[Federal Register Volume 66, Number 80 (Wednesday, April 25, 2001)]
[Rules and Regulations]
[Pages 20752-20758]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-9886]


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FEDERAL COMMUNICATIONS COMMISSION

47 CFR Part 73

[MM Docket No. 93-177; FCC 01-60]


An Inquiry Into the Commission's Policies and Rules Regarding AM 
Radio Service Directional Antenna Performance Verification

AGENCY: Federal Communications Commission.

ACTION: Final rule.

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SUMMARY: In this proceeding the Commission relaxes the technical 
requirements for directional AM stations. The new rules reduce the 
number of measurements required as part of directional AM license 
applications and eliminate outdated operating requirements. The 
changes, consistent with the Commission's streamlining initiatives, 
reduce the regulatory burden upon directional AM stations to the extent 
possible while maintaining the integrity of the service.

DATES: Effective May 25, 2001.

ADDRESSES: Secretary, Federal Communications Commission, 445 12th 
Street, SW., Washington, DC 20554, http://www.fcc.gov.

FOR FURTHER INFORMATION CONTACT: Peter H. Doyle, Audio Services 
Division, Mass Media Bureau (202) 418-2700.

SUPPLEMENTARY INFORMATION: This is a summary of the Commission's Report 
and Order in MM. Docket No. 93-177, adopted February 14, 2001, and 
released March 7, 2001. The new rules adopted here were proposed in an 
earlier Notice of Proposed Rule Making (NPRM) in this proceeding [See 
64 FR 40539, July 27, 1999]. The final rules incorporate comments 
received in response to the NPRM. The complete text of this Report and 
Order is available for inspection and copying during normal business 
hours in the FCC Reference Center (Room CY-A257), 445 12th Street, SW., 
Washington, DC 20554, and may also be purchased from the Commission's 
copy contractor, International Transcription Service, (202) 857-3800, 
1231 20th Street, NW., Washington, DC 20036. The complete text is also 
available on the Internet at http://www.fcc.gov/mmb/asd/welcome2.html#NEWBOX.

Synopsis of Report and Order

1. Introduction

    This Report and Order relaxes the Commission's technical rules for 
AM broadcasters using directional antennas. Directional AM stations use 
antennas which suppress radiated field in some directions and enhance 
it in others. In order to control interference between stations and 
assure adequate community coverage, directional AM stations must 
undergo extensive ``proofs of performance'' to demonstrate that the 
antenna system operates as authorized. This Report and Order 
substantially reduces the number of measurements required in a proof of 
performance, and, consequently, reduces the cost borne by the licensee. 
The Report and Order also eliminates some equipment and measurement 
requirements for directional AM stations, and eliminates the 
designation of some directional AM stations as ``critical arrays,'' a 
classification that imposed additional operating restrictions and 
expenses upon some licensees.

2. Proof of Performance Requirements

    An antenna proof of performance establishes whether the radiation 
pattern of an AM station is in compliance with the station's 
authorization. An AM station must perform a full proof to verify the 
pattern shape when a new directional antenna system is authorized. 
Partial proofs, which require fewer measurements, are occasionally 
necessary to show that an array continues to operate properly. For both 
full and partial proofs, the Commission reduced the required number of 
radials and the number of measurements per radial.

[[Page 20753]]

    Previously, 47 CFR 73.151 required that a permittee measure a 
minimum of eight radials in a full proof of performance. For complex 
patterns, measurements were required on a sufficient number of radials 
to define the pattern shape completely, i.e., three radials in the main 
lobe, and one in each null and minor lobe. The Report and Order reduces 
the minimum number of radials from eight to six for simple directional 
antenna patterns and, generally, requires no more than 12 radials to 
define complex patterns. The Commission also reduces the number of 
measurement points along each radial to 15, from the 20 to 30 points 
previously required, and shortens the minimum length of the radial to 
15 kilometers.
    Partial proofs of performance are required after the installation 
of new equipment on an AM tower or when changes in the electrical 
environment, such as erection of a new tower nearby, could affect the 
radiation pattern. These proofs are conducted to verify that the array 
remains properly adjusted. A partial proof consists of measurements 
taken at selected locations used in the last full proof of performance. 
The field strength values measured at each point are mathematically 
compared to values obtained in the last full proof to yield the current 
value of radiation along each azimuth. The new rules reduce the minimum 
number of radials measured in a partial proof to four, and also reduce 
the number of points per radial from 10 to eight. In addition, a 
partial proof is no longer mandatory when a licensee replaces sampling 
system components or changes a monitoring point location.

