grant will be made upon the express condition that it is subject to being withdrawn if, at the hearing, it is shown that public interest will be better served by a grant of one of the other applications. Such conditional grants will be issued only where it appears:

(1) That some or all of the applications were not filed in good faith but were filed for the purpose of delaying or hindering the grant of another application;

or

(2) That public interest requires the prompt establishment of radio service in a particular community or area; or (3) The grant of one or more applications would be in the public interest and that a delay in making a grant to any applicant until after the conclusion of a hearing on all applications might jeopardize the rights of the United States under the provisions of an international agreement to the use of the frequency in question; or

(4) That a grant of one application would be in the public interest in that it appears from an examination of the remaining applications that they cannot be granted because they are in violation of provisions of the Communications Act, or of other statutes, or of the provisions of this chapter.

[28 F.R. 13002, Dec. 5, 1963, as amended at 29 F.R. 7822, June 19, 1964]

§ 21.28 Transfer and assignment of station authorization.

A station authorization, the frequencies authorized to be used by the grantee of such authorization, and the rights therein granted by such authorization shall not be transferred, assigned, or disposed of in any manner, voluntary or involuntary, directly or indirectly, or by transfer of control of any corporation holding such authorization, to any person, except upon application to the Commission and upon finding by the Commission that the public interest, convenience and necessity will be served thereby. Requests for authority of the type referred to herein shall be submitted on the forms prescribed by § 21.29 (h) and shall be accompanied by the further showing required by § 21.29 (h). § 21.29 Forms to be used.

(a) Application for construction permit for base, auxiliary test and fixed stations. A separate application for construction permit shall be submitted

for each base, each auxiliary test, and each fixed station on FCC Form 401: Provided, however, That in the case of fixed stations to be installed at temporary locations, as set forth hereinafter in the applicable subparts of these rules, where the equipment utilized is of such design as to comprise a "packaged" unit which is ready for installation and use with only nominal construction, request may be made for waiver of the construction permit and for the immediate issuance of a license: And provided further, That an application for an auxiliary test station may be combined with that of the base station with which such auxiliary facility is to be associated when both are at the same location. Such applications shall be accompanied by the supplementary information set forth in § 21.15 as may be appropriate.

(b) Application for license for mobile stations. No construction permit is required for mobile stations. A separate application on FCC Form 401 shall be submitted for a license for the maximum number of mobile units expected to be placed in operation within the ensuing license period: Provided, however, In the Domestic Public Land Mobile Radio Service, an application for license for land mobile units to be licensed in the name of the base station licensee may be combined on the same application form with an application for the base station with which the land mobile units will be associated. In the preparation of such blanket applications, care should be exercised that data furnished therein in all particulars is clearly differentiated between the land mobile and base station installations. In any event, the mobile station license will be issued simultaneously with the issuance of the related base station license in the case of installations in the Domestic Public Land Mobile Radio Service. Applications for mobile stations in the Domestic Public Land Mobile Radio Service which are submitted by persons who propose to become subscribers to a common carrier service for public correspondence shall be accompanied by the supplementary showing set forth in § 21.15 (i).

(c) Application for modification of construction permit. Under circumstances requiring deviation from the terms of a construction permit, before such deviations are begun, application for modification of construction permit

shall be submitted on FCC Form 401. No changes shall be effected until authorized by the Commission through issuance of an appropriate modified construction permit.

(d) Application for extension of expiration date of construction permit. Application for extension of time within which to complete construction of a station shall be filed on FCC Form 701 at least 30 days prior to the expiration date of such permit, if the facts supporting such application for extension are known to applicant in time to permit such filing. In other cases, such applications will be accepted upon a showing, satisfactory to the Commission, of sufficient reasons for filing within less than 30 days prior to the expiration date. Such applications will be granted upon a specific and detailed showing that the failure to complete was due to causes not under the control of the grantee, or upon a specific and detailed showing of other matters sufficient to justify the extension (see also § 21.31 (a)).

(e) Application for station license. Upon completion of construction or installation of a station in exact accordance with the terms and conditions set forth in the construction permit and upon satisfactory completion of equipment tests in accordance with § 21.212 (a), an application for license to operate the station should be filed on FCC Form 403 prior to the expiration date of the construction permit (see § 21.31 (a)).

(f) Renewal of station license. Unless otherwise directed or permitted by the Commission, each application for renewal of license other than special temporary authorizations shall be submitted on FCC Form 405 not less than 30 days nor more than 60 days prior to the expiration date of the license sought to be renewed. Expiring developmental authorizations may be renewed only upon a factual showing of need beyond the expiration date of the authorization sought to be renewed. A blanket application may be submitted for renewal of a group of station licenses in the same service in those cases where the renewal requested is in exact accordance with the terms of the previous authorizations. The individual stations covered by such application shall be clearly identified therein, and sufficient copies of such blanket application shall be filed so as to provide at least two copies thereof for each station affected. Special tempo

rary authorizations may be extended upon informal written requests. (See §§ 21.405 (b) and 21.511.)

