Imágenes de páginas
PDF
EPUB
[graphic]
[ocr errors]
[ocr errors]
[ocr errors]

10 POWER REDUCTION IN DECIBELS

15 20

900 1000

1500 2000

3000 ANTENNA HEIGHT IN FEET ABOVE AVERAGE TERRAIN

( Soo 21.506)

o009

(b) The maximum authorized band-width of emission and, for the cases of frequency or phase modulated emissions, the maximum authorized frequency deviation shall be as follows:

[blocks in formation]
[merged small][merged small][ocr errors]

(c) On frequencies above 500 Mc/s, viation arising from modulation shall not the bandwidth authorized shall not ex exceed the limits specified in § 21.507(b). ceed 400 kc/s for each derived communi (e) Each transmitter, which has more cation channel and may be restricted to than 3 watts plate power input to the lesser bandwidth when appropriate to final radio frequency stage and was inithe type of operation involved in any tially authorized or installed at the staparticular case.

tion in this service after July 1, 1950, (d) Other types of emission or band employing type A3 or F3 emission shall width in excess of those specified in para be equipped with a device which will graph (b) of this section may be author automatically prevent greater than norized upon an adequate showing of need mal audio level from modulating in therefor. An application requesting excess of the limits specified in parasuch authorization shall fully describe graphs (c) and (d) of this section. the modulation characteristics FM (f) Each transmitter, which employs include maximum modulating frequency type A3 or F3 emission, shall be equipped and maximum frequency deviation) with a modulation limiter in accordance emission and bandwidth desired, shall with the provisions of paragraph (e) of specify the bandwidth to be occupied, this section and also shall be equipped and shall state the reasons why such with a low-pass audio filter installed beemission or bandwidth is required.

tween the modulation limiter and the
(e) The authorization to employ any modulated stage. At audio frequencies
of the various types of modulated emis between 3 kc/s and 15 kc/s, the filter
sion in this service shall be construed to shall have an attenuation greater than
include authority to employ unmodu the attenuation at 1 kc/s by a least:
lated emission only for temporary or

40 log,0 (1/3) decibels
short periods necessary for equipment
testing incident to the construction and

where “f” is the audio frequency in maintenance of a radio station.

kilocycles. At audio frequencies above

15 kc/s, the attenuation shall be at least § 21.508 Modulation requirements. 28 decibels greater than the attenuation

(a) The use of modulating frequen at 1 kc/s. cies higher than 3000 cycles per second

21.509 Permissible communications. for radiotelephony or tone signaling is not authorized on frequencies below 500

(a) Mobile stations in this service are Mc/s.

authorized to communicate with and (b) [Reserved]

through base stations only. Such com(c) When amplitude modulation is

munication between base and mobile used, the modulation percentage shall

stations shall be upon frequencies which be sufficient to provide efficient com

are paired in the manner set forth in munication and shall normally be main

§ 21,501 (a), (b), and (c). tained above 70 percent on peaks, but

(b) Base stations in this service are shall not exceed 100 percent on nega normally

authorized to communicate tive peaks.

with associated land mobile stations in (d) When phase or frequency modula

the same service: Provided, however, tion is used for single channel operation

That base stations may also render seryon frequencies below 500 Mc/s, the de ice to properly licensed transient land

mobile stations normally associated with (f) Base stations in this service may another common carrier base station, in communicate with appropriately authorcluding mobile units of Canadian regis ized Rural Subscriber stations in the try. Under specific authorization from Rural Radio Service, where the use of the Commission, service may be rendered wire lines is not practicable or feasible. to stations on board vessels. Authority Authorization for the establishment of a to provide service to vessels may be Rural Subscriber station may be granted granted upon a showing that the rendi upon a satisfactory showing that it will tion of service to vessels will not degrade, not degrade the mobile communication by kind or extent of usage, the service service rendered by the base station and which would be available, in the absence a supplementary showing as set forth of service to vessels, to land vehicles re in § 21.609. Such showing should be inceiving or subsequently requesting such corporated in the application for conservices in the area: Provided, That any struction permit for the fixed point to authorization to render service to ves which communication is to be effected. sels, other than itinerant vessels requir (g) The base and mobile station faing service in other areas where VHF cilities authorized in this service shall public coast service is not available, shall not be used in connection with any taxiautomatically terminate at the expira cab operations wherein the licensee is tion of 60 days after inauguration of VHF directly or indirectly interested through public coast service in the area in stock ownership or otherwise. volved. Applications for authority to (h) Pursuant to the provisions of the communicate with vessels shall be ac "Convention Between the United States companied by a showing of the following: of America and Canada, Relating to Op

