Goto Section: 27.52 | 27.54 | Table of Contents
FCC 27.53
Revised as of October 1, 2016
Goto Year:2015 |
2017
§ 27.53 Emission limits.
(a) For operations in the 2305-2320 MHz band and the 2345-2360 MHz
band, the power of any emission outside a licensee's frequency band(s)
of operation shall be attenuated below the transmitter power P (with
averaging performed only during periods of transmission) within the
licensed band(s) of operation, in watts, by the following amounts:
(1) For base and fixed stations' operations in the 2305-2320 MHz band
and the 2345-2360 MHz band:
(i) By a factor of not less than 43 + 10 log (P) dB on all frequencies
between 2305 and 2320 MHz and on all frequencies between 2345 and 2360
MHz that are outside the licensed band(s) of operation, and not less
than 75 + 10 log (P) dB on all frequencies between 2320 and 2345 MHz;
(ii) By a factor of not less than 43 + 10 log (P) dB on all frequencies
between 2300 and 2305 MHz, 70 + 10 log (P) dB on all frequencies
between 2287.5 and 2300 MHz, 72 + 10 log (P) dB on all frequencies
between 2285 and 2287.5 MHz, and 75 + 10 log (P) dB below 2285 MHz;
(iii) By a factor of not less than 43 + 10 log (P) dB on all
frequencies between 2360 and 2362.5 MHz, 55 + 10 log (P) dB on all
frequencies between 2362.5 and 2365 MHz, 70 + 10 log (P) dB on all
frequencies between 2365 and 2367.5 MHz, 72 + 10 log (P) dB on all
frequencies between 2367.5 and 2370 MHz, and 75 + 10 log (P) dB above
2370 MHz.
(2) For fixed customer premises equipment (CPE) stations operating in
the 2305-2320 MHz band and the 2345-2360 MHz band transmitting with
more than 2 watts per 5 megahertz average EIRP:
(i) By a factor of not less than 43 + 10 log (P) dB on all frequencies
between 2305 and 2320 MHz and on all frequencies between 2345 and 2360
MHz that are outside the licensed band(s) of operation, and not less
than 75 + 10 log (P) dB on all frequencies between 2320 and 2345 MHz;
(ii) By a factor of not less than 43 + 10 log (P) dB on all frequencies
between 2300 and 2305 MHz, 70 + 10 log (P) dB on all frequencies
between 2287.5 and 2300 MHz, 72 + 10 log (P) dB on all frequencies
between 2285 and 2287.5 MHz, and 75 + 10 log (P) dB below 2285 MHz;
(iii) By a factor of not less than 43 + 10 log (P) dB on all
frequencies between 2360 and 2362.5 MHz, 55 + 10 log (P) dB on all
frequencies between 2362.5 and 2365 MHz, 70 + 10 log (P) dB on all
frequencies between 2365 and 2367.5 MHz, 72 + 10 log (P) dB on all
frequencies between 2367.5 and 2370 MHz, and 75 + 10 log (P) dB above
2370 MHz.
(3) For fixed CPE stations operating in the 2305-2320 MHz and 2345-2360
MHz bands transmitting with 2 watts per 5 megahertz average EIRP or
less:
(i) By a factor of not less than 43 + 10 log (P) dB on all frequencies
between 2305 and 2320 MHz and on all frequencies between 2345 and 2360
MHz that are outside the licensed band(s) of operation, not less than
55 + 10 log (P) dB on all frequencies between 2320 and 2324 MHz and
between 2341 and 2345 MHz, not less than 61 + 10 log (P) dB on all
frequencies between 2324 and 2328 MHz and between 2337 and 2341 MHz,
and not less than 67 + 10 log (P) dB on all frequencies between 2328
and 2337 MHz;
(ii) By a factor of not less than 43 + 10 log (P) dB on all frequencies
between 2300 and 2305 MHz, 55 + 10 log (P) dB on all frequencies
between 2296 and 2300 MHz, 61 + 10 log (P) dB on all frequencies
between 2292 and 2296 MHz, 67 + 10 log (P) dB on all frequencies
between 2288 and 2292 MHz, and 70 + 10 log (P) dB below 2288 MHz;
(iii) By a factor of not less than 43 + 10 log (P) dB on all
frequencies between 2360 and 2365 MHz, and not less than 70 + 10 log
(P) dB above 2365 MHz.
