ernet Archive. Yahoo! is not affiliated with the authors of this page or responsible for its content.
Document
25
Federal Communications Commission
§ 73.58
(5) Using transmission line current
meter at transmitter as remote reading
ammeter. See paragraph (c) of this sec-
tion.
(6) Using the indications of the an-
tenna (phase) monitor, provided that
when the monitor is used to obtain re-
mote reading indication of non-direc-
tional antenna base current, the mon-
itor calibration can be independently
made and maintained for each mode of
operation.
(b) Devices used for obtaining remote
reading antenna or common point cur-
rent indications, except antenna mon-
itor coupling elements, shall be located
at the same point as, but below (trans-
mitter side) the associated main am-
meter.
(c) In the case of shunt-excited an-
tennas, the transmission line current
meter at the transmitter may be con-
sidered as the remote antenna amme-
ter provided the transmission line is
terminated directly into the excitation
circuit feed line, which shall employ
series tuning only (no shunt circuits of
any type shall be employed) and inso-
far as practicable, the type and scale of
the transmission line meter should be
the same as those of the excitation cir-
cuit feed line meter (meter in slant
wire feed line or equivalent).
(d) Each remote reading ammeter
shall be accurate to within 2 percent of
the value read on its corresponding
regular ammeter.
(e) All remote reading ammeters
shall conform with the specifications
for regular antenna ammeters.
(f) Meters with arbitrary scale divi-
sions may be used provided that cali-
bration charts or curves are provided
at the transmitter control point show-
ing the relationship between the arbi-
trary scales and the reading of the
main meters.
(g) If a malfunction affects the re-
mote reading indicators of the antenna
or common point ammeter, the oper-
ating power may be determined by a
method using alternative procedures as
described in § 73.51.
[41 FR 36817, Sept. 1, 1976, as amended at 48
FR 38477, Aug. 24, 1983; 49 FR 49850, Dec. 24,
1984; 50 FR 32416, Aug. 12, 1985; 60 FR 55480,
Nov. 1, 1995]
§ 73.58
Indicating instruments.
(a) Each AM broadcast station must
be equipped with indicating instru-
ments which conform with the speci-
fications described in § 73.1215 for deter-
mining power by the direct and indi-
rect methods, and with such other in-
struments as are necessary for the
proper adjustment, operation, and
maintenance of the transmitting sys-
tem. However, auxiliary transmitters
with a nominal power rating of 100
watts or less are not required to be
equipped with instruments to deter-
mine power by the indirect method
provided that the licensee can deter-
mine the antenna input power at all
times.
(b) Since it is usually impractical to
measure the actual antenna current of
a shunt excited antenna system, the
current measured at the input of the
excitation circuit feed line is accepted
as the antenna current.
(c) The function of each instrument
shall be clearly and permanently
shown on the instrument itself or on
the panel immediately adjacent there-
to.
(d) In the event that any one of these
indicating instruments becomes defec-
tive when no substitute which con-
forms with the required specifications
is available, the station may be oper-
ated without the defective instrument
pending its repair or replacement for a
period not in excess of 60 days without
further authority of the Commission. If
the defective instrument is the an-
tenna current meter of a nondirec-
tional station which does not employ a
remote antenna ammeter, or if the de-
fective instrument is the common
point meter of a station which employs
a directional antenna and does not em-
ploy a remote common point meter,
the operating power shall be deter-
mined by a method described in
§ 73.51(a)(1) or § 73.51(d) during the en-
tire time the station is operated with-
out the antenna current meter or com-
mon point meter. However, if a remote
meter is employed and the antenna
current ammeter or common point
meter becomes defective, the remote
meter can be used to determine oper-
ating power pending the return to serv-
ice of the regular meter.
