Daily Image
21-09-2006
Protection
| Submitter: | Rob Millenaar |
| Description: | The WSRT RFI monitoring station has produced this recent spectrogram of a 100 MHz wide patch of the spectrum around the 'channel 38' band (indicated by the red bar at the top). This small band (from 608 to 614 MHz) was set aside for radio astronomy use in the past, as one of the few protected bands in the spectrum. Situated in the middle of a TV broadcasting band, this relatively quiet patch was nevertheless difficult to use because of all the strong TV signals in neighboring channels. Digital TV transmissions have recently begun in The Netherlands and the countries around us as evidenced by the wide well-delimited features in the spectrogram. These signals will replace the old analog signals (the stronger peaks that still ride on top of the digital signals). The digital signals are wider (8 MHz), but weaker than their analog counterparts. After the analog transmitters will be switched off by the end of 2006, the RFI situation at the WSRT will be better than in this picture. The Dutch Administration has worked with ASTRON to safeguard channel 38 against use for digital TV and to keep the use of neigboring channels as far away from Westerbork as possible. The results of these efforts can be seen as a relatively clean band, with some remaining analog features just below 610 MHz. Hopefully those will disappear later this year. |
| Copyright: | ASTRON |
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