Terrasat IBUC - Page 41

IBUC Operation Manual
Terrasat Communications Inc.
Rev. A
4-15
- Connect the LNB to the demodulator RX input by attaching the coaxial cables from
the RX L-band OUT on the LNB to the demodulator RX L-band input port. When
configured with the IFU, connect the IFU RX OUT (J5) to the demodulator RX L-
band input port and connect the LNB to the IFU RX input by attaching the coaxial
cables from the RX L-band OUT on the LNB to the RX input port (J4) on the IFU.
Antenna Alignment
WARNING: WHEN ALIGNING THE ANTENNA, THE IBUC MUST NOT
TRANSMIT.
Ensure that the desired transponder is in operation. To find the satellite and peak the
receive signal, perform the following:
- Apply power to the LNB.
- Sweep the antenna through previously determined azimuth and elevation
adjustments. Note: This must be done very slowly in order to locate the satellite.
- Simultaneously, monitor the RECEIVE signal level at the demodulator. Wideband
signals such as video carriers are easiest to find and should be used when available.
- Tune the antenna and adjust its polarization according to the antenna
manufacturer's instructions until the satellite is found.
TX Power Alignment
Transmit L-band Input Adjustment with Modem or Converter
Warning; DC power may be present on the cable so the use of a DC block is
recommended when performing the following steps.
To set the power level of the modulator output:
- With a spectrum analyzer, measure the power level of the L-band signal at the
output of the coaxial cable that connects to the IBUC at J1 (TX L-band).
- Use the modem or converter level adjust to increase and decrease the power level.
Adjust this for a level of -30 dBm (this will result in rated power at the IBUC output).
For shorter cable runs the attenuator in the IBUC may be used.
- Check that the 10MHz reference signal is between +3 and –12 dBm.
- Disconnect the spectrum analyzer from the coaxial cable.
Transmit RF Output Adjustment with Modem or Converter (70 MHz to L-band)
To adjust the power level of the IBUC transmitter output:
- Connect a waveguide to coax adapter and a 40dB high power attenuator to IBUC TX
waveguide output.
- Connect the TX L-band input signal to J1 (TX L-band) on the IBUC.
- Enable the TX signals in the modem or converter and the IBUC.
- Measure the RF output with the power meter connected at the waveguide output.
For accuracy measure pure carrier.
- With a Satellite modem: Adjust the RF output to the designated power level
(provided by the satellite network operation center, or its engineering staff) with the
L-band output (modem) level adjust.
- Disable the TX signal in the modem or converter.