Radio Astronomy Frequencies List

On behalf on the Radioastronomy Commission 40 of the International Astronomical Union (IAU) representing about 100 countries, International Telecommunications Union (ITU), who represents more than 350 nations, allocated frequencies bands that are strictly reserved to scientific, militaries and public usage. All the spectrum from 9 kHz to 275 GHz is covered and allocated to specific services in order to avoid any interferences. 

However side effects called "harmful interferences" appear from time to time due to parasits generated by unprotected devices or the lack of national regulation.

Some of these bands are reserved for radio astronomy purposes, mainly for the study of spectral lines like the water hole, OH molecule, etc. You will find on the European Radiocommunications Office website, ERO, the complete list of allocated frequencies with their description. 

Here is the global list updated in 2003 of allocated bands in which all emissions are prohibited. Unfortunately most are shared with other services :

Passive Bands 

1.400 -
2.69 -
10.68 -
15.35 -
23.6 -
31.3 -
31.5 -
48.94 -
50.2 -
52.6 -
86 -
100 -
109.5 -
114.25 -
148.5 -
164 -
182 -
190 -
200 -
226 -
250 -

1.427 GHz,
2.70 GHz, except those provided for by No.5.422,
10.70 GHz, except those provided for by No.5.483,
15.4 GHz, except those provided for by No. 5.511,
24 GHz,
31.5 GHz,
31.8 GHz in Region 2,
49.04 GHz from airborne stations,
50.4 GHz, except those provided for by No.5.555A
54.25 GHz,
92 GHz,
102 GHz,
11.8 GHz,
116 GHz,
151.5 GHz,
167 GHz,
185 GHz, except those provided for by No. 5.563
191.8 GHz,
209 GHz,
231.5 GHz,
252 GHz.

Note however that Rules and Procedures from ITU specify that there is no allocation to radio astronomy in the next bands, whatever nationals regulations, so interferences can exist in these bands if they are used for that purpose :

Bands non allocated to Radio Astronomy

73

1330

3260

3332

3345.8

6650

- 74.6 MHz°

- 1400 MHz

- 3267 MHz

- 3339 MHz

- 3352.5 MHz

- 6675.2 MHz

22.01

22.81

23.07

31.20

36.43

93.07

-22.21 GHz

-22.86 GHz

-23.12 GHz

-31.3 GHz

-36.5 GHz

-93.27 GHz

° in Regions 1 and 3.

Hereunder the detail of each band allocated to Radio Astronomy as defined by IAU, modified Dublin 2003 :

FREQUENCIES BANDS ALLOCATED TO RADIO ASTRONOMY

or shared with other services

Below 1 GHz:

Below 1 GHz :

13.360 - 13.410 MHz

FIXED RADIO ASTRONOMY (°)

25.55 - 25.67 MHz

RADIO ASTRONOMY (°)

37.5 - 38.25 MHz

FIXED MOBILE Radio Astronomy (°)

150.05 - 153 MHz

FIXED MOBILE except aeronautical mobile RADIO ASTRONOMY (°)

322 - 328.65 MHz

FIXED MOBILE RADIO ASTRONOMY (°)

406.1 - 410 MHz

FIXED MOBILE except aeronautical mobile RADIO ASTRONOMY (°)

1-10 GHz:

1-10 GHz:

1400 - 1427 MHz

EARTH EXPLORATION-SATELLITE (passive) RADIO ASTRONOMY, SPACE RESEARCH (passive)

1610.6 - 1613.8 MHz

AERONAUTICAL RADIONAVIGATION, MOBILE-SATELLITE (Earth-to-space) RADIO ASTRONOMY (°)

1660 - 1660.5 MHz

MOBILE-SATELLITE (Earth-to-space) RADIO ASTRONOMY (°)

1660.5 - 1668.4 MHz

RADIO ASTRONOMY SPACE RESEARCH (passive) Fixed Mobile except

aeronautical mobile (°)

