Goto Section: 80.211 | 80.215 | Table of Contents
FCC 80.213
Revised as of October 1, 2008
Goto Year:2007 |
2009
Sec. 80.213 Modulation requirements.
(a) Transmitters must meet the following modulation requirements:
(1) When double sideband emission is used the peak modulation must be
maintained between 75 and 100 percent;
(2) When phase or frequency modulation is used in the 156β162 MHz band the
peak modulation must be maintained between 75 and 100 percent. A frequency
deviation of ±5 kHz is defined as 100 percent peak modulation; and
(3) In single sideband operation the upper sideband must be transmitted.
Single sideband transmitters must automatically limit the peak envelope
power to their authorized operating power and meet the requirements in
Sec. 80.207(c).
(b) Radiotelephone transmitters using A3E, F3E and G3E emission must have a
modulation limiter to prevent any modulation over 100 percent. This
requirement does not apply to survival craft transmitters, to transmitters
that do not require a license or to transmitters whose output power does not
exceed 3 watts.
(c) Coast station transmitters operated in the 72.0β73.0 MHz and 75.4β76.0
MHz bands must be equipped with an audio low-pass filter. The filter must be
installed between the modulation limiter and the modulated radio frequency
stage. At frequencies between 3 kHz and 15 kHz it must have an attenuation
greater than at 1 kHz by at least 40log[10](f/3) dB where βfβ is the
frequency in kilohertz. At frequencies above 15 kHz the attenuation must be
at least 28 dB greater than at 1 kHz.
(d) Ship and coast station transmitters operating in the 156β162 MHz and
216β220 bands must be capable of proper operation with a frequency deviation
that does not exceed ±5 kHz when using any emission authorized by Sec. 80.207.
(e) Coast station transmitters operated in the 156β162 MHz band must be
equipped with an audio low-pass filter. The filter must be installed between
the modulation limiter and the modulated radio frequency stage. At
frequencies between 3 kHz and 20 kHz it must have an attenuation greater
than at 1 kHz by at least 60log[10](f/3) dB where βfβ is the audio frequency
in kilohertz. At frequencies above 20 kHz the attenuation must be at least
50 dB greater than at 1 kHz.
(f) Radiodetermination ship stations operating on 154.585 MHz, 159.480 MHz,
160.725 MHz, 160.785 MHz, 454.000 MHz and 459.000 MHz must employ a duty
cycle with a maximum transmission period of 60 seconds followed by a minimum
quiescent period four times the duration of the transmission period.
(g) Radar stations operating in the bands above 2.4 GHz may use any type of
modulation consistent with the bandwidth requirements in Sec. 80.209(b).
(h) Radar transponder coast stations using the 2900β3100 MHz or 9300β9500
MHz band must operate in a variable frequency mode and respond on their
operating frequencies with a maximum error equivalent to 100 meters.
Additionally, their response must be encoded with a Morse character starting
with a dash. The duration of a Morse dot is defined as equal to the width of
a space and 1/3 of the width of a Morse dash. The duration of the response
code must not exceed 50 microseconds. The sensitivity of the stations must
be adjustable so that received signals below β10 dBm at the antenna will not
activate the transponder. Antenna polarization must be horizontal when
operating in the 9300β9500 MHz band and either horizontal or both horizontal
and vertical when operating in the 2900β3100 MHz band. Racons using
frequency agile transmitting techniques must include circuitry designed to
reduce interference caused by triggering from radar antenna sidelobes.
(i) Variable frequency ship station transponders operating in the 2900β3100
MHz or 9300β9500 MHz band that are not used for search and rescue purposes
must meet the following requirements:
(1) Non-selectable transponders must have the following characteristics:
(i) They must respond on all their frequencies with a maximum range error
equivalent to 100 meters;
(ii) They must use a Morse encoding of βPSβ (dot-dash-dash-dot,
dot-dot-dot), meaning βYou should not come any closerβ. The width of a Morse
dot is defined as equal to the width of a space and1/3of the width of a
Morse dash;
(iii) When they employ swept frequency techniques they must not transmit on
any frequency for more than 10 seconds in any 120 second period;
(iv) Any range offset of their response must occur during their pause on the
fixed frequency;
(v) The duration of the response code must not exceed 50 microseconds;
(vi) The sensitivity of the stations must be adjustable so that received
signals below β10 dBm at the antenna input will not activate the
transponder;
(vii) Antenna polarization must be horizontal when operating in the
9300β9500 MHz band and either horizontal or both horizontal and vertical
when operating in the 2900β3100 MHz band.
(viii) Transponders using frequency agile techniques must include circuitry
designed to reduce interference caused by triggering from radar antenna
sidelobes.
(2) Selectable transponders must be authorized under part 5 of the
Commission's rules until standards for their use are developed.
(j) The transmitted signals of search and rescue transponders must cause to
appear on a radar display a series of at least 20 equally spaced dots.
(k) The modulation requirements for EPIRB's are contained in subpart V.
[ 51 FR 31213 , Sept. 2, 1986, as amended at 52 FR 7418 , Mar. 11, 1987; 52 FR 28825 , Aug. 4, 1987; 54 FR 40058 , Sept. 29, 1989; 57 FR 43407 , Sept. 21,
1992; 65 FR 77824 , Dec. 13, 2000; 68 FR 46965 , Aug. 7, 2003; 69 FR 64673 ,
Nov. 8, 2004]
Goto Section: 80.211 | 80.215
Goto Year: 2007 |
2009
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