(d) That the public interest, convenience and/or necessity will be served through the operation of the proposed station.* [Rule 1041] 4.93 Charges for transmission. (a) A licensee of a facsimile broadcast station shall not make any charge, directly or indirectly, for the transmission of programs.

(b) No licensee of any other broadcast station or network shall make any additional charge, directly or indirectly, for the transmission of programs by a facsimile broadcast station, nor shall commercial accounts be solicited by any licensee of another broadcast station_or network, or others acting in their behalf, upon representation that images concerning that commercial program will be transmitted by a facsimile station.*t [Rule 1042]

4.94 Frequency assignments. (a) The following frequencies are allocated for assignment to facsimile broadcast stations on an experimental basis provided no interference is caused to the television stations operating in the band 2,000-2,100 kilocycles:

2,012 kc. 2,016 kc. 2,096 kc.

(b) If the facsimile program of research and experimentation cannot be properly carried forward on the frequencies in paragraph (a) of this section due to the characteristics of these frequencies, applicants may request and be assigned any frequency specified in § 4.156 on an experimental basis.

(c) Other frequencies under the jurisdiction of the Commission may be assigned for experimental operation of facsimile broadcast stations on an experimental basis provided a sufficient need therefor is shown and no interference will be caused to established radio stations.

(d) Each facsimile broadcast station will be licensed for only one frequency except in paragraph (b) of this section more than one frequency may be licensed to one station if need therefor is shown.

(e) Each applicant shall specify the frequency or frequencies desired and the maximum modulating frequencies proposed to be employed.

(f) The operating frequency of a facsimile broadcast station shall be maintained in accordance with the frequency assignments as shown by § 4.1 provided, however, where a more strict adherence to the assigned frequency is necessary to prevent interference, the Commission will specify the tolerance.

(g) A facsimile broadcast station authorized to operate on frequencies regularly allocated to other stations or services shall be required to abide by all rules governing the stations regularly operating thereon, which are applicable to facsimile broadcast stations and are not in conflict with 88 4.1-4.11 and §§ 4.61-4.79 excluding § 4.78.*+ (Sec. 303 (c), 48 Stat. 1082; 47 U.S.C. 303 (c)) [Rule 1043]

4.95 Power. The power output rating of a facsimile broadcast station shall not be in excess of that necessary to carry forward the program of research. The operating power may be maintained at the maximum rating or less, as the conditions of operation may require. [Rule 1044]

**For statutory and source citations, see note to § 4.1.

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4.96 Report filed with renewal application. A supplemental report shall be filed with and made a part of each application for renewal of license and shall include statements of the following:

(a) Number of hours operated for transmission of facsimile programs.

(b) Comprehensive report of research and experimentation conducted.

(c) Conclusions and program for further developments of the facsimile broadcast service.

(d) All developments and major changes in equipment.

(e) Any other pertinent developments.*t (Sec. 303 (j), 48 Stat. 1082; 47 U.S.C. 303 (j)) [Rule 1045]

HIGH FREQUENCY BROADCAST STATIONS

4.111 Definition. The term "high frequency broadcast station" means a station licensed on frequencies above 25,000 kilocycles for transmission of aural programs for general public reception. The frequencies for these stations are allocated on an experimental basis.** [Rule 1050]

4.112 Necessary showing. A license for a high frequency broadcast station will be issued only after a satisfactory showing has been made in regard to the following, among others:

(a) That the applicant has a program of research and experimentation which indicates reasonable promise of substantial contribution to the development of very high frequency broadcasting.

(b) That data will be taken on the propagation characteristics of these frequencies; on the shadows cast by buildings, hills, large bridges, etc.; on the noise level in different parts of the city; on the field intensity necessary to render good broadcast service; on antenna design and characteristics with respect to propagation; and on other allied phases of broadcast coverage.

(c) That the research and experimentation will be conducted by qualified engineers.

(d) That the applicant is legally and financially qualified and possesses adequate technical facilities to carry forward the program.