3. Monitoring Points

    Monitoring points are specific locations on selected radials where 
licensees regularly take field strength measurements. The measured 
field strength at each monitoring point shall not exceed a maximum 
value specified on the station's license. The Report and Order deletes 
the requirement that licensees submit maps and driving directions for 
each monitoring point. The Commission will allow licensees to designate 
a replacement monitoring point without a partial proof on the affected 
radial, provided field strength readings have not changed. In response 
to comments, the Commission will not identify monitoring points by GPS 
coordinates alone. However, AM stations may submit GPS coordinates as 
part of a monitoring point description. Finally, the Commission will 
include a brief description of the monitoring point on the AM station's 
license.

4. AM Station Equipment and Measurements

    The Report and Order deletes or modifies certain operating 
requirements for directional AM stations. Licensees whose directional 
stations use approved antenna sampling systems are no longer required 
to maintain base current ammeters. The requirement to measure antenna 
impedance across a range of frequencies is eliminated. Finally, 
licensees are no longer required to maintain antenna reactance at zero 
ohms.

5. Critical Array Designation

    Because the current and phase measured for each tower in a 
directional antenna system tend to fluctuate, our rules specify 
operating tolerances for these values. In most cases, maintaining 
current and phase variations within normal tolerance will ensure that 
radiated fields remain within authorized limits. The Commission had 
designated as ``critical arrays'' those directional antenna systems 
that were more likely to produce excessive field when operating 
parameters vary. Licensees of critical arrays were required to maintain 
tighter operating tolerances in order to limit potential interference. 
The Commission had proposed to relax the criteria defining a critical 
array, and to apply the revised criteria to all proposals for new or 
modified directional antennas. However, the Commission was persuaded by 
comments to eliminate the critical array designation entirely, 
consistent with recent technical streamlining initiatives. The 
Commission also deletes the critical array designation in all 
outstanding authorizations.

Final Regulatory Flexibility Analysis

    As required by the Regulatory Flexibility Act (``RFA''),\1\ the 
Commission has prepared this present Final Flexibility Analysis 
(``FRFA'') of the possible significant economic impact on small 
entities by the policies and rules adopted in this Report and Order. 
Written and electronically filed public comments were requested in our 
Initial Regulatory Flexibility Analysis (IRFA). None were received. The 
Commission will send a copy of the Report and Order, including this 
FRFA, to the Chief Counsel for Advocacy of the Small Business 
Administration. In addition, the Report and Order and FRFA (or 
summaries thereof) will be published in the Federal Register. See 5 
U.S.C. 604(a).
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    \1\ See U.S.C. 603. The RFA, see 5 U.S.C. 601 et. seq., has been 
amended by the Contract with America Advancement Act of 1996, Public 
Law 194-12, 110 Stat. 848 (1996) (``CWAA''). Title II of the CWAA is 
the Small Business Regulatory Enforcement Fairness Act of 1996 
(``SBREFA'').
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Need for and Objectives of the Rules

    This Report and Order eliminates some of Commission's technical 
rules and relaxes others to materially reduce the regulatory and 
compliance burdens on AM broadcasters using directional antennas. For 
instance, in order to control interference between stations and assure 
adequate community coverage, directional AM stations currently must 
undergo extensive ``proofs of performance'' to demonstrate that the 
antenna system operates as authorized. The field strength measurements 
and technical exhibits which our current rules require as part of a 
``proof'' impose a substantial financial burden upon these AM 
broadcasters, a burden not incurred by licensees in the other broadcast 
services.
    This Report and Order reduces this particular burden, and generally 
reduces the Commission's regulatory requirements to the minimum 
necessary to achieve our policy objectives of controlling interference 
and assuring adequate community coverage.

