Goto Section: 73.37 | 73.45 | Table of Contents
FCC 73.44
Revised as of October 2, 2015
Goto Year:2014 |
2016
§ 73.44 AM transmission system emission limitations.
(a) The emissions of stations in the AM service shall be attenuated in
accordance with the requirements specified in paragraph (b) of this section.
Emissions shall be measured using a properly operated and suitable
swept-frequency RF spectrum analyzer using a peak hold duration of 10
minutes, no video filtering, and a 300 Hz resolution bandwidth, except that
a wider resolution bandwidth may be employed above 11.5 kHz to detect
transient emissions. Alternatively, other specialized receivers or monitors
with appropriate characteristics may be used to determine compliance with
the provisions of this section, provided that any disputes over measurement
accuracy are resolved in favor of measurements obtained by using a
calibrated spectrum analyzer adjusted as set forth above.
(b) Emissions 10.2 kHz to 20 kHz removed from the carrier must be attenuated
at least 25 dB below the unmodulated carrier level, emissions 20 kHz to 30
kHz removed from the carrier must be attenuated at least 35 dB below the
unmodulated carrier level, emissions 30 kHz to 60 kHz removed from the
carrier must be attenuated at least [5 + 1 dB/kHz] below the unmodulated
carrier level, and emissions between 60 kHz and 75 kHz of the carrier
frequency must be attenuated at least 65 dB below the unmodulated carrier
level. Emissions removed by more than 75 kHz must be attenuated at least 43
+ 10 Log (Power in watts) or 80 dB below the unmodulated carrier level,
whichever is the lesser attenuation, except for transmitters having power
less than 158 watts, where the attenuation must be at least 65 dB below
carrier level.
(c) Should harmful interference be caused to the reception of other
broadcast or non-broadcast stations by out of band emissions, the licensee
may be directed to achieve a greater degree of attentuation than specified
in paragraphs (a) and (b) of this section.
(d) Measurements to determine compliance with this section for transmitter
type acceptance are to be made using signals sampled at the output terminals
of the transmitter when operating into an artificial antenna of
substantially zero reactance. Measurements made of the emissions of an
operating station are to be made at ground level approximately 1 kilometer
from the center of the antenna system. When a directional antenna is used,
the carrier frequency reference field strength to be used in order of
preference shall be:
(1) The measure non-directional field strength.
(2) The RMS field strength determined from the measured directional
radiation pattern.
(3) The calculated expected field strength that would be radiated by a
non-directional antenna at the station authorized power.
(e) Licensees of stations complying with the ANSI/EIA-549-1988, NRSC-1 AM
Preemphasis/Deemphasis and Broadcast Transmission Bandwidth Specifications
(NRSC-1), prior to June 30, 1990 or from the original commencement of
operation will, until June 30, 1994, be considered to comply with paragraphs
(a) and (b) of this section, absent any reason for the Commission to believe
otherwise. Such stations are waived from having to make the periodic
measurements required in § 73.1590(a)(6) until June 30, 1994. However,
licensees must make measurements to determine compliance with paragraphs (a)
and (b) of this section upon receipt of an Official Notice of Violation or a
Notice of Apparent Liability alleging noncompliance with those provisions,
or upon specific request by the Commission.
[ 47 FR 8588 , Mar. 1, 1982, as amended at 49 FR 3999 , Feb. 1, 1984]
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Goto Section: 73.37 | 73.45
Goto Year: 2014 |
2016
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