Goto Section: 90.619 | 90.623 | Table of Contents

FCC 90.621
Revised as of October 1, 2020
Goto Year:2019 | 2021
  §  90.621   Selection and assignment of frequencies.

   (a) Applicants for frequencies in the Public Safety and
   Business/Industrial/Land Transportation Categories must specify on the
   application the frequencies on which the proposed system will operate
   pursuant to a recommendation by the applicable frequency coordinator.
   Applicants for frequencies in the SMR Category must request specific
   frequencies by including in their applications the frequencies
   requested.

   (1) For trunked systems, the assignment of frequencies will be made in
   accordance with applicable loading criteria and in accordance with the
   following:

   (i) Channels will be chosen and assigned in accordance with § § 90.615,
   90.617, or 90.619.

   (ii) A mobile station is authorized to transmit on any frequency
   assigned to its associated base station.

   (iii) There are no limitations on the number of frequencies that may be
   trunked. Authorizations for non-SMR stations may be granted for up to
   20 trunked frequency pairs at a time in accordance with the frequencies
   listed in § § 90.615, 90.617, and 90.619.

   (2) For conventional systems the assignment of frequencies will be made
   in accordance with applicable loading criteria. Accordingly, depending
   upon the number of mobile units to be served, an applicant may either
   be required to share a channel, or, if an applicant shows a sufficient
   number of mobile units to warrant the assignment of one or more
   channels for its exclusive use, it may be licensed to use such channel
   or channels on an unshared basis in the area of operation specified in
   its application.

   (i) Channels will be chosen and assigned in accordance with § § 90.615,
   90.617, or 90.619.

   (ii) A mobile station is authorized to transmit on any frequency
   assigned to its associated base station.

   (b) Stations authorized on frequencies listed in this subpart, except
   for those stations authorized pursuant to paragraph (g) of this section
   and EA-based and MTA-based SMR systems, will be assigned co-channel
   frequencies solely on the basis of distance between fixed stations. In
   addition, contour overlap as detailed in paragraph (d) of this section
   will be the basis for geographic separation between fixed stations
   operating on adjacent-channel frequencies in the 809-817 MHz/854-862
   MHz sub-band, except where such fixed stations meet the distance
   separation criteria set out in this paragraph (b).

   (1) Except as indicated in paragraph (b)(4) of this section, no station
   in Channel Blocks A through V shall be less than 169 km (105 mi)
   distant from a co-channel station that has been granted channel
   exclusivity and authorized 1 kW ERP on any of the following mountaintop
   sites: Santiago Peak, Sierra Peak, Mount Lukens, Mount Wilson
   (California). Except as indicated in paragraph (b)(4) of this section,
   no incumbent licensee in Channel Blocks F1 through V that has received
   the consent of all affected parties or a certified frequency
   coordinator to utilize an 18 dBµV/m signal strength interference
   contour shall be less than 229 km (142 mi) distant from a co-channel
   station that has been granted channel exclusivity and authorized 1 kW
   ERP on any of the following mountaintop sites: Santiago Peak, Sierra
   Peak, Mount Lukens, Mount Wilson (California).

   (2) The separation between co-channel stations that have been granted
   exclusivity and that are located at high sites in California north of
   35° N Latitude and west of 118° W Longitude shall be determined as
   follows:

   (i) Required co-channel separations between common antenna sites are
   given by table 1. A channel group assigned to a station on a site
   listed in the vertical column may not be re-assigned to a station on a
   site listed in the horizontal column if there is an "X" in the box
   created by the intersection of the vertical and horizontal lines. The
   geographic coordinates listed in the table represent an average for
   each particular site; all locations within 1.6 km (1 mi) of the
   coordinates will be considered to be at that site.