(4) For mobile and portable stations operating in the 2305-2315 MHz and
2350-2360 MHz bands:
(i) By a factor of not less than: 43 + 10 log (P) dB on all frequencies
between 2305 and 2320 MHz and on all frequencies between 2345 and 2360
MHz that are outside the licensed band(s) of operation, not less than
55 + 10 log (P) dB on all frequencies between 2320 and 2324 MHz and on
all frequencies between 2341 and 2345 MHz, not less than 61 + 10 log
(P) dB on all frequencies between 2324 and 2328 MHz and on all
frequencies between 2337 and 2341 MHz, and not less than 67 + 10 log
(P) dB on all frequencies between 2328 and 2337 MHz;
(ii) By a factor of not less than 43 + 10 log (P) dB on all frequencies
between 2300 and 2305 MHz, 55 + 10 log (P) dB on all frequencies
between 2296 and 2300 MHz, 61 + 10 log (P) dB on all frequencies
between 2292 and 2296 MHz, 67 + 10 log (P) dB on all frequencies
between 2288 and 2292 MHz, and 70 + 10 log (P) dB below 2288 MHz;
(iii) By a factor of not less than 43 + 10 log (P) dB on all
frequencies between 2360 and 2365 MHz, and not less than 70 + 10 log
(P) dB above 2365 MHz.
(5) Measurement procedure. Compliance with these rules is based on the
use of measurement instrumentation employing a resolution bandwidth of
1 MHz or greater. However, in the 1 MHz bands immediately outside and
adjacent to the channel blocks at 2305, 2310, 2315, 2320, 2345, 2350,
2355, and 2360 MHz, a resolution bandwidth of at least 1 percent of the
emission bandwidth of the fundamental emission of the transmitter may
be employed. A narrower resolution bandwidth is permitted in all cases
to improve measurement accuracy provided the measured power is
integrated over the full required measurement bandwidth (i.e., 1 MHz).
The emission bandwidth is defined as the width of the signal between
two points, one below the carrier center frequency and one above the
carrier center frequency, outside of which all emissions are attenuated
at least 26 dB below the transmitter power.
(6) [Reserved]
(7) The measurements of emission power can be expressed in peak or
average values, provided they are expressed in the same parameters as
the transmitter power;
(8) Waiver requests of any of the out-of-band emission limits in
paragraphs (a)(1) through (a)(7) of this section shall be entertained
only if interference protection equivalent to that afforded by the
limits is shown;
(9) [Reserved]
(10) The out-of-band emissions limits in paragraphs (a)(1) through
(a)(3) of this section may be modified by the private contractual
agreement of all affected licensees, who must maintain a copy of the
agreement in their station files and disclose it to prospective
assignees, transferees, or spectrum lessees and, upon request, to the
Commission.
(b) For WCS Satellite DARS operations: The limits set forth in
§ 25.202(f) of this chapter shall apply, except that Satellite DARS
operations shall be limited to a maximum power flux density of −197
dBW/m2/4 kHz in the 2370-2390 MHz band at Arecibo, Puerto Rico.
