Comtech EF Data CDM-570/570L Vipersat - Manual (Page 95)

Chapter 3 - Using the Command Line Interface (CLI) 3-59
Vipersat Configuration
is recommended; although DPC will function using Viterbi, this type requires
significantly more power to operate and is not recommended.
Enter F at the command prompt to set this parameter.
Calculate Max Power
Once all of the Max Power parameters have been set, enter A at the command
prompt to execute the maximum power calculation for this site.
Max Power
This menu item is information only and displays the result of the last calculation
that was performed for the maximum achievable power level. During network
operations, this level will only be reached when the environmental conditions
are at diminished capacities (e.g., rain fade) and all of the DPC power parame-
ters have reached their maximums.
Target EbNo
The Target EbNo is the desired operating receive level for closed loop servo
control. This is the value used by the receiving CDM-570/570L for comparison
with the actual received E
b
/N
0
. This information is sent back to the transmitting
terminal for output power level adjustment as necessary.
Enter T at the command prompt in the DPC Configuration screen to display
the Target EbNo dialog shown in figure 3-77. The default value for this parame-
ter is 10 dB.
Figure 3-77 Target EbNo prompt
Speed Up EbNo
Normally, the DPC message is sent every 60 seconds from each terminal in the
network. If the received E
b
/N
0
level at the demodulator drops below the Speed
Up EbNo set value, the corresponding terminal increases its message send rate
to every 15 seconds until the receive level is greater than the set value. This
provides a loop speed up to rapidly regain link quality.