Goto Section: 101.113 | 101.117 | Table of Contents
FCC 101.115
Revised as of
Goto Year:1996 |
1998
Sec. 101.115 Directional antennas.
(a) Unless otherwise authorized upon specific request by the
applicant, each station authorized under the rules of this part must
employ a directional antenna adjusted with the center of the major lobe
of radiation in the horizontal plane directed toward the receiving
station with which it communicates: provided, however, where a station
communicates with more than one point, a multi- or omni-directional
antenna may be authorized if necessary. New Periscope antenna systems
will not, under ordinary circumstances, be authorized.
(b) Stations operating below 932.5 MHz that are required to use
directional antennas must employ antennas meeting the standards
indicated below. (Maximum beamwidth is for the major lobe of radiation
at the half power points. Suppression is the minimum attenuation
required for any secondary lobe signal and is referenced to the maximum
signal in the main lobe.)
------------------------------------------------------------------------
Maximum
Frequency range beamwidth Suppression
(degrees) (dB)
------------------------------------------------------------------------
512 to 932.5 MHz................................ 20 13
------------------------------------------------------------------------
(c) Fixed stations (other than temporary fixed stations and DEMS
nodal stations) operating at 932.5 MHz or higher must employ
transmitting and receiving antennas (excluding second receiving antennas
for operations such as space diversity) meeting the appropriate
performance Standard A indicated below, except that in areas not subject
to frequency congestion, antennas meeting performance Standard B may be
used, subject to the requirements set forth in paragraph (d) of this
section. Licensees shall comply with the antenna standards table shown
in this paragraph in the following manner:
(1) With either the maximum beamwidth to 3 dB points requirement or
with the minimum antenna gain requirement; and
(2) With the minimum radiation suppression to angle requirement.
Antenna Standards
------------------------------------------------------------------------------------------------
--------------------------------------------------------
Maximum Minimum r
adiation suppression to angle in degrees from centerline
beamwidth
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) to10 deg.
to 15 to 20 to 30 to 100 to 140 to 180
degrees)
deg. deg. deg. deg. deg. deg.
------------------------------------------------------------------------------------------------
--------------------------------------------------------
932.5 to 935............................. A 14.0 n/a n/a
6 11 14 17 20 24
B 20.0 n/a n/a
n/a 6 10 13 15 20
941.5 to 944............................. A 14.0 n/a n/a
6 11 14 17 20 24
B 20.0 n/a n/a
n/a 6 10 13 15 20
952 to 960 2, 3.......................... A 14.0 n/a
n/a 6 11 14 17 20 24
[[Page 766]]
B 20.0 n/a n/a
n/a 6 10 13 15 20
1,850 to 2,500 \4\....................... A 5.0 n/a 12
18 22 25 29 33 39
B 8.0 n/a 5
18 20 20 25 28 36
3,700 to 4,200........................... A 2.7 36 23
29 33 36 42 55 55
B 2.7 36 20
24 28 32 32 32 32
5,925 to 6,425 \5\....................... A 2.2 38 25
29 33 36 42 55 55
B 2.2 38 21
25 29 32 35 39 45
5,925 to 6,425 \6\....................... A 2.2 38 25
29 33 36 42 55 55
B 2.2 38 20
24 28 32 35 36 36
6,525 to 6,875 \5\....................... A 2.2 38 25
29 33 36 42 55 55
B 2.2 38 21
25 29 32 35 39 45
6,525 to 6,875 \6\....................... A 1.5 n/a 26
29 32 34 38 41 49
B 2.0 n/a 21
25 29 32 35 39 45
10,550 to 10,680 5, 7.................... A 2.2 38
25 29 33 36 42 55 55
B 2.2 38 20
24 28 32 35 35 39
10,550 to 10,680 \6\..................... A 3.4 34 20
24 28 32 35 55 55
B 3.4 34 20
24 28 32 35 35 39
10,565 to 10,615......................... n/a 360 n/a n/a
n/a n/a n/a n/a n/a n/a
10,630 to 10,680\8\...................... n/a 3.5 34 20
24 28 32 35 36 36
10,700 to 11,700 \5\..................... A 2.2 38 25
29 33 36 42 55 55
B 2.2 38 20
24 28 32 35 36 36
12,200 to 13,250 \9\..................... A 1.0 n/a 23
28 35 39 41 42 50
B 2.0 n/a 20
25 28 30 32 37 47
17,700 to 18,820......................... A 2.2 38 25
29 33 36 42 55 55
B 2.2 38 20
24 28 32 35 36 36
18,920 to 19,700 \10\.................... A 2.2 38 25
29 33 36 42 55 55
B 2.2 38 20
24 28 32 35 36 36
21,200 to 23,600 \11\.................... A 2.2 38 25
29 33 36 42 55 55
B 2.2 38 20
24 28 32 35 36 36
24,250 to 25,250 \10\.................... A 2.2 38 25
29 33 36 42 55 55
B 2.2 38 20
24 28 32 35 36 36
31,000 to 31,300 12, 13.................. n/a 4.0 38
n/a n/a n/a n/a n/a n/a n/a
Above 31,300............................. A 2.2 38 25
29 33 36 42 55 55
B 2.2 38 20
24 28 32 35 36 36
------------------------------------------------------------------------------------------------
--------------------------------------------------------
\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\ Except for Multiple Address System frequencies listed in Secs. 101.147(b)(1) through (b)(4)
, where omnidirectional antennas may be used.
