nd precautions shall be taken "to avoid aterference to other stations." = 91.152 Station identification. (a) Each station in these services which capable of being identified by transmislon of its assigned call signal shall transit such call signal at the end of each ransmission or exchange of transmislons, or once each fifteen minutes of the perating period, as the licensee may refer. (b) In lieu of the requirement of pararaph (a) of this section, mobile units ommunicating with a Base Station hich transmits on the same frequency nay transmit, once during each exhange of transmissions, any unit idenifier which is on file in the station recrds of such Base Station. (c) In lieu of the requirement of pararaph (a) of this section, mobile units ommunicating with a Base Station which transmits on a different frequency nay transmit, once during each exhange of transmissions, any unit idenifier which is on file in the station ecords of such Base Station and the Assigned call signal of either the Mobile Station or the Base Station. (d) A station which is transmitting for elemetering purposes or retransmitting by self-actuating means a radio signal received from another radio station or stations will be considered for exemption from the requirements of paragraph (a) of this section in specific instances, upon request. (e) A unit designator may be used in addition to the station identification required by this section, to identify an individual unit or transmitter of a base station or a fixed station which is authorized to be operated at temporary locations. § 91.153 Suspension of transmissions required. The radiation of the transmitter shall be suspended immediately upon detection or notification of a deviation from the technical requirements of the station authorization until such deviation is corrected, except for transmissions concerning the immediate safety of life or property, in which case the transmissions shall be suspended as soon as the emergency is terminated. § 91.154 Operator requirements. (a) All transmitter adjustments or tests during or coincident with the in stallation, servicing, or maintenance of a radio station, which may affect the proper operation of such station, shall be made by or under the immediate supervision and responsibility of a person holding a first- or second-class commercial radio operator license, either radiotelephone or radiotelegraph, who shall be responsible for the proper functioning of the station equipment: Provided, however, That only persons holding a radiotelegraph first- or second-class operator license shall perform such functions at radiotelegraph stations transmitting by any type of the Morse code. (b) Except under the circumstances specified in paragraph (a) of this section, only a person holding a commercial radiotelegraph operator license or permit of any class issued by the Commission shall operate a station during the course of normal rendition of service when transmitting radiotelegraphy by any type of the Morse code. (c) Except under the circumstances specified in paragraphs (a) and (b) of this section, and except as limited by paragraphs (g) and (h) of this section, an unlicensed person, after being authorized by the station licensee to do so, may operate from a control point a mobile base, or fixed station, or from a dispatch point a base or fixed station, during the course of normal rendition of service when transmitting on frequencies above 25 Mc/s. (d) Except under the circumstances specified in paragraphs (a) and (b) of this section, and except as limited by paragraphs (g) and (h) of this section, only a person holding a commercial radio operator license or permit of any class issued by the Commission shall operate a mobile station during the course of normal rendition of service when transmitting on frequencies below 25 Mc/s: Provided, however, That an unlicensed person, after being authorized to do so by the station licensee, may operate such a mobile station during the course of normal rendition of service when transmitting on frequencies below 25 Mc/s while it is associated with and under the operational control of a base station of the same station licensee. (e) Except under the circumstances specified in paragraphs (a) and (b) of this section, and except as limited by paragraphs (g) and (h) of this section, base stations and fixed stations shall be operated in accordance with the following when transmitting during the course of normal rendition of service on frequencies below 25 Mc/s: (1) From a control point, only a person holding a commercial radio operator license or permit of any class issued by the Commission shall operate a base station or fixed station. (2) From a dispatch point, an unlicensed person may operate a base station or fixed station after being authorized to do so by the station licensee: Provided, however, That such operation shall be under the direct supervision and responsibility of a person who (i) holds a commercial radio operator license or permit of any class issued by the Commission and who (ii) is on duty at a control point meeting the requirements of Subpart C of this part. (f) Except under the circumstances specified in paragraph (a) of this section, and except as limited by paragraphs (g) and (h) of this section, no person, whether or not a licensed operator, is required to be in attendance at a station when transmitting during the course of normal rendition of service and when either (1) transmitting for telemetering purposes or (2) retransmitting by self-actuating means a radio signal received from another radio station or stations. (g) The provisions of this section authorizing certain unlicensed persons to operate certain stations, or authorizing unattended operation of stations in certain circumstances, shall not be construed to change or diminish in any respect the responsibility of station licensees to have and to maintain control over the stations licensed to them (including all transmitter units thereof), or for the proper functioning and operation of those stations (including all transmitter units thereof) in accordance with the terms of the licenses of those stations. (h) Notwithstanding any other provisions of this section, unless the transmitter is so designed that none of the operations necessary to be performed during the course of normal rendition of service may cause off-frequency operation or result in any unauthorized radiation, and unless the transmitter is so installed that all controls which may cause improper operation or radiation are not readily accessible to the person operating the transmitter, such transmitter shall be operated by a person holding a first- or second-class commE cial radio operator license, either raĈOtelephone or radiotelegraph, as may z appropriate for the type of emissi being