Goto Section: 90.185 | 90.201 | Table of Contents
Revised as of September 1, 2021
Goto Year:2020 |
§ 90.187 Trunking in the bands between 150 and 512 MHz.
(a) Applicants for centralized and decentralized trunked systems
operating on frequencies between 150 and 512 MHz (except 220-222 MHz)
must indicate on their applications (radio service and 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) Except as provided in paragraphs (c) and (d) of this section,
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 harmful interference to other systems.
(c) The monitoring requirement in paragraph (b) of this section does
not apply to trunked systems operating in the 470-512 MHz band that
meet the loading requirements of § 90.313 and have exclusive use of
their frequencies in their service area.
(d) The monitoring requirement in paragraph (b) of this section does
not apply if the application is accompanied by written consent from all
(1) Affected licensees for the purposes of this section are licensees
(and previously filed pending applicants) meeting both a spectral and a
contour overlap as defined:
(i) Spectral overlap. Licensees (and filers of previously filed pending
applications) with an assigned (or proposed) frequency having a
spectral separation from a frequency of the proposed centralized
trunked station that does not exceed these values:
Proposed station Incumbent authorized bandwidth
25 kHz 12.5 kHz 6.25 kHz
25 kHz 15.0 kHz 15.0 kHz 15.0 kHz
12.5 kHz 15.0 kHz 7.5 kHz 7.5 kHz
6.25 kHz 15.0 kHz 7.5 kHz 5.0 kHz
The left column is the authorized bandwidth requested for the proposed
trunked station. The second row is the authorized bandwidth of the
incumbent. The other cells in the table show the frequency range above
and below the frequency of the proposed centralized trunked station
that must be considered.
(ii) Contour overlap. (A) Licensees (and filers of previously filed
pending applications) with a service contour (37 dBu for stations in
the 150-174 MHz band, and 39 dBu for stations in the 421-512 MHz band)
that is overlapped by the proposed centralized trunked station's
interference contour (19 dBu for stations in the 150-174 MHz band, and
21 dBu for stations in the 421-512 MHz band). Contour calculations are
required for base station facilities. Contour calculations are required
for associated mobile stations only in the 150-174 MHz band, with the
associated base station's service contour used as both the mobile
station's service contour and its interference contour.
(B) The calculation of service and interference contours shall be
performed using generally accepted engineering practices and standards,
including appropriate derating factors, agreed to by a consensus of all
certified frequency coordinators. Frequency coordinators shall make
this information available to the Commission upon request.
(C) For purposes of this section, the authorized operating area of a
station or proposed station with no associated base station shall be
used as both the station's service contour and its interference
(D) After January 1, 2013, licensees with an authorized bandwidth
exceeding 12.5 kHz will not be deemed affected licensees, unless the
licensee meets the efficiency standard set forth in § 90.203(j)(3) or
the licensee was granted a waiver of § 90.209(b).
(2) The written consent from an affected licensee shall 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 centralized
trunked station and be made available to the Commission upon request.
An application for a centralized trunked station shall include either a
certification from the applicant that written consent has been obtained
from all affected licensees, or a certification from the frequency
coordinator that there are no affected licensees.
(3) In addition, the service contour for proposed centralized trunked
stations on Industrial/Business Pool frequencies shall not be
overlapped by an incumbent licensee's interference contour. An
application filed for Public Safety Pool frequencies, see § 90.20, for a
proposed centralized trunked station in which the service contour of
the proposed station is overlapped by the interference contour of the
incumbent station(s) is allowed, but the applicant must accept any
(e) The exclusive service area of a station that has been authorized
for centralized trunked operation will be protected from proposed
centralized trunked, decentralized trunked or conventional operations
in accordance with the standards of paragraph (d) of this section.
(f) Trunking of systems licensed on paging-only channels or licensed in
the Radiolocation Service (subpart F) is not permitted.
(g) Channel limits. (1) No more than 10 channels for new centralized
trunked operation in the Industrial/Business Pool may be applied for at
a single transmitter location or at locations with overlapping service
contours as specified in paragraph (d) of this section. Subsequent
applications for centralized trunked operation are limited to no more
than an additional 10 channels, and 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 centralized trunked operation at that location
or at locations with overlapping service contours 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
(2) Applicants for Public Safety Pool channels may request more than 10
centralized trunked channels at a single location or at locations with
overlapping service contours if 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 the grant of the application.
(h) If a licensee authorized for centralized trunked operation
discontinues trunked operation for a period of 30 consecutive days, the
licensee, within 7 days thereafter, shall file a conforming application
for modification of license with the Commission.
[ 78 FR 28754 , May 16, 2013, as amended at 80 FR 18146 , Apr. 3, 2015]
Subpart I—General Technical Standards
Goto Section: 90.185 | 90.201
Goto Year: 2020 |
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