Legal Basis

    Authority for the actions proposed in this Report and Order may be 
found in sections 4(i), 4(j), 303, 308, 309, 316 and 319 of the 
Communications Act of 1934, as amended, 47 U.S.C. 154(i), 154(j), 303, 
308, 309, 316 and 319.

Description and Estimate of the Number of Small Entities to Which the 
Proposed Rules Will Apply

    The RFA directs agencies to provide a description of, and where 
feasible, an estimate of the number of small entities that may be 
affected by the proposed rules, if adopted. 5 U.S.C. 603(b)(3). The RFA 
generally defines the term ``small entity'' as having the same meaning 
as the terms ``small business,'' ``small organization,'' and ``small 
governmental jurisdiction.'' In addition, the term ``small business'' 
has the same meaning as the term ``small business concern'' under the 
Small Business Act. See 5 U.S.C. 601(3); 15 U.S.C. 632. A small 
business concern is one which: (1) Is independently owned and operated; 
(2) is not dominant in its field of operation; and (3) satisfies any 
additional criteria established by the Small Business Administration 
(SBA). Small Business Act, 15 U.S.C. 632 (1996). A small organization 
is generally ``any not-for-profit enterprise which is independently 
owned and operated and is not dominant in its field.'' 5 U.S.C. 601(4). 
Nationwide, as of 1992, there were approximately 275,801 small

[[Page 20754]]

organizations. 1992 Economic Census, U.S. Bureau of the Census, Table 6 
(special tabulation of data under contract to Office of Advocacy of 
U.S. Small Business Administration). ``Small governmental 
jurisdiction'' generally means ``governments of cities, counties, 
towns, townships, villages, school districts, or special districts, 
with a population of less than 50,000.'' 5 U.S.C. 601(5). As of 1992, 
there were approximately 85,006 such jurisdictions in the United 
States. U.S. Department of Commerce, Bureau of the Census, ``1992 
Census of Governments.'' This number includes 38,978 counties, cities, 
and towns; of these, 37,566, or 96 percent, have populations of fewer 
than 50,000. The Census Bureau estimates that this ratio is 
approximately accurate for all governmental entities. Thus, of the 
85,006 governmental entities, we estimate that 81,600 (91 percent) are 
small entities.
    The rules and policies will apply to certain AM radio broadcasting 
licensees and potential licensees. The Small Business Administration 
defines a radio broadcasting station that has no more than $5 million 
in annual receipts as a small business. 13 CFR 121.201, SIC 4832. A 
radio broadcasting station is an establishment primarily engaged in 
broadcasting aural programs by radio to the public. Executive Office of 
the President, Office of Management and Budget, Standard Industrial 
Classification Manual (1987), SIC 4832. Included in this industry are 
commercial, religious, educational, and other radio stations. Radio 
broadcasting stations which primarily are engaged in radio broadcasting 
and which produce radio program materials are similarly included. 
However, radio stations which are separate establishments and are 
primarily engaged in producing radio program material are classified 
under another SIC number. The 1992 Census indicates that 96 percent 
(5,861 of 6,127) of radio station establishments produced less than $5 
million in revenue in 1992. The Census Bureau counts radio stations 
located at the same facility as one establishment. Therefore, each 
colocated AM/FM combination counts as one establishment. Official 
Commission records indicate that 11,334 individual radio stations were 
operating in 1992. FCC News Release, No. 31327 (January 13, 1993). As 
of February 1, 2001, official Commission records indicate that 12,751 
radio stations were operating, of which 4,674 were AM stations.
    Thus, because only 40 percent of AM stations operate with 
directional antennas, the rules affect 1,870 radio stations. We use the 
96% figure of radio station establishments with less than $5 million 
revenue from the Census data and apply it to the 1,870 radio stations 
using directional antennas to arrive at 1,795 individual AM stations as 
small businesses. These estimates may overstate the number of small 
entities since the revenue figures on which they are based do not 
include or aggregate revenues from non-radio affiliated companies.
    In addition to owners of operating radio stations, any entity that 
seeks or desires to obtain a radio broadcast license may be affected by 
rule changes adopted in this Report and Order. The number of entities 
that may seek to obtain a radio broadcast license is unknown.

