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)
National Arrangements for Radio Astronomy different from ITU-R Radio Regulations
Astrophysical importance of the band 86 - 92 GHz
Threshold levels of interference detrimental to radio astronomy
Radio Astronomy use of this band in Europe
Threats to the Radio Astronomy Service

ITU-RR allocations (+ footnotes):

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
			

92 - 94	GHz:		FIXED
			MOBILE
			RADIO ASTRONOMY
			RADIOLOCATION
		
			5.149

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

Liechtenstein: no allocation
Turkey: no allocation

Astrophysical importance of the band 86 - 92 GHz

This frequency band is used for both spectral line and continuum observations. Among the important spectral lines in this band the lines of Hydrogen cyanide (HC¹⁵N) 86.055 GHz 85.97 - 86.14 GHz Silicon monoxide (SiO), Hydrogen cyanide (H¹³CN), Formylium (H¹³CO⁺), Hydrogen isocyanide (HN¹³C), Silicon monoxide (SiO), Ethynyl radical (C₂H), Hydrogen cyanide (HCN), Hydrogen isocyanide (H¹⁵NC), Formylium (HCO⁺), Hydrogen isocyanide (HNC), Cyanoacetylene (HC₃N) and Methyl cyanide (CH₃CN) with rest frequencies of 86.243 GHz, 86.340 GHz, 86.754 GHz, 87.091 GHz, 86.847 GHz, 87.300 GHz, 88.632 GHz, 88.866 GHz, 89.189 GHz, 90.664 GHz, 90.979 GHz and 91.98 GHz, respectively, should be noted.

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

System Sensitivity (noise fluctuations) Threshold Interference Levels
Temperature Power Spectral Density Input Power Power Flux Density Spectral Power Flux Density
Single Dish 2.85 mK -254 dB(WHz^-1) -204 dBW -144 dB(Wm^-2) -204 dB(Wm^-2Hz^-1)

Threshold levels of interference detrimental to radio astronomy continuum observations:

System Sensitivity (noise fluctuations) Threshold Interference Levels
Temperature Power Spectral Density Input Power Power Flux Density Spectral Power Flux Density
Single Dish 0.037 mK -273 dB(WHz^-1) -185 dBW -125 dB(Wm^-2) -222 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 86 - 92 GHz is used by the Radio Astronomy Service in:

Threats to the Radio Astronomy Service:

Out-of-band emission from the following services:

Last modified: January 25, 2005

	System Sensitivity (noise fluctuations)		Threshold Interference Levels
	Temperature	Power Spectral Density	Input Power	Power Flux Density	Spectral Power Flux Density
Single Dish	2.85 mK	-254 dB(WHz^-1)	-204 dBW	-144 dB(Wm^-2)	-204 dB(Wm^-2Hz^-1)