Goto Section: 1.30001 | 1.30003 | Table of Contents
FCC 1.30002
Revised as of October 2, 2015
Goto Year:2014 |
2016
§ 1.30002 Tower construction or modification near AM stations.
(a) Proponents of construction or significant modification of a tower which
is within one wavelength of a nondirectional AM station, and is taller than
60 electrical degrees at the AM frequency, must notify the AM station at
least 30 days in advance of the commencement of construction. The proponent
shall examine the potential impact of the construction or modification as
described in paragraph (c) of this section. If the construction or
modification would distort the radiation pattern by more than 2 dB, the
proponent shall be responsible for the installation and maintenance of any
detuning apparatus necessary to restore proper operation of the
nondirectional antenna.
(b) Proponents of construction or significant modification of a tower which
is within the lesser of 10 wavelengths or 3 kilometers of a directional AM
station, and is taller than 36 electrical degrees at the AM frequency, must
notify the AM station at least 30 days in advance of the commencement of
construction. The proponent shall examine the potential impact of the
construction or modification as described in paragraph (c) of this section.
If the construction or modification would result in radiation in excess of
the AM station's licensed standard pattern or augmented standard pattern
values, the proponent shall be responsible for the installation and
maintenance of any detuning apparatus necessary to restore proper operation
of the directional antenna.
(c) Proponents of construction or significant modification of a tower within
the distances defined in paragraphs (a) and (b) of this section of an AM
station shall examine the potential effects thereof using a moment method
analysis. The moment method analysis shall consist of a model of the AM
antenna together with the potential re-radiating tower in a lossless
environment. The model shall employ the methodology specified in § 73.151(c)
of this chapter, except that the AM antenna elements may be modeled as a
series of thin wires driven to produce the required radiation pattern,
without any requirement for measurement of tower impedances.
(d) A significant modification of a tower in the immediate vicinity of an AM
station is defined as follows:
(1) Any change that would alter the tower's physical height by 5 electrical
degrees or more at the AM frequency; or
(2) The addition or replacement of one or more antennas or transmission
lines on a tower that has been detuned or base-insulated.
(e) The addition or modification of an antenna or antenna-supporting
structure on a building shall be considered a construction or modification
subject to the analysis and notice requirements of this subpart if and only
if the height of the antenna-supporting structure alone exceeds the
thresholds in paragraphs (a) and (b) of this section.
(f) With respect to an AM station that was authorized pursuant to a
directional proof of performance based on field strength measurements, the
proponent of the tower construction or modification may, in lieu of the
study described in paragraph (c) of this section, demonstrate through
measurements taken before and after construction that field strength values
at the monitoring points do not exceed the licensed values. In the event
that the pre-construction monitoring point values exceed the licensed
values, the proponent may demonstrate that post-construction monitoring
point values do not exceed the pre-construction values. Alternatively, the
AM station may file for authority to increase the relevant monitoring-point
value after performing a partial proof of performance in accordance with
§ 73.154 to establish that the licensed radiation limit on the applicable
radial is not exceeded.
(g) Tower construction or modification that falls outside the criteria
described in the preceding paragraphs is presumed to have no significant
effect on an AM station. In some instances, however, an AM station may be
affected by tower construction or modification notwithstanding the criteria
set forth above. In such cases, an AM station may submit a showing that its
operation has been affected by tower construction or modification. Such a
showing shall consist of either a moment method analysis as described in
paragraph (c) of this section, or of field strength measurements. The
showing shall be provided to:
(1) The tower proponent if the showing relates to a tower that has not yet
been constructed or modified and otherwise to the current tower owner; and
(2) To the Commission, within two years after the date of completion of the
tower construction or modification. If necessary, the Commission shall
direct the tower proponent or tower owner, if the tower proponent or tower
owner holds a Commission authorization, to install and maintain any detuning
apparatus necessary to restore proper operation of the AM antenna. An
applicant for a Commission authorization may not propose, and a party
holding a Commission authorization may not locate, an antenna on any tower
or support structure that has been shown to affect an AM station's operation
pursuant to this subparagraph, or for which a disputed showing of effect on
an AM station's operation is pending, unless the applicant, party, or tower
owner notifies the AM station and takes appropriate action to correct the
disturbance to the AM pattern.
(h) An AM station may submit a showing that its operation has been affected
by tower construction or modification that was commenced or completed prior
to or on the effective date of the rules adopted in this Part pursuant to MM
Docket No. 93-177. Such a showing shall consist of either a moment method
analysis as described in paragraph (c) of this section, or of field strength
measurements. The showing shall be provided to the current tower owner and
the Commission within one year of the effective date of the rules adopted in
this Part pursuant to MM Docket No. 93-177. If necessary, the Commission
shall direct the tower owner, if the tower owner holds a Commission
authorization, to install and maintain any detuning apparatus necessary to
restore proper operation of the AM antenna.
(i) An applicant for a Commission authorization may not propose, and a party
holding a Commission authorization may not locate, an antenna on any tower
or support structure, whether constructed before or after December 5, 2013,
that meets the criteria in paragraphs (a) and (b) of this section, unless
the analysis and notice process described in this subpart, and any necessary
measures to correct disturbances of the AM radiation pattern, have been
completed by the tower owner, the party proposing to locate the antenna, or
any other party, either prior to construction or at any other time prior to
the proposal or antenna location.
[ 78 FR 66295 , Nov. 5, 2013]
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Goto Section: 1.30001 | 1.30003
Goto Year: 2014 |
2016
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