   (ii) Required co-channel separations involving antenna sites not listed
   in table 1 shall be determined by Commission staff on a case by case
   basis. The interference potential of proposed assignments will be
   evaluated considering parameters such as antenna height, effective
   radiated power, terrain irregularities, and market conditions.
   eCFR graphic ec02ap91.013.gif

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   (3) Except as indicated in paragraph (b)(4) of this section, stations
   in Channel Blocks A through V that have been granted channel
   exclusivity and are located in the State of Washington at the locations
   listed in the table below shall be separated from co-channel stations
   by a minimum of 169 km (105 mi). Except as indicated in paragraph
   (b)(4) of this section, incumbent licensees in Channel Blocks F1
   through V that have received the consent of all affected parties or a
   certified frequency coordinator to utilize an 18 dBµV/m signal strength
   interference contour, have been granted channel exclusivity and are
   located in the State of Washington at the locations listed in the table
   below shall be separated from co-channel stations by a minimum of 229
   km (142 mi). Locations within one mile of the geographical coordinates
   listed in the table below will be considered to be at that site.

   Note: Coordinates are referenced to North American Datum 1983 (NAD83).
         Site name        North latitude West longitude
   Mount Constitution      48° 40' 47.4'' 122° 50' 28.7''
   Lyman Mountain          48° 35' 41.4'' 122° 09' 39.6''
   Cultus Mountain         48° 25' 30.4'' 122° 08' 58.5''
   Gunsite Ridge           48° 03' 22.4'' 121° 51' 41.5''
   Gold Mountain           47° 32' 51.3'' 122° 46' 56.5''
   Buck Mountain           47° 47' 05.3'' 122° 59' 34.6''
   Cougar Mountain         47° 32' 39.4'' 122° 06' 34.4''
   Squak Mountain          47° 30' 14.4'' 122° 03' 34.4''
   Tiger Mountain          47° 30' 13.4'' 121° 58' 32.4''
   Devils Mountain         48° 21' 52.4'' 122° 16' 06.6''
   McDonald Mountain       47° 20' 11.3'' 122° 51' 30.5''
   Maynard Hill            48° 00' 58.3'' 122° 55' 35.6''
   North Mountain          47° 19' 07.3'' 123° 20' 48.6''
   Green Mountain          47° 33' 40.3'' 122° 48' 31.5''
   Capitol Peak            46° 58' 21.3'' 123° 08' 21.5''
   Rattlesnake Mountain    47° 28' 09.4'' 121° 49' 17.4''
   Three Sisters Mountain  47° 07' 19.4'' 121° 53' 34.4''
   Grass Mountain          47° 12' 14.1'' 121° 47' 42.4''
   Spar Pole Hill          47° 02' 51.4'' 122° 08' 39.4''

   (4) Upon an applicant's specific request to the Commission or a
   frequency coordinator, co-channel stations may be separated by less
   than 113 km (70 mi) by meeting certain transmitter ERP and antenna
   height criteria. The following table indicates separations assignable
   to such co-channel stations for various transmitter power and antenna
   height combinations. The minimum separation permitted is 88 km (55 mi).
   Applicants will provide the Commission with a statement that the
   application is submitted for consideration under the table, a list of
   all co-channel stations within 113 km (70 mi), and the DHAATs and ERPs
   for these stations and the applicant's proposed station. Applicants
   seeking to be licensed for stations located at distances less than
   those prescribed in the table are required to secure a waiver and must
   submit with the application, in addition to the above, an interference
   analysis, based upon any of the generally-accepted terrain-based
   propagation models, that shows that co-channel stations would receive
   the same or greater interference protection than provided in the table.
   Requests for separations less than 88 km (55 mi) must also include an
   analysis of interference potential from mobile transmitters to existing
   co-channel base station receivers. Applicants seeking a waiver must
   submit with their application a certificate of service indicating that
   concurrent with the submission of the application to the Commission or
   a coordinator, all co-channel licensees within the applicable area were
   served with a copy of the application and all attachments thereto.
   Licensees thus served may file an opposition to the application within
   30 days from the date the application is filed with the Commission.

   (i) The directional height of the antenna above average terrain (DHAAT)
   is calculated from the average of the antenna heights above average
   terrain from 3 to 16 km (2 to 10 mi) from the proposed site along a
   radial extending in the direction of the existing station and the
   radials 15 degrees to either side of that radial.