used, issued by the Commission. § 91.155 Posting of operator license. (a) The original license of each base cr fixed station operator, other than a operator exclusively performing service and maintenance duties, shall be posted or kept immediately available at the place where he is on duty as an operator Provided, however, That if an operat who is on duty holds a restricted radiotelephone operator permit of the card form (as distinguished from such does ment of the diploma form) or holds valid license verification card (FCC Form 758-F) attesting to the existence of an other valid commercial radio operat license, he may have such permit or verification card, as the case may be, in h personal possession. (b) Whenever a licensed operators required for a Mobile Station, the orignal license of each such operator, othe than an operator exclusively performing service and maintenance duties, shall be kept in his personal possession whenever he performs the duties of an operator at such station: Provided, That in lieu of an original license of the diploma form (as distinguished from such document of the card form) he may have in his personal possession a valid verification card attesting to its existence. (c) The original license of every st3tion operator who exclusively performs service and maintenance duties at that station shall be posted at the transmitter involved whenever the transmitter is in actual operation while service or maintenance work is being performed by him or under his immediate supervision and responsibility: Provided, That in lieu of posting his license, he may have o his person his license or a valid verication card. § 91.156 Posting station licenses and transmitter identification cards a plates. (a) The current authorization fat each mobile station and each base o fixed station authorized to be operated at temporary locations shall be retained as a permanent part of the station records but need not be posted. In addition, executed Transmitter Identification Card (FCC Form 452-C) or a plate of metal or other durable substance, legibly indi cating the call sign and the licensee's name and address, shall be affixed readily visible for inspection, to each of such transmitters: Provided, That, if the transmitter is not in view of the operating position or is not readily accessible for inspection, then such card or plate Shall be affixed to the control equipment at the transmitter operating position or posted adjacent thereto. (b) The current authorization for each base or fixed station at a fixed location shall be posted at the principal control point of the station, and a photocopy of such authorization shall be posted at all other control points listed on the authorization. In addition, an executed Transmitter Identification Card (FCC Form 452-C) or a plate of metal or other durable substance, legibly indicating the call sign and the licensee's name and address, shall be affixed, readily visible for inspection, to each transmitter operated at a fixed location, when such transmitter is not in view of, or is not readily accessible to, the operator at the principal control point. § 91.157 Inspection of stations. All stations and records of stations in these services shall be made available for inspection by an authorized representative of the Commission at any time while the station is in operation, and, when not in operation, shall be made available for inspection upon reasonable request of such representative. § 91.158 Inspection and maintenance of tower marking and associated control equipment. The licensee of any radio station which has an antenna structure required to be painted or illuminated pursuant to the provisions of section 303 (q) of the Communications Act of 1934, as amended, and/or Part 17 of this chapter, shall operate and maintain the tower marking and associated control equipment in accordance with the following: (a) The tower lights shall be observed at least once each 24 hours, either visually or by observing an automatic and properly maintained indicator designed to register any failure of such lights, to insure that all such lights are functioning properly as required; or, alternatively, there shall be provided and properly maintained an automatic alarm system designed to detect any failure of the tower lights and to provide indication of such failure to the licensee. (b) Any observed or otherwise known failure of a code or rotating beacon light or top light not corrected within thirty minutes, regardless of the cause of such failure, shall be reported immediately by telephone or telegraph to the nearest Flight Service Station or Office of the Federal Aviation Agency. Further notification by telephone or telegraph shall be given immediately upon resumption of the required illumination. (c) All automatic or mechanical control devices, indicators, and alarm systems associated with the tower lights shall be inspected at intervals not to exIceed three months, to insure that such apparatus is functioning properly. (d) All lighting shall be exhibited from sunset to sunrise unless otherwise specified in the instrument of station authorization. (e) A sufficient supply of spare lamps shall be maintained for immediate replacement purposes at all times. (f) All towers shall be cleaned or re painted as often as is necessary to maintain good visibility. § 91.159 Notice of violations. (a) Any licensee who appears to have violated any provision of the Communications Act or any provision of this chapter shall be served with a written notice calling the facts to his attention and requesting a statement concerning the matter. FCC Form 793 may be used for this purpose. (b) Within 10 days from receipt of notice or such other period as may be specified, the licensee shall send a written answer, in duplicate, direct to the office of the Commission originating the official notice. If an answer cannot be sent nor an acknowledgment made within such 10-day period by reason of illness or other unavoidable circumstances, acknowledgment and answer shall be made at the earliest practicable date with a satisfactory explanation of the delay. (c) The answer to each notice shall be complete in itself and shall not be abbreviated by reference to other communications or answers to other notices. If the notice relates to violations that may be due to the physical or electrical characteristics of transmitting apparatus, the answer shall state fully what steps, if any, have been taken to prevent future violations, and, if any new apparatus is to be installed, the date such apparatus was ordered, the name of the manufacturer, and the promised date of delivery. If the installation of such apparatus requires a construction permit, the file number of the application shall be given, or if a file number has not been assigned