ESF logo Committee on Radio Astronomy Frequencies

 The Committee on Radio Astronomy Frequencies (CRAF) is an Expert Committee of the European Science Foundation (ESF).

Frequency band allocated to the Radio Astronomy Service:

ITU-RR allocations (+ footnotes):


1626.5 - 1660   MHz:	MOBILE-SATELLITE (Earth-to-space)  5.351A
			
			5.341 5.351 5.353A 5.354 5.355 5.357A 5.359 5.362A 
			5.374 5.375 5.376
			

1660   - 1660.5 MHz: 	MOBILE-SATELLITE (Earth-to-space) 5.351A
			RADIO ASTRONOMY
			
			5.149 5.341 5.351 5.354 5.362A 5.376A

			
			
1660.5 - 1668 MHz:	RADIO ASTRONOMY
			SPACE RESEARCH (passive)
			Fixed
			Mobile except aeronautical mobile 
			
			5.149 5.341 5.379 5.379A
			
1668 - 1668.4 MHz:	MOBILE-SATELLITE (Earth-to-space) 5.351A 5.348C 5.379B 5.379C
			RADIO ASTRONOMY
			SPACE RESEARCH (passive)
			Fixed
			Mobile except aeronautical mobile 
			
			5.149 5.341 5.379 5.379A
			
1668.4 - 1670   MHz:	METEOROLOGICAL AIDS
			FIXED
			MOBILE except aeronautical mobile
			MOBILE-SATELLITE (Earth-to-space) 5.351A 5.379B 5.379C
			RADIO ASTRONOMY
			
			5.149 5.341 5.379D 5.379E
			
			
1670 - 1675   MHz:	METEOROLOGICAL AIDS
			FIXED
			METEOROLOGICAL-SATELLITE (space-to Earth)
			MOBILE
			MOBILE-SATELLITE (Earth-to-space) 5.351A 5.379B
			
			5.341 5.379D 5.379E 5.380A

Astrophysical importance of the band 1660.0 - 1670.0 MHz

The band 1660 - 1670 MHz is an important radio astronomy band for measurements of both the OH lines and the continuum. The present allocation of the band 1660 - 1660.5 MHz to the Mobile Service may lead to its serious degradation. In addition this band is used for continuum observations and also for VLBI. Successful use of this band will depend also on the avoidance of interference from meteorological satellites having assignments in the adjacent band (see No. 5.149 and 5.379A). Desired is an allocation for radio astronomy with improved sharing for the total band (See also ITU-R Recommendation RA.314-10, 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)

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 Dish0.16 mK-267 dB(WHz-1)-207 dB W-181 dB(W m-2)-251 dB(Wm-2Hz-1)
Interferometer-237 dB(Wm-2Hz-1)
VLBI-221 dB(Wm-2Hz-1)

NOTE:

For further details the reader is referred to ITU-R Recommendation RA.769. 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 1660.0 - 1670.0 MHz is used by the Radio Astronomy Service in:

Threats to the Radio Astronomy Service:

Last modified: June 4, 2009