Description of Projected Recording, Recordkeeping, and Other Compliance 
Requirements

    A number of rule changes adopted in this Report and Order reduce 
the reporting requirements of prospective and current AM licensees. In 
order to control interference between stations and assure adequate 
community coverage, directional AM stations must undergo extensive 
``proofs of performance'' when initially constructed, and from time to 
time thereafter, to verify conformance with authorized operating 
parameters. AM licensees incur substantial costs in performing the 
measurements and preparing the required technical exhibits for a proof 
of performance. This Report and Order reduces the number of measurement 
radials required and shortens the length of measured radials. We have 
deleted the requirement to include maps showing each field measurement 
location with a license application. In addition, we have eliminated 
the requirement for a proof of performance in certain circumstances. 
Taken together, these changes reduce the cost of a proof of performance 
for all AM licensees and for prospective new applicants. We also delete 
the requirement for base current ammeters, and eliminate the 
designation of some directional antenna systems as critical arrays. 
These measures reduce operating costs for directional AM stations. None 
of the rule changes adopted here impose new recording, record keeping, 
or other compliance requirements on prospective or current AM 
licensees. Overall, the changes we are adopting are designed to reduce 
the overall administrative burdens of the Commission's rules on both 
regulatees and the Commission staff.

Steps Taken To Minimize Significant Economic Impact on Small Entities 
and Significant Alternatives Considered

    This Report and Order enhances opportunities for improvement of 
technical facilities and service and minimizes the administrative 
burdens and delays associated with our radio broadcast licensing 
processes. The changes adopted in this Report and Order will reduce the 
costs of operating a directional AM station, of modifying the station's 
facilities, and of constructing a new AM station. While we expect that 
the changes adopted here will benefit directional AM stations 
regardless of size, we note that the cost reductions may be of 
particular value to small entities.
    All significant alternatives presented in the comments were 
considered. In particular, several commenters dissented from our 
proposal to relax the criteria for designating critical arrays, and to 
apply the new criteria to all applications for new or modified 
directional AM facilities. After considering this alternative suggested 
by the commenters, we were persuaded that we could eliminate the 
critical array designation entirely without compromising the integrity 
of the AM service. This rule change eases operating requirements for 
those AM stations which might have been designated as critical arrays, 
a benefit which is irrespective of the station's size or ownership, but 
which may be a boon to a small business.

Report to Congress

    The Commission will send a copy of An Inquiry Into the Commission's 
Policies and Rules Regarding AM Radio Service Directional Antenna 
Performance Verification, including this FRFA, in a report to be sent 
to Congress pursuant to the Small Business Regulatory Enforcement 
Fairness Act of 1996. See 5 U.S.C. 801(a)(1)(A). In addition, the 
Commission will send a copy of this Report and Order, including this 
FRFA, to the Chief Counsel for Advocacy of the Small business 
Administration. A copy of this Report and Order, including this FRFA, 
(or summaries thereof) will also be published in the Federal Register. 
See 5 U.S.C. 604(b).

List of Subjects in 47 CFR Part 73

    Radio.


[[Page 20755]]


Federal Communications Commission.
William F. Caton,
Deputy Secretary.

Rules Changes

    For the reasons discussed in the preamble, the Federal 
Communications Commission amends part 73 of title 47 of the Code of 
Federal Regulations as follows:

PART 73--RADIO BROADCAST SERVICES

    1. The authority citation for part 73 continues to read as follows:

    Authority: 47 U.S.C. 154, 303, 334, and 336.

