§  73.35   Calculation of improvement factors.

   A petition for an allotment (See § 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 § 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
   § 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 § 73.183(c)(1).

   [ 56 FR 64858 , Dec. 12, 1991]