Terrasat Rx 1+1, Руководство по эксплуатации

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Introduction
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4-3
Setting Threshold Levels
1. Navigate to the Rx Configuration Tab shown on page E-12 . Compare your current
consumption readings to the high and low threshold levels.
Note:
Remember that the low-noise block converters (LNBs) consume 224 mA.
Terrasat recommends that you set the higher threshold level to 10% higher than
your current consumption levels and the lower threshold level to 10% lower.
10 MHz Low Alarm
The 10 MHz Low alarm occurs when the level of the 10 MHz reference signal from
the modem is either low or not present. If the LNB that you are using has an internal
10 MHz signal, the modem will not supply one and you will need to disable the
10 MHz low alarm.
To disable a 10 MHz low alarm,
• Use one of these monitor and control (M&C) interfaces:
•
Web Page: Navigate to the Alarm Configuration Tab shown on page E-19 and
set the 10 MHz alarm setting to “Disable.”
•
Telnet: After initiating a Telnet session, type the command
CTD=0
and press
Enter.
Note:
If your system is not operating under revision 0.10 of the firmware, you will need
to upgrade in order to use the CTD command. To upgrade, you can download Rx
1+1 revision 0.10 from the Support page of the Terrasat website. Visit

http://www.terrasatinc.com/support.htm
To perform the upgrade, connect a laptop directly to the interface and use the laptop
to install the upgrade.
Rx Input Level Low Threshold Alarm
The Rx 1+1 interface monitors the input level (coming from the LNB output) to verify
whether each LNB has proper gain.
When the LNBs have proper gain, the interface module for the unit that is operating in
Standby mode will detect the composite level at the input at the interface. This
composite level is the noise at the input of that LNB which has been degraded,
amplified, and converted by the LNB and integrated over the bandwidth of the LNB
response. If one stage of the internal low-noise amplifier (LNA) fails, you would
expect to see a drop in the composite level.
To prevent an Rx input level low threshold alarm,
1. Measure the composite level when the LNB is in standby mode.