1240-1300 MHz 1. Band .1240-1300 MHz 1. Band Introduction ... (ATC) in the national airspace, border

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  • 1240-1300 MHz

    March 1, 2014

    1240-1300 MHz

    1. Band Introduction

    The band 1240-1300 MHz is used by Federal agencies for operating various types of

    long-range radar systems that perform missions critical to safe and reliable air traffic

    control (ATC) in the national airspace, border surveillance, early warning missile

    detection, and drug interdiction. These radar systems ensure the safe transportation of

    people and goods, encourage the flow of commerce, and provide for national defense.

    Long-range radar systems are operated in this portion of the radio frequency spectrum

    because the effects of rain and fog on radar target detection are very low, the external

    background noise levels are low, and high-power transmitter tubes operate very

    efficiently. These factors are important to achieve the long-range detection of different

    size aircraft as well as other targets.

    2. Allocations

    2a. Allocation Table

    The frequency allocation table shown below is extracted from the Manual of Regulations

    and Procedures for Federal Radio Frequency Management, Chapter 4 Allocations,

    Allotments and Plans.

    Table of Frequency Allocations

    United States Table

    Federal Table Non-Federal Table FCC Rule Part(s) 1240-1300 EARTH EXPLORATION-SATELLITE (active) RADIOLOCATION G56 SPACE RESEARCH (active) AERONAUTICAL RADIONAVIGATION 5.332 5.335

    1240-1300 AERONAUTICAL RADIONAVIGATION Amateur Earth exploration-satellite (active) Space research (active) 5.282

    Amateur (97)

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    2b. Additional Allocation Table Information

    G56 Federal radiolocation in the bands 1215-1300, 2900-3100, 5350-5650 and 9300-

    9500 MHz is primarily for the military services; however, limited secondary use is

    permitted by other Federal agencies in support of experimentation and research programs.

    In addition, limited secondary use is permitted for survey operations in the band 2900-

    3100 MHz.

    5.282 In the bands 435-438 MHz, 1 260-1 270 MHz, 2 400-2 450 MHz, 3 400-3 410

    MHz (in Regions 2 and 3 only) and 5650-5670 MHz, the amateur-satellite service may

    operate subject to not causing harmful interference to other services operating in

    accordance with the Table (see No. 5.43). Administrations authorizing such use shall

    ensure that any harmful interference caused by emissions from a station in the amateur-

    satellite service is immediately eliminated in accordance with the provisions of No.

    25.11. The use of the bands 1 260-1 270 MHz and 5 650-5 670 MHz by the amateur-

    satellite service is limited to the Earth-to-space direction.

    5.332 In the band 1 215-1 260 MHz, active spaceborne sensors in the Earth exploration-

    satellite and space research services shall not cause harmful interference to, claim

    protection from, or otherwise impose constraints on operation or development of the

    radiolocation service, the radionavigation- satellite service and other services allocated on

    a primary basis. (WRC-2000)

    5.335 In Canada and the United States in the band 1 240-1 300 MHz, active spaceborne

    sensors in the earth exploration-satellite and space research services shall not cause

    interference to, claim protection from, or otherwise impose constraints on operation or

    development of the aeronautical radionavigation service.

  • 1240-1300 MHz

    Page 3 of 26

    3. Federal Agency Use

    3a. Federal Agency Frequency Assignments Table

    The following table identifies the frequency band, types of allocations, types of

    applications, and the number of frequency assignments in the Government Master File

    (GMF) by agency.

    Federal Frequency Assignment Table

    1240-1300 MHz Band

    SHARED BAND

    AGENCY

    AERONAUTICAL RADIONAVIGATION

    AMATEUR

    EARTH EXPLORATION-SATELLITE (active)

    RADIOLOCATION

    RADIONAVIGATION-SATELLITE (space-to-Earth) (space-to-

    space)

    SPACE RESEARCH (active)

    TYPE OF APPLICATION

    AE

    RO

    NA

    UT

    ICA

    L

    RA

    DIO

    NA

    VIG

    AT

    ION

    EA

    RT

    H E

    XP

    LO

    RA

    TIO

    N

    SA

    TE

    LL

    ITE

    LA

    ND

    RA

    DIO

    LO

    CA

    TIO

    N

    MO

    BIL

    E

    RA

    DIO

    LO

    CA

    TIO

    N

    RE

    SE

    AR

    CH

    DE

    VE

    LO

    PM

    EN

    T

    TE

    ST

    ING

    EV

    AL

    UA

    TIO

    N

    TO

    TA

    L

    AF 3 20 35 58

    AR 2 144 5 2 153

    DHS 4 4

    DOE 8 8

    FAA 228 2 230

    MC 12 87 2 101

    N 4 14 1 1 27

    NASA 1 1 2 16

    TOTAL 257 1 269 7 56 590

    The number of actual systems, or number of equipments, may exceed and sometimes

    far exceed, the number of frequency assignments in a band. Also, a frequency

    assignment may represent, a local, state, regional or nationwide authorization.