(c) For operations in the 746-758 MHz band and the 776-788 MHz band,
the power of any emission outside the licensee's frequency band(s) of
operation shall be attenuated below the transmitter power (P) within
the licensed band(s) of operation, measured in watts, in accordance
with the following:
(1) On any frequency outside the 746-758 MHz band, the power of any
emission shall be attenuated outside the band below the transmitter
power (P) by at least 43 + 10 log (P) dB;
(2) On any frequency outside the 776-788 MHz band, the power of any
emission shall be attenuated outside the band below the transmitter
power (P) by at least 43 + 10 log (P) dB;
(3) On all frequencies between 763-775 MHz and 793-805 MHz, by a factor
not less than 76 + 10 log (P) dB in a 6.25 kHz band segment, for base
and fixed stations;
(4) On all frequencies between 763-775 MHz and 793-805 MHz, by a factor
not less than 65 + 10 log (P) dB in a 6.25 kHz band segment, for mobile
and portable stations;
(5) Compliance with the provisions of paragraphs (c)(1) and (c)(2) of
this section is based on the use of measurement instrumentation
employing a resolution bandwidth of 100 kHz or greater. However, in the
100 kHz bands immediately outside and adjacent to the frequency block,
a resolution bandwidth of at least 30 kHz may be employed;
(6) Compliance with the provisions of paragraphs (c)(3) and (c)(4) of
this section is based on the use of measurement instrumentation such
that the reading taken with any resolution bandwidth setting should be
adjusted to indicate spectral energy in a 6.25 kHz segment.
(d) [Reserved]
(e) For operations in the 775-776 MHz and 805-806 MHz bands,
transmitters must comply with either paragraphs (d)(1) through (5) of
this section or the ACP emission limitations set forth in paragraphs
(d)(6) to (d)(9) of this section.
(1) On all frequencies between 758-775 MHz and 788-805 MHz, the power
of any emission outside the licensee's frequency bands of operation
shall be attenuated below the transmitter power (P) within the licensed
band(s) of operation, measured in watts, by a factor not less than 76 +
10 log (P) dB in a 6.25 kHz band segment, for base and fixed stations;
(2) On all frequencies between 758-775 MHz and 788-805 MHz, the power
of any emission outside the licensee's frequency bands of operation
shall be attenuated below the transmitter power (P) within the licensed
band(s) of operation, measured in watts, by a factor not less than 65 +
10 log (P) dB in a 6.25 kHz band segment, for mobile and portable
stations;
(3) On any frequency outside the 775-776 MHz and 805-806 MHz bands, the
power of any emission shall be attenuated outside the band below the
transmitter power (P) within the licensed band(s) of operation,
measured in watts, by at least 43 + 10 log (P) dB;
(4) Compliance with the provisions of paragraphs (e)(1) and (e)(2) of
this section is based on the use of measurement instrumentation such
that the reading taken with any resolution bandwidth setting should be
adjusted to indicate spectral energy in a 6.25 kHz segment;
(5) Compliance with the provisions of paragraph (e)(3) of this section
is based on the use of measurement instrumentation employing a
resolution bandwidth of 100 kHz or greater. However, in the 100 kHz
bands immediately outside and adjacent to the frequency block, a
resolution bandwidth of at least 30 kHz may be employed.
(6) The adjacent channel power (ACP) requirements for transmitters
designed for various channel sizes are shown in the following tables.
Mobile station requirements apply to handheld, car mounted and control
station units. The tables specify a value for the ACP as a function of
the displacement from the channel center frequency and measurement
bandwidth. In the following tables, “(s)” indicates a swept measurement
may be used.
