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):


1710 - 1930   MHz:	FIXED
			MOBILE    5.380 5.384A 5.388A
			
			5.149 5.341 5.385 5.386 5.387 5.388

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

Astrophysical importance of the band 1718.8 - 1722.2 MHz

The band 1718.8 - 1722.2 MHz is used for observations of the OH lines associated with those in the band 1660 - 1670 MHz and protection needs to be improved beyond No. 5.149 by excluding airborne and space transmissions (See also ITU-R Recommendation RA.314-8, table 1).

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 Dish3.48 mK-253 dB(WHz-1)-220 dBW-194 dB(Wm-2)-237 dB(Wm-2Hz-1)
Interferometer-223 dB(Wm-2Hz-1)
VLBI-208 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 1718.8 - 1722.2 MHz, allocated to the Radio Astronomy Service on a secondary basis is used by this service in:

Threats to the Radio Astronomy Service:

Last modified: March 16, 2005