Goto Section: 78.104 | 78.106 | Table of Contents
FCC 78.105
Revised as of
Goto Year:1996 |
1998
Sec. 78.105 Antenna systems.
(a) For fixed stations operating in the 12.7-13.2 and 17.7-19.07 GHz
bands, and for fixed and mobile stations operating in the 31.0-31.3 GHz
bands, the following standards apply:
(1) Fixed CARS stations shall use directional antennas that meet the
performance standards indicated in the following table.
(i) Stations must employ an antenna that meets the performance
standards for Category B. In areas subject to frequency congestion,
where proposed facilities would be precluded by continued use of a
Category B antenna, a Category A antenna must be employed. The
Commission may require the use of a high performance antenna where
interference problems can be resolved by the use of such antennas.
(ii) Upon adequate showing of need to serve a larger sector, or more
than a single sector, greater beamwidth or multiple antennas may be
authorized. Applicants shall request and authorization for stations in
this service will specify the polarization of each transmitted signal.
(iii) Licensees shall comply with the antenna standards table shown
in this paragraph in the following manner:
(A) With either the maximum beamwidth to 3 dB points requirement or
with the minimum antenna gain requirement; and
(B) With the minimum radiation suppression to angle requirement.
Antenna Standards
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--------------------------------------------------------
Maximum Min
imum radiation suppression to angle in degrees from
beamwidith
centerline of main beam in decibels
to 3 dB Minimum ---------
--------------------------------------------------------
Frequency (MHz) Category points \1\ antenna
(included gain 5 deg.
10 deg. 15 deg. 20 deg. 30 deg. 100 deg. 140 deg.
angle in (dbi) to 10
to 15 to 20 to 30 to 100 to 140 to 180
degrees) deg.
deg. deg. deg. deg. deg. deg.
------------------------------------------------------------------------------------------------
--------------------------------------------------------
12,700 to 13,250.................................... A
B 1.0
2.0 n/a
n/a 23
20
28
25 35
28 39
30 41
32 42
37 50
47
17,700 to 19,700.................................... A
B 2.2
2.2 38
38 25
20
29
24 33
28 36
32 42
35 55
36 55
36
31,000 to 31,300 \2\................................ n/a \3\ 4.0 38 n/a
n/a n/a n/a n/a n/a n/a
[[Page 685]]
38,600 to 40,000.................................... A
B 2.2
2.2 38
38 25
20
29
24 33
28 36
32 42
35 55
36 55
36
------------------------------------------------------------------------------------------------
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\1\ If a licensee chooses to show compliance using maximum beamwidth to 3 dB points, the beamwid
th limit shall apply in both the azimuth and the
elevation planes.
\2\ Mobile, except aeronautical, mobile, stations need not comply with these standards.
\3\ The minimum front-to-back ratio shall be 38 dBi.
(2) New periscope antenna systems will be authorized upon a
certification that the radiation, in a horizontal plane, from an
illuminating antenna and reflector combination meets or exceeds the
antenna standards of this section. This provision similarly applies to
passive repeaters employed to redirect or repeat the signal from a
station's directional antenna system.
(3) The choice of receiving antennas is left to the discretion of
the licensee. However, licensees will not be protected from interference
which results from the use of antennas with poorer performance than
defined in paragraph (a) of this section.
(4) The transmitting antenna system of stations employing maximum
equivalent isotropically radiated power exceeding +45 dBW in the
frequency band between 12.70 and 12.75 GHz shall be oriented so that the
direction of maximum radiation of any antenna shall be at least 1.5 deg.
away from the geostationary satellite orbit, taking into account the
effect of atmospheric refractions.1
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1 See Chapter I, Article 1, Section III of the (International)
Radio Regulations (Geneva, 1959), as amended, for Technical
Characteristics Terms and Definitions. Additional information and
methods for calculating azimuths to be avoided may be found in the
following: Report 393, International Radio Consultative Committee
(C.C.I.R.); ``Geostationary Orbit Avoidance Computer Program,'' Reort
CC-7220, Federal Communications Commission, available from the National
Technical Information Service, Springfield, VA 22151, in printed form
(PB-211 500) or source card deck (PB-211 501).
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(5) Pickup stations are not subject to the performance standards
herein stated. The provisions of this paragraph are effective for all
new applications accepted for filing after October 1, 1981.
(b) Any fixed station licensed pursuant to an application accepted
for filing prior to October 1, 1981, may continue to use its existing
antenna system, subject to periodic renewal until April 1, 1992, After
April 1, 1992, all licensees are to use antenna systems in conformance
with the standards of this section. TV auxiliary broadcast stations are
considered to be located in an area subject to frequency congestion and
must employ a Category A antenna when:
(1) A showing by an applicant of a new CAR service or TV auxiliary
broadcast, which shares the 12.7-13.20 GHz band with CARS, indicates
that use of a category B antenna limits a proposed project because of
interference, and
(2) That use of a category A antenna will remedy the interference
thus allowing the project to be realized.
(c) As an exception to the provisions of this section, the FCC may
approve requests for use of periscope antenna systems where a persuasive
showing is made that no frequency conflicts exist in the area of
proposed use. Such approvals shall be conditioned to require conversion
to a standard antenna as required in paragraph (a) of this section when
an applicant of a new TV auxiliary broadcast or Cable Television Relay
station indicates that the use of the existing antenna system will cause
interference and the use of a category A or B antenna will remedy the
interference.
(d) As a further exception to the provision of paragraph (a) of this
section the Commission may approve antenna
[[Page 686]]
systems not conforming to the technical standards where a persuasive
showing is made that:
(1) Indicates in detail why an antenna system complying with the
requirements of paragraph (a) of this section cannot be installed, and
(2) Includes a statement indicating that frequency coordination as
required in Sec. 78.18a was accomplished.
[ 45 FR 78694 , Nov. 26, 1980, as amended at 49 FR 37779 , Sept. 26, 1984;
50 FR 7343 , Feb. 22, 1985; 51 FR 19841 , June 3, 1986; 56 FR 50664 , Oct.
8, 1991; 62 FR 4923 , Feb. 3, 1997]
Goto Section: 78.104 | 78.106
Goto Year: 1996 |
1998
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