6.25 kHz Mobile Transmitter ACP Requirements
Offset from center
frequency
(kHz) Measurement bandwidth
(kHz) Maximum ACP
(dBc)
6.25 6.25 −40
12.5 6.25 −60
18.75 6.25 −60
25.00 6.25 −65
37.50 25.00 −65
62.50 25.00 −65
87.50 25.00 −65
150.00 100.00 −65
250.00 100.00 −65
350.00 100.00 −65
>400 kHz to 12 MHz 30(s) −75
12 MHz to paired receive band 30(s) −75
In the paired receive band 30(s) −100
12.5 kHz Mobile Transmitter ACP Requirements
Offset from center
frequency
(kHz) Measurement bandwidth
(kHz) Maximum ACP
(dBc)
9.375 6.25 −40
15.625 6.25 −60
21.875 6.25 −60
37.50 25.00 −60
62.50 25.00 −65
87.50 25.00 −65
150.00 100 −65
250.00 100 −65
350.00 100 −65
>400 to 12 MHz 30(s) −75
12 MHz to paired receive band 30(s) −75
In the paired receive band 30(s) −100
25 kHz Mobile Transmitter ACP Requirements
Offset from center
frequency
(kHz) Measurement bandwidth
(kHz) Maximum ACP
(dBc)
15.625 6.25 −40
21.875 6.25 −60
37.50 25 −60
62.50 25 −65
87.50 25 −65
150.00 100 −65
250.00 100 −65
350.00 100 −65
>400 kHz to 12 MHz 30(s) −75
12 MHz to paired receive band 30(s) −75
In the paired receive band 30(s) −100
150 kHz Mobile Transmitter ACP Requirements
Offset from center
frequency
(kHz) Measurement bandwidth
(kHz) Maximum ACP relative (dBc)
100 50 −40
200 50 −50
300 50 −50
400 50 −50
600-1000 30(s) −60
1000 to receive band 30(s) −70
In the receive band 30(s) −100
6.25 kHz Base Transmitter ACP Requirements
Offset from center
frequency
(kHz) Measurement bandwidth
(kHz) Maximum ACP
(dBc)
6.25 6.25 −40
12.50 6.25 −60
18.75 6.25 −60
25.00 6.25 −65
37.50 25 −65
62.50 25 −65
87.50 25 −65
150.00 100 −65
250.00 100 −65
350.00 100 −65
>400 kHz to 12 MHz 30(s) −80
12 MHz to paired receive band 30(s) −80
In the paired receive band 30(s) ^1−85
^1Although we permit individual base transmitters to radiate a maximum
ACP of −85 dBc in the paired receive band, licensees deploying these
transmitters may not exceed an ACP of −100 dBc in the paired receive
band when measured at either the transmitting antenna input port or the
output of the transmitter combining network. Consequently, licensees
deploying these transmitters may need to use external filters to comply
with the more restrictive ACP limit.
12.5 kHz Base Transmitter ACP Requirements
Offset from center
frequency
(kHz) Measurement bandwidth
(kHz) Maximum ACP
(dBc)
9.375 6.25 −40
15.625 6.25 −60
21.875 6.25 −60
37.5 25 −60
62.5 25 −65
87.5 25 −65
150 100 −65
250 100 −65
350.00 100 −65
>400 kHz to 12 MHz 30(s) −80
12 MHz to paired receive band 30(s) −80
In the paired receive band 30(s) ^1−85
^1Although we permit individual base transmitters to radiate a maximum
ACP of −85 dBc in the paired receive band, licensees deploying these
transmitters may not exceed an ACP of −100 dBc in the paired receive
band when measured at either the transmitting antenna input port or the
output of the transmitter combining network. Consequently, licensees
deploying these transmitters may need to use external filters to comply
with the more restrictive ACP limit.
25 kHz Base Transmitter ACP Requirements
Offset from center
frequency
(kHz) Measurement bandwidth
(kHz) Maximum ACP
(dBc)
15.625 6.25 −40
21.875 6.25 −60
37.5 25 −60
62.5 25 −65
87.5 25 −65
150 100 −65
250 100 −65
350 100.00 −65
>400 kHz to 12 MHz 30(s) −80
12 MHz to paired receive band 30(s) −80
In the paired receive band 30(s) ^1−85
^1Although we permit individual base transmitters to radiate a maximum
ACP of −85 dBc in the paired receive band, licensees deploying these
transmitters may not exceed an ACP of −100 dBc in the paired receive
band when measured at either the transmitting antenna input port or the
output of the transmitter combining network. Consequently, licensees
deploying these transmitters may need to use external filters to comply
with the more restrictive ACP limit.
