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SM28 Rev. 2.10 
NTX Series Remote Mount FM Transceivers Manual 
 
Avoid sharp bends in the coax cables (minimum 3" radius) to prevent severe reflections.  
If sharp bends are required use 90
° elbow adapters. 
 
Fabrication and installation of wiring harness should be in accordance with AC43.13-1B 
chapter 11, sections 5 to 13, 16 and 17. 
 
Grounding and bonding should be in accordance with AC43.13-1B chapter 11, section 15. 
 
2.3.5 Antennas 
Correct antenna placement and mounting is critical in order to achieve the best possible 
performance.  In general, keep all antennas as widely separated as possible and clear 
of any large airframe obstructions.  Avoid any placement that puts antennas of like 
frequencies close together.  
 
Installation of the antenna should be in accordance with AC43.13-1B chapter 11, 
section 15 and AC 43.13-2A chapter 3.  If possible, the antenna should be located a 
minimum of 12 ft from aircraft navigation receiver antennas and a minimum of 4 ft from 
aircraft communications and ELT antennas.  Be careful not to choose separations that 
closely approximate ¼, ½ or whole number multiples of the navigation or 
communication system wavelengths. 
 
Bottom mounted antennas will perform best in flight, but poorest on the ground during 
testing.  Antennas may be severely degraded by 'masking' effects of the fuselage or 
stabilizers, and generally give best performance when bottom mounted. 
 
Surround any blade or whip antenna with a ground plane surface (metallic, grounded 
material) having a radius equal to or greater than the height of the antenna.  Poor 
grounding will result in severe reflected power and high levels of RFI throughout the 
airframe. 
 
Any antenna will be less prone to interference from rotor modulation and other undesirable 
stimuli if installed correctly and surrounded by a large metallic ground plane.  Under the 
same conditions, it is also much less likely to cause interference to other aircraft systems 
(e.g., coupling into audio system, fluctuations in instrumentation, etc.). Poor grounding will 
result in severe reflected power and high levels of RFI throughout the airframe. 
 
Avoid antenna locations that will become fouled with oil, water, fuel or dirt as this will 
degrade performance.  Roof mounts (in close proximity to rotor blades) are permissible.    
 
2.3.6 Mechanical 
Mounting 
Installation of the transceiver should be in accordance with AC 43.13-1B chapter 7, 
section 2 to 7, and AC 43.13-2A chapter 2. 
 
The NTX Series Transceiver is a tray-mounted device and uses a standard 1/4 ATR 
style tray.  Mount (with counter-sunk screws) onto a clean, grounded surface having a 
resistance of less than 0.5 ohms to airframe ground. 
Oct 25, 2002 
Page 2-3 
 
ENG-FORM: 805-0104.DOT  
 
 
 
 
PROPRIETARY AND CONFIDENTIAL TO NORTHERN AIRBORNE TECHNOLOGY LTD.