MicroAir Avionics T2000SFL, Installation Manual

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Microair Avionics T2000SFL Transponder Installation Manual
4.0 ANTENNA
The T2000SFL requires an antenna tuned to 1090MHz. Microair recommends the use of a TSO’d antenna for
transponder purpose.
4.1 Mounting
The transponder signal is primarily directed to ground stations (Radar sites), hence the antenna is typically
located on the underside of the fuselage. The position should give the antenna a full 360 degree view of the
horizon. The position should be away from other protrusions from the airframe, such as footsteps, and
undercarriage legs.
To avoid possible interference the antenna must be mounted a minimum of 0.3m (12 inches) away from the
T2000SFL . The transponder antenna outputs high level of RF energy, and should be located at least 1m (3ft)
away from vulnerable part of the human body, or be separated by a metal panel.
If the VHF comm. Antenna is already located on the underside of the fuselage, the transponder antenna should
be located at least 1 metre (3ft) away. The transponder antenna should be mounted 2metres (78 inches) from the
DME antenna, 1.5 metres (58 inches) from the ADF sense antenna, and 1metre (39 inches) from TCAS
antennas.
4.2 Ground Plane
In metal skin aircraft the skin forms the ground plane. To ensure a good electrical connection, it may be
necessary to remove paint/primer from the inside face of the skin, before attaching the antenna. This may be
resealed after the antenna is installed. On pressurised aircraft, the antenna should be sealed using RTV-3145 or
equivalent, to seal around the connector and mounting hardware. All antenna mounts should be sealed around
the outside for moisture protection, using RTV-3145 or equivalent.
In a composite aircraft the skin of the airframe cannot be used, and a
suitable ground plane must be fabricated. The ground plane is
typically an aluminium disc with a radius equal to the height of the
antenna (approx. 75mm or 3”). The antenna is mounted in the centre
of the ground plane.
The ground plane does not have to be circular however, but the area
should be approx the same size. Fibreglass aircraft can mount the
ground plane on the inside of the aircraft.
Although carbon fibre is a good reflector of RF, it is not a suit
material for a ground plane. A metal ground plane located outside the
aircraft is ideal.
It is important to ensure that a good electrical contact is established, as
some antennas have sealing O-rings which can isolate this connection.
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