Page 3-13
Installation Instructions
TQG191-IM
Rev 0: 28 Feb 2019
KTX2
Installation Manual
C144a), the unit may be installed utilizing this antenna, as per DO-229D Note 1, Section
2.1.1.10.
3.3.9 L-Band (1090MHz) Antenna
The 1090MHz L-Band antenna must meet the minimum performance requirements for the
KTX2 system. Only the antennas listed in paragraph 2.6.2 are known to meet these
requirements.
Antennas meeting the minimum performance specifications needed by the KTX2 may already
be installed in the aircraft and may be available for use. Use the antenna location information
below to verify an existing antenna location is acceptable for use.
Installation approval for the L-Band Antenna is not provided through this manual.
3.3.9.1 L-Band (1090MHz) Antenna Location
The 1090MHZ antenna installation should be installed in accordance with AC 43.13-2B Chapter
3. The following guidance provides information to aid the installer in determining that the best
location is selected for the installation of the L-band Antenna.
The 1090MHz antenna must be mounted vertically on the bottom of the aircraft fuselage. The
antenna shall be located to minimize obstruction to fields in the horizontal plane.
The total attenuation including connectors shall not exceed 1.5 dB. Based on this, the length of
the cable can be decided assuming RG-400 cable. RG type coaxial cable insertion loss can
vary significantly between manufacturers. Refer to the cable manufacturer's specification sheet
for actual attenuation (insertion loss) for the cable being used.
The 1090MHZ antenna should be located away from major protrusions, such as engine(s),
propeller(s), and antenna masts. It should be as far as practical from landing gear doors, access
doors, or other openings that could affect its radiation pattern.
The 1090MHZ antenna must be mounted no closer than 20 inches from any FADEC (Full
Authority Digital Engine Control).
The 1090MHZ antenna must be mounted no closer than 36 inches to any DME antenna.
The 1090MHZ antenna must be mounted no closer than 36 inches to any
TAS/TCAS/Transponder/Com antenna. L-Band (1090MHZ) Antenna Installation.
Refer to the aircraft manufacturer's data and the antenna manufacturer's installation instructions
to mount the antenna(s). The installer may use other FAA approved data to gain a separate
antenna installation approval.
3.3.9.2 Electrical Bonding Requirements:
Each L-Band antenna requires a minimum ground plane radius of 12 inches of contiguous metal
(no access panels, etc.) around the perimeter of the antenna. For metal aircraft, the surrounding
metal skin on which the antenna is mounted supplies the ground plane. For non-metal aircraft,
the ground plane can be composed of heavy duty aluminum foil tape, such as 3M P/N 438 or
other adhesive backed dead soft aluminum foil minimum 0.012 inches thick. It should be noted
that if the antenna is struck by lightning, the foil by itself may not be sufficient to dissipate
lightning currents. Additional protection may be needed depending on the construction of the
structure to which the antenna is mounted.
Connection to the antenna should be made in accordance with the system interconnect diagram
Figure 3-3.
