System information

9497B-20 Ku-Band TVRO Setup
5-1
5. Setup
Below are basic steps to guide you in setting up the ACU for your specific antenna pedestal. Assure that the Antenna Pedestal
(ADE) has been properly installed before proceeding. Refer to the Setup section of you ACU manual for additional parameter
setting details.
5.1. Operator Settings
Refer to the Operation chapter of this manual to set the Ship information. Latitude and Longitude should
automatically update when the GPS engine mounted above decks triangulates an accurate location, but you may enter
this information manually to begin. If your gyro source is providing Heading information in any format other than
NMEA-0183 format, you will have to enter in the initial Ship’s Heading position, the Gyro Compass will then keep the
ACU updated.
Set the Satellite information, for the satellite you will be using. The receiver settings are especially important. At this
point you should be able to target the desired satellite. Continue with the setup steps below to optimize the
parameters for your installation.
5.2. Optimizing Targeting
First, assure that all of your Ship & Satellite settings in the ACU are correct. Target the desired satellite, immediately
turn Tracking OFF, and record the Azimuth and Elevation positions in the “ANTENNA“ display of the ACU (these are
the Calculated positions). Turn Tracking ON, allow the antenna to “Search” for the targeted satellite and assure that
it has acquired (and peaks up on) the satellite that you targeted. Allow several minutes for the antenna to “peak” on
the signal, and then record the Azimuth and Elevation positions while peaked on satellite (these are the Peak
positions). Again, assure that it has acquired the satellite that you targeted!
Subtract the Peak Positions from the Calculated Positions to determine the amount of Trim which is required. Refer to
the ACU Setup information to key in the required value of Elevation Trim. Continue with Azimuth trim, then re-target
the satellite several times to verify that targeting is now driving the antenna to a position that is within +/- 1.0 degrees
of where the satellite signal is located.
EXAMPLE: The ACU targets to an Elevation position of 30.0 degrees and an Azimuth position of 180.2 (Calculated),
you find that Peak Elevation while ON your desired satellite is 31.5 degrees and Peak Azimuth is 178.0. You would
enter an EL TRIM value of –1.5 degrees and an AZ TRIM of +2.2 degrees. After these trims values had been set, your
peak on satellite Azimuth and Elevation displays would be very near 180.2 and 30.0 respectively.
5.3. Optimizing Auto-Polarization TVRO
If your system is fitted with a circular feed you do not need to optimize the polarity angle and can skip this procedure.
This procedure optimizes the linear polarization of the feed. Verify that tracking is ON and that the antenna is peaked
on your targeted satellite (targeting calculates the azimuth, elevation and polarization angles). Assure that you are in
Auto-Pol mode (POL TYPE parameter in the ACU is set to 0072) and set one of your satellite receivers to view its signal
level display. Go to the POL OFFSET parameter in the Setup menu of the ACU.
Default setting is 0030 and may be incremented, or decremented, to adjust polarization while in Auto-Pol mode. Each
increment equals one degree of polarization rotation (0038 = +8 degrees), decrement below 30 for minus polarization
(0022 = -8 degrees). Press the UP arrow to increment or the DOWN arrow to decrement the value and then hit the
ENTER key to adjust the feed to the new value.
Adjust the polarization UP until you see the signal level on the receiver fall. Note the “high” offset value and adjust the
offset DOWN until you see the signal peak and then begin to fall. Note this “low” offset value. Set POL OFFSET to a
value that is mid-way between the high & low values you just observed. Save your new POL OFFSET value (refer to
Save New Parameters in your ACU manual).
5.4. Calibrating Relative Antenna Position (Home Flag Offset)
During initialization, azimuth drives the CW antenna until the Home Switch is contacted, which “presets” the relative
position counter to the value stored in the Home Flag Offset. This assures that the encoder input
increments/decrements from this initialization value so that the encoder does not have to be precision aligned.
The Home Switch is a micro switch with a roller arm which is actuated by cam mounted on the azimuth driven
sprocket, or it is a hall sensor which is actuated by a magnet mounted on the azimuth driven sprocket, which produces
the “Home Flag” signal.