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):


75.2  - 87.5  MHz:	FIXED
			MOBILE except aeronautical mobile
			
			5.175 5.179 5.184 5.187

Note:

The Radio Astronomy Service has a primary allocation in Region 3

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

Astrophysical importance of the band 79.25 - 80.25 MHz

The primary exclusive allocation of the band 79.25 - 80.25 MHz for the Radio Astronomy Service applies only in Region 2 (before WARC 79 it also applied in Region 3). Observations with the Arecibo 305-m radio telescope may be affected by active use of this band by the Fixed and Mobile Services in Cuba and other countries included in Footnote 5.178. A primary exclusive allocation on a worldwide basis is highly desirable; notification of use is required. In the United Kingdom the band 80.5 - 82.5 MHz is used in lieu of the Region 1 allocation 73-74.6 MHz (for historical reasons).

These bands are used for e.g. monitoring the interplanetary "weather" structure in the solar wind by an international network of instruments.

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 Dish14.3 mK-247 dB(WHz-1)-195 dBW-196 dB(Wm-2)-258 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 79.25 - 80.25 MHz is used by the Radio Astronomy Service in:

Threats to the Radio Astronomy Service:

Last modified: January 25, 2005