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)
• National Arrangements for Radio Astronomy different from ITU-R Radio Regulations
• Astrophysical importance of the band 1330.0 - 1400.0 MHz
• Threshold levels of interference detrimental to radio astronomy
• Radio Astronomy use of this band in Europe
• Threats to the Radio Astronomy Service

ITU-RR allocations (+ footnotes):

1300 - 1350  MHz: 	AERONAUTICAL RADIONAVIGATION 5.337
			RADIOLOCATION
			RADIONAVIGATION-SATELLITE (Earth-to-space)
			
			5.149 5.337A
			

1350 - 1400  MHz: 	FIXED
			MOBILE
			RADIOLOCATION
			
			5.149 5.338 5.339 5.339A
			

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

• Armenia: no reference to FN 5.149
• Belgium: no assignment to radio astronomy
• Bulgaria: no reference to FN 5.149
• Byelorussia: no reference to FN 5.149
• Denmark: no allocation to radio astronomy
• Estonia: no reference to FN 5.149
• Finland: no reference to FN 5.149
• Iceland: no assignment to radio astronomy
• Ireland: no assignment to radio astronomy
• Italy: "footnote" secondary allocation
• Liechtenstein: no reference to FN 5.149
• Luxembourg: no reference to FN 5.149
• the Netherlands: secondary allocation
• Russian Federation: no reference to FN 5.149
• Spain: no reference to FN 5.149
• Turkey: no allocation or reference to FN 5.149
• United Kingdom: in the band 1350 - 1400 MHz: notification of use

Astrophysical importance of the band 1330.0 - 1400.0 MHz

The band 1330 - 1400 MHz is needed for important observations of Doppler-shifted radiation from hydrogen. FN 5.149 provides some protection to facilitate observations on more distant sources at those observatories with the largest aerials. Such observations can often be made at frequencies shared with low-power ground transmitters, but high power transmitters especially for radiolocation and any transmitters in aircraft or satellites can cause interference. Especially in Europe this band suffers bad sharing conditions (i.e. by radar).

Threshold levels of interference detrimental to radio astronomy spectral-line observations:

	System Sensitivity (noise fluctuations)		Threshold Interference Levels
	Temperature	Power Spectral Density	Input Power	Power Flux Density	Spectral Power Flux Density
Single Dish	3.48 mK	-253 dB(WHz-1)	-220 dBW	-196 dB(Wm-2)	-239 dB(Wm-2Hz-1)
Interferometer					-222 dB(Wm-2Hz-1)
VLBI					-199 dB(Wm-2Hz-1)

Threshold levels of interference detrimental to radio astronomy continuum observations:

	System Sensitivity (noise fluctuations)		Threshold Interference Levels
	Temperature	Power Spectral Density	Input Power	Power Flux Density	Spectral Power Flux Density
Single Dish	0.095 mK	-269 dB W Hz-1	-205 dB W	-180 dB W m-2	-255 dB W m-2 Hz-1
Interferometer					-238 dB W m-2 Hz-1
VLBI					-209 dB W m-2 Hz-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 1330.0 - 1400.0 MHz is used by the Radio Astronomy Service in:

• Czechia
• France
• Germany
• Italy
• the Netherlands
• Poland
• Russia
• Sweden
• Turkey
• United Kingdom

Threats to the Radio Astronomy Service:

Sharing problems with the following services:

• Aeronautical Radionavigation Service
• Fixed Service
• Mobile Service
• Radiolocation Service