Sec. 73.14  [Revised]

    2. Section 73.14 is revised by removing the definition of 
``Critical directional antenna.''

    3. Section 73.53 is amended by revising paragraphs (b)(5) and 
(b)(12) and by removing paragraph (c).


Sec. 73.53  Requirements for authorization of antenna monitors.

* * * * *
    (b) * * *
    (5) The device used to indicate relative amplitudes shall be 
graduated in increments which are 1 percent, or less, of the full scale 
value. If a digital indicator is provided, the smallest increment shall 
be 0.1 percent, or less, of the full scale value.
* * * * *
    (12) The performance specifications set forth in paragraph (b)(11) 
of this section, shall be met when the monitor is operated and tested 
under the following conditions.
* * * * *

    4. Section 73.54 is revised to read as follows:


Sec. 73.54  Antenna resistance and reactance measurements.

    (a) The resistance of an omnidirectional series fed antenna is 
measured at either the base of the antenna without intervening coupling 
or tuning networks, or at the point the transmission line connects to 
the output terminals of the transmitter. The resistance of a shunt 
excited antenna may be measured at the point the radio frequency energy 
is transferred to the feed wire circuit or at the output terminals of 
the transmitter.
    (b) The resistance and reactance of a directional antenna shall be 
measured at the point of common radiofrequency input to the directional 
antenna system after the antenna has been finally adjusted for the 
required radiation pattern.
    (c) A letter of notification must be filed with the FCC in 
Washington, DC, Attention: Audio Services Division, Mass Media Bureau, 
when determining power by the direct method pursuant to Sec. 73.51. The 
letter must specify the antenna or common point resistance at the 
operating frequency. The following information must also be kept on 
file at the station:
    (1) A full description of the method used to make measurements.
    (2) A schematic diagram showing clearly all components of coupling 
circuits, the point of resistance measurement, the location of the 
antenna ammeter, connections to and characteristics of all tower 
lighting isolation circuits, static drains, and any other fixtures 
connected to and supported by the antenna, including other antennas and 
associated networks. Any network or circuit component used to dissipate 
radio frequency power shall be specifically identified, and the 
impedances of all components which control the level of power 
dissipation, and the effective input resistance of the network must be 
indicated.
    (d) AM stations using direct reading power meters in accordance 
with Sec. 73.51, can either submit the information required by 
paragraph (c) of this section or submit a statement indicating that 
such a meter is being used. Subsequent station licenses will indicate 
the use of a direct reading power meter in lieu of the antenna 
resistance value in such a situation.

    5. Section 73.58 is amended by removing paragraph (b), 
redesignating paragraphs (c) through (f) as paragraphs (b) through (e), 
and by revising newly redesignated paragraph (d) to read as follows:


Sec. 73.58  Indicating instruments.

* * * * *
    (d) In the event that any one of these indicating instruments 
becomes defective when no substitute which conforms with the required 
specifications is available, the station may be operated without the 
defective instrument pending its repair or replacement for a period not 
in excess of 60 days without further authority of the Commission. If 
the defective instrument is the antenna current meter of a 
nondirectional station which does not employ a remote antenna ammeter, 
or if the defective instrument is the common point meter of a station 
which employs a directional antenna and does not employ a remote common 
point meter, the operating power shall be determined by a method 
described in Sec. 73.51(a)(1) or Sec. 73.51(d) during the entire time 
the station is operated without the antenna current meter or common 
point meter. However, if a remote meter is employed and the antenna 
current ammeter or common point meter becomes defective, the remote 
meter can be used to determine operating power pending the return to 
service of the regular meter.
* * * * *

    6. Section 73.62 is amended by revising paragraph (a) to read as 
follows:


Sec. 73.62  Directional antenna system tolerances.

    (a) Each AM station operating a directional antenna must maintain 
the indicated relative amplitudes of the antenna monitor currents 
within 5% of the values specified therein. Directional antenna relative 
phase currents must be maintained to within 3 deg. of the 
values specified on the instrument of authorization.
* * * * *

    7. Section 73.68 is amended by revising paragraphs (a)(2), (d)(2), 
and (d)(3) to read as follows:


Sec. 73.68  Sampling systems for antenna monitors.

