Comtech EF Data DST - Manual (Page 57)

Digital Satellite Terminal System Revision 1
Operation MN/DST.IOM
5–5
TX Side Setup:
Step
No. Selection / Programming Menu Location
13. Disconnect BUC.
14. Determine the ODU voltage required by the BUC and record for reference
15. Turn the ODU Power = ON and Verify the BUC/ODU Voltage is correct.
The ODU voltage sent to the BUC is verified two ways per the next step. Configuration: Modulator
16. The ODU voltage is reported under the Monitor Menu.
To avoid damage to the BUC, confirm voltage matches the BUC voltage
requirement. (Typical Voltage is +24 or +48 VDC
± 5%)
Function Select: Monitor
For CEFD BUCs, refer to
Chapter 3, Table 3-1
17. To protect the equipment, select the ODU Power = OFF. This is necessary
before connecting the L-Band coaxial cables to the unit Configuration: Modulator
18. Set the TX Terminal LO (MHz) and MIX (+ or -). The LO frequency is the
BUC local oscillator frequency and the MIX is.
Mix = “-” if the BUC LO > Satellite Frequency
Mix = “+” if the BUC LO < Satellite Frequency
Utility: Modulator
For CEFD BUCs, refer to
Chapter 3, Table 3-1
19. Set Mod Spectrum to Normal or Invert. Utility: Modulator
20. Program the satellite frequency under the TX Terminal Frequency menu Configuration: Modulator
21. Set the TX Power Level to a safe (low) value Configuration: Modulator
22. Turn TX carrier to Off. Configuration: Modulator
23. Connect BUC.
24. Turn TX reference to On. Configuration: Modulator
25. Turn TX ODU power to On. Configuration: Modulator
26. To automate warm up and delay carrier turn ON for a programmed delay
after prime power is applied see the ODU Output Delay menu. Configuration: Modulator
27. Record the nominal BUC current after the unit is warmed up and
functioning normally. Function Select: Monitor
28. Set the High alarm about 20% higher than nominal Utility: Modulator
29. Set the Low alarm about 20% to 40% lower for the ODU (BUC). Utility: Modulator
IMPORTANT
At this point, the unit will start transmitting when the TX-IF output is tuned On
(under Configuration: Modulator menu).
5.4 Initial Operation of the Modem with the ODU and LNB
RX Side Setup:
Step
No.
Selection / Programming Menu Location
30. Disconnect LNB.
31. Set the RX Terminal LO (MHz) and MIX (+ or -). The LO frequency is the BUC
local oscillator frequency and the MIX is.
Mix = “-” if the LNB LO > Satellite Frequency
Mix = “+” if the LNB LO < Satellite Frequency
Utility: Demodulator
For CEFD LNBs, refer to
Chapter 4, Table 4-1
32. Set Demod Spectrum to Normal or Invert. Utility: Demodulator
33. Program the satellite frequency under the Rx Terminal Frequency menu Configuration: Demodulator
34. Select 10 MHz Ref = ON Configuration: Demodulator
35. Program LNB Voltage to the correct value (13, 18, or 24 VDC) Configuration: Demodulator
36. LNB Voltage OFF.
37. Connect LNB.
38. Program LNB Power = ON Configuration: Demodulator
39. Record the nominal ODU and LNB current after the units are warmed up and
functioning normally. Function Select: Monitor
40. Set the High alarm about 20% higher than nominal Utility: Demodulator
41. Set the Low alarm about 20% to 40% lower than nominal. Utility: Demodulator