Obstructions (Adu Shadowing) - Furuno FV-110GX Operator's Manual

Site preparation
2.2.2

Obstructions (ADU shadowing)

The ADU is stabilized in 3-axis (plus skew) and can be used in environments with
elevations of -25° to + 125° to allow for continuous pointing even in heavy sea
conditions. The ADU beam is approximately 1 m in diameter for the first 30 m from the
ADU. Beyond 30 m the beam gradually widens so that it is approximately 5 m in
diameter at 100 m distance. This beam expansion continues with increasing distance. Any
obstructions, such as masts, funnels, bridge house etc. within this field can cause signal
degradation or signal loss.
Note
For optimum performance adhere to the following guidelines:
1. Place the ADU so that it has as much free line-of-sight as possible without any
structures in the beam through one full 360 degrees turn of the vessel.
2. Do not place the ADU close to large objects that may block the signal.
3. Elevate the ADU by mounting it on a mast or on a mounting pedestal on a deck or
deck house top to avoid obstruction.
Figure 2-1: Signal degradation because of obstructing objects
2-4
Note that due to the short wavelength at Ka band and the
narrow beam width of the ADU even a 6 mm steel wire
placed within 50 m inside the beam can causes signal
degradation.