Terrasat IBUC 2, Operation Manual

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Common Errors
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4-9
Engineered to Endure
4. Use the following formulas to calculate IF frequency
low side IF = RF - LO Non-inverting
high side IF = LO - RF Inverting
The LO for each IBUC band is found in Table 2.1 through Table 2.4 .
5. Check the Tx output state via TST command on page C-45 , and Tx output level
via TPO command on page C-42 .
When Tx output power is disabled, the Tx output level will read - 99.0 dBm. This is
not an actual power reading; rather it indicates the loss of power.
When conditions cause the automatic shut-off of the Tx output signal, the Tx output
level will read - 96.0 dBm. This is not an actual power reading; rather it indicates the
automatic shut-off of power.
Transmit Power in Saturation
The IBUC, at minimum attenuation, makes rated power at - 30 dBm input. Operating
the IBUC at higher levels will result in spectral distortion and high intermodulation
levels. Terrasat recommends operating with power back-off levels sufficient to meet
the spectral density mask.
To avoid signal saturation,
1. Reduce input power from the modem.
2. Open Terminal session using either
RS232 or SSHv2 and issue the command TPT
on page C - 43 to modify the internal attenuation.
Tx Input/Output Level Verification
To verify the Tx IF Input level,
1. Open Terminal session using either RS232 or SSHv2 , described in Chapter 5,
Monitor and Control Features and login or by the steps provided in Appendix B,
Embedded Web Pages .
2. Query the IBUC unit via TDT command, on page C-37 .
To verify the Tx RF Output level,
1. Open Terminal session using either RS232 or SSHv2 , described in Chapter 5,
Monitor and Control Features and login or by the steps provided in Appendix B,
Embedded Web Pages .
2. Query the IBUC unit via TPO command, on page C-42 .