A medium-frequency interferometer for studying auroral radio emissions

An interferometer for use between 2.5 and 3.0 MHz has recently been develop ed for the purpose of studying auroral radio emissions. The instrument cons ists of an array of 17 antennas, associated electronics for amplitude and p hase measurements, and computer hardware for instrument control and data re cording. In its standard operational mode, the instrument sweeps from 2.5 t o 3.0 MHz in 1 kHz steps every 1.5 s. The intensity of the received signal and the phase at each antenna is measured for each 1-kHz-wide bin. These da ta can be used to produce spectrograms showing the intensity of the receive d signal versus frequency and time and for determining the direction of arr ival for any signal in the instrument bandwidth. (C) 2000 American Institut e of Physics. [S0034-6748(00)03908-3].