[Code of Federal Regulations]
[Title 47, Volume 2]
[Revised as of October 1, 2007]
From the U.S. Government Printing Office via GPO Access
[CITE: 47CFR73.35]

[Page 17-18]
 
                       TITLE 47--TELECOMMUNICATION
 
        CHAPTER I--FEDERAL COMMUNICATIONS COMMISSION (CONTINUED)
 
PART 73_RADIO BROADCAST SERVICES--Table of Contents
 
                     Subpart A_AM Broadcast Stations
 
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

[[Page 18]]

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]