OPERATION MANUAL
NAV-402AP-3
1-2-3
Page 1
Sep 1/04
3. GENERAL OPERATING PROCEDURES
3.1 GENERAL
This section contains operating instructions for
the NAV-402AP-3. The operating instructions
contain general procedures, identifying the
controls, connectors, indicators used for the
individual test functions. For specific Unit
Under Test (UUT) Procedures, refer to the
appropriate UUT Manual.
CAUTION: WHEN OPERATING THE TEST
SET IN A VERTICAL POSITION,
REMOVE THE LID TO PREVENT
THE TEST SET FROM TIPPING
OVER.
Refer to 1-2-2, Figure 2 for location of
controls, connectors and indicators.
3.2 SIGNALS SIMULATED
The NAV-402AP-3 is a bench and ramp test
instrument for MARKER, VOR, ILS and COM
equipment.
The NAV-402AP-3 simulates MARKER signals
with Inner (3000 Hz), Middle (1300 Hz) and
Outer (400 Hz) tones.
VOR Ground Station signals are simulated by
an RF signal modulated by a 30 Hz reference
signal, a variable 30 Hz signal and a 9960 Hz
signal.
Localizer (LOC) signals are simulated by
modulating RF with 90 and 150 Hz tones.
Glide Slope (G/S) signals are simulated by
modulating RF with 90 and 150 Hz tones.
COM signals are simulated by modulating RF
with the 400, 1300 or 3000 Hz MARKER tones
or the 1020 Hz IDENT tone. IDENT can also
be applied to MARKER, VOR or Localizer
signals.
3.3 OPERATION CAUTIONS
The NAV-402AP-3 must be used in the
following frequency fixed modes during ramp
use:
O COM
O G/S
O LOC
O VOR
3.4 RAMP OPERATION
With the exception of Marker Beacon, most
NAV COM systems of a typical avionics
package can be checked when the Test Set is
placed in a vertical position in the cockpit.
The antenna is extended vertically 2-3 ft. With
the antenna on the RF Output Connector, the
VOR, LOC and G/S modes of NAV COM
Receivers can be checked and indicators
operated through the limits. The COM
Receiver can also be operated, modulating the
Test Set with either the 400, 1300 or 300 Hz
tones or the 1020 Hz IDENT tone.
On some installations, the Marker Antenna is
located far aft on the fuselage. When this
occurs, and receiver sensitivity is low (-35 to -
45 dBm), the Test Set situated in the cockpit
radiates RF insufficient to operate the
Receiver. Moving the Test Set outside the
aircraft normally provides more than enough
signal strength to completely check Marker
audio and lights.
To check COM Transmitter frequencies from
the cockpit, connect the COM Transmitter
output to the COM Transmitter Input Connector
and select MHz on the COUNTER MODE
Switch. The Test Set reads out the COM
Transmitter frequency when the COM
Transmitter is keyed.
