(7)
The antenna mounting should be capable of dissipating at least 60W of heat from the antenna
when in use.
– The heat load is primarily through the bottom metal surface of the antenna.
– Ensure that the mounting either conducts the heat away from the antenna or that there is
sufficient airflow over the bottom of the antenna to take the heat out
.
(8)
The antenna should be mounted on, and electrically bonded to, a ground plane.
– The ground plane affects the antenna gain pattern. The larger the ground plane is the more
reliable the satellite signal will be, particularly for lower satellite elevations.
– The minimum ground plane size should be 18cm in width by 30cm in length.
– The ground plane should be a conductive surface, level with the bottom surface of the
antenna.
– The ground plane should have a resistivity of 6μΩ/cm or better.
– Where the ground plane leaves the plane of the bottom of the antenna, for example following
the curve of a fuselage, its efficiency will drop.
(9)
The antenna has a provision for mounting on the top surface of a UAV fuselage
– The hole for the RF connector should be 0.63 in. (16 mm) diameter.
(10) The O-ring for sealing the fuselage against water ingress should be fitted on the antenna.
(11) On metal skinned UAV’s the thermal and ground plane requirements may be met if the antenna
is thermally and electrically bonded to the surface of the aircraft. If the surface requires
preparation to achieve electrical bond, refer to SAE AR 1870 Section 5.
– The electrical bond between the antenna and local structure must be less than or equal to 3
milliohm direct current (DC) resistance. Compliance should be verified using a calibrated
milliohm meter.
– Any paint removed from the UAV skin to meet the bonding requirement should have a
corrosion resistance protective coating applied that meets MIL-DTL-5541 TY II CL3 or
MIL-C-5541 CL3, commonly known as Alodine.
– A doubler plate fabricated by the installer is normally used.
(12) On composite UAVs, additional structure may need to be added to meet the antenna thermal
and ground plane requirements.
– The electrical bond between the antenna and ground plane must be less than or equal to 3
milliohm direct current (DC) resistance. Compliance should be verified using a calibrated
milliohm meter.
– 2000 series aluminium or copper is recommended to meet the ground plane conductivity
requirements.
– Normally, carbon fibre structures have too high a thermal and electrical resistance to meet
the thermal and ground plane requirements.
(13) The antenna should be secured to the airframe using the 4 mounting screws supplied
(MS24693-C279: 10-32 UNF-2A X 1.50 long cross recessed flat head 100°, SST).
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Feb 2021
© Honeywell International Inc. Do not copy without express permission of Honeywell.
SYSTEM DESCRIPTION, INSTALLATION, AND MAINTENANCE MANUAL
SMALL SATCOM
