(a) Except as otherwise provided in this section, the requirements of paragraphs (a), (b), (c), (d), and (e) of § 73.687 of this chapter shall apply to stations in this service transmitting standard television signals.

(b) The average power of radio frequency harmonics of the visual and aural carriers, measured at the output terminals of the transmitter, shall be attenuated no less than sixty (60) decibels below the peak visual output power within the assigned channel. All other emissions appearing on frequencies more than fifty (50) percent of the authorized bandwidth above or below the upper and lower edges, respectively, of the assigned channel shall be attenuated no less than: (i) Thirty (30) decibels for transmitters rated at less than ten (10) watts visual peak power output; or (ii) forty (40) decibels for transmitters rated at ten (10) watts or more visual peak power output. However, should interference occur as the result of emissions outside the assigned channel, greater attenuation may be required.

(c) The provisions of § 21.101 shall apply with respect to the frequency tolerance for the visual carrier in lieu of § 73.687(c)(1) except for the frequency of the aural carrier which shall be maintained in accordance with § 73.687(c)(1) of this chapter. (d)

The requirements

of

§ 73.687(c)(2) will be considered to be satisfied insofar as measurements of operating power are concerned if the transmitter is equipped with instruments for determining the combined visual and aural operating power. However, licensees are expected to maintain the operating powers within the limits specified in § 21.904. Measurements of the separate visual and aural operating powers should be made at sufficiently frequent intervals to insure compliance with the rules and in no event less than once a month.

(e) Television transmitting equipment designed for stations whose authorized bandwidth is 4 MHz or less

for the visual and accompanying aural signal is subject to the provisions of § 21.101 with respect to the frequency tolerance of the visual and aural carriers in lieu of paragraph (c) of this section. Such equipment is also subject to paragraphs (a) and (b) of this section, except that the provisions of § 73.687(a), (b), and (c)(1) of this chapter shall not apply.

(f) As a further exception to the other requirements of this section, transmitting equipment characteristics may vary from these requirements to the extent necessary to insure that transmitted information is not likely to be received in intelligible form by unauthorized subscribers or licensees, provided such variations permit recovery of the transmitted information without perceptible degradation as compared to the same information transmitted without such variations.

§ 21.909 MDS response stations.

(a) An MDS response station is authorized to provide communication by voice and/or data signals with its associated MDS station. An MDS response station may be operated only by the licensee of the MDS station or its subscriber and only at receiving location of the MDS station with which it is communicating. More than one response station may be operated at the same or different receiving locations. All MDS response stations communicating with a single MDS station shall operate within the same frequency channel. The specified frequency channel which may be used by the response station is determined by the channel assigned to the MDS station with which it communicates. The specified frequency channel may be subdivided to provide a distinct operating frequency for each of more than one response station.

(b) Authorization of an MDS response station is subject to the following terms and conditions:

(1) The response station shall not cause interference to any station operating beyond the service area of the MDS station with which it communicates.

(2) The Commission's Engineer-InCharge of the radio district in which

intended operation is located shall be notified prior to the commencement of the operation of each response station. Such notice shall include:

(i) The authorized call sign of the MDS station, the transmitter location number (assigned by the carrier in sequence of use beginning with number one) and the response station location coordinates.

(ii) The exact frequency or frequencies to be used.

(iii) Anticipated date of commencement of operation.

(3) The Engineer-In-Charge shall be notified witnin 10 days after termination of any operation. The notice shall contain similar information to that contained in the notice of commencement of operation.

(4) Each station shall have posted a copy of the notification provided to the Engineer-In-Charge.

(5) The antenna structure height employed at any location shall not exceed the criteria set forth in § 17.7 of this chapter.

[48 FR 33901, July 26, 1983]

as

(a) The rules in this part are issued pursuant to titles I through III of the Communications Act of 1934, amended, which vest authority in the Federal Communications Commission to regulate common carriers of interstate and foreign communications and to regulate radio transmission and issue licenses for radio stations.

(b) The purpose of the rules in this part is to prescribe the conditions under which portions of the spectrum are made available for domestic common carrier radio communications which utilize transmitters on land or in specified offshore coastal areas within the continental shelf, and certain other situations as authorized under this part.

(c) The rules in this part apply only to stations authorized under this part. Rules in a subpart apply only to stations authorized under that subpart.

(d) Correspondence relating to this part of the rules may be sent to the Mobile Services Division, Federal Communications Commission, Washington, D.C. 20554.

