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):


1559 - 1610 MHz:	AERONAUTICAL RADIONAVIGATION
                        RADIONAVIGATION-SATELLITE (space-to-Earth)(space-to-space)
                        5.208B 5.328B 5.329A 

                        5.341 5.362B 5.362C
			

1610 - 1610.6 MHz: 	MOBILE-SATELLITE (Earth-to-space) 5.351A
			AERONAUTICAL RADIONAVIGATION
			
			5.341 5.355 5.359 5.364 5.366
			5.367 5.368 5.369 5.371 5.372
			
			
1610.6 - 1613.8 MHz:	MOBILE SATELLITE (Earth-to-space) 5.351A
			RADIO ASTRONOMY
			AERONAUTICAL RADIONAVIGATION
			
			5.149 5.341 5.355 5.359 5.364 5.366
			5.367 5.368 5.369 5.371 5.372
			
			
1613.8 - 1626.5 MHz:	MOBILE-SATELLITE (Earth-to-space) 5.351A
			AERONAUTICAL RADIONAVIGATION
			Mobile-Satellite (space-to-Earth) 5.208B
			
			5.341 5.355 5.359 5.364 5.365 
			5.366 5.367 5.368 5.369 5.371 
			5.372

Astrophysical importance of the band 1610.6 - 1613.8 MHz

The band 1610.6 - 1613.8 MHz is an important band for OH line observations and is used in conjunction with the main OH bands in the next higher OH-band (1660-1670 MHz).
The ITU-RR Footnotes 5.149 and 5.372 urge to protect radioastronomy operations within band 1610.6 - 1613.8 MHz.
This band suffers strong pressure by satellite systems.
Better protection is needed and with an extension of protection to a somewhat slightly wider band of 1610 - 1614 MHz to take account of the larger Doppler shifts now being detected.

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 Dish3.35 mK-253 dB(WHz-1)-220 dBW-194 dB(Wm-2)-238 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 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(Wm-2Hz-1) (see ITU-R "Handbook on Radio Astronomy", 1995/2003, chapter 4).

In Europe, the band 1610.6 - 1613.8 MHz is used by the Radio Astronomy Service in:

Threats to the Radio Astronomy Service:

Last modified: June 4, 2009