    (a) * * *
    (2) Sampling lines for directional antennas may be of different 
lengths provided the phase difference of signals at the monitor are 
less than 0.5 degrees between the shortest and longest cable lengths 
due to temperature variations to which the system is exposed.
* * * * *
    (d) * * *
    (2) Immediately prior to modification or replacement of components 
of the sampling system, and after a verification that all monitoring 
point values and operating parameters are within the limits or 
tolerances specified in the rules, the following indications must be 
recorded for each radiation pattern: Final plate current and plate 
voltage, common point current, antenna monitor phase and current 
indications, and the field strength at each monitoring point. 
Subsequent to these modifications or changes the procedure must be 
repeated.
    (3) If monitoring point field strengths or antenna monitor 
parameters exceed allowable limits following the replacement or 
modification of that portion of the sampling system above the base of 
the towers, a partial proof of performance shall be executed in 
accordance with Sec. 73.154 . The partial proof of performance shall be 
accompanied by common point impedance measurements made in accordance 
with Sec. 73.54.
* * * * *

[[Page 20756]]


    8. Section 73.69 is amended by revising paragraphs (a), (d)(2), and 
(d)(4) to read as follows:


Sec. 73.69  Antenna monitors.

    (a) Each station using a directional antenna must have in operation 
at the transmitter site an FCC authorized antenna monitor.
* * * * *
    (d) * * *
    (2) Immediately before the replacement of the antenna monitor, 
after a verification that all monitoring point values and the common 
point current reading are within the limits or tolerances specified in 
the rules, the following indications must be recorded for each 
radiation pattern: Final plate current and plate voltage, common point 
current, antenna monitor phase and current indications, and the field 
strength at each monitoring point.
* * * * *
    (4) If it cannot be established by the observations required in 
paragraph (d)(2) of this section that the common point current reading 
and the monitoring point values are within the tolerances or limits 
prescribed by the rules and the instrument of authorization, or if the 
substitution of the new antenna monitor for the old results in changes 
in these parameters, a partial proof of performance shall be executed 
and analyzed in accordance with Sec. 73.154.
* * * * *

    9. Section 73.151 is amended by revising paragraph's (a)(1), 
(a)(2), and (a)(3) to read as follows:


Sec. 73.151  Field strength measurements to establish performance of 
directional antennas.

    (a) * * *
    (1) A tabulation of inverse field strengths in the horizontal plane 
at 1 km, as determined from field strength measurements taken and 
analyzed in accordance with Sec. 73.186, and a statement of the 
effective measured field strength (RMS). Measurements shall be made in 
the following directions:
    (i) Those specified in the instrument of authorization.
    (ii) In major lobes. Generally, one radial is sufficient to 
establish a major lobe; however, additional radials may be required.
    (iii) Along additional radials to establish the shape of the 
pattern. In the case of a relatively simple directional antenna 
pattern, a total of six radials is sufficient. If two radials would be 
more than 90 deg. apart, then an additional radial must be specified 
within that arc. When more complicated patterns are involved, that is, 
patterns having several or sharp lobes or nulls, measurements shall be 
taken along as many as 12 radials to definitely establish the 
pattern(s). Pattern symmetry may be assumed for complex patterns which 
might otherwise require measurements on more than 12 radials.
    (2) A tabulation of:
    (i) The phase difference of the current in each element with 
respect to the reference element, and whether the current leads (+) or 
lags (-) the current in the reference element, as indicated by the 
station's antenna monitor.
    (ii) The ratio of the amplitude of the radio frequency current in 
each element to the current in the reference element, as indicated on 
the station's antenna monitor.
    (3) A monitoring point shall be established on each radial for 
which the construction permit specifies a limit. The following 
information shall be supplied for each monitoring point:
    (i) Measured field strength.
    (ii) An accurate and detailed description of each monitoring point. 
The description may include, but shall not be limited to, geographic 
coordinates determined with a Global Positioning System receiver.
    (iii) Clear photographs taken with the field strength meter in its 
measuring position and with the camera so located that its field of 
view takes in as many pertinent landmarks as possible.
* * * * *

