Committee on Radio Astronomy Frequencies

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

Frequency band allocated to the Radio Astronomy Service:

ITU-RR allocations (+ footnotes):


81 - 84 GHz:		FIXED
			FIXED-SATELLITE (Earth-to-space)
			MOBILE
			MOBILE-SATELLITE (Earth-to-space)
			RADIO ASTRONOMY
			Space research (space-to-Earth)
			
			5.149 5.560A


84 - 86 GHz:		FIXED
			FIXED-SATELLITE (Earth-to-space) 5.561A
			MOBILE
			RADIO ASTRONOMY
						
			5.149


86 - 92 GHz:		EARTH EXPLORATION-SATELLITE (passive)
			RADIO ASTRONOMY
			SPACE RESEARCH (passive)
			
			5.340

National Arrangements for Radio Astronomy different from ITU-R Radio Regulations:

Astrophysical importance of the band 84 - 86 GHz

This frequency band is used for both spectral line and continuum observations. Among the important spectral lines in this band the lines of Cyclopropenylidene (C3H2), Methyl acetylene (CH3CCH) and Deuterated Ammonia (NH2D) with rest frequencies of 85.339 GHz, 85.5 GHz and 85.926 GHz, respectively, should be noted.

See also: mm-Wavelength Astronomy.

Threshold levels of interference detrimental to radio astronomy spectral-line observations:

System Sensitivity (noise fluctuations)Threshold Interference Levels
TemperaturePower Spectral DensityInput PowerPower Flux DensitySpectral Power Flux Density
Single Dish2.86 mK-254 dB(WHz-1)-204 dBW-143 dB(Wm-2)-203 dB(Wm-2Hz-1)

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 Dish0.040 mK-273 dB(WHz-1)-186 dBW-127 dB(Wm-2)-223 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 84 - 86 GHz is used by the Radio Astronomy Service in:

Threats to the Radio Astronomy Service:

Last modified: January 25, 2005