Sec.  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  Sec. 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  Sec. 73.51) and request special temporary authority
   pursuant to  Sec. 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  Sec. 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  Sec. 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  Sec. 73.51) and request special temporary authority pursuant to
    Sec. 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  Sec. 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]