FCC 73.53 Revised as of December 4, 2012
Goto Year:2011 |
§ 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
(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 2Â°, or less. If a
digital indicator is provided, the smallest increment shall be 0.5Â°, or
(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
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
(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 Â±1Â°, or better, for signal amplitude
ratios of from 2:1 to 1:1, and Â±2Â°, 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 Â±1Â°, 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 Â±2 percent of the amplitude
ratio, or better, and for amplitude ratios in excess of 2:1 and up to
5:1, Â±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 Â±2 percent of the amplitude ratio, or
(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 Â±0.5Â°.
(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
(ii) The monitor shall be subjected to variations in ambient
temperature between the limits of 10 and 40 Â°C; external meters
furnished by the manufacturer will be subjected to variations between
15 and 30 Â°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 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]
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