   (ii) Except for the sites listed in paragraphs (b)(1), (b)(2), and
   (b)(3) of this section, additional co-channel distance separation must
   be afforded to an existing station from an applicant wishing to locate
   a station less than 113 km (70 mi) from a co-channel station, where
   either the applicant's or the existing station is located at sites with
   DHAATs of 458 m (1500 ft) and above. The separation between
   short-spaced co-channel stations shall be determined as follows:

   (A) Calculate the DHAAT in each direction between every existing
   co-channel station with 113 km (70 mi) and the proposed station.

   (B) In the table, locate the approximate ERP and DHAAT values for the
   proposed and existing stations.

   (C) When DHAAT values are greater than 458 m (1500 ft), use the
   required separation for 305 m (1000 ft) and add 1.6 km (1 mi) for every
   30.5 km (100 ft), or increment thereof, of DHAAT above 458 m (1500 ft)
   to the distance indicated in the table. If both the proposed existing
   stations have DHAATs of 458 m (1500 ft) or more, the additional
   distance is separately determined for each station and the combined
   distance is added to the distance obtained from the table. Protection
   to existing stations will be afforded only up to 113 km (70 mi).

   Short-Spacing Separation Table
   Proposed station ERP (watts)/DHAAT(m)^3 Distance between stations
   (km)^1 2
   Existing station DHAAT (meters)^3
   305 215 150 108 75 54 37
   1000/305 113 113 113 113 113 113 113
   1000/215 113 113 113 113 113 113 110
   1000/150 113 113 113 113 112 108 103
   1000/108 113 113 113 110 107 103 98
   1000/75 113 112 108 103 100 96 91
   1000/54 113 109 105 100 97 93 88
   1000/37 109 104 100 95 92 88 88
   500/305 113 113 113 113 113 113 110
   500/215 113 113 113 112 109 105 100
   500/150 113 112 108 103 100 96 91
   500/108 112 107 103 98 95 91 88
   500/75 107 102 98 93 90 88 88
   500/54 103 98 94 89 88 88 88
   500/37 99 94 90 88 88 88 88
   250/305 113 113 113 112 109 105 100
   250/215 113 113 107 102 99 95 90
   250/150 109 104 100 95 92 88 88
   250/108 105 100 96 91 88 88 88
   250/75 99 94 90 88 88 88 88
   250/54 95 90 88 88 88 88 88
   250/37 91 88 88 88 88 88 88
   125/305 113 111 107 102 99 95 90
   125/215 108 103 99 94 91 88 88
   125/150 103 98 94 89 88 88 88
   125/108 98 93 89 88 88 88 88
   125/75 93 88 88 88 88 88 88
   125/54 88 88 88 88 88 88 88
   125/37 88 88 88 88 88 88 88
   62/305 108 103 99 94 91 88 88
   62/215 103 98 94 89 88 88 88
   62/150 97 92 88 88 88 88 88
   62/108 92 88 88 88 88 88 88
   62/75 88 88 88 88 88 88 88
   62/54 88 88 88 88 88 88 88
   62/37 88 88 88 88 88 88 88

   ^1Separations for stations on Santiago Peak, Sierra Peak, Mount Lukens,
   and Mount Wilson (CA) and the locations in the State of Washington
   listed in paragraph (b)(3) of this section are 56 km (35 mi) greater
   than those listed in the table above. In the event of conflict between
   this table and the table of additional California high elevation sites
   shown in paragraph (b)(2) of this section, the latter will apply.

   ^2Distances shown are derived from the R-6602 curves and are based upon
   a non-overlap of the 22 dBu (F50,10) interference contour of the
   proposed station with the 40 dBu (F50,50) contour of the existing
   station(s). No consideration is given to the 40 dBu service contour of
   the proposed station and the 22 dBu contour of the existing station(s).
   The minimum separation of stations will be 88 km (55 mi).

   ^3All existing stations are assumed to operate with 1000 watts ERP.
   When the ERP and/or DHAAT of a proposed station or the DHAAT of an
   existing station is not indicated in the table, the next higher
   value(s) must be used.