    Therefore, care must be taken in evaluating bands strictly on the basis of assignment

    counts or percentages of assignments.

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    3b. Percentage of Frequency Assignments Chart

    The following chart displays the percentage of frequency assignments in the GMF for the

    systems operating in the frequency band 1240-1300 MHz.

    AERONAUTICAL RADIONAVIGATION - 43%

    EARTH EXPLORATION SATELLITE - 0.32%

    LAND RADIOLOCATION - 46%

    MOBILE RADIOLOCATION - 1.18%

    RESEARCH, DEVELOPMENT, TESTING,

    EVALUATION - 9.5%

    1240 - 1300 MHz Band

  • 1240-1300 MHz

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    4. Frequency Band Analysis By Application

    4a. Aeronautical Radionavigation

    The Federal Aviation Administration (FAA) and Department of Defense (DoD) operate

    long-range aeronautical radionavigation radar systems in the band 1240-1300 MHz.

    These radars are capable of operating throughout the 1215-1400 MHz frequency range.

    These radar systems are used to monitor aircraft and other targets within the national

    airspace, along the border areas, and around military bases and airfields. The Air Route

    Surveillance Radar (ARSR) systems that operate throughout this band measure range,

    bearing, and velocity of aircraft and other targets.1 They are used in directing aircraft en-

    route across the United States within the National Airspace System.

    The aeronautical radionavigation radar systems operating in the band 1215-1240 MHz use

    a continually rotating antenna mounted on a tower. The antennas are mounted on a tower

    to provide an unobstructed view of the airspace they are monitoring. The antennas are

    directed slightly upwards to remove the effects of local obstructions (e.g., ground clutter),

    that would degrade the performance of the radar system. Each system installation is unique

    but the typical antenna height is approximately 45 feet for fixed radar systems, and

    approximately 20 feet for transportable radar systems. The typical antenna rotation rate for

    radar systems operating in this band is 5 to 6 revolutions per minute.

    4b. Radiolocation

    The military operates tactical radar systems in the band 1240-1300 MHz.

    Tactical radars are designed to be more easily tuned than air traffic control radars, since

    they may have to operate in a battlefield environment with many other systems and

    require the flexibility to change frequencies to reduce their exposure to hostile forces.

    The Tethered Aerostat Radar (TAR) system also operates in this band. The TAR consists

    of balloon mounted radars that are used for monitoring the southern boarders and

    Caribbean airspace for drug interdiction. The balloon is tethered to a ground station and

    the radar monitors the airspace, sending data down to the ground control station and the

    information is relayed to appropriate authorities.

    1 The radar systems operating in this band transmit pulsed radio frequency signals that are reflected from

    the surface of aircraft or target. The time required for a reflected signal that is transmitted to return from an

    aircraft and the direction of the reflected signal are measured. From this information, the radar can

    determine the distance of the aircraft from the antenna, the direction of the aircraft relative to the antenna,

    and in some cases the altitude.

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    The technical characteristics of systems operating in this band can be found in ITU-R M

    1463-2 titled Characteristics of and protection criteria for radars operating in the

    radiodetermination service in the frequency band 1 215-1 400 MHz. The systems in the

    band 1240-1300 MHz operated by the federal government and DoD are similar to the

    ones described in the following tables.

  • 1240-1300 MHz

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    TABLE 1

    1 215-1 400 MHz radiodetermination system characteristics

    Parameter Units System 1 System 2 System 3 System 4 System 5 System 6 System 7 System 8

    Peak power into

    antenna

    dBm 97 80 76.5 80 73.9 96 93 78.8

    Frequency range MHz 1 215-1 400 1 280-1 350 1 215-1 350 1 240-1 350

    Pulse duration s 2 88.8; 58.8

    (Note 1)

    0.4; 102.4; 409.6

    (Note 2)