150 kHz Base Transmitter ACP Requirements
Offset from center
frequency
(kHz) Measurement bandwidth
(kHz) Maximum ACP
(dBc)
100 50 −40
200 50 −50
300 50 −55
400 50 −60
600-1000 30(s) −65
1000 to receive band 30(s) −75 (continues at −6dB/oct
In the receive band 30(s) ^1−85
^1Although we permit individual base transmitters to radiate a maximum
ACP of −85 dBc in the paired receive band, licensees deploying these
transmitters may not exceed an ACP of −100 dBc in the paired receive
band when measured at either the transmitting antenna input port or the
output of the transmitter combining network. Consequently, licensees
deploying these transmitters may need to use external filters to comply
with the more restrictive ACP limit.
(7) ACP measurement procedure. The following procedures are to be
followed for making ACP transmitter measurements. For time division
multiple access (TDMA) systems, the measurements are to be made under
TDMA operation only during time slots when the transmitter is on. All
measurements must be made at the input to the transmitter's antenna.
Measurement bandwidth used below implies an instrument that measures
the power in many narrow bandwidths (e.g., 300 Hz) and integrates these
powers across a larger band to determine power in the measurement
bandwidth.
(i) Setting reference level. Using a spectrum analyzer capable of ACP
measurements, set the measurement bandwidth to the channel size. For
example, for a 6.25 kHz transmitter, set the measurement bandwidth to
6.25 kHz; for a 150 kHz transmitter, set the measurement bandwidth to
150 kHz. Set the frequency offset of the measurement bandwidth to zero
and adjust the center frequency of the spectrum analyzer to give the
power level in the measurement bandwidth. Record this power level in
dBm as the “reference power level”.
(ii) Non-swept power measurement. Using a spectrum analyzer capable of
ACP measurements, set the measurement bandwidth as shown in the tables
above. Measure the ACP in dBm. These measurements should be made at
maximum power. Calculate the coupled power by subtracting the
measurements made in this step from the reference power measured in the
previous step. The absolute ACP values must be less than the values
given in the table for each condition above.
(iii) Swept power measurement. Set a spectrum analyzer to 30 kHz
resolution bandwidth, 1 MHz video bandwidth and sample mode detection.
Sweep ±MHz from the carrier frequency. Set the reference level to the
RMS value of the transmitter power and note the absolute power. The
response at frequencies greater than 600 kHz must be less than the
values in the tables above.
(8) Out-of-band emission limit. On any frequency outside of the
frequency ranges covered by the ACP tables in this section, the power
of any emission must be reduced below the unmodulated carrier power (P)
by at least 43 + 10 log (P) dB.
(9) Authorized bandwidth. Provided that the ACP requirements of this
section are met, applicants may request any authorized bandwidth that
does not exceed the channel size.
(f) For operations in the 746-758 MHz, 775-788 MHz, and 805-806 MHz
bands, emissions in the band 1559-1610 MHz shall be limited to −70
dBW/MHz equivalent isotropically radiated power (EIRP) for wideband
signals, and −80 dBW EIRP for discrete emissions of less than 700 Hz
bandwidth. For the purpose of equipment authorization, a transmitter
shall be tested with an antenna that is representative of the type that
will be used with the equipment in normal operation.
(g) For operations in the 600 MHz band and the 698-746 MHz band, the
power of any emission outside a licensee's frequency band(s) of
operation shall be attenuated below the transmitter power (P) within
the licensed band(s) of operation, measured in watts, by at least 43 +
10 log (P) dB. Compliance with this provision is based on the use of
measurement instrumentation employing a resolution bandwidth of 100
kilohertz or greater. However, in the 100 kilohertz bands immediately
outside and adjacent to a licensee's frequency block, a resolution
bandwidth of at least 30 kHz may be employed.
(h) AWS emission limits—(1) General protection levels. Except as
otherwise specified below, for operations in the 1695-1710 MHz,
1710-1755 MHz, 1755-1780 MHz, 1915-1920 MHz, 1995-2000 MHz, 2000-2020
MHz, 2110-2155 MHz, 2155-2180 MHz, and 2180-2200 bands, the power of
any emission outside a licensee's frequency block shall be attenuated
below the transmitter power (P) in watts by at least 43 + 10 log10 (P)
dB.
