NPX138N Series Panel Mount FM Transceiver
SM41 Installation and Operation Manual
Section 2 Rev: 1.00
Issue 4
Page 2-4
ENG-FORM: 805-0121.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
2.4.7
Post-Installation Checks
2.4.7.1
Voltage/resistance checks
Do not attach the NPX138N until the following conditions are met.
Check the following:
a) P101
pins
<12> and <13>
for +28 Vdc relative to ground.
b) P101
pins
<22>, <23>, <24> and <25>
for continuity to ground (below 0.5
Ω
).
c)
Light voltage as listed in the table below.
P101 Pin #
Voltage
28 Volt Models
11
28 Vdc
14 Volt Models
10
14 Vdc
5 Volt Models
10
5 Vdc
Light Voltage
Ensure that the antenna is disconnected for the following test or erroneous readings may be
obtained.
d)
Radio coax connector for continuity to the antenna coax connector (shield and center conductor),
and for open circuit from the center conductor to ground and open circuit from the center
conductor to the shield.
2.4.7.2
Power On Checks
a)
Install the NPX138N and power up the ship’s systems. Turn on the radio. Check the operation of all
front panel controls. Adjust brightness and volume levels as required.
b)
Check all transmit and receive functions. Ensure the RX/TX status indicator lights green when
the radio is keyed to transmit and amber when receiving.
c)
Check the SCAN function.
Note:
It may not be possible to hear the received audio if the tones do not match those set in
the radio. To avoid any confusion, tones should be set to
OFF
(via the status edit mode)
during scanning so that all channels will be heard.
d)
Check the antenna feedline at the R/T with a through-line wattmeter and suitable frequency
elements to ensure correct antenna matching. Reflected power in excess of 25% represents a
serious problem, and should be investigated carefully, or serious RFI and system interference as
well as possible radio damage may result. A VSWR measurement over 3.0:1 represents a
significant loss in signal power to the antenna. Check that forward power is to specifications over
the frequency band of the radio.
Upon satisfactory completion of all performance checks, make all required log book entries, electrical
load, weight and balance amendments and other documentation as required by your local regulatory
agency before releasing the aircraft for service.
The document reference is online, please check the correspondence between the online documentation and the printed version.