1668.4 - 1670 MHz

METEOROLOGICAL AIDS FIXED MOBILE except aeronautical mobile RADIO ASTRONOMY (°)

2655 - 2670 MHz

FIXED MOBILE except aeronautical mobile BROADCASTING SATELLITE Earth Exploration-Satellite (passive) Radio Astronomy Space Research (passive) (°)

2670 - 2690 MHz

FIXED MOBILE except aeronautical mobile MOBILE-SATELLITE (Earth-to-space) Earth Exploration-Satellite (passive) Radio Astronomy Space Research (passive) (°)

2690 - 2700 MHz

EARTH EXPLORATION-SATELLITE (passive) RADIO ASTRONOMY SPACE RESEARCH (passive)

4800 - 4990 MHz

FIXED MOBILE Radio Astronomy (°)

4990 - 5000 MHz

FIXED MOBILE except aeronautical mobile RADIO ASTRONOMY Space Research (passive) (°)

10-100 GHz:

10-100 GHz:

10.6 - 10.68 GHz

EARTH EXPLORATION-SATELLITE (passive) FIXED MOBILE except aeronautical mobile RADIO ASTRONOMY SPACE RESEARCH (passive) Radiolocation (°)

10.68 - 10.7 GHz

EARTH EXPLORATION-SATELLITE (passive) RADIO ASTRONOMY SPACE RESEARCH (passive)

14.47 - 14.5 GHz

FIXED FIXED-SATELLITE (Earth-to-space) S5.506 MOBILE except aeronautical mobile Land Mobile-Satellite (Earth-to-space) Radio Astronomy (°)

14.8 - 15.35 GHz*

FIXED MOBILE Space Research Radio Astronomy (°)

15.35 - 15.4 GHz

EARTH EXPLORATION-SATELLITE (passive) RADIO ASTRONOMY SPACE RESEARCH (passive)

22.21 - 22.50 GHz

EARTH EXPLORATION-SATELLITE (passive) FIXED MOBILE except aeronautical mobile RADIO ASTRONOMY SPACE RESEARCH (passive) (°)

22.50 - 22.55 GHz*

EARTH EXPLORATION-SATELLITE (passive) FIXED MOBILE except aeronautical mobile RADIO ASTRONOMY SPACE RESEARCH (passive) (°)

22.55 - 23 GHz*

FIXED MOBILE INTER-SATELLITE RADIO ASTRONOMY SPACE RESEARCH (passive) (°)

23.6 - 24 GHz

EARTH EXPLORATION-SATELLITE (passive) RADIO ASTRONOMY SPACE RESEARCH

31.3 - 31.5 GHz

EARTH EXPLORATION-SATELLITE (passive) RADIO ASTRONOMY SPACE RESEARCH (passive)

31.5 - 31.8 GHz

EARTH EXPLORATION-SATELLITE (passive) RADIO ASTRONOMY SPACE RESEARCH (passive) Fixed Mobile except aeronautical mobile

36 - 37 GHz*

EARTH EXPLORATION-SATELLITE (passive) FIXED MOBILE SPACE RESEARCH (passive) Radio Astronomy

42.5 - 43.5 GHz

FIXED FIXED-SATELLITE (Earth-to-space) S5.552 MOBILE except aeronautical mobile SPACE RESEARCH (passive) RADIO ASTRONOMY

48.5 - 50.2 GHz*

FIXED FIXED-SATELLITE (Earth-to-space) S5.552 MOBILE RADIO ASTRONOMY

51.4 - 52.6 GHz*

FIXED MOBILE RADIO ASTRONOMY

58.2 - 59 GHz*

EARTH EXPLORATION-SATELLITE (passive) FIXED SPACE

RESEARCH (passive) RADIO ASTRONOMY

76 - 77.5 GHz

RADIO ASTRONOMY RADIOLOCATION Amateur Amateur-Satellite Space research (space-to-Earth) (°)

