Equipment Location; Transponder And Mounting Tray Locations; Antenna - Honeywell BENDIX KING KT 73 Installation Manual

Preliminary - Subject To Change Without Notice
BENDIX/KING
2.3.4

EQUIPMENT LOCATION

Care should be exercised to avoid mounting components near equipment operating with high
pulse current or high power outputs such as radar and satellite communications equipment. In
general, the equipment should be installed in a location convenient for operation, inspection, and
maintenance, and in an area consistent with the TSO environmental limits.
Refer to the mechanical installation drawing (figure 2-4), cable and connector assembly diagrams
(figures 2-1, 2-2, 2-11 through 2-15, interconnection drawings (figures 2-5 through 2-10), and con-
nector pin assignments diagrams (figure 2-3) as required. Determine the mounting location for
system components following the guidelines below.
2.3.4.1

Transponder And Mounting Tray Locations

The tray-mounted KT 73 Mode S Transponder can be installed in any convenient location on the
panel that is free from excessive heat and vibration and which provides reasonable access for in-
spection and maintenance. To achieve maximum performance, the KT 73 should be installed ad-
jacent to other receivers with similar functions.
To allow for inspection or repair of the wiring of the connector assembly itself, sufficient lead length
should be left so that when the mounting hardware for the rear connectors and antenna coaxial
cable is removed the assembly may be pulled forward several inches. Also, a bend should be
made in the harness (at the rear connectors) to allow water droplets that might form on the har-
ness due to condensation, to drip off at the bend and not collect in the connection.
Except for antenna cables, (see Figure 2-12) the lengths of the cables from the KT 73 transponder
mounting tray connector to other system units are not critical because unit interfaces are designed
with high impedance inputs, low impedance outputs, and low noise susceptibility characteristics.
Forced air cooling is recommended but is not a requirement. Outline drawing Figure 2-4 shows
transponder and mounting tray dimensions.
2.3.4.2

Antenna

The antenna should be well removed from other antenna projections, the engine(s), and propel-
ler(s). It should also be well removed from landing gear doors, access doors, or other openings
which will break the ground plane for the antenna. The surface directly beneath the antenna
should be a flat plane over as large an area as possible.
A back-up plate should be used for added strength on thin-skinned aircraft.
To prevent rf interference, the antenna must be physically mounted a minimum distance of three
feet from the KT 73 and the wiring harness.
The transponder antenna should be mounted a minimum of six feet away from the DME antenna
and four feet from the ADF sense antenna.
Where practical, plan the antenna location to keep cable lengths as short as possible and avoid
sharp bends in the cable to minimize the VSWR.
Avoid running other cables or wires near the antenna cable.
On pressurized aircraft, the antenna should be sealed using RTV No. 3145 (P/N 016-01082-0000)
or equivalent around the connector and mounting hardware.
The antenna mounting should be sealed from the outside for moisture protection using RTV or
equivalent.
Mount the antenna in as clean as environment as possible, away from exhaust gases and oils.
The antenna should be kept clean. If left dirty (oil covered), the range of the transponder may be
affected.
Rev 0, October/2002 10563I00.JA
KT 73
Page 2-7