Printout page
- HOME>
- System of Radio Use>
- Spectrum User Fee System>
- Objectives of the System>
- Maintenance and Operation of Radio Facilities
1.The importance 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.
To prevent such problems from occurring, it has become increasingly important to protect the radio use environment, with more efficient and effective radio monitoring systems being needed to better prevent and eliminate illegal radio stations.
Based on this need, the Detect Unlicensed Radio Stations system (DEURAS system) for monitoring radio waves was developed by utilizing revenue obtained from spectrum user fees and began operating in April 1993. This system is being deployed in major cities nationwide.
2.Detect Unlicensed Radio Stations System (DEURAS system)
DEURAS system, sensor stations, are installed on building roofs, mountaintops, and in vehicles, and receive radio waves to measure the direction of the radio wave transmission source and other details, in order to determine the location and other details of an illegal radio station.
3.Reported Unlicensed Radio Stations Cases and Number of Stations
Illegal radio stations not only cause interference and obstruction to important radio communications and general operational radio, but there are some which emit extremely powerful illegal radio waves to the surrounding environment, resulting in TV and radio signal obstructions along roads, or making it difficult to use cellular telephones.
The following is the number of unlicensed radio stations, etc. that have been confirmed by regional bureaus of communications. The DEURAS system will continue its efforts in locating and eliminating unlicensed radio stations.
| FY | 1993 | '94 | '95 | '96 | '97 | '98 | '99 | '00 | '01 | '02 | '03 | '04 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Detected unlicensed radio stations, etc. | 30,858 | 31,114 | 34,008 | 35,955 | 36,316 | 45,136 | 37,422 | 34,067 | 23,329 | 17,670 | 20,720 | 15,765 |
[Number of unlicensed radio stations, etc.]
5.Maintenance Plans for the DEURAS System
The DEURAS system will be constructed and expanded in three phases, from FY1993 to FY2001.
| Phase 1 (FY1993 - 1995) |
Phase 2 (FY1996 - 1998) |
Phase 3 (FY1999 - 2001) |
|
|---|---|---|---|
| Target areas | Tokyo, major city designated by government ordinance designated cities,prefectural capitals, and other regional major cities | Cities with a population of 100,000 or more | Cities with a population of 50,000 or more |
6.Space Monitoring Facility(SMF)
The Space Monitoring Facility uses radio waves received from stationary satellites to measure the satellite's orbit path and radio wave quality (frequency, etc.) to monitor whether operations are in accordance with international agreements and adjustments.
The information gathered through this system is used to ensure correct international satellite operations.
[Types of Radio Monitoring Systems]
