Sec.  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  Sec. 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  Sec. 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  Sec. 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