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1.Purpose of Radio Monitoring

Radio waves emitted from illegally modified radio equipment, or unlicensed equipment, can cause TV reception and radio signal problems, or obstruct radio signals used by the fire department, ambulances, and trains, which could result in serious threat to human safety concerns.

With increasing importance being placed on environmental protection relevant to radio wave use, more efficient and effective means of radio-wave monitoring is needed to prevent and strengthen controls on a rising number of unlicensed radio stations.

Since FY1993, the Ministry of Internal Affairs and Communications (MIC) has used spectrum user fees to maintain facilities for improvement of radio wave monitoring. As part of such activities, DEURAS System, main monitoring system for radio waves which detects unlicensed radio waves, has been developed and is being installed in main cities across Japan.

(DEURAS: DEtect Unlicensed RAdio Stations)

2.Outline of radio monitoring systems

(1) DEURAS-D System
   DEURAS-D system locates unlicensed radio stations by detecting the direction of radio emissions or monitoring radio reception from stationary sensor stations mounted atop buildings or vehicles, or from vehicle-mounted mobile sensors.

(2) DEURAS-H System(Shortwave Monitoring System)
   DEURAS-H System is composed of five sensor stations throughout Japan which detect the direction of radio wave in the shortwave (300kHz to 30MHz) band, and of a main central station (located at the Kanto Bureau of Telecommunications) and regional central stations which remotely control the sensor stations via dedicated lines. Through remote control of sensor stations by the main central stations, the system detects the location of radio broadcast sources.


Schematic diagram of shortwave monitoring system

(3) DEURAS-S System (Space Radio Monitoring System)
   DEURAS-S System is a system that receives radio wave from geostationary and orbiting satellites, identifying the location of orbiting satellites and quality of radio wave (frequency, etc.), and determining whether each one is operating properly in accordance with international agreements and international adjustment results.
   Information obtained from this system is utilized to ensure administration of satellites on an international level.


Panoramic view of space radio monitoring facility



      Orbiting satellite monitoring antenna     Geostationary satellite monitoring antenna                                 Main central station

(4) Maintenance Plans for DEURAS System
   The construction and enhancement of DEURAS System is taking place over seven terms beginning in FY1993.

Table: Maintenance Plans for Radio Monitoring Systems
  First Term(FY1993 - FY 1995) Second Term(FY1996 - FY1998) Third Term(FY1999 - FY2001) Fourth Term(FY2002 - FY2004) Fifth Term(FY2005 - FY2007) Sixth Term(FY2008 - FY2010) Seventh Term(FY2011 - FY2013)
DEURAS System Construction of sensor stations in key cities, particularly Tokyo and the other major cities designated by government ordinance, and prefectural capitals Construction of sensor stations in cities with populations of more than 100,000 Construction of sensor stations in cities with populations of more than 50,000 Construction of sensor stations in cities with populations of more than 30,000 inhabitants which receive constant reports of interference or disturbance Improvement and updating of systems installed during the first through fourth terms
DEURAS-H System Construction of main central station and sensor stations Improvement and updating of systems installed during the first through third terms
DEURAS-S System   Construction of DEURAS-S System (L/S/C/Ku/Ka bands) Construction of DEURAS-S System (VHF/UHF bands)   Improvement and updating of systems installed during the second and third terms

3.Number of Unlicensed Radio Stations Detected and Dealt With

Unlicensed radio stations not only disrupt and interfere with important radio communications and general operational radio, some also generate illegally powerful radio waves that interfere with neighboring television and radio, or cause disruptions to cellular phone service.
   The following shows the number of unlicensed radio stations detected thus far by Bureaus of Telecommunications in each region of Japan. These stations are being dealt with through legal prosecution or administrative guidance as needed.
   Using the DEURAS System, we intend to continue and reinforce the effort to detect and eliminate unlicensed radio stations.

Table: Number of unlicensed radio stations detected
FY
  1993  
  1994  
  1995  
  1996  
  1997  
  1998  
  1999  
  2000  
  2001  
Number of unlicensed
radio stations detected
  30,858  
  31,114  
  34,008  
  35,955  
  36,316  
  45,136  
  37,422  
  34,067  
  23,329  
FY
  2002  
  2003  
  2004  
  2005  
  2006  
  2007  
  2008  
  2009  
  2010  
Number of unlicensed
radio stations detected
  17,670  
  20,720  
  15,765  
  13,966  
  12,168  
  12,083  
  10,232  
     9,270 
  8,538   
FY
  2011  
Number of unlicensed
radio stations detected
    8,903  

4.Change in radio monitoring budget

Change in radio monitoring budget (unit: 100 million yen)
Phase of maintenance plan First Term Second Term Third Term Fourth Term Fifth Term Sixth Term Seventh Term
Fiscal year 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
No. of facilities 19.1 15.7 31.4 42.2 34.7 28.6 23.5 26.7 34.6 28.4 28.4 34.3 33.3 35.4 37.2 31.5 24.5 26.5 23.6 26.5 -
Maintenance and operation 7.4 5.1 12.4 16.8 20.0 29.1 39.8 49.5 34.7 33.0 36.6 31.1 30.1 27.0 31.3 29.4 26.9 25.5 28.4 26.6 -
Expenses for publicity and information dissemination activities 1.4 1.8 1.8 3.8 6.1 7.3 9.6 10.7 11.6 9.2 7.2 6.9 6.9 6.7 7.4 7.4 3.6 3.5 3.3 3.5 -
Total 27.9 22.6 45.6 62.8 60.8 65.0 72.9 86.9 80.9 70.6 72.2 72.3 70.3 69.1 75.9 68.3 55.0 55.5 55.3 56.6 -
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Copyright(C)Telecommunications Bureau of the Ministry of Internal Affairs and Communications All Rights Reserved.