(g) Application for modification of station license. An application for modification of any station license in these services may be filed at any time during the term of that license. Application for modification of a station license shall be made on FCC Form 403 and shall be submitted in duplicate not less than 60 days prior to the date contemplated for such modification, unless otherwise permitted.

(h) Application for consent to assignment, or transfer of control of corporation holding radio station construction permit or license. An application on FCC Form 702 or FCC Form 703, as the circumstances require, shall be submitted to the Commission when a construction permit or license, or the control of a corporation holding such permit or license, is to be transferred as a result of a voluntary act (contract or other agreement) or an involuntary act (death or legal disability) of the grantee of a permit or station license, or by involuntary assignment of the physical property of the station pursuant to a court decree in bankruptcy proceedings, or other court order, or by operation of law in any other manner. Applications filed on FCC Form 702 or FCC Form 703 shall be accompanied by a factual showing by the assignee of his legal, financial, technical and other qualifications to be the licensee of the radio facilities described in such application. Upon completion of an approved transfer, written notification thereof shall be filed with the Commission.

(i) Application for authority to operate mobile units of Canadian registry in the United States. Applications for authority to operate mobile units of Canadian registry within the United States shall be made upon FCC Form 410 which shall be filed with the Secretary, Federal Communications Commission, Washington, D.C., 20554. Forms may be obtained from the FCC Secretary or from the Director, Telecommunications and Electronics Branch, Department of Transport, Ottawa, Ontario, Canada.

(j) Applications for authority to operate mobile units in Canada. Applications for authority to operate mobile units, which have been licensed in this service by the Commission, shall be

made upon proper form and be filed with the Director, Telecommunications and Electronics Branch, Department of Transport, Ottawa, Ontario, Canada, from whom the application forms are obtainable.

§ 21.30 Period of construction.

(a) Except for stations in the Pointto-Point Microwave Radio Service, and except as may be limited by § 21.32(b), each construction permit for a radio station in the Domestic Public Radio Services will specify a maximum of 60 days from the date of grant thereof as the time within which construction of the station shall begin, and a maximum of eight months from the date of grant as the time within which construction shall be completed and the station ready for operation, unless otherwise determined by the Commission upon proper showing in any particular case (see §§ 21.29 (d) and 21.31(a)).

(b) For stations in the Point-to-Point Microwave Radio Service, and except as may be limited by § 21.32 (b), the construction permit issued by the Commission will specify the date of grant as the earliest date of commencement of construction and a maximum of 18 months thereafter as the time within which construction shall be completed and the station be ready for operation, unless otherwise determined by the Commission upon proper showing in any particular

case.

§ 21.31 Forfeiture of station authorizations.

(a) A construction permit shall be automatically forfeited if construction has not been commenced within the time specified therein or if the station is not ready for operation within the term of the construction permit. or within such additional time as the Commission may have allowed upon a proper showing, upon FCC Form 701 filed prior to the date sought to be extended, that failure to commence or complete construction was due to causes not under the control of the permittee (see §§ 21.29 (d) and 21.30(a)).

(b) A license or special temporary authorization shall be automatically forfeited upon the expiration date specified therein unless prior thereto an applica

tion for renewal of such license or authorization shall have been filed with the Commission (see § 21.29 (f)).

§ 21.32 License period.

(a) Licenses for stations in the Pointto-Point Microwave Radio and Local Television Transmission Services will be issued for a period not to exceed five years; in the case of common carrier Television-STL and Television Pickup stations to which are assigned frequencies allocated to the broadcast services, the authorization to use frequencies shall, in any event terminate simultaneously with the expiration of the authorization for the broadcast station to which such service is rendered; licenses for stations in the Domestic Public Land Mobile Radio and Rural Radio Services will be issued for a period not to exceed three years; except that licenses for developmental stations will be issued for a period not to exceed one year. The expiration date of licenses of miscellaneous common carriers in the Domestic Public Land Mobile Radio Service shall be the first day of April in the year of expiration; the expiration date of licenses of telephone company common carriers in the Domestic Public Land Mobile Radio Service shall be the first day of July in the year of expiration; the expiration date of licenses in the Rural Radio Service shall be the first day of November in the year of expiration; the expiration date of licenses in the Point-to-Point Microwave Radio and Local Television Transmission Services shall be the first day of February in the year of expiration; and the expiration date of developmental licenses shall be one year from the date of grant thereof. When a license is granted subsequent to the last renewal date of the class of license involved, the license shall be issued only for the unexpired period of the current license term of such class.

(b) The Commission reserves the right to grant or renew station licenses in this service for a shorter period of time than that generally prescribed for such stations if, in its judgment, public interest, convenience or necessity would be served by such action.

