Measuring solar radio bursts in 20–650 MHz

Abstract

The solar radiospectrograph of the University of Athens is installed at the Thermopylae Satellite Telecommunication Station. The observations cover the frequency range from 20 to 650 MHz. The spectrograph has a 7-m moving parabola feeding by a log-period antenna for 100–650 MHz and a stationary inverted V fat dipole antenna for 20–100 MHz. Two receivers are operating in parallel: a sweep frequency for the whole range (10 spectra/s, 630 channels/spectrum) and an acousto-optical receiver for the range 270–450 MHz (10 spectra/s, 128 channels/spectrum). The data acquisition system consists of two PCs (equipped with 12 bit, 225 ksamples/s DAC, one for every receiver). The daily operation is fully automated: receiving universal time from a GPS, pointing the antenna to the Sun, initiating system calibration, starting and stopping the observations at preset times, data acquisition, and archiving on DVD. We can also control the whole system through modem or Internet. The instrument can be used either by itself to study the onset and evolution of solar radio bursts and associated interplanetary phenomena or in conjunction with other instruments.