ESF logo Committee on Radio Astronomy Frequencies

 

The Committee on Radio Astronomy Frequencies (CRAF) is an Expert Committee of the European Science Foundation (ESF).


Frequency band allocated to the Radio Astronomy Service:


ITU-RR allocations (+ footnotes):


470   - 790  MHz:		BROADCASTING
			
			5.149 5.291A 5.294 5.296 5.300 5.302
			5.304 5.306 5.311A 5.312
			

Note:

The Radio Astronomy Service has a primary allocation in Region 2.


Astrophysical importance of the band 608 - 614 MHz

Various RA allocations are made within this range, with various degrees of protection, to fit in with local television assignments, one television channel usually being made available for RA. Several ITU-R footnotes apply to this band: 5.304, 5.305, 5.306 and 5.307, 5.208A (WRC-07). The radio astronomy attaches considerable importance to the maintenance of this allocation since without it, there would be a large gap between the 410 and the 1400 MHz allocations, in one of the most important parts of the spectrum. The band is of special importance for (worldwide) VLBI observations. It is requested that in those parts of the world in which the allocation to Radio Astronomy is on a temporary basis, greater security can be afforded and Radio Astronomy given the maximum possible protection from both in-band and adjacent band transmissions. Primary allocations with several MHz in common to all regions are needed.


Threshold levels of interference detrimental to radio astronomy continuum observations:

System Sensitivity (noise fluctuations)Threshold Interference Levels
TemperaturePower Spectral DensityInput PowerPower Flux DensitySpectral Power Flux Density
Single Dish0.73 mK-260 dB(WHz-1)-202 dBW-185 dB(Wm-2)-253 dB(Wm-2Hz-1)
Interferometer-236 dB(Wm-2Hz-1)
VLBI-211 dB(Wm-2Hz-1)

NOTE:

For further details the reader is referred to ITU-R Recommendation RA769. It should, however, be noted that the observed spectral power flux densities are much lower than the harmful interference levels because they are made in the main beam of the radio astronomy antennas whereas the harmful levels correspond to reception in the sidelobes, i.e. the differences are related to the gain of the antennas. The differences can be of the order of 50 to 80 dB W m-2 Hz-1 (see ITU-R "Handbook on Radio Astronomy", 1995/2003, chapter 4).


In Europe, the band 608 - 614 MHz is used by the Radio Astronomy Service in:


Threats to the Radio Astronomy Service:


Last modified: October 7, 2009