9.71 AvL-TracStar

This page describes the device driver and the device window for the AvL TracStar car mounted antenna controller.

Basic Operation

The following short description of operating the TracStar with the sat-nms software presumes you are already used to operate the TracStar using it's handheld terminal or indoor unit. If in doubt, consult the TracStar user manual.

The buttons at the bottom of the TracStar device window control the basic functions of the device:

• STOP --- Stops the antenna motors.
• JOG --- Turns the TracStar to jog mode. In jog mode you may command the antenna pointing angles directly or increments them using the arrow buttons. The 'rx pol' setting directly controls the receive polarization plane in jog mode and setting the 'sat location' makes the device driver calculate and command the pointing angles for the given satellite orbit position
• STOW --- Moves the antenna to stow position. Unfortunately the TracStar does not deliver a reliable 'STOWED' indication to the VLC, hence you should inspect visually if the antenna is stowed properly before you move the car.
• POSITION --- Makes the TracStar elevate the antenna and search the target satellite which has been defined at the Satellites page. In most cases this starts the full search procedure including compass calibration, reference satellite identification and peaking to the target satellite. When the TracStar successfully peaked the target satellite, the driver switches to jog mode and applies the polarization offset.

To point the TracStar antenna to a satellite, you will typically perform the following steps:

1. At the Satellites page select two reference satellites.
2. Enter the parameters of the target satellite at the top of this page. Alternatively you may want to recall a device preset which contains these selections.
3. At the Main page of the device window click 'POSITION'. The TracStar now wil start it's full positioning cycle, after typically 2 or 3 minutes the antenna os positioned to the satellite.

Device window pages

The following table shows which device window pages are available with this individual device type. Tool-bar functions not mentioned here are described at the general description of device windows .

• --- The main parameter page displays/controls the antenna pointing.
• --- This page shows the readings of the GPS receiver, the inclinometer and the receive levels.
• --- This page contains the identification parameters of the target satellite and the reference satellites.
• --- This page gives access to a number of parameters which tell the TrackStar how to reach and identify satellites. You should only change these values if you are already used to tweak the TracStar's behaviour ba modifying it's 'LOCKVAL' parameter.
• --- The faults page.
• --- The device info page.
• --- The maintenance page. The configuration parameters described below are set at this page.

Configuration parameters

At the maintenance page of the device window there are a couple of configuration parameters which must be set to make the software talk to the antenna controller.

Receive Band Switching

The TracStar itself does not support a switch between two receive bands as commonly used in Europe. The sat-nms device driver add (limited) support for this. For this you require a LNB power supply which can be controlled by the VLC in order to switch the receive band. With the configuration setting above, configure the message ID and parameter values necessary to switch the band. Then, using the rxBand configuration parameter (it is available at the Satellites page as well), you may select the frequency band as required.

Any time you command the TracStar through the sat-nms software to position the antenna to the target satellite or to perform a sky scan, the driver first sets the receive band as selected and commands the LO frequency and scan start / stop frequencies configured for the selected receive band. satellite or to

As the TracStar itself is not aware of this extension, the following limitations apply:

• No plausibility check between the selected receive / channel frequencies and the selected band is done. The TracStar probably will not find the satellite if you select the high band and supply low abd frequencies.
• The frequencies used with the target satellite and the reference satellites must be in the same frequency band because the TracStar is not capable to switch the band while positioning the antenna.

The wildcard frequency 10799 MHz applies to both frequency bands, you may use it with the high frequency as well if you want to make the TracStar search any channel at this satellite.

Polarization Plane Handling

The TracStar provides a polarization plane parameter which turns the feed by 90 degree if set to vertical. The polarization angle displayed (and commanded) is meant as an offset to the selected polarization plane.

The polarization plane parameter only actively changes the feed angle if the TracStar is in jog mode. In IDLE / STOPPED mode the polarization setting is memorized, the setting is postponed until a POSITION command is given.

When positioning to a satellite, the TracStar applies a polarization offset which is calculated from the antenna's geodetic location and the satellite's orbit position. It does not know about the particular skew offset of the satellite. The sat-nms driver adds this feature to the satellite positioning procedure:

The parameter 'pol offs' refers to the skew offset of the target satellite. The parameter gets saved with each particular device (=satellite) preset. After the TracStar has successfully positioned the antenna to the target satellite, the driver switches to jog mode and applies the skew offset. This way you may use stored device presets as an instant setup for already polarization-optimized pointing.

ATTENTION: The TracStar does not honour the polarization plane parameter when performing a sky scan. The channel frequencies of the reference satellites always are searched at horizontal polarization. If you want to manage a list of frequencies found at vertical polarization, you have to search these frequencies manually, e.g. with a spectrum analyzer.

Device Presets

The device driver stores complete setups, including the target satellite parameters, all reference satellites and the selection of those. A device preset of the AvL-TracStar device is intended to act as a data file of all information required to point the antenna to a certain satellite. When the preset is recalled, the satellite parameters get programmed to the TracStar, but no positioning is commanded. Due to this fact, you may recall presets in order to view / edit / copy them without moving the antenna. Once you have recalled the preset with the satellite parameters you are looking for, click 'POSITION' to make the TracStar point the antenna to the selected satellite.

Variables defined by this device driver