77.5 - 78 GHz

AMATEUR AMATEUR-SATELLITE Radio astronomy Space research (space-to-Earth)

78 - 79 GHz

RADIOLOCATION Amateur Amateur-satellite Radio Astronomy Space research (space-to-Earth) (°)

79 - 81 GHz

RADIO ASTRONOMY RADIOLOCATION Amateur Amateur-satellite Space research (space-to-Earth) (°)

81 - 84 GHz

FIXED FIXED-SATELLITE (Earth-to-space) MOBILE MOBILE-SATELLITE (Earth-to-space) RADIO ASTRONOMY Space research (space-to-Earth) (°)

84 - 86 GHz

FIXED FIXED-SATELLITE (Earth-to-space) MOBILE RADIO ASTRONOMY (°)

86 - 92 GHz

EARTH EXPLORATION-SATELLITE (passive) RADIO ASTRONOMY SPACE RESEARCH (passive)

92 - 94 GHz

FIXED MOBILE RADIO ASTRONOMY RADIOLOCATION (°)

94 - 94.1 GHz

EARTH EXPLORATION-SATELLITE (active) RADIOLOCATION SPACE RESEARCH (active) Radio Astronomy

94.1 - 95 GHz

FIXED MOBILE RADIO ASTRONOMY RADIOLOCATION

95 - 100 GHz

FIXED MOBILE RADIO ASTRONOMY RADIOLOCATION RADIONAVIGATION RADIONAVIGATION-SATELLITE

Over 100 GHz:

Over 100 GHz:

100 - 102 GHz

EARTH EXPLORATION-SATELLITE (passive) RADIO ASTRONOMY SPACE RESEARCH (passive)

102 - 105 GHz

FIXED MOBILE RADIO ASTRONOMY (°)

105 - 109.5 GHz

FIXED MOBILE RADIO ASTRONOMY SPACE RESEARCH (passive) (°)

109.5 - 111.8 GHz

EARTH EXPLORATION-SATELLITE (passive) RADIO ASTRONOMY SPACE RESEARCH (passive)

111.8 - 114.25 GHz

FIXED MOBILE RADIO ASTRONOMY SPACE RESEARCH (passive) (°)

114.25 - 116 GHz

EARTH EXPLORATION-SATELLITE (passive) RADIO ASTRONOMY SPACE RESEARCH (passive)

123 - 126 GHz

FIXED-SATELLITE (space-to-Earth) MOBILE-SATELLITE (space-to-Earth) RADIONAVIGATION RADIONAVIGATION-SATELLITE Radio Astronomy

126 - 130 GHz

FIXED-SATELLITE (space-to-Earth) MOBILE-SATELLITE (space-to-Earth) RADIONAVIGATION RADIONAVIGATION-SATELLITE Radio Astronomy

130 - 134 GHz

EARTH EXPLORATION-SATELLITE (active) FIXED INTER-SATELLITE MOBILE RADIO ASTRONOMY (°)

134 - 136 GHz

AMATEUR AMATEUR-SATELLITE Radio Astronomy

136 - 141 GHz

RADIO ASTRONOMY RADIOLOCATION Amateur Amateur-satellite (°)

141 - 148.5 GHz

FIXED MOBILE RADIO ASTRONOMY RADIOLOCATION (°)

148.5 - 151.5 GHz

EARTH EXPLORATION-SATELLITE (passive) RADIO ASTRONOMY SPACE RESEARCH (passive)

151.5 - 155.5 GHz

FIXED MOBILE RADIO ASTRONOMY RADIOLOCATION

155.5 - 158.5 GHz

EARTH EXPLORATION-SATELLITE (passive) FIXED MOBILE RADIO ASTRONOMY SPACE RESEARCH (passive) (°)

