[Code of Federal Regulations]
[Title 47, Volume 5]
[Revised as of October 1, 2006]
From the U.S. Government Printing Office via GPO Access
[CITE: 47CFR87.139]
[Page 196-198]
TITLE 47--TELECOMMUNICATION
CHAPTER I--FEDERAL COMMUNICATIONS COMMISSION (CONTINUED)
PART 87_AVIATION SERVICES--Table of Contents
Subpart D_Technical Requirements
Sec. 87.139 Emission limitations.
(a) Except for ELTs and when using single sideband (R3E, H3E, J3E),
or frequency modulation (F9) or digital modulation (F9Y) for telemetry
or telecommand in the frequency bands 1435-1535 MHz and 2310-2390 MHz or
digital modulation (G7D) for differential GPS, the mean power of any
emission must be attenuated below the mean power of the transmitter (pY)
as follows:
(1) When the frequency is removed from the assigned frequency by
more than 50 percent up to and including 100 percent of the authorized
bandwidth the attenuation must be at least 25 dB;
(2) When the frequency is removed from the assigned frequency by
more than 100 percent up to and including 250 percent of the authorized
bandwidth the attenuation must be at least 35 dB.
(3) When the frequency is removed from the assigned frequency by
more than 250 percent of the authorized bandwidth the attenuation for
aircraft station transmitters must be at least 40 dB; and the
attenuation for aeronautical station transmitters must be at least 43 +
10 log10 pY dB.
(b) For aircraft station transmitters and for aeronautical station
transmitters first installed before February 1, 1983, and using H2B,
H3E, J3E, J7B or J9W, the mean power of any emissions must be attenuated
below the mean power of the transmitter (pY) as follows:
(1) When the frequency is removed from the assigned frequency by
more than 50 percent up to and including 150 percent of the authorized
bandwidth of 4.0 kHz, the attenuation must be at least 25 dB.
(2) When the frequency is removed from the assigned frequency by
more than 150 percent up to and including 250 percent of the authorized
bandwidth of 4.0 kHz, the attenuation must be at least 35 dB.
(3) When the frequency is removed from the assigned frequency by
more than 250 percent of the authorized bandwidth of 4.0 kHz for
aircraft station transmitters the attenuation must be at least 40 dB;
and for aeronautical station transmitters the attenuation must be at
least 43 + 10 log10 pY dB.
(c) For aircraft station transmitters first installed after February
1, 1983, and for aeronautical station transmitters in use after February
1, 1983, and using H2B, H3E, J3E, J7B or J9W, the peak envelope power of
any emissions must be attenuated below the peak envelope power of the
transmitter (pX) as follows:
(1) When the frequency is removed from the assigned frequency by
more than 50 percent up to and including 150 percent of the authorized
bandwidth of 3.0 kHz, the attenuation must be at least 30 dB.
(2) When the frequency is removed from the assigned frequency by
more than 150 percent up to and including 250 percent of the authorized
bandwidth of 3.0 kHz, the attenuation must be at least 38 dB.
(3) When the frequency is removed from the assigned frequency by
more than 250 percent of the authorized bandwidth of 3.0 kHz for
aircraft transmitters the attenuation must be at least 43 dB. For
aeronautical station transmitters with transmitter power up to and
including 50 watts the attenuation must be at least 43 + 10
log10 pX dB and with transmitter power more than 50 watts the
attenuation must be at least 60 dB.
(d) Except for telemetry in the 1435-1535 MHz band, when the
frequency is removed from the assigned frequency
[[Page 197]]
by more than 250 percent of the authorized bandwidth for aircraft
stations above 30 MHz and all ground stations the attenuation must be at
least 43+10 log10 pY dB.
(e) When using frequency modulation or digital modulation for
telemetry or telecommand in the 1435-1535 MHz and 2310-2390 MHz
frequency bands with an authorized bandwidth equal to or less than 1 MHz
the emissions must be attenuated as follows:
(1) On any frequency removed from the assigned frequency by more
than 100 percent of the authorized bandwidth up to and including 100
percent plus 0.5 MHz, the attenuation must be at least 60 dB, when
measured in a 3.0 kHz bandwidth. This signal need not be attenuated more
than 25 dB below 1 milliwatt.
(2) On any frequency removed from the assigned frequency by more
than 100 percent of the authorized bandwidth plus 0.5 MHz, the
attenuation must be at least 55 + 10 log10 pY dB when
measured in a 3.0 kHz bandwidth.
(f) When using frequency modulation or digital modulation for
telemetry or telecommand in the 1435-1535 MHz or 2310-2390 MHz frequency
bands with an authorized bandwidth greater than 1 MHz, the emissions
must be attenuated as follows:
(1) On any frequency removed from the assigned frequency by more
than 50 percent of the authorized bandwidth plus 0.5 MHz up to and
including 50 percent of the authorized bandwidth plus 1.0 MHz, the
attenuation must be 60 dB, when measured in a 3.0 kHz bandwidth. The
signal need not be attenuated more than 25 dB below 1 milliwatt.
(2) On any frequency removed from the assigned frequency by more
than 50 percent of the authorized bandwidth plus 1.0 MHz, the
attenuation must be at least 55 + 10 log10 pY dB, when
measured in a 3.0 kHz bandwidth.
