Introduced at the 2009 International Broadcasting Convention in Amsterdam, the HMAM motorized satellite antenna mount is designed for two-way VSAT communication or receive-only downlink applications. It includes high-grade drives for azimuth and elevation plus a high-accuracy polarization drive and is fully compatible with our standard HACU antenna positioning system. A combined head and drive are incorporated, forming a three-axis motorized system with 180 degrees of azimuth adjustment, 90 degrees of elevation adjustment range and fully adjustable polarization. Positioning accuracy is +/- 0.015 degrees and position-display resolution is 0.01 degrees.
Figures 1 and 2 show the HMAM from front and rear. The antenna control unit and associated motor-control electronics are contained in an IP65-rated weatherproof outdoor housing with a hinged front access port secured by dual key screws. An emergency cut-off switch is accessible to the left of this housing. Above the housing is a resolver which is used to measure the azimuth angle of the antenna. A second identical resolver allows constant monitoring of antenna elevation. The azimuth and elevation drive motors are also visible, each operating through a reduction gear. Feed cable and sub-reflector are visible at the top right of Figure 2.
Figure 3 shows the interior of the antenna control unit. This is designed for IP-based control from a PC running a graphic user interface compatible with standard web browsers. The control GUI, seen in Figure 4 on page 75, displays all the information required to set and maintain azimuth, elevation and polarization, including current position and target position plus a database of potentially accessible satellites. Once a satellite is selected, precise access parameters can be calculated at the press of a single button.
Users have the option of interacting with the system via a traditional keyboard and mouse-controlled or trackball-controlled, or by using a touchscreen. Azimuth and elevation can be adjusted at up to three different speeds. Maximum travel rates are 12 degree/s (azimuth), 10 degree/s (elevation) and 20 degree/s (polarization).
Supplied with the HMAM is a flexible support plate allowing the attachment of all kinds of reflectors with a diameter between 1.2 and 3.4 metres. The entire system is built to withstand atmospheric pollutants such as salt encountered in coastal and industrial areas, and from zero to 100 per cent humidity over a temperature range of 60 down to -30 degrees Celsius. The rotating pedestal mount is made of corrosion-resistant hot-dip galvanized steel.
Azimuth movement is accomplished via an axle bearing with a drive motor and allows the entire satellite arc to be covered from any position on the planet. Elevation movement is via a jackscrew with a further drive motor. This design and the use of resolver-angle indicators provide highly reliable and very accurate positioning far beyond the stability of commercial-grade actuator devices. The very high rigidity of the construction ensures essentially zero backlash. The HMAM can operate in winds of up to 125 km/h and survive up to 200 km/h. Total weight excluding the dish itself is 200 kg.
Options for the Hiltron HMAM motorized antenna mount include a satellite tracking system, inclined orbit tracking, integration of parabolic reflectors according to customer preference, de-ice systems, and a choice of standard steel mounts or non-penetrating mounts. Compatible with 95 to 245 V AC at 47 to 63 Hz power supplies, the Hiltron HMAM is designed for worldwide markets.
About the author
Michael Schiestl is the Managing Director of Hiltron GmbH.