Special Issues at Low frequencies: Interferences(ctd.)
		• Mean level interferences ( <40db above quiet sun) – At the lower end of the band (< 300 MHz): • It is very difficult to find a 1 Mhz clean band • Interferences have a small bandwidth ( 5-20 kHz) – This imply: • Small observing bandwidth, very good filters. • Digital interference excision will require high dynamic, high resolution spectra and filters. – There are (at present) less problems above 300 MHz… • Don ’t forget internal interferences, mainly from high speed digital electronics.