Section 171.113

14 CFR Ch. I (1-1-19 Edition)

(b) Power output. The normal carrier
power output must be of a value which
will provide coverage requirements of
Section 171.109(a)(6) when reduced by 3 dB to
the monitor RF power reduction alarm
point specified in Section 171.111(j)(3).
(c) VSWR. (1) The VSWR of carrier
and sideband feedlines must be a nominal value of 1/1 and must not exceed 1.2/
1.
(2) The sponsor will also provide additional manufacturer-s ground standards and tolerances for all VSWR parameters peculiar to the equipment
which can effect performance of the facility in meeting the requirements
specified in SectionSection 171.109 and 171.111.
(d) Insulation resistance. The insulation resistance of all coaxial feedlines
must be greater than 20 megohms.
(e) Depth of modulation. (1) The depth
of modulation of the radio frequency
carrier due to each of the 90 Hz and 150
Hz tones must be 20 percent Section2 percent
along the course line.
(2) The depth of modulation of the
radio frequency carrier due to the 1020
Hz identification signal must be within
5 percent to 15 percent.
(f) Course sector width. The standard
course sector width must be 6Section or 12Section.
The course sector must be maintained
with Section17 percent of the standard.
(g) Course alignment. Course alignment
must
be
as
specified
in
Section 171.109(a)(8).
(h) Back course alignment and width. If
a back course is provided, standards
and tolerances for back course sector
width and alignment must be the same
as course sector width and course
alignment specified in paragraphs (f)
and (g) of this section.
(i) Clearance. Clearance must be as
specified in Section 171.109(a)(10).
(j) Monitor standards and tolerances.
(1) The monitor system must provide a
warning to the designated control
point(s) when any of the conditions described in this paragraph occur, within
the time periods specified in paragraph
(j)(6) of this section.
(2) Course shift alarm: The monitor
must alarm and cause radiation to
cease, or identification and navigation
signals must be removed, if the course
alignment deviates from standard
alignment by 10 percent or more of the
standard course sector width.

(3) RF power reduction alarm: The
monitor must alarm and cause radiation to cease, or identification and
navigation signals must be removed, if
the output power is reduced by 3 db or
more from normal.
(4) Modulation level alarm: The monitor must alarm and cause radiation to
cease, or identification and navigation
signals must be removed, if the 90 Hz
and 150 Hz modulation levels decrease
by 17 percent or more.
(5) Course sector width alarm: The
monitor must alarm and cause radiation to cease, or identification and
navigation signals must be removed,
for a change in course sector width to
a value differing by Section17 percent or more
from the standard.
(6) Monitor delay before shutdown:
Radiation must cease, or identification
and navigation signals must be removed, within 10 seconds after a fault
is detected by the monitor, and no attempt must be made to resume radiation for a period of at least 20 seconds.
If an automatic recycle device is used,
not more than three successive recycles may be permitted before a complete SDF shutdown occurs.
(k) Mean time between failures. The
mean time between failures must not
be less than 800 hours. This measure is
applied only to equipment failures
(monitor or transmitting equipment,
including out of tolerance conditions)
which result in facility shutdown. It
does not relate to the responsiveness of
the maintenance organization.
(l) Course alignment stability. Drift of
the course alignment must not exceed
one-half the monitor limit in a 1-week
period.
[Doc. No. 10116, 35 FR 12711, Aug. 11, 1970, as
amended by Amdt. 171-9, 38 FR 28558, Oct. 15,
1973]

Section 171.113 Installation requirements.
(a) The facility must be installed according to accepted good engineering
practices, applicable electric and safety codes, and FCC requirements.
(b) The SDF facility must have the
following basic components:
(1) VHF SDF equipment and associated monitor system;
(2) Remote control, and indicator
equipment (remote monitor) when required by the FAA;

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