EchoStar 4 - Manual (Page 15)

2.4 Watching Television
TracVision 4 allows you to watch satellite TV whether your vessel
is in motion or at rest.
Cable Unwrap
The antenna can rotate a full 720° before reaching the end of its
cable. If it does so, the system automatically unwraps the cable
by quickly rotating the dish in the opposite direction. During this
time, your television transmission will freeze momentarily while
the cable unwraps and the antenna reacquires the satellite.
Conical Scan Tracking
The antenna uses conical scanning to maintain peak signal
strength to the receiver and to update the satellite’s position.
When conical scan tracking is active, the antenna moves
continually in a circular motion to sweep across the satellite’s
peak signal. The signal strength is then fed back to the control
circuits to keep pointed in the direction of the strongest signal.
If the satellite signal is lost while the system is in conical scan
track mode, the control software imposes a 45-second time-out
delay. If the signal is not regained during that time, the antenna
will search for the satellite signal. This is an automatic process
that does not require user intervention.
Sleep Mode
When the vessel has come to a stop and holds its position for one
minute (e.g., at a dock), the antenna unit enters Sleep Mode,
which locks the antenna in place to conserve power. As soon as
the vessel moves beyond a 1° - 2° window, or the RF level
changes significantly, Sleep Mode automatically turns off and the
system begins tracking the satellite again (or enters Search mode
to find the satellite).
KVH recognizes that some customers may not want to take
advantage of this convenient feature. In this case, it is possible to
disable Sleep Mode using a simple software command as follows:
1. Connect a laptop computer to the system using the
maintenance port and a terminal emulation
program, as described in “Using a PC to Switch
Between Satellites” on the previous page.
54-0150-01 14
TracVision 4 User’s Guide