(g) The requirements of paragraphs (e) and (f) of this section apply
to transmitters approved after January 1, 1977, and to all transmitters
first installed after January 1, 1983.
(h) For ELTs operating on 121.500 MHz, 243.000 MHz and 406.0-406.1
MHz the mean power of any emission must be attenuated below the mean
power of the transmitter (pY) as follows:
(1) When the frequency is moved from the assigned frequency by more
than 50 percent up to and including 100 percent of the authorized
bandwidth the attenuation must be at least 25 dB;
(2) When the frequency is removed from the assigned frequency by
more than 100 percent of the authorized bandwidth the attenuation must
be at least 30 dB.
(i) In case of conflict with other provisions of Sec. 87.139, the
provisions of this paragraph shall govern for aircraft earth stations.
When using G1D, G1E, or G1W emissions in the 1646.5-1660.5 MHz frequency
band, the emissions must be attenuated as shown below.
(1) At rated output power, while transmitting a modulated single
carrier, the composite spurious and noise output shall be attenuated by
at least:
------------------------------------------------------------------------
Frequency (MHz) Attenuation (dB)\1\
------------------------------------------------------------------------
0.01 to 1525.............................. -135 dB/4 kHz
1525 to 1559.............................. -203 dB/4 kHz
1559 to 1585.............................. -155 dB/MHz
1585 to 1605.............................. -143 dB/MHz
1605 to 1610.............................. -117 dB/MHz
1610 to 1610.6............................ -95 dB/MHz
1610.6 to 1613.8.......................... -80 dBW/MHz\3\
1613.8 to 1614............................ -95 dB/MHz
1614 to 1626.5............................ -70 dB/4 kHz
1626.5 to 1660............................ -70 dB/4 kHz\2,3,4\
1660 to 1670.............................. -49.5 dBW/20 kHz\2,3,4\
1670 to 1735.............................. -60 dB/4 kHz
1735 to 12000............................. -105 dB/4 kHz
12000 to 18000............................ -70 dB/4 kHz
------------------------------------------------------------------------
\1\ These values are expressed in dB referenced to the carrier for the
bandwidth indicated, and relative to the maximum emission envelope
level, except where the attenuation is shown in dBW, the attenuation
is expressed in terms of absolute power referenced to the bandwidth
indicated.
\2\ Attenuation measured within the transmit band excludes the band
35 kHz of the carrier frequency.
\3\ This level is not applicable for intermodulation products.
\4\ The upper limit for the excess power for any narrow-band spurious
emission (excluding intermodulation products within a 30 kHz
measurement bandwidth) shall be 10 dB above the power limit in this
table.
(2) The transmitter emission limit is a function of the modulation
type and symbol rate (SR). Symbol Rate is expressed in symbols per
second.
(3) While transmitting a single modulated signal at the rated output
power of the transmitter, the emissions must be attenuated below the
maximum emission level by at least:
------------------------------------------------------------------------
Attenuation
Frequency Offset (normalized to SR) (dB)
------------------------------------------------------------------------
0.75 x SR............................ 0
1.40 x SR............................ 20
2.95 x SR............................ 40
------------------------------------------------------------------------
Where:
[[Page 198]]
SR = Symbol Rate,
SR = 1 x channel rate for BPSK,
SR = 0.5 x channel rate for QPSK.
The mask shall be defined by drawing straight lines through the
above points.
(j) When using G7D for differential GPS in the 112-118 MHz band, the
amount of power during transmission under all operating conditions when
measured over a 25 kHz bandwidth centered on either of the second
adjacent channels shall not exceed -25 dBm and shall decrease 5 dB per
octave until -52 dBm.
(k) For VHF aeronautical stations and aircraft stations operating
with G1D or G7D emissions:
(1) The amount of power measured across either first adjacent 25 kHz
channel shall not exceed 2 dBm.
(2) For stations first installed before January 1, 2002, the amount
of power measured across either second adjacent channel shall be less
than -25 dBm and the power measured in any other adjacent 25 kHz
channels shall monotonically decrease at a rate of at least 5 dB per
octave to a maximum value of -52 dBm. For stations first installed on or
after January 1, 2002,
(i) The amount of power measured across either second adjacent 25
kHz channel shall be less than -28 dBm;
(ii) The amount of power measured across either fourth adjacent 25
kHz channel shall be less than -38 dBm; and
(iii) From thereon the power measured in any other adjacent 25 kHz
channel shall monotonically decrease at a rate of at least 5 dB per
octave to a maximum value of -53 dBm.
(3) The amount of power measured over a 16 kHz channel bandwidth
centered on the first adjacent 25 kHz channel shall not exceed -18 dBm.
[53 FR 28940, Aug. 1, 1988, as amended at 56 FR 11518, Mar. 19, 1991; 57
FR 45749, Oct. 5, 1992; 58 FR 30127, May 26, 1993; 58 FR 67695, Dec. 22,
1993; 59 FR 35269, July 11, 1994; 63 FR 36607, July 7, 1998; 64 FR
27475, May 20, 1999; 66 FR 26799, May 15, 2001; 67 FR 4676, Jan. 31,
2002; 69 FR 32881, June 14, 2004]