[Code of Federal Regulations]
[Title 47, Volume 2]
[Revised as of October 1, 2007]
From the U.S. Government Printing Office via GPO Access
[CITE: 47CFR73.53]
[Page 22-24]
TITLE 47--TELECOMMUNICATION
CHAPTER I--FEDERAL COMMUNICATIONS COMMISSION (CONTINUED)
PART 73_RADIO BROADCAST SERVICES--Table of Contents
Subpart A_AM Broadcast Stations
Sec. 73.53 Requirements for authorization of antenna monitors.
(a) Antenna monitors shall be verified for compliance with the
technical requirements in this section. The procedure for verification
is specified in subpart J of part 2 of the FCC's rules.
(b) An antenna monitor shall meet the following specifications:
(1) The monitor shall be designed to operate in the 535-1705 kHz
band.
(2) The monitor shall be capable of indicating any phase difference
between two RF voltages of the same frequency over a range of from 0 to
360[deg].
(3) The monitor shall be capable of indicating the relative
amplitude of two RF voltages.
(4) The device used to indicate phase differences shall indicate in
degrees, and shall be graduated in increments of 2[deg], or less. If a
digital indicator is provided, the smallest increment shall be 0.5[deg],
or less.
(5) The device used to indicate relative amplitudes shall be
graduated in increments which are 1 percent, or less, of the full scale
value. If a digital indicator is provided, the smallest increment shall
be 0.1 percent, or less, of the full scale value.
(6) The monitor shall be equipped with means, if necessary, to
resolve ambiguities in indication.
(7) If the monitor is provided with more than one RF input terminal
in
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addition to a reference input terminal, appropriate switching shall be
provided in the monitor so that the signal at each of these RF inputs
may be selected separately for comparison with the reference input
signal.
(8) Each RF input of the monitor shall provide a termination of such
characteristics that, when connected to a sampling line of an impedance
specified by the manufacturer the voltage reflection coefficient shall
be 3 percent or less.
(9) The monitor, if intended for use by stations operating
directional antenna systems by remote control, shall be designed so that
the switching functions required by paragraph (b)(7) of this section may
be performed from a point external to the monitor, and phase and
amplitude indications be provided by external meters. The indications of
external meters furnished by the manufacturer shall meet the
specifications for accuracy and repeatability of the monitor itself, and
the connection of these meters to the monitor, or of other indicating
instruments with electrical characteristics meeting the specifications
of the monitor manufacturer shall not affect adversely the performance
of the monitor in any respect.
(10) Complete and correct schematic diagrams and operating
instructions shall be retained by the party responsible for verification
of the equipment and submitted to the FCC upon request. For the purpose
of equipment authorization, these diagrams and instructions shall be
considered as part of the monitor.
(11) When an RF signal of an amplitude within a range specified by
the manufacturer is applied to the reference RF input terminal of the
monitor, and another RF signal of the same frequency and of equal or
lower amplitude is applied to any other selected RF input terminal,
indications shall be provided meeting the following specifications.
(i) The accuracy with which any difference in the phases of the
applied signals is indicated shall be 1[deg], or
better, for signal amplitude ratios of from 2:1 to 1:1, and 2[deg], or better, for signal amplitude ratios in excess
of 2:1 and up to 5:1.
(ii) The repeatability of indication of any difference in the phases
of the applied signals shall be 1[deg], or better.
(iii) The accuracy with which the relative amplitudes of the applied
signals is indicated, over a range in which the ratio of these
amplitudes is between 2:1 and 1:1, shall be 2
percent of the amplitude ratio, or better, and for amplitude ratios in
excess of 2:1 and up to 5:1, 5 percent of the
ratio, or better.
(iv) The repeatability of indication of the relative amplitudes of
the applied signals, over a range where the ratio of these amplitudes is
between 5:1 and 1:1, shall be 2 percent of the
amplitude ratio, or better.
(v) The modulation of the RF signals by a sinusoidal wave of any
frequency between 100 and 10,000 Hz, at any amplitude up to 90 percent
shall cause no deviation in an indicated phase difference from its
value, as determined without modulation, greater than 0.5[deg].
(12) The performance specifications set forth in paragraph (b)(11)
of this section, shall be met when the monitor is operated and tested
under the following conditions.
(i) After continuous operation for 1 hour, the monitor shall be
calibrated and adjusted in accordance with the manufacturer's
instructions.
(ii) The monitor shall be subjected to variations in ambient
temperature between the limits of 10 and 40 [deg]C; external meters
furnished by the manufacturer will be subjected to variations between 15
and 30 [deg]C.
(iii) Powerline supply voltage shall be varied over a range of from
10 percent below to 10 percent above the rated supply voltage.
(iv) The amplitude of the reference signal shall be varied over the
operating range specified by the manufacturer, and in any case over a
range of maximum to minimum values of 3 to 1.
(v) The amplitude of the comparison signal shall be varied from a
value which is 0.2 of the amplitude of the reference signal to a value
which is equal in amplitude to the reference signal.
(vi) Accuracy shall be determined for the most adverse combination
of conditions set forth above.
(vii) Repeatability shall be determined as that which may be
achieved under the specified test conditions over
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a period of 7 days, during which no calibration or adjustment of the
instrument, subsequent to the initial calibration, shall be made.
(viii) The effects of modulation of the RF signal shall be
separately determined, and shall not be included in establishing values
for accuracy and repeatability.
Note: In paragraph (b)(1) of this section, the requirement that
monitors be capable of operation in the 535-1705 kHz band shall apply
only to equipment manufactured after July 1, 1992. Use of a monitor in
the 1605-1705 kHz band which is not approved for such operation will be
permitted pending the general availability of 535-1705 kHz band monitors
if a manufacturer can demonstrate, in the interim, that its monitor
performs in accordance with the standards in this section on these 10
channels.
(Secs. 4, 5, 303, 48 Stat., as amended, 1066, 1068, 1082 (47 U.S.C. 154,
155, 303))
[38 FR 1917, Jan. 19, 1973, as amended at 49 FR 3999, Feb. 1, 1984; 49
FR 29069, July 18, 1984; 50 FR 32416, Aug. 12, 1985; 50 FR 47054, Nov.
14, 1985; 51 FR 2707, Jan. 21, 1986; 56 FR 64859, Dec. 12, 1991; 57 FR
43290, Sept. 18, 1992; 60 FR 55480, Nov. 1, 1995; 63 FR 36604, July 7,
1998; 66 FR 20755, Apr. 25, 2001]