(e) That the public interest, convenience and necessity will be served through the operation of the proposed station.*+ [Rule 1051]

4.113 Charges for transmission. (a) A licensee of a high frequency broadcast station shall not make any charge, directly or indirectly, for the transmission of programs, but may transmit the programs of a regular broadcast station or network including commercial programs, if the call letter designation when identifying the high frequency broadcast station is given on its assigned frequencies only and the statement is made over the high frequency broadcast station that the program of a broadcast station or network (identify by call letters or name of network) is being broadcast. In case of the rebroadcast of the program of any broadcast station, § 3.157 applies.

(b) No licensee of any other broadcast station or network shall make any additional charge, directly or indirectly, for the simulta

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**For statutory and source citations, see note to § 4.1.

neous transmissions of programs by the high frequency broadcast station, nor shall commercial accounts be solicited by a licensee of another broadcast station or network, or by others acting in their behalf upon representation that the commercial program will also be transmitted by a high frequency broadcast station.*t (Sec. 303 (b), 48 Stat. 1082; 47 U.S.C. 303 (b)) [Rule 1052]

4.114 Frequency assignments. (a) The following groups of frequencies are allocated for high frequency broadcast stations on an experimental basis:

(b) Frequencies in Groups A and B will be assigned exclusively for amplitude modulation with a band width for high fidelity transmission (30 kilocycles maximum). Frequencies in Groups C and E will be assigned for either amplitude modulation with the above band width or frequency modulation with a total band width not greater than 200 kilocycles. Frequencies in Group D will be assigned exclusively for frequency modulation with a band width of not greater than 200 kilocycles.

(c) In Groups A, B and D only one frequency from each group will be assigned a licensee for operation in the same service area. A separate license and call letters will be assigned for each frequency. In Group C all four frequencies and in Group E any four frequencies will be authorized by each license. A license authorizes operation on only one of the four assigned frequencies at any one time.

(d) An applicant shall file separate application for each frequency requested in Groups A, B, or D. Each application therefor shall specify all four frequencies in Group C and any four frequencies in Group E.

(e) An applicant shall select the frequency which it is believed is best suited for the experiments to be conducted and which will cause the least or no interference to established stations.

(f) A licensee operating on a frequency in Groups A or B shall request reports concerning any reception outside the North American Continent. The request for reports shall be made several times each day, when the station identification is given.*t (Sec. 303 (c), 48 Stat. 1082; 47 U.S.C. 303 (c) [Rule 1053]

4.115 Power. (a) No high frequency broadcast station will be licensed for an output power rating greater than 1,000 watts unless the applicant can show that greater power is needed to carry on a special program of research.

(b) While conducting apparatus experiments and in case adequate signal for reliable service can be delivered with less power, the operating output may be reduced accordingly.*t [Rule 1054]

**For statutory and source citations, see note to § 4.1.

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4.116 Frequency control. Each high frequency broadcast station transmitter shall be equipped with automatic frequency control apparatus so designed and constructed that it is capable of maintaining the operating frequency within plus or minus 0.01 percent of the assigned frequency.*t [Rule 1055]

4.117 Report filed with renewal application. A supplemental report shall be filed with each and made a part of the application for renewal of license and shall include statements of the following, among others:

(a) The number of hours operated.

(b) Data taken in compliance with § 4.112 (b).

(c) Outline of reports of reception and interference and conclusions with regard to propagation characteristics of the frequency assigned. (d) Research and experiments being carried on to improve transmission and to develop broadcasting on the very high frequencies. (e) All developments or major changes in equipment. (f) Any other pertinent developments.

(g) Comprehensive summary of all reports received. See § 4.114 (f).*t (Sec. 303 (j), 48 Stat. 1082; 47 U.S.C. 303 (j)) [Rule 1056]

NONCOMMERCIAL EDUCATIONAL BROADCAST STATIONS

4.131 Definition. The term "noncommercial educational broadcast station" means a high frequency broadcast station licensed to an organized nonprofit educational agency for the advancement of its educational work and for the transmission of educational and entertainment programs to the general public.* [Rule 1057, FCC, Jan. 26, 1938, 3 F.R. 312]

4.132 Operation and service. The operation of, and the service furnished by, noncommercial educational broadcast stations shall be governed by the following regulations in addition to the rules and regulations in this part governing high frequency broadcast stations.