\3\ Antennas used at outlying stations as part of a central protection alarm system need conform
to only the following 2 standards:
(i) The minimum on-beam forward gain must be at least 10 dBi, and
(ii) The minimum front-to-back ratio must be at least 20 dB.
\4\ Omnidirectional antennas may be authorized in the band 2150-2160 MHz.
\5\ These antenna standards apply to all point-to-point stations authorized after June 1, 1997.
Existing licensees and pending applicants on that date
are grandfathered and need not comply with these standards.
\6\ These antenna standards apply to all point-to-point stations authorized on or before June 1,
1997.
\7\ Except for antennas between 140 deg. and 180 deg. authorized or pending on January 1, 1989,
in the band 10,550 to 10,565 MHz for which minimum
radiation suppression to angle (in degrees) from centerline of main beam is 36 decibels.
\8\ These antenna standards apply only to DEMS User Stations licensed, in operation, or applied
for prior to July 15, 1993.
\9\ Except for temporary-fixed operations in the band 13200-13250 MHz with output powers less th
an 250 mW and as provided in Sec. 101.147(q).
\10\ DEMS User Station antennas in this band must meet performance Standard B and have a minimum
antenna gain of 34 dBi. The maximum beamwidth
requirement does not apply to DEMS User Stations. DEMS Nodal Stations need not comply with the
se standards.
\11\ Except as provided in Sec. 101.147(t).
Note to footnote 11: Stations must employ an antenna that meets the performance standards for Ca
tegory A, except that in areas not subject to frequency
congestion, antennas meeting standards for Category B may be employed. Note, however, that the
Commission may require the use of high performance
antennas where interference problems can be resolved by the use of such antennas.
\12\ The minimum front-to-back ratio shall be 38 dBi.
\13\ Mobile, except aeronautical mobile, stations need not comply with these standards.
(d) The Commission shall require the replacement of any antenna or
periscope antenna system of a permanent fixed station operating at 932.5
MHz or
[[Page 767]]
higher that does not meet performance Standard A specified in paragraph
(c) of this section, at the expense of the licensee operating such
antenna, upon a showing that said antenna causes or is likely to cause
interference to (or receive interference from) any other authorized or
applied for station whereas a higher performance antenna is not likely
to involve such interference. Antenna performance is expected to meet
the standards of paragraph (c) of this section for parallel
polarization. For cases of potential interference, an antenna will not
be considered to meet Standard A unless the parallel polarization
performance for the discrimination angle involved meets the
requirements, even if the cross-polarization performance controls the
interference.
(e) In cases where passive reflectors are employed in conjunction
with transmitting antenna systems, the foregoing paragraphs of this
section also will be applicable. However, in such instances, the center
of the major lobe of radiation from the antenna normally must be
directed at the passive reflector, and the center of the major lobe of
radiation from the passive reflector directed toward the receiving
station with which it communicates.
(f) Periscope antennas used at an electric power facility plant area
will be excluded from the requirements of paragraph (c) of this section
on a case-by-case basis where technical considerations or safety
preclude the use of other types of antenna systems.
(g) In the event harmful interference is caused to the operation of
other stations, the Commission may, after notice and opportunity for
hearing, order changes to be made in the height, orientation, gain and
radiation pattern of the antenna system.
[ 61 FR 26677 , May 28, 1996, as amended at 62 FR 4924 , Feb. 3, 1997; 62 FR 24582 , May 6, 1997]
Goto Section: 101.113 | 101.117
Goto Year: 1996 |
1998
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