Bruny Island Radio Spectrometer - BIRS

Bruny Island lies off the south-eastern corner of Tasmania, Australia.

Since 1 January 1998 low frequency solar radio burst observations have been made daily with the Bruny Island Radio Spectrometer (BIRS) and, since 15 September 2006, they appear on the Green Bank Solar Radio Burst Spectrometer at http://gbsrbs.nrao.edu.

Earlier data were on a University of Tasmania web site and can be made available only by contacting

     bill.erickson @ utas.edu.au.  

The frequency range of the observations is from the low frequency ionospheric cutoff to 62.5 MHz.  The ionospheric cutoff occurs at a frequency at which radio waves from the Sun suffer total reflection by the Earth's ionosphere and is normally between 7MHz and 12 MHz: it is a strong function of the local elevation of the Sun. Only the 12 to 62 MHZ frequency range is normally displayed on the website.

The frequency range observed by BIRS is filled with interference from terrestrial stations. The BIRS system adapts to this ever changing interference environment to observe only in spaces between the interfering signals and this allows successful observations to lower frequencies than other solar spectrometers. This low frequency range is important because it provides an overlap in frequency between ground-based solar observations and satellite observations that extend down to the kHz frequency range. In spite of the RFI avoidance procedures, a significant amount of residual interference remains in the raw records.