(e) Unless otherwise specified, the section numbers referenced in this part are contained in Chapter I, Title 47 CFR.

[49 FR 3323, Jan. 26, 1984]

§ 22.1 Other applicable rule parts.

Other Commission rule parts of importance that may be referred to with respect to licensing and operations in radio services governed under this part include the following:

(a) Part 0 of the Commission's Rules describes the Commission's organization and delegations of authority. This part also lists available Commission publications and standards and procedures for access to Commission records, and location of Commission Field Offices.

(b) Part 1 includes rules of practice and procedure for adjudicatory proceedings including hearing proceedings, rule making proceedings, procedures for reconsideration and review of the Commission's actions; provisions concerning violation notices and forfeiture proceedings; and the requirements for environmental impact statements.

(c) Part 2 contains the table of frequency allocations and special requirements in international regulations, agreements, and treaties. This part also contains standards and procedures for marketing of radio frequency devices, and for obtaining equipment type acceptance and type approval.

(d) Part 5 contains standards and procedures for obtaining experimental authorizations.

(e) Conditions under which the operations of incidental and restricted radio devices are permitted are in Part 15.

(f) Part 17 contains detailed requirements for constructions, marking, and lighting of antenna towers.

[49 FR 3323, Jan. 26, 1984]

§ 22.2 Definitions:

Airborne station. A mobile station licensed for use only on an aircraft.

Air-ground radiotelephone service. A public radio service between a base station and airborne mobile stations.

Antenna structure. The antenna, its supporting structure, and anything attached to it.

Antenna power input. The radio frequency peak or RMS power, as the case may be, supplied to the antenna from the antenna transmission line and its associated impedance matching network.

Assignment. The transfer, by any means, of an authorization from the present holder to another person as defined in Section 3(i) of the Communications Act.

Authorized bandwidth. The maximum width of the band of frequencies permitted to be used by a station. This is normally considered to be the necessary or occupied bandwidth, whichever is greater.

Authorized frequency. The frequency assigned to a station by the Commission and specified in the instrument of authorization.

Authorized power. The maximum power a station is permitted to use. This power is specified in the station's authorization.

Auxiliary test station. A fixed station used for test transmissions.

Base station. A land station in the public mobile service communicating with authorized mobile and fixed stations.

Carrier frequency. The output of a transmitter when the modulating wave is made zero.

Cell. The are reliably served by a transmitter location in a cellular system. Cellular Geographic Service Area. The geographic area served by a cellular system within which the licensee is required to provide reliable service.

Cellular System. A high capacity land mobile system in which assigned spectrum is divided into discrete channels which are assigned in groups to geographic cells covering a cellular geographic service area. The discrete channels are capable of being reused in different cells within the service area.

Central Office. A landline termination center used for switching and interconnection of public message communication circuits.

Central Office Station. A fixed station used for transmitting communica

tions to rural subscriber stations associated therewith.

Co-channel Electrical Harmful Interference. An undesired electromagnetic signal at the same frequency as a desired signal which reduces the intelligibility of the desired signal to the extent that the ratio of the desired signal to that of the undesired signal is less than R, equation 8, FCC Report R-6406.

Channel occupancy time. The total time a channel is utilized for the transmission of communications, including necessary signaling. It does not include time waiting for a channel to become available. Communication

common carrier. Any person engaged in rendering communication services for hire to the public.

Control Channel. The channel used for transmission of digital control information from the base station to the mobile station or from the mobile station to the base station.

Control point. The location at which the base station is controlled and supervised by the licensee.

Control station. A fixed point-topoint or point-to-multi-point station used to control a remote base station transmitter.

Digital modulation. The process by which some characteristic (frequency, phase, amplitude or combination thereof) of a carrier frequency is varied in accordance with a digital signal, e.g., one consisting of coded pulses or states.

Dispatch communication. Two-way voice communication, normally of not more than one minute's duration, between a common carrier base and land mobile stations, or between a common carrier land mobile station and a landline telephone station not connected to a public message telephone system. Dispatch point. See dispatch station. Dispatch station. A fixed station operating on a mobile station frequency and operated by the subscriber to communicate with the subscriber's own mobile station or stations.

Effective radiated power. The product of the antenna power input and the antenna power gain. This product should be expressed in watts. (If specified for a particular direction, effec

33-168 0-85--7