(c) Upon the expiration or termination of any station license, any related

construction permit, which bears a later expiration date, shall be automatically terminated concurrently with the related station license, unless it shall have been determined by the Commission that the public interest, convenience or necessity would be served by continuing in effect said construction permit.

§ 21.33 Status of amendments to applications.

(a) All applications governed by this part, except those enumerated in § 21.27 (a), and major amendments thereto (e.g., any amendment which will change or add a frequency; or improve the operating characteristics of an existing or proposed station; or enlarge the service contour or significantly change the location or points of communication of an existing or proposed station; or which will materially alter the nature of an existing or proposed service) are subject to the provisions of § 21.27.

(b) Amendments, other than major amendments as defined in paragraph (a) of this section, will be considered on a case-by-case basis and, if found to materially alter an existing or proposed station, will be listed in a public notice and thereafter be subject to the provisions of § 21.27.

Subpart C-Technical Standards § 21.100

Frequencies.

(a) The frequencies available for use in the services covered by this part of the rules are listed in the applicable subparts of this part. Assignment of frequencies will be made only in such a manner as to facilitate the rendition of communication service on an interference-free basis in each service area. Unless otherwise indicated, each frequency available for use by stations in these services will be assigned exclusively to a single applicant in any service area. All applicants for, and licensees of, stations in these services shall cooperate in the selection and use of the frequencies assigned in order to minimize interference and thereby obtain the most effective use of the authorized facilities. In the event harmful interference occurs or appears likely to occur between two or more radio systems and

such interference cannot be resolved between the licensees thereof, the Commission may specify a time sharing arrangement for the stations involved or may, after notice and opportunity for hearing, require the licensees to make such changes in operating techniques or equipment as it may deem necessary to avoid such interference. Frequency diversity transmission will not be authorized in these services in the absence of a factual showing, in each case, that the required communications cannot practicably be achieved by other means.

(b) Persons authorized pursuant to this part to operate radio stations on frequencies in the band 25–50 Mc/s must recognize that the band is shared with various services in other countries; that harmful interference may be caused by tropospheric and ionospheric propagation of signals from distant stations of all services of the United States and other countries operating on frequencies in this band; and that no protection from such harmful interference generally can be expected. Persons desiring to avoid such harmful interference should consider operation on available frequencies higher in the radio spectrum not generally subject to this type of difficulty. § 21.101 Frequency stability.

(a) Except as provided in paragraph (b) of this section, a permittee or licensee in these services shall maintain the carrier frequency of each authorized transmitter within the folling percentage of the reference frequency:

(c) For the purpose of determining the frequency tolerance applicable to a particular transmitter in accordance with the foregoing provisions of this section, the power of a transmitter shall be the maximum rated plate power input to its final radio frequency stage, as specified by the Commission's Radio Equipment List, Part C.

(d) The reference frequency of a station shall be deemed to be the assigned frequency, unless otherwise specified.

§ 21.102 Frequency measuring or calibrating apparatus.

The frequency measuring or calibrating device used to determine compliance of transmitting equipment with the station authorization and the applicable rules and regulations shall be independent of the transmitter frequency control elements and shall have an accuracy within onehalf of the allowed frequency tolerance of the transmitter being measured. § 21.103 Standards and limitations governing authorization and use of frequencies in the 72-76 Mc/s band.

(a) Assignments on frequencies in the band 72-76 Mc/s will be made

only to stations located 10 or more miles from a channel 4 or 5 television station (or from the post office of the city to which such television channels are allocated, in cases where a television station has not been authorized) and shall be subject to the condition that no harmful interference is caused to reception of such television stations. Applications for use of frequencies involving less than 10 miles separation from such television stations will be returned without action.

(b) Assignments on frequencies in the band 72-76 Mc/s will be made only upon the applicant's affirmative showing that he agrees to eliminate any harmful interference which may be caused by his operation to television reception on either channel 4 or 5 and, if said interference cannot be eliminated within 90 days of the time the matter is first brought to his attention by the Commission, operation of the interfering fixed station will be discontinued.

(c) In cases where it is proposed to locate a 72-76 Mc/s fixed station less than 80, but more than 10, miles from the site of a television transmitter operating on either channel 4 or 5 (or from the post office of a community to which such television channels are allocated, in cases where a television station has not been authorized), the fixed station shall be authorized only if there are fewer than 100 family dwelling units (as defined by the United States Bureau of Census) located within a circle centered at the location of the fixed station (family dwelling units 70 or more miles distant from the television station antenna site are not to be counted) the radius of which shall be determined by use of the following charts entitled "Chart For Determining Radius From Fixed Station In 72-76 Mc/s Band To Interference Contour Along Which 10 Percent of Service From Adjacent Channel Television Station Would Be Destroyed":