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 150.05 - 153.0 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):

149.9  - 150.05 MHz:	MOBILE-SATELLITE (Earth-to-space)
			5.209 5.224A

			RADIONAVIGATION-SATELLITE 5.224B
			
			5.220 5.222 5.223
			

150.05  - 153  MHz: 	FIXED
			MOBILE except aeronautical mobile
			RADIO ASTRONOMY
			
			5.149
			

153  -  154  MHz:	FIXED
			MOBILE except aeronautical mobile (R)
			Meteorological Aids
			

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

• Armenia: no allocation
• Austria: no allocation - only mention of No. 5.149
• Bulgaria: no reference to foonote No. 5.149
• Estonia: no allocation
• Finland: no allocation
• Iceland: no allocation
• Ireland: no allocation
• Italy: "footnote" secondary allocation
• Liechtenstein: no allocation
• Luxembourg: no allocation
• Poland: no allocation - only mention of No. 5.149
• Portugal: no allocation
• Russian Federation: no allocation
• Sweden: no allocation
• Switzerland: priority for military applications
• Turkey: no allocation
• United Kingdom: no allocation for the band 152 - 153 MHz

Astrophysical importance of the band 150.05 - 153.0 MHz

The Radio Astronomy Service has in the band 150.05 - 153.0 MHz a shared primary allocation in Region 1. It falls near the middle of a wide gap in continuum coverage. In the United States, a large amount of interference occurs in this band. A clear continuum band is badly needed between the current 74 and 327 MHz allocations. This band is widely used in the United Kingdom and is a major band for the Giant Metre-wave Radio Telescope, GMRT, in India. Further worldwide consolidation would be most desirable.

This band is also used for pulsar observations and solar observations.

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	2.73 mK	-254 dB(WHz-1)	-199 dBW	-194 dB(Wm-2)	-259 dB(Wm-2Hz-1)
Interferometer					-244 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 150.05 - 153.0 MHz is used by the Radio Astronomy Service in:

• Austria
• France
• Germany
• the Netherlands
• Poland
• Portugal
• Russia
• United Kingdom

Threats to the Radio Astronomy Service:

Sharing problems with the following services:

• Fixed Service
• Mobile Service

  Out-of-band emission from the following services:

• Fixed Service
• Land Mobile-Satellite Service
• Meteorological Aids Service
• Mobile Service
• Radinavigation-Satellite Service

  Spurious emission from the following services:

• Mobile-Satellite Service in the bands 137 - 137.025 MHz, 137.175 - 137.825 MHz, 137.825 - 138 MHz and 148 - 149.9 MHz (see No. 5.208A).