(2) Additional protection levels. Notwithstanding the foregoing
paragraph (h)(1) of this section:
(i) Operations in the 2180-2200 MHz band are subject to the out-of-band
emission requirements set forth in § 27.1134 for the protection of
federal government operations operating in the 2200-2290 MHz band.
(ii) For operations in the 2000-2020 MHz band, the power of any
emissions below 2000 MHz shall be attenuated below the transmitter
power (P) in watts by at least 70 + 10 log10(P) dB.
(iii) For operations in the 1915-1920 MHz band, the power of any
emission between 1930-1995 MHz shall be attenuated below the
transmitter power (P) in watts by at least 70 + 10 log10(P) dB.
(iv) For operations in the 1995-2000 MHz band, the power of any
emission between 2005-2020 MHz shall be attenuated below the
transmitter power (P) in watts by at least 70 + 10 log10(P) dB.
(3) Measurement procedure. (i) Compliance with this provision is based
on the use of measurement instrumentation employing a resolution
bandwidth of 1 megahertz or greater. However, in the 1 megahertz bands
immediately outside and adjacent to the licensee's frequency block, a
resolution bandwidth of at least one percent of the emission bandwidth
of the fundamental emission of the transmitter may be employed. The
emission bandwidth is defined as the width of the signal between two
points, one below the carrier center frequency and one above the
carrier center frequency, outside of which all emissions are attenuated
at least 26 dB below the transmitter power.
(ii) When measuring the emission limits, the nominal carrier frequency
shall be adjusted as close to the licensee's frequency block edges,
both upper and lower, as the design permits.
(iii) The measurements of emission power can be expressed in peak or
average values, provided they are expressed in the same parameters as
the transmitter power.
(4) Private agreements. (i) For AWS operations in the 2000-2020 MHz and
2180-2200 MHz bands, to the extent a licensee establishes unified
operations across the AWS blocks, that licensee may choose not to
observe the emission limit specified in paragraph (h)(1), above,
strictly between its adjacent block licenses in a geographic area, so
long as it complies with other Commission rules and is not adversely
affecting the operations of other parties by virtue of exceeding the
emission limit.
(ii) For AWS operations in the 2000-2020 MHz band, a licensee may enter
into private agreements with all licensees operating between 1995 and
2000 MHz to allow the 70 + 10 log10(P) dB limit to be exceeded within
the 1995-2000 MHz band.
(iii) An AWS licensee who is a party to a private agreement described
in this section (4) must maintain a copy of the agreement in its
station files and disclose it, upon request, to prospective AWS
assignees, transferees, or spectrum lessees and to the Commission.
(i) When an emission outside of the authorized bandwidth causes harmful
interference, the Commission may, at its discretion, require greater
attenuation than specified in this section.
(j)(1) For operations in the unpaired 1390-1392 MHz band and the paired
1392-1395 MHz and 1432-1435 MHz bands, the power of any emission
outside the licensee's frequency band(s) of operation shall be
attenuated below the transmitter power (P) by at least 43 + 10 log (P)
dB. Compliance with these provisions is based on the procedures
described in paragraph (a)(4) of this section.
(2) In the 1390-1395 MHz and 1432-1435 MHz bands, licensees are
encouraged to take all reasonable steps to ensure that unwanted
emission power does not exceed the following levels in the band
1400-1427 MHz:
(i) For stations of point-to-point systems in the fixed service: −45
dBW/27 MHz.
(ii) For stations in the mobile service: −60 dBW/27 MHz.
(k) For operations in the 1670-1675 MHz band, the power of any emission
outside the licensee's frequency band(s) of operation shall be
attenuated below the transmitter power (P) by at least 43 + 10 log (P)
dB. Compliance with these provisions is based on the procedures
described in paragraph (a)(4) of this section.