by the Commission, such identification shall be given as will permit ready identification of the application. If the notice of violation relates to lack of attention to or improper operation of the transmitter, the name and license number of the operator in charge shall be given. § 91.160 Station records. Each licensee of a station in these services shall maintain records as required elsewhere in this part and in accordance with the following: (a) For all stations, the results and dates of the transmitter measurements required by § 91.108, and the name of the person or persons making the measurements. (b) For all stations, when service or maintenance duties are performed which may affect their proper operation, the responsible operator shall sign and date an entry in the station record concerned, giving: (1) Pertinent details of all duties performed by him or under his supervision; (2) His name and address; and (3) The class, serial number, and expiration date of his license: Provided, however, That the information called for under subparagraphs (2) and (3) of this paragraph, so long as it remains unchanged, is not required to be repeated in the case of a person who is regularly employed as operator on a full-time basis at the station. (c) For base stations and operational fixed stations only, excepting stations authorized to operate at temporary locations, the name or names of persons responsible for the operation of transmitting equipment each day, together with the period of their duty. (d) For base stations only, excepting base stations authorized to operate at temporary locations, when they communicate with other base stations or with operational fixed stations: (1) Call signs of other stations; and (2) Date, time, and approximate duration of each transmission. (e) When a Base Station or Operational Fixed Station has an antenna structure which is required to be illum nated, appropriate entries shall be made as follows: (1) The time the tower lights an turned on and off each day, if manual controlled. (2) The time the daily check proper operation of the tower lights wa made. (3) In the event of any observed c otherwise known failure of a tower light (i) Nature of such failure. (ii) Date and time the failure w observed or otherwise noted. (iii) Date, time and nature of the adjustments, repairs, or replacements made. (iv) Identification of the Flight Serv ice Station (Federal Aviation Agency notified of the failure of any code or rotating beacon light not corrected within thirty minutes, and the date and time such notice was given. (v) Date and time notice was given to the Flight Service Station (Federal Aviation Agency) that the required 1lumination was resumed. (4) Upon completion of the threemonth periodic inspection required by § 91.158: (i) The date of the inspection and the condition of all tower lights and associated tower lighting control devices, indicators and alarm systems. (il) Any adjustments, replacements. or repairs made to insure compliance with the lighting requirements and the date such adjustments, replacements, or repairs were made. (f) The records shall be kept in an orderly manner, and in such detail that the data required are readily available. Key letters or abbreviations may be used if proper meaning or explanation is set forth in the record. (g) Each entry in the records of each station shall be signed by a person quali fled to do so, having actual knowledge of the facts to be recorded. (h) No record or portion thereof shall be erased, obliterated, or wilfully destroyed within the required retention period. Any necessary correction may be made only by the person originating the entry, who shall strike out the erroneous portion, initial the correction made and indicate the date of correction (1) Records required by this part shal be retained by the licensee for a period of at least one year. An authorization for developmental operation in any of the services under this part will be issued only to those persons who are eligible to operate stations in = such service on a regular basis. § 91.202 Showing required. (a) Except as provided in paragraph (b) of this section, each application for developmental operation shall be accompanied by a showing that: (1) The applicant has an organized plan of development leading to a specific objective; (2) A point has been reached in the program where actual transmission by radio is essential to the further progress thereof; (3) The program has reasonable promise of substantial contribution to the expansion or extension of the radio art, or is along lines not already investigated; (4) The program will be conducted by qualified personnel; (5) The applicant is legally and financially qualified, and possesses adequate technical facilities for conduct of the program as proposed; and (6) The public interest, convenience, or necessity will be served by the proposed operation. (b) The provisions of paragraph (a) of this section do not apply when an application is made for developmental operation solely for the reason that the frequency requested is restricted to such developmental use. § 91.203 Limitations on use. Stations used for developmental operation shall be constructed and used in such a manner as to conform with all of the technical and operating requirements of Subparts C and D of this part, unless deviation therefrom is specifically provided in the instrument of authorization. § 91.204 Frequencies available for assignment. Stations engaged in developmental operation may be authorized to use a frequency, or frequencies, available for the service in which they propose to operate. The number of channels assigned will depend upon the specific re quirements of the developmental program itself, and the number of frequencies available in the particular area where the station will be operated. § 91.205 Interference. The operation of any station engaged in developmental work shall be subject to the condition that no harmful interference is caused to the operation of stations licensed on a regular basis under any part of this chapter. § 91.206 Special provisions. (a) The developmental program as described by the applicant in the application for authorization shall be substantially followed unless the Commission shall otherwise direct. (b) Where some phases of the developmental program are not covered by the general rules in this chapter and the rules in this part, the Commission may specify supplemental or additional requirements or conditions in each case, as deemed necessary in the public interest, convenience, or necessity. (c) The Commission may, from time to time, require a station engaged in developmental work to conduct special tests which are reasonable and desirable to the authorized developmental program. § 91.207 Required supplementary state |