Spectrum Managementfor Radio Astronomy
NAOJ
Masatoshi Ohishi
masatoshi.ohishi@nao.ac.jp

Interfered image at VLA
Credit: G.B. Taylor, NRAO/AUI/NSF.

star
Satellite interference
25 deg away from the star

No interference

2019/9/6

https://public.nrao.edu/telescopes/radio-frequency-interference/2

Car radar experiment @ NRO~76 GHz !!
477m from 45m tel.

2019/9/6

NRO Workshop

3Radio astronomers want to observe
all frequency range.
Other radio users may want to emit at
all frequency range.
All radio users, including astronomers,
have to SHARE the frequency resource.

2019/9/6

NRO Workshop

4RA bands to be protected
Frequency Bands(MHz)13.360 - 13.410
25.550 - 25.670
37.5 - 38.25
73 - 74.6
150.05 - 153
322 - 328.6
406.1 - 410
608 - 614
1 400 - 1 427 (HI)
1 610.6 - 1 613.8 (OH)
1 660 - 1 670 (OH)2 655 - 2 700
4 800 - 5 000 (H2CO)

2019/9/6

Frequency Bands(GHz)10.6 - 10.7
14.47 – 14.50 (H2CO)015.35 - 15.40
22.21- 22.50 (H2O)
23.6 - 24.0 (NH3)
31.3 - 31.80
42.5 - 43.5 (SiO)
76 - 116
123 - 158.5164 - 16700
200 - 231.500
241 - 275

NRO Workshop

5Frequency bands for 5G Mobile

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NRO Workshop

6

Coordination• International– Global: International Telecommunication
Union @ Geneva– Regional: Asia-Pacific region, Europe,Americas, Arab league, African union• National (Japan)– Ministry of Internal affairs and Communication à Radio act 
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NRO Workshop

7

Targets and Intensities
10m25
L 40
3530
25
20:00

21:00
2001/1/9

22:00

output voltage(V)

104

103

!;&  .<&1& 

0.7
0.65

0.55
0.582)

020000

40000

60000

80000

100000120000140000160000

sweep number

IEH
↑ 
MHiyama=POOQN

untSpeiaA#"M31102

10.8
0.75

↓?K>JBJK

ssio

39.&2 6;2(-537532 5&).&7.32
734 &2) 630&5 + '37731

102019/9/6
GAD
&66.34*.&

0.9
0.85

0.6

ie
Qu

Ca

"CNavg040427001ch560.dat"u 0:1

oon30

Radio flux density [Jy]Freqency [MHz]35105

Cosmic noise 2004/4/27JST f=35.02861MHz (min=5step avg=40sec)
10.95/ , 53r

R 40

10cm

RSTVSU'&(Jupite↓ CL@B(Konno et al. 2002)

19:00

&0&:;

106

CL@B@F>BH↑
(http://sunbase.nict.go.jp)

1mActive SunM

107

WavelengthJupiter"*( $%" "
10100

1,000

10,000Threshold for
RAS obs.

Frequency [MHz](ModifiedNRO
fromWorkshopKraus, 1986)(1Jy=10-26W/m2/Hz)

8

Spectrum Management forRadio Astronomy• In April, 2019, NAOJ has established a
new division, Spectrum ManagementOffice  .
– A unified gateway to the international/nationalcoordination– More radio use in higher frequency ranges• Before April, 2019, the frequency subcommittee took the role on a voluntarybasis.
2019/9/6

NRO Workshop

9

Example of Recent
Coordination• 60 GHz sensors:
57-66 GHz, 10mW
• 2nd harmonic falls into
CO J=1-0
à requested toreduce power of the
2nd harmonicà sensors must be
shut down within the
NRO premise
2019/9/6

NRO Workshop

10Starlink• A project by Space X
for providing fastinternet service worldwide through 12,000
satellite constellation.
• Concerns not only on
radio observations (bysatellite downlink) but
optical observations.
NGC 5353/4 at Lowell Observatory
2019/9/6

NRO Workshop

11Optical data on Starlink

Operational
Non-operationaldebris

2019/9/6

NRO Workshop

12For more information• Spectrum Management Info:

https://prc.nao.ac.jp/freqras/index.html• Position statements on Starlink
https://www.iau.org/news/announcements/
detail/ann19035/?lang
https://www.nao.ac.jp/news/topics/2019/20
190709-satellites.html
2019/9/6

NRO Workshop

13