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 73.0 - 74.6 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):

68    - 74.8  MHz:	FIXED
			MOBILE except aeronautical mobile
			
			5.149 5.174 5.175 5.177 5.179
			

Note:

The Radio Astronomy Service has a primary allocation in Region 2

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

• Armenia: no allocation or reference to No. 5.149
• Bulgaria: no allocation or reference to No. 5.149
• Estonia: no allocation or reference to No. 5.149
• Finland: no allocation or reference to No. 5.149
• Iceland: no allocation or reference to No. 5.149
• Italy: "footnote" secondary allocation
• Liechtenstein:no allocation or reference to No. 5.149
• Luxembourg: no allocation or reference to No. 5.149
• Lithuania: secondary allocation
• Norway: secondary allocation
• Russian Federation: no allocation or reference to No. 5.149
• Sweden: no allocation or reference to No. 5.149
• Turkey: no allocation or reference to No. 5.149
• United Kingdom: no allocation or reference to No. 5.149

Astrophysical importance of the band 73.0 - 74.6 MHz

The importance of the band 73.0 - 74.6 MHz for the Radio Astronomy Service in Regions 1 and Region 3 is reflected in Footnote 5.149.

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
	Temperature	Power Spectral Density	Input Power	Power Flux Density	Spectral Power Flux Density
Single Dish	14.3 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 73.0 - 74.6 MHz is used by the Radio Astronomy Service in:

• Austria
• France
• the Netherlands
• Germany
• Russia

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
• Mobile Service