§  90.187   Trunking in the bands between 150 and 512 MHz.

   (a) Applicants for trunked systems operating on frequencies between 150
   and 512 MHz (except 220-222 MHz) must indicate on their applications
   (class of station code, instructions for FCC Form 601) that their
   system will be trunked. Licensees of stations that are not trunked, may
   trunk their systems only after modifying their license (see § 1.927 of
   this chapter).

   (b) Trunked systems operating under this section must employ equipment
   that prevents transmission on a trunked frequency if a signal from
   another system is present on that frequency. The level of monitoring
   must be sufficient to avoid causing harmful interference to other
   systems. However, this monitoring requirement does not apply if the
   conditions in paragraph (b)(1) or (b)(2) of this section, are met:

   (1) Where applicants for or licensees operating in the 470-512 MHz band
   meet the loading requirements of § 90.313 and have exclusive use of
   their frequencies in their service area.

   (2) On frequencies where an applicant or licensee does not have an
   exclusive service area provided that all frequency coordination
   requirements are complied with and written consent is obtained from
   affected licensees using either the procedure set forth in paragraphs
   (b)(2)(i) and (b)(2)(ii) of this section (mileage separation) or the
   procedure set forth in paragraph (b)(2)(iii) of this section (protected
   contours).

   (i) Affected licensees for the purposes of this section are licensees
   of stations that have assigned frequencies (base and mobile) that are
   15 kHz or less removed from proposed stations that will operate with a
   25 kHz channel bandwidth; stations that have assigned frequencies (base
   and mobile) that are 7.5 kHz or less removed from proposed stations
   that will operate with a 12.5 kHz bandwidth; or stations that have
   assigned frequencies (base and mobile) 3.75 kHz or less removed from
   proposed stations that will operate with a 6.25 kHz bandwidth.

   (ii) Where such stations' service areas (37 dBu contour for stations in
   the 150-174 MHz band and 39 dBu contour for stations in the 421-512 MHz
   bands; see § 90.205) overlap a circle with radius 113 km (70 mi.) from
   the proposed base station.

   (iii) In lieu of the mileage separation procedure set forth in
   paragraphs (b)(2)(i) and (b)(2)(ii) of this section, applicants for
   trunked facilities may obtain consent only from stations that would be
   subjected to objectionable interference from the trunked facilities.
   Objectionable interference will be considered to exist when the
   interference contour (19 dBu for VHF stations, 21 dBu for UHF stations)
   of a proposed trunked station would intersect the service contour (37
   dBu for VHF stations, 39 dBu for UHF stations) of an existing station.
   The existing stations that must be considered in a contour overlap
   analysis are a function of the channel bandwidth of the proposed
   trunked station, as follows:

   (A) For trunked stations proposing 25 kHz channel bandwidth: Existing
   co-channel stations and existing stations that have an operating
   frequency 15 kHz or less from the proposed trunked station.

   (B) For trunked stations proposing 12.5 kHz channel bandwidth: Existing
   co-channel stations and existing stations that have an operating
   frequency 7.5 kHz or less from the proposed trunked station.

   (C) For trunked stations proposing 6.25 kHz channel bandwidth: Existing
   co-channel stations and existing stations that have an operating
   frequency 3.75 kHz or less from the proposed trunked station.

   (iv) The calculation of service and interference contours referenced in
   paragraph (b)(2)(iii) of this section shall be done using generally
   accepted engineering practices and standards which, for purposes of
   this section, shall presumptively be the practices and standards agreed
   to by a consensus of all certified frequency coordinators.

   (v) The written consent from the licensees specified in paragraphs
   (b)(2)(i) and (b)(2)(ii) or (b)(2)(iii)(A), (b)(2)(iii)(B) and
   (b)(2)(iii)C of this section shall specifically state all terms agreed
   to by the parties and shall be signed by the parties. The written
   consent shall be maintained by the operator of the trunked station and
   be made available to the Commission upon request. The submission of a
   coordinated trunked application to the Commission shall include a
   certification from the applicant that written consent has been obtained
   from all licensees specified in paragraphs (b)(2)(i) and (b)(2)(ii) or
   (b)(2)(iii)(A), (b)(2)(iii)(B) and (b)(2)(iii)(C) of this section that
   the written consent documents encompass the complete understandings and
   agreements of the parties as to such consent; and that the terms and
   conditions thereof are consistent with the Commission's rules. Should a
   potential applicant disagree with a certified frequency coordinator's
   determination that objectionable interference exists with respect to a
   given channel or channels, that potential applicant may request the
   Commission to overturn the certified frequency coordinator's
   determination. In that event, the burden of proving by clear and
   convincing evidence that the certified frequency coordinator's
   determination is incorrect shall rest with the potential applicant. If
   a licensee has consented to the use of trunking, but later decides
   against the use of trunking, that licensee may request that the
   licensee(s) of the trunked system(s) cease the use of trunking. Should
   the trunked station(s) decline the licensee's request, the licensee may
   request a replacement channel from the Commission. A new applicant
   whose interference contour overlaps the service contour of a trunked
   licensee will be assigned the same channel as the trunked licensee only
   if the trunked licensee consents in writing and a copy of the written
   consent is submitted to the certified frequency coordinator responsible
   for coordination of the application.

   (c) Trunking of systems licensed on paging-only channels or licensed in
   the Radiolocation Service (subpart F) is not permitted.

   (d) Potential applicants proposing trunked operation may file written
   notice with any certified frequency coordinator for the pool (Public
   Safety or Industrial/Business) in which the applicant proposes to
   operate. The notice shall specify the channels on which the potential
   trunked applicant proposes to operate and the proposed effective
   radiated power, antenna pattern, height above ground, height above
   average terrain and proposed channel bandwidth. On receipt of such a
   notice, the certified frequency coordinator shall notify all other
   certified frequency coordinators in the relevant pool within one
   business day. For a period of sixty days thereafter, no application
   will be accepted for coordination which specifies parameters that would
   result in objectionable interference to the channels specified in the
   notice. Potential applicants shall not file another notice for the same
   channels within 10 km (6.2 miles) of the same location unless six
   months shall have elapsed since the filing of the last such notice.
   Certified frequency coordinators shall return without action, any
   coordination request which violates the terms of this paragraph (d).

   (e) No more than 10 channels for trunked operation in the
   Industrial/Business Pool may be applied for in a single application.
   Subsequent applications, limited to an additional 10 channels or fewer,
   must be accompanied by a certification, submitted to the certified
   frequency coordinator coordinating the application, that all of the
   applicant's existing channels authorized for trunked operation have
   been constructed and placed in operation. Certified frequency
   coordinators are authorized to require documentation in support of the
   applicant's certification that existing channels have been constructed
   and placed in operation. Applicants in the Public Safety Pool may
   request more than 10 channels at a single location provided that any
   application for more than 10 Public Safety Pool channels must be
   accompanied by a showing of sufficient need. The requirement for such a
   showing may be satisfied by submission of loading studies demonstrating
   that requested channels in excess of 10 will be loaded with 50 mobiles
   per channel within a five year period commencing with grant of the
   application.

   (f) If a licensee authorized for trunked operation discontinues trunked
   operation for a period of 30 consecutive days, the licensee, within 7
   days of the expiration of said 30 day period, shall file a conforming
   application for modification of license with the Commission. Upon grant
   of that application, new applicants may file for the same channel or
   channels notwithstanding the interference contour of the new
   applicant's proposed channel or channels overlaps the service contour
   of the station that was previously engaged in trunked operation.

   [ 65 FR 60875 , Oct. 13, 2000]

Subpart I--General Technical Standards