User guide

Vipersat Configuration

3-16 Vipersat CDD-56X Series User Guide

This value can be modified by entering a G at the command prompt to display

the dialog shown in figure 3-14 and entering a new value.

Figure 3-14

Slot Guardband prompt

Note: The value entered at the command line in figure 3-14 is in milliseconds.

The corresponding value expressed in bytes is calculated by the

CDD-56X based on the STDMA transmit bit rate as shown in the menu

in figure 3-7.

Slot Preamble Length

This menu item, which appears in all Hub configurations, displays the current

Slot Preamble size in milliseconds and bytes for the remotes in the group. The

Slot Preamble is the period between when the remote begins to transmit (sends

an ACK) to the Hub and when the first data packet is sent. This allows time for

signal lock to occur before data is sent, thus preventing data loss. Higher data

rates allow for a shorter preamble, since it is easier to achieve signal lock. The

setting for this parameter should be obtained using the Vipersat STDMA Calcu-

lator.

Note: When the BFAT feature is enabled, the preamble length is set automati-

cally for the unit.

Entering a P at the command prompt allows changing the preamble duration in

milliseconds.

Figure 3-15

Slot Preamble Length prompt

NOTE