[Code of Federal Regulations]
				   [Title 47, Volume 4]
				[Revised as of October 1, 2002]
		   From the U.S. Government Printing Office via GPO Access
				    [CITE: 47CFR73.154]

					[Page 40-41]
 
                       TITLE 47--TELECOMMUNICATION COMMISSION (CONTINUED)
 
		      PART 73--RADIO BROADCAST SERVICES--Table of Contents
 
                            Subpart A--AM Broadcast Stations


 
Sec. 73.154  AM directional antenna partial proof of performance measurements.

    (a) A partial proof of performance consists of at least 8 field 
strength measurements made on each of the radials that includes a 
monitoring point. If the directional pattern has fewer than 4 monitored 
radials, the partial proof shall include measurements on those radials 
from the latest complete proof of performance which are adjacent to the 
monitored radials.
    (b) The measurements are to be made within 3 to 15 kilometers from 
the center of the antenna array. When a monitoring point as designated 
on the station authorization lies on a particular radial, one of the 
measurements must be made at that point. One of the following methods 
shall be used for the partial proof:
    (1) Measurement points shall be selected from the points measured in 
latest full proof of performance provided that the points can be 
identified with

[[Page 41]]

reasonable certainty, and that land development or other factors have 
not significantly altered propagation characteristics since the last 
full proof. At each point, the licensee shall measure directional field 
strength for comparison to either the directional or the nondirectional 
field strength measured at that point in the last full proof.
    (2) In the event that a meaningful comparison to full proof 
measurements cannot be made, the licensee shall measure both directional 
and nondirectional field strength at eight points on each radial. The 
points need not be limited to those measured in the last full proof of 
performance.
    (c) The results of the measurements are to be analyzed as follows. 
Either the arithmetic average or the logarithmic average of the ratios 
of the field strength at each measurement point to the corresponding 
field strength in the most recent complete proof of performance shall be 
used to establish the inverse distance fields. (The logarithmic average 
for each radial is the antilogarithm of the mean of the logarithms of 
the ratios of field strength (new to old) for each measurement location 
along a given radial). When new nondirectional measurements are used as 
the reference, as described in paragraph (b)(2) of this section, either 
the arithmetic or logarithmic averages of directional to nondirectional 
field strength on each radial shall be used in conjunction with the 
measured nondirectional field from the last proof to establish the 
inverse distance field.
    (d) The result of the most recent partial proof of performance 
measurements and analysis is to be retained in the station records 
available to the FCC upon request. Maps showing new measurement points, 
i.e., points not measured in the last full proof, shall be associated 
with the partial proof in the station's records, and shall be provided 
to the FCC upon request.

[66 FR 20756, Apr. 25, 2001]