User's Manual

THALES COMMUNICATIONS
OIM
AHV1600-SYSTEM
Page 203
July 16/09
A. CHOICE OF ANTENNAE LOCATION
−
Choose the location of the antennae carefully. On it will depend the operation of the Trans-
ceiver in all flight configurations.
− Antennae are generally mounted:
•
Under the fuselage.
•
Such that the H fields are collinear - this configuration corresponds to maximum decoupling
between antennae. The antennae centre line should be preferably parallel to the aircraft
Fore and AFT axis.
•
Along a plane parallel to the ground for a normal aircraft flight attitude; if it is not possible to
mount the antennae horizontally, a maximum angle of 5 degrees may be tolerated.
CAUTION:
Pitch and roll performances may be degraded for angles exceeding this figure.
•
At a location that is preferably perfectly clear of any obstacles in order to avoid hindrance of
the Transceiver by fixed obstacles (landing gear, fuel tanks, other antennae).
• The distance between antennae should be chosen on the basis of two criteria:
−
Sufficiently large distance to ensure proper decoupling.
−
Sufficiently small distance to ensure proper overlapping of radiation lobes for the mini-
mum height of the antennae above the ground (touchdown or parking position).
• The distance between antennae should be the following (see Figure 201).