(1) The total number of land mobile eration by Citizens of Either Country of units being served through the base Certain Radio Equipment or Stations in station.

the Other Country,” United States li(2) The total number of land mobile censed mobile units in this service which units to which it is reasonably expected are in Canada may be authorized by the that such service will be furnished at any Canadian Government to communicate time in the next 12 months.

with or through Canadian licensed com(3) The total number of stations on mon carrier base stations in the land board vessels initially proposed to be mobile radio service or with base stations served through the base station.

licensed under the rules of this part. (4) The total number of stations on Canadian licensed mobile units in the board vessels to which it is reasonably common carrier land mobile radio seryexpected that such service will be fur ice which are in the United States may nished at any time in the next 12 months. communicate with and through United

(5) Other public radio facilities avail States licensed base stations in this servable in the area providing service to ice provided authority for such commobile stations on board vessels.

munication has been granted by the (6) Such other information as may be Commission upon proper application deemed pertinent, showing that com therefor. (See $ 21.29 (i) and (j).) munication with vessels will not degrade (1) Unless otherwise prohibited by or deny service to land vehicles receiv agreements, laws, rules, regulations, etc. ing or requesting land vehicular com of the foreign country concerned, base munication service over the radio facili stations in this service are not prohibited ties of the base station, and that such from rendering trans-border communiservice to vessels is necessary and cation service for hire to mobile units in desirable.

that country which are properly licensed (c) Applications requesting renewal of to operate in the common carrier land authority to render service to vessels mobile service of either country. shall be accompanied by a current show (j) Auxiliary test stations in this ing of information as required in para service shall normally be operated upon graph (b) of this section.

mobile station frequencies only for the (d) Mobile stations in this service may purpose of determining the performance not be operated aboard aircraft.

of fixed receiving equipment remotely (e) Base stations in this service which located from the base station with which are authorized to render one-way signal it is associated or where the receiving ing service may also render such service equipment is located with the base stato receivers installed aboard vessels and tion and both are remote from the conaircraft.

trol point of the station: Provided, how

ever, That a transmitter used in an aux $ 21.512 Priorities for service to subiliary test station may be

used as a

scribers. standby transmitter upon the frequency

(a) Subscriptions to mobile teleof the base station with which it is asso

phone service shall be afforded in the ciated whenever such base station is out al service for maintenance or repair.

following order of precedence and in

chronological order of filing of request (k) A subscriber's dispatch station in

for service within each of the following this service is authorized to intercommu

customer categories: nicate only with the mobile stations of

(1) Category 1: Public safety and said subscriber through the base station

health. Official federal, state, county with which it is associated. Where more

and municipal government agencies prothan one subscriber jointly operate a dis

tecting the public safety and health; patch station, each subscriber shall com

private organizations and persons enmunicate only with his own mobile

gaged primarily in protecting the public stations.

safety and health such as physicians, 821.510 Base stations may be author. hospitals, ambulance services, volunteer

ized only as part of integrated radio fire departments, American Red Cross, system.

licensed protective patrols and armored Base stations will be authorized

cars and similar agencies.

(2) Category 2: Public service. Cononly as a part of an integrated com. munication system wherein mobile units tract carriers, common carriers, and pub

lic utilities (exclusive of taxicab and Associated therewith are also licensed to the base station licensee (see § 21.15 (i)). livery service), for communications other

than correspondence of the general pub$21.511 Communication service to own

lic. mobile units.

(3) Category 3: Quasi public service. (a) Upon filing an application for re Emergency repair organizations, not inDewal of station license for a base sta cluded in Category 1, protecting health tion in this service, a miscellaneous com and property; press associations, newsmon carrier applicant shall submit a papers and broadcasting stations. factual statement to show that, during (4) Category 4: Physically handithe preceding license period, at least capped. Persons who because of physan average of 50 percent of the mo ical handicaps, operate specifically bile units on any channel to which equipped vehicles and are unable to leave

such vehicles without assistance. communication service has been ren

(5) Category 5: Industrial. Gas or oil dered by a base station have been

producing or drilling operators; producused by persons not directly or in

ers and distributors of fuel and lumber directly controlling or controlled by, or

and other construction materials and under direct or indirect common control

equipment; food processing, distribution with the applicant. It an applicant is

and storage organizations; producers of unable to meet such criterion, he shall substantial quantities of food; business show what efforts have been made to concerns engaged in construction of achleve use of the service by the public housing and industrial or public works; and offer such further showing or ex taxicabs and livery service. planation as he may deem appropriate. (6) Category 6: Traveling public. (b) Wire-line communication com Trains and watercraft where service is

made available to passengers. mon carriers may be authorized to establish land mobile radio facilities under

