Sec.  73.35   Calculation of improvement factors.

   A petition for an allotment (See  Sec. 73.30) in the 1605–1705 kHz band filed by
   an existing fulltime AM station licensed in the 535–1605 kHz band will be
   ranked according to the station's calculated improvement factor. (See
    Sec. 73.30). Improvement factors relate to both nighttime and daytime
   interference conditions and are based on two distinct considerations: (a)
   Service area lost by other stations due to interference caused by the
   subject station, and (b) service area of the subject station. These
   considerations are represented by a ratio. The ratio consists, where
   applicable, of two separate additive components, one for nighttime and one
   for daytime. For the nighttime component, to determine the numerator of the
   ratio (first consideration), calculate the RSS and associated service area
   of the stations (co- and adjacent channel) to which the subject station
   causes nighttime interference. Next, repeat the RSS and service area
   calculations excluding the subject station. The cumulative gain in the above
   service area is the numerator of the ratio. The denominator (second
   consideration) is the subject station's interference-free service area. For
   the daytime component, the composite amount of service lost by co-channel
   and adjacent channel stations, each taken individually, that are affected by
   the subject station, excluding the effects of other assignments during each
   study, will be used as the numerator of the daytime improvement factor. The
   denominator will consist of the actual daytime service area (0.5 mV/m
   contour) less any area lost to interference from other assignments. The
   value of this combined ratio will constitute the petitioner's improvement
   factor. Notwithstanding the requirements of  Sec. 73.153, for uniform comparisons
   and simplicity, measurement data will not be used for determining
   improvement factors and FCC figure M-3 ground conductivity values are to be
   used exclusively in accordance with the pertinent provisions of
    Sec. 73.183(c)(1).

   [ 56 FR 64858 , Dec. 12, 1991]