Furuno Felcom 50 Operator's Manual page 195

Antenna search pattern
Azimuth sweep
A 360° rotation of the antenna in azimuth at a fixed elevation angle.
Hemispheric search
A hemispheric search is constituted by azimuth sweeps at elevation angles 5°,
25°, 45°, 65° and 85°.
The antenna searches on the NCS Common TDM channel frequency (NCSC),
initiated by the FELCOM 50 Communication Unit (CU).
When finding the satellite signal, it completes the hemispheric search and moves
to the position where the strongest signal was detected.
The Antenna reports back to the CU for verification of valid NCSC.
If no valid signal is detected, no further automatic action occurs until the CU
initiates a new search.
A search request from the CU may contain channel frequency and an order to
make a full 360° search at a specific elevation, calculated from map and GPS
information. If no satellite is found, a hemispheric search will be performed.
Tracking
At the end of a search, FELCOM 50 performs a fine-tuning of the antenna
position around the strongest detected signal. The fine-tuning is obtained by a
squinting function based on satellite signal quality.
T
Note: FELCOM 50 remembers the last
used Ocean Region when
switching the terminal off/on.
9. SYSTEM DESCRIPTION
85˚
65˚
45˚
25˚
5˚
9-3