KVH Industries TracVision 4 User Manual download pdf (Page 32)

EchoStar and Expressvu Satellite Subscribers

EchoStar and Expressvu subscribers will need to use the

maintenance port switching method.

3.1.1 Watching TV Underway and at Rest

TracVision 4 is designed to operate as efficiently and as reliably

as possible both when your vessel is underway and at rest (e.g.,

at the dock).

“Instant On” Operation

As part of its operation, TracVision 4 routinely saves the satellite

position to memory and retains it when the system is turned off.

When TracVision 4 is powered up, the system looks at the

satellite’s last saved position. If the vessel has not changed its

location, the antenna will immediately acquire the satellite and

receive the signal without initializing the antenna.

If the antenna has acquired the satellite through the “Instant On”

feature, then once the vessel begins to move, the Antenna Unit

will quickly carry out its normal initialization routine to prepare

for active tracking, resulting in a brief (~30 seconds) freeze in the

satellite signal and image. As soon as initialization is complete,

satellite tracking will resume and the television image will be

restored.

Conical Scan Tracking While Underway

The antenna control unit generates a conical scanning function 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 with a circular motion to sweep

across the satellite’s peak signal. The signal strength is then fed

back to the control circuits to keep coming back to 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 30-second time-out delay. If the signal is not regained

during that time, the antenna reverts to the set of Search Modes

to start looking for the satellite signal. This is an automatic

process that does not require user intervention.

3-3

Antenna Unit Operation

54-0150 Rev. D

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KVH Industries TracVision 4 User Manual Page 32