Montag, 29. Juli 2013

New Callisto spectrometer in Sri Lanka installed

The CALLISTO Solar Radio Observatory is established in the Arthur C Clarke Institute (ACCIMT), Colombo, Sri Lanka. The location of the CALLISTO system is 6o 47 37’’ N, 79o 53 53’’ E at an altitude of 40 m and the time zone is +5.30 from UT. The log-periodic antenna was completely designed by the ACCIMT and constructed locally. Design constant (t) 0.822 and the relative spacing (s) 0.149 give 7 dBi theoretical gain for the log – periodic antenna and it covers the frequency range of 45 – 600 MHz with 18 dipoles. The theoretical impedance of the antenna 58.3 Ω is well agreed with the impedance measured in the entire frequency range. The total height of the antenna is 5.38 m and the longest dipole is 3.33 m. The linear polarized antenna is pointing to zenith and the dipoles directed to north-south direction.
The pre-amplifier is made by ACCIMT using MAR-8ASM Monolithic surface mount amplifier which gives 31.5 dB gain at 100 MHz.    

The members of astronomy division. From left; Saraj Gunasekara, Janaka  Adassuriya, Kamal Perera, Indika Medagangoda.

1st ligth, a type III burst. X-axis is local time
Rather crowded spectrum, nevertheless solar observations are still possible.