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):


217   - 226   GHz:	FIXED
			FIXED-SATELLITE (Earth-to-space)
			MOBILE
			RADIO ASTRONOMY
			SPACE RESEARCH (passive) 5.562B
			
			5.149 5.341


226   - 231.5 GHz:	EARTH EXPLORATION-SATELLITE (passive)
			RADIO ASTRONOMY
			SPACE RESEARCH (passive)
			
			5.340


231.5 - 232   GHz:	FIXED
			MOBILE
			Radiolocation

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

Astrophysical importance of the band 226 - 231.5 GHz

This frequency band is used for both spectral line and continuum observations. Among the important spectral lines in this band the lines of Cyano radical (CN), Carbon monoxide (CO) with rest frequencies of 226.600 GHz, 226.800 GHz for the former one and 230.538 GHz for the latter 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 Dish2.40 mK-255 dB(WHz-1)-201 dBW-133 dB(Wm-2)-197 (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 Dish0.032 mK-274 dB(WHz-1)-182 dBW-114 dB(Wm-2)-215 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 226 - 231.5 GHz is used by the Radio Astronomy Service in:

Threats to the Radio Astronomy Service:

Last modified: March 16, 2005