Antenna Mast Design - KVH Industries TracPhone F55 Installation Manual

Chapter 3: Placing the Antenna

3.4 Antenna Mast Design

The antenna mast must be designed to carry the weight of the antenna unit,
which for F55 is approximately 18 kg and for F77 is approximately 27 kg.
It must also be able to withstand wind forces up to 140 knots on the radome as
well as onboard vibrations.
The top of the antenna mast should be fitted with a flange with holes matching
the bosses in the radome. The flange diameter must be less than 380 mm in
order to avoid interference with the F77 hatch and the antenna beam.
The flange thickness must be at least 10 mm. The antenna is to be mounted on
the flange by means of 4 M10 bolts. The bolt engagement shall be 15 ±5 mm.
Drill a hole in the centre of the flange for radome drain pipe.
See Outline Dimensions, Flange on page 87 in Appendix B.
The holes in the flange must be positioned symmetrically around the
longitudinal axis of the ship, to ensure the correct heading of the antenna. See
Appendix B F55/77 ADU Technical Specifications on page 81 for heading mark.
The Antenna tracking system is directional why the heading direction of the
ADU is extremely important, as setting the wrong heading will cause the
antenna to lose track of the satellite as soon the ship start to move.
In some cases it may be necessary to install the antenna such that it is
misaligned to the ship, e.g. to insure F77 hatch accessibility. Compensation for
mount pos can only be done in steps of 90°. See User Manual chapter 4 "Ant.
Setup". Antenna Set-up for installation angle set-up in case the angle is
different from the default 0°.
The F55/F77 heading is defined by the ADU N-type connector placement. For
the F77 the hatch may be used for locating the heading direction as well.
14 Antenna Mast Design