   (5) The separation between co-channel systems may be less than the
   separations defined above if an applicant submits with its application
   letters of concurrence indicating that the applicant and each
   co-channel licensee within the specified separation agree to accept any
   interference resulting from the reduced separation between their
   systems. Each letter from a co-channel licensee must certify that the
   system of the concurring licensee is constructed and fully operational.
   The applicant must also submit with its application a certificate of
   service indicating that all concurring co-channel licensees have been
   served with an actual copy of the application.

   (6) A station located closer than the distances provided in this
   section to a co-channel station that was authorized as short-spaced
   under paragraph (b)(4) of this section shall be permitted to modify its
   facilities as long as the station does not extend its 22 dBu contour
   beyond its maximum 22 dBu contour (i.e., the 22 dBu contour calculated
   using the station's maximum power and antenna height at its original
   location) in the direction of the short-spaced station.

   (7) Offset frequencies in the 811-821/856-866 MHz band for use only
   within U.S./Mexico border area, as designated in § 90.619(a), shall be
   considered co-channel with non-offset frequencies in this band as
   designated in § 90.613. New applications for frequencies in this band
   for stations adjacent to the U.S./Mexico border area must comply with
   the co-channel separation provisions of this section.

   (c) Conventional systems authorized on frequencies in the Public Safety
   (except for those systems that have participated in a formal regional
   planning process as described in § 90.16) and Business/Industrial/Land
   Transportation categories which have not met the loading levels
   necessary for channel exclusivity will not be afforded co-channel
   protection.

   (d) Geographic separation between fixed stations operating on adjacent
   channels in the 809-817/854-862 MHz Mid-Band segment must be based on
   lack of contour overlap as detailed in paragraphs (d)(1) through (4),
   unless the co-channel distance separation criteria in paragraph (b) of
   this section are met.

   (1) Forward contour analysis. An applicant seeking to license a fixed
   station on a channel in the 809-817 MHz/854-862 MHz band segment will
   only be granted if the applicant's proposed interference contour
   creates no overlap with the 40 dBu F(50,50) contour of an incumbent
   operating a fixed station on an upper- or lower-adjacent channel. The
   applicant's interference contour is determined using the dBu level
   listed in the appropriate table in paragraph (d)(3) of this section.
   For this analysis the applicant shall plot the interference contour of
   its proposed fixed station at its proposed ERP but assume that any
   adjacent-channel incumbent licensee is operating at the maximum
   permitted ERP for the licensed antenna height.

   (2) Reciprocal contour analysis. In addition to the contour analysis
   described in paragraph (d)(1) of this section, any applicant seeking to
   license a fixed station on a channel in the 809-817 MHz/854-862 MHz
   band segment must also pass a reciprocal contour analysis. Under the
   reciprocal analysis, the interference contour, F(50,10) of an incumbent
   operating a fixed station on an upper- or lower-adjacent channel must
   create no contour overlap with the proposed 40 dBu F(50,50) contour of
   the applicant's fixed station. The incumbent's interference contour is
   determined using the dBu level listed in the appropriate table in
   paragraph (d)(3) of this section. For this analysis the applicant shall
   plot the coverage contour of its fixed station, F(50,50), at its
   proposed ERP and antenna height above average terrain but plot the
   interference contour, F(50,10), of any adjacent-channel incumbent
   licensee at its maximum permitted ERP for the licensed antenna height.

   (3) Contour matrix. Interference contour levels for the contour
   analysis described in paragraphs (d)(1) and (2) of this section are
   determined using Table 4 or Table 5 to this paragraph (d)(3). Table 4
   is used to determine the interference contour F(50,10) level of a fixed
   station operating on a 12.5 kilohertz bandwidth channel while Table 5
   is used to determine the interference contour F(50,10) level of a fixed
   station operating on a 25 kilohertz bandwidth channel. The dBu level of
   the interference contour is determined by cross-referencing the
   modulation type of the station operating on the 25 kilohertz bandwidth
   channel with the modulation type of the station operating on the 12.5
   kilohertz bandwidth channel.
   eCFR graphic er10jy20.001.gif

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   eCFR graphic er10jy20.002.gif

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   eCFR graphic er10jy20.003.gif

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   (4) Letters of concurrence. Applicants may submit applications which
   cause overlap under the forward contour analysis described in paragraph
   (d)(1) of this section provided the applicant includes a letter of
   concurrence from each incumbent that receives contour overlap. In the
   letter of concurrence, the incumbent operator must agree to accept any
   interference that occurs as a result of the contour overlap. Applicants
   may also submit applications which receive contour overlap under the
   reciprocal analysis described in paragraph (d)(2) of this section
   provided the applicant includes a letter of concurrence from each
   incumbent that causes contour overlap. In this case, the incumbent
   operator must state in its letter of concurrence that it does not
   object to the applicant receiving contour overlap from the incumbent's
   facility.

