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identical DVB carrier is not present on an adjacent satellite (low probability).
This requires the DVB tuner to be configured with the correct carrier parameters, such
as frequency, symbol rate, and FEC.
4.2.1.5 External Lock Bit
The antenna searches for the satellite using the logical voltage status of an external
contact closure (CC). Lock bit state by the logical voltage depends on the type of modem.
In the case of an HNS modem, when the voltage level of the CC is logical high
(2.6~5VDC), the lock bit is considered to be on. Conversely, the iDirect modem’s lock bit is
on when the logical voltage is low. For the specifications of each, please refer to the
modem manual.
Like the in-built DVB tuner, some external demodulators are capable of generating a
lock signal when the carrier is locked. This information can be used for searching in the
same manner as the DVB carrier lock. However, the response time of the external
device between detecting lock and setting lock on must be as fast as the speed of the
VS61 searching process.
To keep the response times to a minimum, it is necessary to use a lower value for the
acquisition range (no higher than 30 KHz) and a PLL-based LNB (LNB stability should be
/-10Khz).
NOTE
: A drawback occurs when antenna is in the tracking process and the lock bit is off
(logically unlocked) stemming from the loss of CC connection. And then, the antenna
returns to the searching process. This will also apply to the External AGC threshold if used
for searching.
4.2.1.6 External AGC Threshold
The antenna searches for the satellite using the AGC threshold level of an external
device like an in-built DVB tuner. Some external demodulators are capable of generating
an AGC level RX carrier strength from an analog voltage level.
This information can be used for searching in the same manner as the RSSD or DVB
AGC threshold. However, if the response time between detecting the change of the
carrier level and generating an AGC level is slow, it cannot be used. To keep the
response time to a minimum, it is necessary to use a minimum value of acquisition range
Summary of Contents for Ku-BAND RX
Page 1: ...INSTALLATION AND OPERATION MANUAL FOR VSAT VS61 Ku BAND TX RX ANTENNAS...
Page 15: ...7 Figure 3 1 Best Location Figure 3 2 Antenna Blockages...
Page 46: ...38 Figure 4 1 Step 1 of Reference Searching Definition...
Page 65: ...57 Figure 6 3 Co pol Kits Optional...
Page 120: ...d Appendix C Layout of Radome and Antenna Mounting Holes Figure C 1 Plastic Radome...
Page 121: ...e Figure C 2 FRP Radome Option...
Page 122: ...f...
Page 123: ...g Maritime Satellite Antenna...