(l) [Reserved]
(m) For BRS and EBS stations, the power of any emissions outside the
licensee's frequency bands of operation shall be attenuated below the
transmitter power (P) measured in watts in accordance with the
standards below. If a licensee has multiple contiguous channels,
out-of-band emissions shall be measured from the upper and lower edges
of the contiguous channels.
(1) Prior to the transition, and thereafter, solely within the MBS, for
analog operations with an EIRP in excess of −9 dBW, the signal shall be
attenuated at the channel edges by at least 38 dB relative to the peak
visual carrier, then linearly sloping from that level to at least 60 dB
of attenuation at 1 MHz below the lower band edge and 0.5 MHz above the
upper band edge, and attenuated at least 60 dB at all other
frequencies.
(2) For digital base stations, the attenuation shall be not less than
43 + 10 log (P) dB, unless a documented interference complaint is
received from an adjacent channel licensee with an overlapping
Geographic Service Area. Mobile Satellite Service licensees operating
on frequencies below 2495 MHz may also submit a documented interference
complaint against BRS licensees operating on channel BRS No. 1 on the
same terms and conditions as adjacent channel BRS or EBS licensees.
Provided that a documented interference complaint cannot be mutually
resolved between the parties prior to the applicable deadline, then the
following additional attenuation requirements shall apply:
(i) If a pre-existing base station suffers harmful interference from
emissions caused by a new or modified base station located 1.5 km or
more away, within 24 hours of the receipt of a documented interference
complaint the licensee of the new or modified base station must
attenuate its emissions by at least 67 + 10 log (P) dB measured at 3
megahertz, above or below, from the channel edge of its frequency block
and shall immediately notify the complaining licensee upon
implementation of the additional attenuation. No later than 60 days
after the implementation of such additional attenuation, the licensee
of the complaining base station must attenuate its base station
emissions by at least 67 + 10 log (P) dB measured at 3 megahertz, above
or below, from the channel edge of its frequency block of the new or
modified base station.
(ii) If a pre-existing base station suffers harmful interference from
emissions caused by a new or modified base station located less than
1.5 km away, within 24 hours of receipt of a documented interference
complaint the licensee of the new or modified base station must
attenuate its emissions by at least 67 + 10 log (P)−20 log (Dkm/1.5) dB
measured at 3 megahertz, above or below, from the channel edge of its
frequency block of the complaining licensee, or if both base stations
are co-located, limit its undesired signal level at the pre-existing
base station receiver(s) to no more than −107 dBm measured in a 5.5
megahertz bandwidth and shall immediately notify the complaining
licensee upon such reduction in the undesired signal level. No later
than 60 days after such reduction in the undesired signal level, the
complaining licensee must attenuate its base station emissions by at
least 67 + 10 log (P) dB measured at 3 megahertz, above or below, from
the channel edge of its frequency block of the new or modified base
station.
(iii) If a new or modified base station suffers harmful interference
from emissions caused by a pre-existing base station located 1.5 km or
more away, within 60 days of receipt of a documented interference
complaint the licensee of each base station must attenuate its base
station emissions by at least 67 + 10 log (P) dB measured at 3
megahertz, above or below, from the channel edge of its frequency block
of the other licensee.
(iv) If a new or modified base station suffers harmful interference
from emissions caused by a pre-existing base station located less than
1.5 km away, within 60 days of receipt of a documented interference
complaint: (a) The licensee of the new or modified base station must
attenuate its OOBE by at least 67 + 10 log (P)−20 log (Dkm/1.5)
measured 3 megahertz above or below, from the channel edge of its
frequency block of the other licensee, or if the base stations are
co-located, limit its undesired signal level at the other base station
receiver(s) to no more than −107 dBm measured in a 5.5-megahertz
bandwidth; and (b) the licensee causing the interference must attenuate
its emissions by at least 67 + 10 log (P) dB measured at 3 megahertz,
above or below, from the channel edge of its frequency block of the new
or modified base station.
(v) For all fixed digital user stations, the attenuation factor shall
be not less than 43 + 10 log (P) dB at the channel edge.