    10. Section 73.152 is amended by:
    A. Revising paragraph (a).
    B. Redesignating paragraphs (b) through (d) as paragraphs (c) 
through (e).
    C. Adding a new paragraph (b).
    D. Revising newly redesignated paragraphs (d) introductory text, 
(d)(2) introductory text, (d)(2)(iii), and (d)(2)(iv).
    The revisions and additions read as follows:


Sec. 73.152  Modification of directional antenna data.

    (a) If, after construction and final adjustment of a directional 
antenna, a measured inverse distance field in any direction exceeds the 
field shown on the standard radiation pattern for the pertinent mode of 
directional operation, an application shall be filed, specifying a 
modified standard radiation pattern and/or such changes as may be 
required in operating parameters so that all measured effective fields 
will be contained within the modified standard radiation pattern. 
Permittees may also file an application specifying a modified standard 
radiation pattern, even when measured radiation has not exceeded the 
standard pattern, in order to allow additional tolerance for monitoring 
point limits.
    (b) If, following a partial proof of performance, a licensee 
discovers that radiation exceeds the standard pattern on one or more 
radials because of circumstances beyond the licensee's control, a 
modified standard pattern may be requested. The licensee shall submit, 
concurrently, Forms 301-AM and 302-AM. Form 301-AM shall include an 
exhibit demonstrating that no interference would result from the 
augmentation. Form 302-AM shall include the results of the partial 
proof, along with full directional and nondirectional measurements on 
the radial(s) to be augmented, including close-in points and a 
determination of the inverse distance field in accordance with 
Sec. 73.186.
* * * * *
    (d) The following general principles shall govern the situations in 
paragraphs (a), (b), and (c) in this section:
* * * * *
    (2) Where any excessive field does not result in objectionable 
interference to another station, a modification of construction permit 
application may be submitted with a modified standard pattern 
encompassing all augmented fields. The modified standard pattern shall 
supersede the previously submitted standard radiation pattern for that 
station in the pertinent mode of directional operation. Following are 
the possible methods of creating a modified standard pattern:
* * * * *
    (iii) A combination of paragraphs (d)(2)(i) and (d)(2)(ii), of this 
section, with (d)(2)(i) being applied before (d)(2)(ii) is applied.
    (iv) Where augmentation is allowable under the terms of this 
section, the requested amount of augmentation shall be centered upon 
the measured radial and shall not exceed the following:
    (A) The actual measured inverse distance field value, where the 
radial does not involve a required monitoring point.
    (B) 120% of the actual measured inverse field value, where the 
radial has a monitoring point required by the instrument of 
authorization.
* * * * *

    11. Section 73.154 is revised to read as follows:


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.

[[Page 20757]]

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 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.

    12. Section 73.158 is revised to read as follows:


Sec. 73.158  Directional antenna monitoring points.

    (a) When a licensee of a station using a directional antenna system 
finds that a field monitoring point, as specified on the station 
authorization, is no longer accessible or is unsuitable because of 
nearby construction or other disturbances to the measured field, an 
application to change the monitoring point location, including FCC Form 
302-AM, is to be promptly submitted to the FCC in Washington, DC.
    (1) If the monitoring point has become inaccessible or otherwise 
unsuitable, but there has been no significant construction or other 
change in the vicinity of the monitoring point which may affect field 
strength readings, the licensee shall select a new monitoring point 
from the points measured in the last full proof of performance. A 
recent field strength measurement at the new monitoring point shall 
also be provided.
    (2) Alternatively, if changes in the electromagnetic environment 
have affected field strength readings at the monitoring point, the 
licensee shall submit the results of a partial proof of performance, 
analyzed in accordance with Sec. 73.154, on the affected radial.
    (3) The licensee shall submit an accurate, written description of 
the new monitoring point in relation to nearby permanent landmarks.
    (4) The licensee shall submit a photograph showing the new 
monitoring point in relation to nearby permanent landmarks that can be 
used in locating the point accurately at all times throughout the year. 
Do not use seasonal or temporary features in either the written 
descriptions or photographs as landmarks for locating field points.
    (b) When the description of the monitoring point as shown on the 
station license is no longer correct due to road or building 
construction or other changes, the licensee must prepare and file with 
the FCC, in Washington, DC, a request for a corrected station license 
showing the new monitoring point description. The request shall include 
the information specified in paragraphs (a)(3) and (a)(4) of this 
section, and a copy of the station's current license. A copy of the 
description is to be posted with the existing station license.

