Troubleshooting guide

ARTEX AIRCRAFT SUPPLIES, INC. 570-1600
2.4 Mount Antenna
The ELT antenna must be mounted in accordance with the requirements of RTCA/DO-204,
Section 3.1.10 and RTCA/DO-183 Section 3.1.10. Locate the antenna at least 30 inches (75
cm) away from other antennas, wires, vertical stabilizer, etc. to minimize distortion of the
radiated field and interference with other equipment. The antenna must be installed
VERTICALLY (within ±15º of the vertical plane is acceptable). Artex has no performance data
for installations that deviate from the stated requirements.
The ME406 is certified to be used with the following antennas (automatic fixed “AF”
configuration):
• Artex Whip Antenna, 121.5/406 MHz, P/N 110-773
• Artex Rod Antenna, 121.5/406 MHz, P/N 110-338
The antenna requires a ground plane. On aircraft constructed with non-conductive materials,
such as composite materials or fiberglass, a ground plane must be added. Ideally, the ground
plane should extend out from the antenna mounting point at least 24 inches (60cm) in every
direction. Many times this is not possible, but an effective plane can be constructed as follows:
A ‘doubler’ layer of sheet metal, such as aluminum, can be mounted under the aircraft skin.
Alternatively, four or more ‘radials’ fastened to the underside of the fuselage skin can be used
to fashion a ground plane. Each radial can be metallic tape, 22 AWG wire, etc. Tape should be
at least 1 inch (25.4 mm) wide and each radial 24 inches (60 cm), minimum. The ground plane
connects to the shield of the RF antenna connector. Resistance between the ground plane and
shield connection should be maintained at 0.003Ω maximum. A star washer should be used
between the antenna connector housing and ground plane. Take precautions to guard against
corrosion, loosening, etc. See diagram below:
An effective, light-weight, ground plane can be
formed from radial strips of copper foil. A doubler
may be required to strengthen resistance to
impact, vibration, ice, etc. and can serve as
connection points for the radials.
Figure 6 – Antenna Ground Plane
Specific antenna installation instructions follow. AC 43.13 provides additional guidance for
antenna installations.
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