SKY497
Installation Manual
2-2
Rev. C
Directional Antenna
The mounting site should be on the top forward fuselage, as close to the
centerline as possible, and within -10° of the in-flight horizon (see figure
2-1). The optimum mounting point for maximum coverage is as far forward
as possible without exceeding the -10° forward pitch. If necessary,
consideration should be given to relocating other antennas to obtain the
furthest forward location for the directional antenna. The antenna should
be mounted on the aircraft with at least 20 dB isolation (about 30 inches)
from other L-band frequency antennas and 24 inches from other antennas
or obstructions. The ground-plane should be as large as possible,
BFGoodrich Avionics Systems recommends a 30-inch ground-plane
diameter.
The directional antenna can be bottom mounted only if a suitable top
mount location is not available. Each bottom mount installation must be
evaluated on a case-by-case basis. Before starting a bottom mount
installation, contact BFGoodrich Avionics Systems Field Service
Engineering at 1-800-453-0288 or 1-616-949-6600.
Figure 2-1. Directional Antenna Mounting Location
2.4 TRC LOCATION
Typically the TRC is installed in the electronics bay. In selecting a location, consider the following:
Cable Length
Cable runs should be as short as practicable in order to minimize potential
electrical interference. Cable length to antennas must not exceed the
values listed in table 2-1.
Cooling
While the TRC has no special cooling requirements, it should be mounted
to permit adequate ventilation. Caution should be observed to not inhibit
airflow from the rear mounted fan. Allow at least three inches (8 cm) of
rear clearance.
Pressurized Aircraft
The TRC may mount inside or outside the pressure vessel. The TRC
contains no batteries or potentially explosive components and will operate
up to 55,000 ft.