164 - 167 GHz

EARTH EXPLORATION-SATELLITE (passive) RADIO ASTRONOMY SPACE RESEARCH (passive)

182 - 185 GHz

EARTH EXPLORATION-SATELLITE (passive) RADIO ASTRONOMY SPACE RESEARCH (passive)

200 - 202 GHz

EARTH EXPLORATION-SATELLITE (passive) RADIO ASTRONOMY SPACE RESEARCH (passive)

202 - 209 GHz

EARTH EXPLORATION-SATELLITE (passive) RADIO ASTRONOMY SPACE RESEARCH (passive)

209 - 217 GHz

FIXED FIXED-SATELLITE (Earth-to-space) MOBILE RADIO ASTRONOMY (°)

217 - 226 GHz

FIXED FIXED-SATELLITE (Earth-to-space) MOBILE RADIO ASTRONOMY SPACE RESEARCH (passive) (°)

226 - 231.5 GHz

EARTH EXPLORATION-SATELLITE (passive) RADIO ASTRONOMY SPACE RESEARCH (passive)

241 - 248 GHz

RADIO ASTRONOMY RADIOLOCATION Amateur Amateur-satellite (°)

248 - 250 GHz

AMATEUR AMATEUR-SATELLITE Radio Astronomy

250 - 252 GHz

EARTH EXPLORATION-SATELLITE (passive) RADIO ASTRONOMY SPACE RESEARCH (passive)

252 - 265 GHz

FIXED MOBILE MOBILE-SATELLITE (Earth-to-space) RADIO ASTRONOMY RADIONAVIGATION RADIONAVIGATION-SATELLITE

265 - 275 GHz

FIXED FIXED-SATELLITE (Earth-to-space) MOBILE RADIO ASTRONOMY

275 - 1000 GHz

(Not allocated)

Comments

* Extensions for European common allocation only. They differ from RR Region 1 allocations and RR footnotes relevant to CEPT and frequency bands.

(°) In these allocated frequencies bands, national administrations are urged to take all practicable dispositions to protect the radio astronomy service from harmful interference, in particular emissions from spaceborne or airborne stations.

Harmful Interference to the Radio Astronomy Service

According ITU, interference levels are considered to be harmful to the Radio Astronomy Service when the rms fluctuations of the system noise increase at the receiver output by 10% due to the presence of interference.

ITU-R RA.769-1 gives the levels of harmful interference for the Radio Astronomy Service based on this criterion and the adopted integration time of 2000 seconds. It should be noted that in practice it depends completeley on the type of telescope and the operating parameters used whether interferences is considered harmful. For example: the conditions are different for single dish observations, radio interferometry and Very Long Baseline Interferometry (VLBI); or whether observations are done of spectral lines or in a broadband continuum mode. Usualy each instruments has a number of different operating parameters. The values given in ITU-R RA.769-1 general "averages" and give an indication of the levels at which an interfering signal degrades the observations significantly.

Percentage of time lost by the Radio Astronomy Service due to harmful interference

In cases where the strength of an interfering signal varies as a result of time-varying propagation conditions, for example in the case of propagation by tropospheric scatter, the usual practice in interference calculations for radio astronomy is to consider the level for which the propagation loss is exceeded for 90% of time. Thus the harmful threshold would be exceeded for 10% of time, and in removing contaminated data 10% of the observations would be lost. Radio astronomers generally agree that this is the maximum tolerable loss. In general this figure applies to interference which intermittently exceeds the harmful threshold for time periods such that no more than 10% of the data is contaminated. In terms of the time averaging no more than 10% of the initially-averaged data (for example of tens of milliseconds to tens of seconds) should be lost when contaminated data is rejected. Thus, for example, interference from a radar signal, the mean power of which exceeds the harmful threshold, would not be tolerable even if the duty cycle of the transmitter is less than 10% (according ITU-R Handbook on Radio Astronomy).

For more information

IAU list of important spectral lines (on this site)

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