VerDate Aug<31>2005
10:37 Nov 09, 2007
Jkt 211200
PO 00000
Frm 00035
Fmt 8010
Sfmt 8010
Y:\SGML\211200.XXX
211200
ebenthall on PRODPC61 with CFR 26
47 CFR Ch. I (10107 Edition)
§ 73.61
(e) If conditions beyond the control
of the licensee prevent the restoration
of the meter to service within the
above allowed period, information re-
quested in accordance with § 73.3549
may be filed by letter with the FCC in
Washington, DC, Attention: Audio Di-
vision, Media Bureau, to request addi-
tional time as may be required to com-
plete repairs of the defective instru-
ment.
[41 FR 36817, Sept. 1, 1976, as amended at 48
FR 38477, Aug. 24, 1983; 49 FR 49850, Dec. 24,
1984; 50 FR 32416, Aug. 12, 1985; 51 FR 2707,
Jan. 21, 1986; 53 FR 2498, Jan. 28, 1988; 63 FR
33876, June 22, 1998; 66 FR 20755, Apr. 25, 2001;
67 FR 13231, Mar. 21, 2002]
§ 73.61
AM directional antenna field
strength measurements.
(a) Each AM station using a direc-
tional antenna must make field
strength measurements at the moni-
toring point locations specified in the
instrument of authorization, as often
as necessary to ensure that the field at
those points does not exceed the values
specified in the station authorization.
Additionally, stations not having an
approved sampling system must make
the measurements once each calendar
quarter at intervals not exceeding 120
days. The provision of this paragraph
supersedes any schedule specified on a
station license issued prior to January
1, 1986. The results of the measure-
ments are to be entered into the sta-
tion log pursuant to the provisions of
§ 73.1820.
(b) Partial proof of performance
measurements using the procedures de-
scribed in § 73.154 must be made when-
ever the licensee has reason to believe
that the radiated field may be exceed-
ing the limits for which the station
was most recently authorized to oper-
ate.
(c) A station may be directed to
make a partial proof of performance by
the FCC whenever there is an indica-
tion that the antenna is not operating
as authorized.
[50 FR 47054, Nov. 14, 1985]
§ 73.62
Directional antenna system op-
eration and tolerances.
(a) Each AM station operating a di-
rectional antenna must maintain the
relative amplitudes of the antenna cur-
rents, as indicated by the antenna
monitor, within 5% of the values speci-
fied on the instrument of authoriza-
tion. Directional antenna relative
phases must be maintained within 3 de-
grees of the values specified on the in-
strument of authorization.
(b) In the event of a failure of system
components, improper pattern switch-
ing or any other event that results in
operation substantially at variance
from the radiation pattern specified in
the instrument of authorization for the
pertinent time of day, operation must
be terminated within three minutes
unless power can be reduced suffi-
ciently to eliminate any excessive radi-
ation.
See § 73.1350(e).
(1) Any variation of operating param-
eters by more than
±
15 percent sample
current ratio or
±
10 degrees in phase,
any monitor point that exceeds 125 per-
cent of the licensed limit, or any oper-
ation at variance that results in com-
plaints of interference shall be consid-
ered operation substantially at vari-
ance from the license and will require
immediate corrective action.
(2) [Reserved]
(c) In the event of minor variations
of directional antenna operating pa-
rameters from the tolerances specified
in paragraph (a) of this section, the fol-
lowing procedures will apply:
(1) The licensee shall measure and log
every monitoring point at least once
for each mode of directional operation.
Subsequent variations in operating pa-
rameters will require the remeasuring
and logging of every monitoring point
to assure that the authorized moni-
toring point limits are not being ex-
ceeded. The licensee will be permitted
24 hours to accomplish these actions;
provided that, the date and time of the
failure to maintain proper operating
parameters have been recorded in the
station log.
(2) Provided each monitoring point is
within its specified limit, operation
may continue for a period up to 30 days
before a request for Special Temporary
Authority (STA) must be filed, pursu-
ant to paragraph (c)(4) of this section,
to operate with parameters at variance
from the provisions of paragraph (a) of
this section.
VerDate Aug<31>2005
10:37 Nov 09, 2007
Jkt 211200
PO 00000
Frm 00036
Fmt 8010
Sfmt 8010
Y:\SGML\211200.XXX
211200
ebenthall on PRODPC61 with CFR