Comtech EF Data VMS v3.12.x Vipersat - Manual (Page 260)

Network MN/22156, rev 12
4-42 VMS User Guide
Guard Band
This parameter displays the current length of the Slot Guard Band in
milliseconds for the Remotes in the group. The Slot Guard Band is the
amount of time between the point when one Remote completes transmitting
data and the point when the next Remote in the cycle begins transmitting.
This prevents the Remote from overrunning the next terminal in the cycle.
The setting for this parameter should be obtained using the Vipersat ECM
Calculator. Typically, a value of 30 ms is sufficient.
To modify this parameter on a Hub unit, enter a value from 0–1000 in the
Guard Band field. The value represents time in milliseconds (ms).
Caution: The following two parameter settings—LNB LO and Frequency
Conversion—are very critical for determining RF frequency
translations between Hub and Remote offsets or data spectral
inversions. Take care in setting these correctly.
LNB LO
Important: Enter the correct LNB Local Oscillator frequency (MHz) that
this Hub unit will be receiving.
Frequency Conversion
Important: Enter the correct satellite Frequency Conversion value (MHz) for
this Hub unit.
Configuring Remote ECM
Configure the ECM Remote(s) by clicking on the ECM menu item for the
CDM-840 (figure 4-28).
Mode
Each Remote can be set to a designated mode of operation in ECM:
• Disable – the ECM function for this Remote is disabled.
• Offline – the Remote will not transmit.
This mode may be chosen for radio silence applications.
• Wait – the Remote will register with the controller and remain in the
ECM wait queue without assignment for switching into dSCPC mode.
This mode may be chosen by operators who wish to manually control
when a Remote is to be switched and utilize bandwidth from the pool.