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 1997 FR 64858 , Dec. 12, 1991]