§  73.1692   Broadcast station construction near or installation on an AM
broadcast tower.

   Where a broadcast licensee or permittee proposes to mount a broadcast
   antenna on an AM station tower, or where construction is proposed
   within 0.8 km of an AM nondirectional tower or within 3.2 km of an AM
   directional station, the broadcast licensee or permittee is responsible
   for ensuring that the construction does not adversely affect the AM
   station, as follows:

   (a) Installations on an AM nondirectional tower. During installation of
   the broadcast antenna and related equipment, the AM station shall
   determine operating power by the indirect method ( see § 73.51). Upon
   the completion of the installation, antenna impedance measurements on
   the AM antenna shall be made, and, prior to or simultaneously with the
   filing of the license application covering the broadcast station
   installation, an application on FCC Form 302–AM (including a tower
   sketch of the installation) shall be filed with the Commission for the
   AM station to return to direct power measurement.

   (b) Installations on an AM directional array. Prior to commencing
   construction, the broadcast permittee or licensee shall notify the AM
   station so that, if necessary, the AM station may determine operating
   power by the indirect method ( see § 73.51) and request special
   temporary authority pursuant to § 73.1635 to operate with parameters at
   variance in order to maintain monitoring point field strengths within
   authorized limits. Both prior to the commencement of construction and
   upon completion of construction, a partial proof of performance (as
   defined by § 73.154) shall be conducted to establish that the AM array
   has not been adversely affected. Prior to or simultaneously with filing
   of the license application to cover the broadcast station construction,
   the results of the partial proof of performance shall be filed with the
   Commission on Form 302–AM.

   (c) Tower erections or modifications within 0.8 km of an AM
   nondirectional tower. Prior to commencing the construction of tower
   modifications, or the erection of a new tower, within 0.8 km of an AM
   nondirectional tower, the broadcast permittee or licensee is required
   to notify the AM station so that the AM station may commence
   determining operating power by the indirect method ( see § 73.51). The
   broadcast licensee or permittee shall be responsible for the
   installation and continued maintenance of detuning apparatus necessary
   to prevent adverse effects on the radiation pattern of the AM station.
   Both prior to construction of the tower modifications and upon
   completion of construction, antenna impedance measurements of the AM
   station shall be made. In addition, sufficient field strength
   measurements taken at a minimum of 10 locations along each of 8 equally
   spaced radials, shall be made to establish that the AM radiation
   pattern is essentially omnidirectional. Prior or simultaneously with
   the filing of the application for license to cover this permit, the
   results of the impedance measurements and the field strength
   measurements shall be filed with the Commission on FCC Form 302–AM for
   the AM station to return to the direct method of power determination.

   (d) Tower erections or modifications within 3.2 km of an AM directional
   station. Prior to commencing construction of tower modifications, or
   the erection of a new tower structure, within 3.2 km of an AM
   directional array, the broadcast permittee or licensee shall notify the
   AM station so that, if necessary, the AM station may determine
   operating power by the indirect method ( see § 73.51) and request
   special temporary authority pursuant to § 73.1635 to operate with
   parameters at variance in order to maintain monitoring point field
   strengths within authorized limits. The broadcast licensee or permittee
   shall be responsible for the installation and continued maintenance of
   detuning apparatus necessary to prevent adverse effects upon the
   radiation pattern of the AM station. Both prior to the commencement of
   construction and upon completion of construction, a partial proof of
   performance (as defined by § 73.154) shall be conducted to establish
   that the AM array has not been adversely affected. Prior to or
   simultaneously with filing of the license application to cover the
   broadcast station construction, the results of the partial proof of
   performance shall be filed with the Commission on Form 302–AM.

   [ 62 FR 51062 , Sept. 30, 1997]