NTX VHF FM Series Remote Mount Transceiver
SM28 Installation and Operation Manual
May 9, 2012 Rev: 5.00
Page 2-3
ENG-FORM: 805-0100.DOTX
CONFIDENTIAL AND PROPRIETARY TO ANODYNE ELECTRONICS MANUFACTURING CORP.
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 the aircraft
manufacturer’s instructions
for
continued airworthiness or AC43.13-1B Change 1, 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 the
aircraft manufacturer’s instructions
for
continued airworthiness or AC 43.13-1B Change 1, chapter 7, sections 2 to 7, and AC 43.13-2A chapter
2.
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.
