The radio spectrum monitoring daemon ``spektrd'' has been running continuously since November 1999. Detailed RFI spectral information is collected in the frequency band from 400 MHz to 2 GHz in UTC time-tagged ASCII files. Currently the database contains 1.8 GB of raw data.
``spektrd'' controls antenna rotation, spectrum analyzer settings, and archiving of the measured values. Analyzing and post-processing these raw data files requires further development. Interesting development is on-going at NFRA (Netherlands) where a set of RFI detection and visualization software packages is being developed as a part of an EU project.
The most severe sources of interference at Metsähovi are GSM mobile
phone base stations in the frequency range 890
960 MHz. This
coincides with the IF bands used to transmit signals from receivers in
telescope to control room. During the year 2000 the GSM 1800 network
continued to grow outside Helsinki area and a relatively strong
1800 MHz base station signal can be measured at Metsähovi.