   (e) Frequencies in the 809-817/854-862 MHz bands listed as available
   for eligibles in the Public Safety and Business/Industrial/Land
   Transportation Categories are available for inter-category sharing
   under the following conditions:

   (1) Channels in the Public Safety and Business/Industrial/Land
   Transportation categories will be available to eligible applicants in
   those categories only if there are no frequencies in their own category
   and no public safety systems are authorized on those channels under
   consideration to be shared.

   (2) Notwithstanding paragraph (e)(5) of this section, licensees of
   channels in the Business/Industrial/Land Transportation category may
   request a modification of the license, see § 1.947 of this chapter, to
   authorize use of the channels for commercial operation. The licensee
   may also, at the same time or thereafter, seek authorization to
   transfer or assign the license, see § 1.948 of this chapter, to any
   person eligible for licensing in the General or SMR categories.
   Applications submitted pursuant to this paragraph must be filed in
   accordance with the rules governing other applications for commercial
   channels, and will be processed in accordance with those rules. Grant
   of requests submitted pursuant to this paragraph is subject to the
   following conditions:

   (i) A licensee that modifies its license to authorize commercial
   operations will not be authorized to obtain additional 800 MHz
   Business/Industrial/Land Transportation category channels for sites
   located within 113 km (70 mi.) of the station for which the license was
   modified, for a period of one year from the date the license is
   modified. This provision applies to the licensee, its controlling
   interests and their affiliates, as defined in § 1.2110 of this chapter.

   (ii) With respect to licenses the initial application for which was
   filed on or after November 9, 2000, requests submitted pursuant to
   paragraph (e)(2) of this section may not be filed until five years
   after the date of the initial license grant. In the case of a license
   that is modified on or after November 9, 2000 to add 800 MHz
   Business/Industrial/Land Transportation frequencies or to add or
   relocate base stations that expand the licensee's interference contour,
   requests submitted pursuant to paragraph (e)(2) of this section for
   these frequencies or base stations may not be filed until five years
   after such modification.

   (iii) Requests submitted pursuant to paragraph (e)(2) of this section
   must include a certification that written notice of the modification
   application has been provided to all Public Safety licensees, see
   § 90.20(a), with base stations within 113 km (70 mi.) of the site of the
   channel(s) for which authorization for commercial use is sought that
   operate within 25 kHz of the center of those channel(s). If, pursuant
   to paragraph (e)(2) of this section, modification and assignment or
   transfer applications are filed at different times, the written notice
   required by this paragraph must be provided each time.

   (iv) The applicant must certify that it will take reasonable
   precautions to avoid causing harmful interference to Public Safety
   licensees, see § 90.20(a), and to take such action as may be necessary
   to eliminate interference to such licensees caused by its operations.
   (When an assignment or transfer application is filed pursuant to
   paragraph (e)(2) of this section, this representation is required only
   of the assignee or transferee.) Licensees of stations suffering or
   causing harmful interference are expected to cooperate and resolve this
   problem by mutually satisfactory arrangements. If the licensees are
   unable to do so, the Commission may impose restrictions including
   specifying the transmitter power, antenna height, or area or hours of
   operation.

   (3) Licensees granted authorizations pursuant to paragraph (e)(2) of
   this section may at any time request modification of the license to
   authorize use of the channels consistent with the rules governing the
   category to which they are allocated, provided that the licensee meets
   the applicable eligibility requirements.

   (4) [Reserved]

   (5) The frequency coordinator must certify that frequencies are not
   available in the applicant's own category, and coordination is required
   from the applicable out-of-category coordinator.

