TY96/97 VHF Radio Installation Manual 29 July 2016
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Trig Avionics Limited Page 13
case (section 5.6.4).
Where practical, plan the antenna location to keep the cable lengths as short as possible and
avoid sharp bends in the cable to minimise the VSWR.
Electrical connection to the antenna should be protected to avoid loss of efficiency as a result of the
presence of liquids or moisture. All antenna feeders shall be installed in such a way that a minimum of
RF energy is radiated inside the aircraft.
5.5.1 Antenna Ground Plane
When a conventional aircraft monopole antenna is used it relies on a ground plane for correct
behaviour. For ideal performance the ground plane should be as large as practical; in any case at least
1 metre square. In a metal skinned aircraft this is usually easy to accomplish, but is more difficult in a
composite or fabric skinned aircraft. In these cases a metallic ground plane should be fabricated and
fitted under the antenna.
The thickness of the material used to construct the ground plane is not critical, providing it is
sufficiently conductive. A variety of proprietary mesh and grid solutions are available. Heavyweight
cooking foil meets the technical requirements, but obviously needs to be properly supported.
5.5.2 Antenna Cable
Use a high quality 50 ohm coaxial cable, such as RG400 or RG142B.
When routing the cable, ensure that you:
Route the cable away from sources of heat.
Route the cable away from potential interference sources such as ignition wiring, 400Hz
generators, fluorescent lighting and electric motors.
Allow a minimum separation of 300mm (12 inches) from any ADF or transponder antenna
cables.
Keep the cable run as short as possible.
Avoid routing the cable round tight bends.
Avoid kinking the cable even temporarily during installation.
Secure the cable so that it cannot interfere with other systems.
The antenna cable should be terminated with BNC type male connector
5.5.3 BNC Connection
Feed the supplied blind mate BNC connector to the TY96 mounting tray back plate and attach the
washer combination in the following order:
Wave washer (p/n 00317-00).
Plain washer (p/n 00241-00).
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