(a) A noncommercial educational broadcast station will be licensed only to an organized nonprofit educational agency and upon a showing that the station will be used for the advancement of the agency's educational program.

(b) Each station may transmit programs directed to specific schools in the system for use in connection with the regular courses as well as routine and administrative material pertaining to the school system and may transmit educational and entertainment programs to the general public.

(c) Each station shall furnish a nonprofit and noncommercial broadcast service. No sponsored or commercial program shall be transmitted nor shall commercial announcements of any character be made. A station shall not transmit the programs of other classes of broadcast stations unless all commercial announcements and commercial reference in the continuity are eliminated.

(d) The transmitting equipment, installation, and operation as well as the location of the transmitter shall be in conformity with the

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**For statutory and source citations, see note to § 4.1.

requirements of good engineering practice as released from time to time by the Commission.29

20

Section 4.132 (d) specifies that the transmitting equipment of all noncommercial educational broadcast stations shall be designed, constructed, installed and operated in conformity with the requirements of good engineering practice as specified from time to time by the Commission. Also the location of the transmitter shall conform with the same requirements. The general principles of these requirements to insure satisfactory service from the station are enunciated below for the guidance of applicants and licensees. These principles are based on the best information available at this time but since the development of transmission and reception on the very high frequencies is only in the early stages, these standards may be departed from in case experience warrants the same. Each case will be treated on its individual merits as to details. The general principles are as follows:

Transmitter and antenna location. To accomplish satisfactory coverage of any area, it is necessary that the transmitter and antenna be located at or near the highest point in such an area and as near the center thereof as obtainable and yet meet the height requirements. The area desired to serve may be only a section of the city, and the site should permit placing the antenna higher than the surrounding buildings or obstructions so as to obtain as large an area as possible in the line of sight from the antenna. In compromising between height and central location, it is generally considered the height is of more importance. Any area behind a large hill or in a valley out of line of sight of the antenna may receive materially reduced signal depending upon several factors as to the formation of the hill, distance, receiving conditions, etc.

Antenna system. Since at the frequencies allocated for this service, one half wave length is only approximately 12 feet, the antenna system design may vary within wide limits without unreasonable expense even for a very elaborate installation. It has not been definitely determined whether horizontal or vertical polarization is superior. However, it is considered that at the frequencies of these stations horizontal polarization (radiating element horizontal) is superior for general broadcast purposes. In addition to meeting the above requirement relative to location, the antenna itself should be above the immediate surrounding obstructions as explained above. Where a central location is not obtainable, a directional antenna for increasing the service in the farther areas should be considered. In cases where the radiating elements are horizontal, consideration should be given to concentrating the radiation in a small angle with the horizontal by means of several elements and also to avoid directional properties in the horizontal plane when not desirable, elements in different vertical planes are necessary.

Transmitter design and construction. The transmitter shall be capable of delivering satisfactorily the authorized power with modulation of at least 85 per cent with combined audio frequency harmonics generated by the transmitter not in excess of 10 per cent. The system of modulation is not prescribed, but must be a system that has been tested and proven satisfactory in operation. The carrier hum and extraneous noise level shall be kept at a minimum and shall be at least 50 decibals below 100 per cent modulation. Automatic frequency control shall be provided for automatically maintaining the operating frequency within 0.01 per cent of the assigned frequency. Adequate margin shall be provided in all component parts to avoid over-heating at the maximum rated power output. The maximum output power rating will be accepted as that given by the manufacturer unless it appears unsatisfactory. The transmitter shall be constructed in keeping with modern practice as to frame, panels and mounting, complete shielding, safety of life provisions, proper wiring, adequate meters (plate voltage, total plate current, output RF current, and others, as required) and control facilities.

Installation of equipment. The installation must be made in a suitable room with no exposed high voltage leads or connections. The output connection shall be made through suitable bushings of minimum length and with protection from contact. A transmission line to antenna is recommended in all except very special

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