   (6) The out-of-category licensee must operate by the rules applicable
   to the category to which the frequency is allocated.

   (f) Licensees of channels in the Business/Industrial/Land
   Transportation Categories in the 896-901/935-940 MHz bands may request
   a modification of the license, see § 1.947 of this chapter, to authorize
   use of the channels for commercial operation. The licensee may also, at
   the same time, or thereafter, seek authorization to transfer or assign
   the license, see § 1.948 of this chapter, to any person eligible for
   licensing in the General or SMR categories. Applications submitted
   pursuant to this paragraph must be filed in accordance with the rules
   governing other applications for commercial channels, and will be
   processed in accordance with those rules.

   (g) Applications for Public Safety systems (both trunked and
   conventional) in the 806-809/851-854 MHz bands will be assigned and
   protected based on the criteria established in the appropriate regional
   plan. See § 90.16 and the Report and Order in General Docket 87-112.

   (h) [Reserved]

   [ 47 FR 41032 , Sept. 16, 1982]

   Editorial Notes: 1. For Federal Register citations affecting § 90.621,
   see the List of CFR Sections Affected, which appears in the Finding
   Aids section of the printed volume and at www.govinfo.gov.

   2. At  63 FR 68968 , Dec. 14, 1998, § 90.621 was amended by adding a note
   before Table 1 and revising the first two columns of Table 1. However,
   Table 1 of § 90.621 as it appears in the October 1, 1998 revision of
   title 47 parts 80-end is an illustration and cannot be edited for
   amendments. For the convenience of the user, the revised text is set
   forth as follows:

   § 90.621   Selection and assignment of frequencies.

*   *   *   *   *

   (b) *  *  *

   Table 1--Co-Channel Separations Between Common Antenna Sites in the
   State of California North of 35° North Latitude and West of 118° West
   Longitude

   [Note: Coordinates are referenced to North American Datum 1983 (NAD83)]
   North latitude West longitude *  *  *
   38°03'39.7''   122°36'20.9''  *  *  *
   37°55'43.7''   122°35'14.9''  *  *  *
   37°50'56.7''   122°29'59.9''  *  *  *
   37°52'53.7''   121°55'08.9''  *  *  *
   37°51'11.7''   122°12'33.9''  *  *  *
   37°52'57.7''   122°13'14.9''  *  *  *
   37°50'59.7''   122°11'33.9''  *  *  *
   37°43'32.8''   122°24'55.9''  *  *  *
   37°41'20.8''   122°26'11.9''  *  *  *
   37°24'38.8''   122°18'23.9''  *  *  *
   37°19'12.8''   122°08'36.9''  *  *  *
   37°10'36.8''   121°54'27.8''  *  *  *
   37°07'08.8''   121°50'01.8''  *  *  *
   37°06'39.8''   121°50'32.8''  *  *  *
   36°31'44.9''   121°36'27.8''  *  *  *
   37°29'14.8''   121°52'06.8''  *  *  *
   40°15'45.6''   122°05'41.0''  *  *  *
   39°51'49.6''   121°41'23.9''  *  *  *
   39°12'16.6''   121°49'05.9''  *  *  *
   39°08'00.6''   121°06'01.8''  *  *  *
   38°52'14.6''   121°07'42.8''  *  *  *
   38°24'19.7''   122°06'33.9''  *  *  *
   38°01'14.7''   120°35'09.7''  *  *  *
   37°30'30.8''   121°22'29.8''  *  *  *
   37°32'31.8''   120°03'48.6''  *  *  *
   37°04'09.8''   119°25'42.5''  *  *  *
   36°44'37.8''   119°17'02.4''  *  *  *
   36°18'09.8''   120°24'06.6''  *  *  *
   36°17'06.8''   118°50'22.3''  *  *  *
   35°38'28.8''   118°47'11.3''  *  *  *
   35°33'08.8''   118°49'23.3''  *  *  *
   35°17'16.9''   119°30'58.4''  *  *  *
   35°17'26.9''   119°45'51.5''  *  *  *
   35°16'50.9''   119°44'55.5''  *  *  *

*   *   *   *   *

   


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