(3) Prior to transition and thereafter solely within the MBS, and
notwithstanding paragraph (l)(2) of this section, the maximum
out-of-band power of a digital transmitter operating on a single 6 MHz
channel with an EIRP in excess of −9 dBW employing digital modulation
for the primary purpose of transmitting video programming shall be
attenuated at the 6 MHz channel edges at least 25 dB relative to the
licensed average 6 MHz channel power level, then attenuated along a
linear slope to at least 40 dB at 250 kHz beyond the nearest channel
edge, then attenuated along a linear slope from that level to at least
60 dB at 3 MHz above the upper and below the lower licensed channel
edges, and attenuated at least 60 dB at all other frequencies.
(4) For mobile digital stations, the attenuation factor shall be not
less than 40 + 10 log (P) dB on all frequencies between the channel
edge and 5 megahertz from the channel edge, 43 + 10 log (P) dB on all
frequencies between 5 megahertz and X megahertz from the channel edge,
and 55 + 10 log (P) dB on all frequencies more than X megahertz from
the channel edge, where X is the greater of 6 megahertz or the actual
emission bandwidth as defined in paragraph (m)(6) of this section. In
addition, the attenuation factor shall not be less that 43 + 10 log (P)
dB on all frequencies between 2490.5 MHz and 2496 MHz and 55 + 10 log
(P) dB at or below 2490.5 MHz. Mobile Satellite Service licensees
operating on frequencies below 2495 MHz may also submit a documented
interference complaint against BRS licensees operating on channel BRS
Channel 1 on the same terms and conditions as adjacent channel BRS or
EBS licensees.
(5) Notwithstanding the provisions of paragraphs (l)(2) and (l)(4) of
this section, prior to transition, a licensee may continue to operate
facilities deployed as of January 10, 2005 provided that such
facilities operate in compliance with the emission mask applicable to
those services prior to January 10, 2005.
(6) Measurement procedure. Compliance with these rules is based on the
use of measurement instrumentation employing a resolution bandwidth of
1 megahertz or greater. However, in the 1 MHz bands immediately outside
and adjacent to the frequency block a resolution bandwidth of at least
one percent of the emission bandwidth of the fundamental emission of
the transmitter may be employed; for mobile digital stations, in the 1
megahertz bands immediately outside and adjacent to the frequency block
a resolution bandwidth of at least two percent may be employed, except
when the 1 megahertz band is 2495-2496 MHz, in which case a resolution
bandwidth of at least one percent may be employed. A narrower
resolution bandwidth is permitted in all cases to improve measurement
accuracy provided the measured power is integrated over the full
required measurement bandwidth (i.e. 1 megahertz or 1 percent of
emission bandwidth, as specified; or 1 megahertz or 2 percent for
mobile digital stations, except in the band 2495-2496 MHz). The
emission bandwidth is defined as the width of the signal between two
points, one below the carrier center frequency and one above the
carrier center frequency, outside of which all emissions are attenuated
at least 26 dB below the transmitter power. With respect to television
operations, measurements must be made of the separate visual and aural
operating powers at sufficiently frequent intervals to ensure
compliance with the rules.
(7) Alternative out of band emission limit. Licensees in this service
may establish an alternative out of band emission limit to be used at
specified band edge(s) in specified geographical areas, in lieu of that
set forth in this section, pursuant to a private contractual
arrangement of all affected licensees and applicants. In this event,
each party to such contract shall maintain a copy of the contract in
their station files and disclose it to prospective assignees or
transferees and, upon request, to the FCC.
(n) When an emission outside of the authorized bandwidth causes harmful
interference, the Commission may, at its discretion, require greater
attenuation than specified in this section.
[ 62 FR 16497 , Apr. 7, 1997]
Editorial Note: For Federal Register citations affecting § 27.53, see
the List of CFR Sections Affected, which appears in the Finding Aids
section of the printed volume and at www.fdsys.gov.
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