Northern Airborne Technology NTX - Manual (Page 24)

NTX VHF-FM Series Remote Mount Transceivers Manual SM28 Rev. 4.10
The transceiver is tray-mounted and uses a custom 1/4 ATR style tray. Mount (with
countersunk screws) onto a clean, grounded surface having a resistance of less than
0.5 ohms to airframe ground.
The transceiver may be mounted in any attitude, but upright (mounting hook at the
bottom) is preferred for access and condensation drainage.
2.3.7
Post-Installation Checks
2.3.7.1 Voltage/resistance checks
Do not attach the transceiver until the following conditions are met.
Check the following:
a) P101 pins <5> and <6> for +28 Vdc relative to ground.
b) P101 pins <8> and <20> for continuity to ground (below 0.5 Ω).
Ensure that the antenna is disconnected for the following test or erroneous
readings may be obtained.
c) 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.
2.3.7.2
Power On checks
a) Install the transceiver and power up the ship’s systems. Turn on the control head.
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 keying the radio to transmit and amber when receiving.
c) Check the SCAN function.
Note: You may be unable to hear the received audio if the tones do not match
those set in the radio. To avoid any confusion, set the tones 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.
Page 2-4 Jun 1, 2004
ENG-FORM: 805-0108.DOT
Amendment # 3 Jan 14, 2008
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.