    13. Section 73.186 is amended by revising paragraphs (a)(1) and (b) 
to read as follows:


Sec. 73.186  Establishment of effective field at one kilometer.

    (a) * * *
    (1) Beginning as near to the antenna as possible without including 
the induction field and to provide for the fact that a broadcast 
antenna is not a point source of radiation (not less than one wave 
length or 5 times the vertical height in the case of a single element, 
i.e., nondirectional antenna or 10 times the spacing between the 
elements of a directional antenna), measurements shall be made on six 
or more radials, at intervals of approximately 0.2 kilometer up to 3 
kilometers from the antenna, at intervals of approximately one 
kilometer from 3 kilometers to 5 kilometers from the antenna, at 
intervals of approximately 2 kilometers from 5 kilometers to 15 
kilometers from the antenna, and a few additional measurements if 
needed at greater distances from the antenna. Where the antenna is 
rurally located and unobstructed measurements can be made, there shall 
be at least 15 measurements on each radial. These shall include at 
least 7 measurements within 3 kilometers of the antenna. However, where 
the antenna is located in a city where unobstructed measurements are 
difficult to make, measurements shall be made on each radial at as many 
unobstructed locations as possible, even though the intervals are 
considerably less than stated above, particularly within 3 kilometers 
of the antenna. In cases where it is not possible to obtain accurate 
measurements at the closer distances (even out to 8 or 10 kilometers 
due to the character of the intervening terrain), the measurements at 
greater distances should be made at closer intervals.
* * * * *
    (b) Complete data taken in conjunction with the field strength 
measurements shall be submitted to the Commission in affidavit form 
including the following:
    (1) Tabulation by number of each point of measurement to agree with 
the maps required in paragraph (c) of this section, the date and time 
of each measurement, the field strength (E), the distance from the 
antenna (D) and the product of the field strength and distance (ED) (if 
data for each radial are plotted on semilogarithmic paper, see 
paragraph (a)(2)(ii) of this section) for each point of measurement.
    (2) Description of method used to take field strength measurements.
    (3) The family of theoretical curves used in determining the curve 
for each radial properly identified by conductivity and dielectric 
constants.

[[Page 20758]]

    (4) The curves drawn for each radial and the field strength 
pattern.
    (5) The antenna resistance at the operating frequency.
    (6) Antenna current or currents maintained during field strength 
measurements.
    (c) Maps showing each measurement point numbered to agree with the 
required tabulation shall be retained in the station records and shall 
be available to the FCC upon request.

    14. Section 73.3538 is amended by revising paragraph (b) to read as 
follows:


Sec. 73.3538  Application to make changes in an existing station.

* * * * *
    (b) An informal application filed in accordance with Sec. 73.3511 
is to be used to obtain authority to make the following changes in the 
station authorization:
    (1) To modify or discontinue the obstruction marking or lighting of 
the antenna supporting structure where that specified on the station 
authorization either differs from that specified in 47 CFR 17, or is 
not appropriate for other reasons.
    (2) Relocation of a main studio outside the principal community 
contour may require the filing and approval of a letter request for 
authority to make this change prior to implementation. See 
Sec. 73.1125.

[FR Doc. 01-9886 Filed 4-24-01; 8:45 am]
BILLING CODE 6712-01-U