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):


122.25 - 123 GHz:	FIXED
			INTER-SATELLITE
			MOBILE  5.558
			Amateur
			
			5.138


123    - 126 GHz:	FIXED-SATELLITE (space-to-Earth)
			MOBILE-SATELLITE (space-to-Earth)
			RADIONAVIGATION
			RADIONAVIGATION-SATELLITE
			Radio astronomy
			
			5.554


126    - 130 GHz:	FIXED-SATELLITE (space-to-Earth)
			MOBILE-SATELLITE (space-to-Earth)
			RADIONAVIGATION
			RADIONAVIGATION-SATELLITE
			Radio astronomy 5.562D

			5.149 5.554

Astrophysical importance of the band 123 - 126 GHz

This frequency band is used for both spectral line and continuum observations.

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 Dish2.88 mK-254 dB(WHz-1)-204 dBW-140 dB(Wm-2)-201 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 Dish0.034 mK-273 dB(WHz-1)-184 dBW-121 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 123 - 126 GHz is used by the Radio Astronomy Service in:

Threats to the Radio Astronomy Service:

Last modified: January 19, 2005