HIGH SENSITIVITY WIDE BAND DIGITAL SOLAR POLARIMETRIC SPECTROSCOPE

Abstract Frequency range of existing narrow band (1.6 ± 0.1) GHz high sensitivity digital spectroscope is extended to (0.2 – 2.5) GHz in conjunction with a 9-meter diameter polar mounted antenna. This spectroscope will be recording two circular polarizations almost simultaneously. Normally two spectroscopes will be operated simultaneously in the frequency ranges of (0.2 – 1.0) GHz and (1.0 – 2.5) GHz with time resolution of 100 ms. However, flexibility of each receiver independently will permit us to select the desired band of observation and frequency and time resolutions. This is the major advantage of this system over similar ones operating in the world. Digital HP8595E spectrum analyser will be used in the frequency range of (1.0 – 2.5) GHz as variable frequency radiometer which will enable us to change time and frequency resolution quickly. Also, necessary hardware and software developed by HP will be used in conjunction with spectrum analyser, in order to digitize 200 frequency channels with desired resolutions. Data will be stored in PC486 and also will be tranfered to “SUN Station” in real time. Following details of the instrumentation are presented here: i) field tests of the “front end” including wide band (0.2 – 2.5) GHz antenna, low noise pre-amplifiers, and polarization switches; ii) typical example of the solar microwave type III burst analysed using software that will be used in the broad band system.