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):

23.55 - 23.6   GHz:	FIXED
			MOBILE
			
			
23.6  - 24     GHz:	EARTH EXPLORATION-SATELLITE (passive)
			RADIO ASTRONOMY
			SPACE RESEARCH (passive)
			
			5.340
			
			
24    - 24.05  GHz:	AMATEUR
			AMATEUR-SATELLITE
			
			5.150
			
			
24.05 - 24.25  GHz:	RADIOLOCATION
			Amateur
			Earth Exploration-Satellite (active)
			
			5.150

Astrophysical importance of the band 23.6 - 24.0 GHz

The band 23.6 - 24.0 GHz, a band with exclusive allication to passive frequency use, is for radio astronomy band the main ammonia band and also important for continuum observations and for observations of a number of other spectral lines.

(see also IAU list of important spectral lines)

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 Dish2.91 mK-254 dB(WHz-1)-210 dBW-161 dB(Wm-2)-215 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 Dish0.050 mK-271 dB(WHz-1)-195 dBW-147 dB(Wm-2)-233 dB(Wm-2Hz-1)
Interferometer-208 dB(Wm-2Hz-1)
VLBI-182 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 23.6 - 24.0 GHz is used by the Radio Astronomy Service in:

Threats to the Radio Astronomy Service:

Last modified: June 16, 2009