(7) Category 7: All others this part of the rules for the purpose of

(b) After initial establishment of

service in accordance with the table of providing communication facilities for

priorities in paragraph (a) of this sectheir own use incident to construction

tion when facilities in a given area are and maintenance of public communica

insufficient to furnish service to all who top facilities: Provided however, That

desire mobile radiotelephone service, apthe use of the authorized facilities on

plications for new or additional mobile buch frequencies shall be on a second

units shall be ranked within the cateary basis and subject to use by public

gories in order

of date of filing and serysubscribers at any time when required

ice shall be afforded such applicants as for the rendition of public communica

facilities become available, in descending tion service.

order of precedence.

be

$ 21.513 Location of message center.

Within the service area encompassed by the field strength contour of each base station as defined in $ 21.504, there shall be at least one message center so located that the major portion of subscribers' local exchange landline telephone calls, which originate or terminate in such area in conjunction with messages transmitted or received by said station, cost no more per call than the local message single unit rate. In cases where the control point of a base station is not so located, a public foreign exchange telephone circuit shall be provided to afford service so that a radio service subscriber may communicate between such points at a cost per call not in excess of the local message single unit rate. 21.514 Responsibility for operational

control and maintenance of mobile

units. (a) The licensee of a base station in this service shall be responsible for exercising effective operational control over all mobile units with which it communicates. The proper installation and maintenance of such mobile units shall be the responsibility of the respective licensees thereof.

(b) A mobile unit normally associated with and licensed to a specified base station will be deemed, when communicating with a different base station pursuant to legally effective tariff provisions, to be temporarily associated with and licensed to such different base station and the licensee of such different base station shall, for such temporary period, assume the same licensee responsibility for such mobile unit as if such unit were regularly licensed to it. $ 21.515 Control points, dispatch points

and dispatch stations. (a) Dispatch stations, other than those installed pursuant to § 21.519(a), may be installed only with specific authorization from the Commission. Upon removal of a specifically licensed dispatch station, the licensee must within 30 days thereafter submit to the Commission in Washington, D.C., the dispatch station license for cancellation. Dispatch points may be installed or removed without authorization. Dispatch point circuit facilities shall be installed in conformance with the requirements of paragraph (c) (2) of this section.

(b) To insure the maintenance of station control, means shall be provided

whereby each dispatch station and each dispatch point is maintained under continuous effective operational supervision of one or more control points.

(c) At each control point for a base station or fixed station in this service, the following facilities will be installed:

(1) Equipment to permit the responsible radio operator to monitor aurally, at such intervals as may be necessary to insure proper operation of the integrated communication system, all transmissions originating at dispatch points under his supervision and at stations with which the base station communicates.

(2) Facilities which will permit the responsible radio operator either to disconnect immediately the dispatch point circuits from the transmitter or immediately to render the transmitter inoperative from any dispatch point associated therewith.

NOTE: Reference should made to $ $ 21.118 and 21.518 for additional control point requirements and also to $ 21.205 concerning operator requirements. [28 F.R. 13002, Dec. 5, 1963, as amended at 29 F.R. 11362, Aug. 6, 1964] § 21.516 Additional showing required

with application for assignment of

additional channel. An application requesting the assignment of an additional channel at an existing Domestic Public Land Mobile radio station (other than control, dispatch or repeater), in addition to the information required by other sections of the rules, shall include a showing of the following:

(a) The number of mobile units for which orders for service are being held.

(b) Data showing the actual traffic loading on each channel assignment of the present radio system during the busiest 12 hour periods on three days (within a seven day period) having normal message traffic not more than 30 days prior to the date of filing. This information should be reported separately for each of the three days selected, which should be identified by dates, and should disclose the following:

(1) The number of mobile units using the service during each of the days specified.

(2) The number of calls completed each hour.

(3) For systems that provide message relay service, (i) the number of calls held, (ii) the total holding time, and (iii) the maximum holding time for a

« AnteriorContinuar »