical path parameters, such as entry angles into the atmosphere and observed velocity, have been published. The authors analyzed the Doppler frequency of the meteor head echoes and the time at which the meteor head reached the point where the meteor path and transmitted waves were orthogonal (f0 point) by using the free FFT software. The radio meteor paths and observed velocities which were derived from the radio observation data were in good agreement with the published optical meteor path specifications. These findings indicate that this meteor radio observation method can serve as a substitute for the optical meteor observation method during daytime or bad weather conditions. If we install observation devices in several locations throughout Japan, we will be able to find several meteorites falling on our country during daytime or bad weather conditions, which have been overlooked to date.