The physical construction of large antenna rotors require the ability to handle not only the sheer weight of a particular antenna but also spontaneous structural stresses associated with weather. For example, in Colorado, where significant snow falls, the additional "free weight" of ice, or snow buildup on the external motor structure can exceed well beyond 1,000 pounds per square per inch. Thus the best systems should be "overbuilt" to handle these incidental loads.
In the same way that "free weight" plays against the overall construction strength of the rotor, weather-proofing is a crucial area of investigation. In this case, all gaskets, O-rings or other flexible closures must be able to handle any range of temperature or environmental incident common to your location. This can include heavy rain, wind, dust storms and mud. Additionally, metal closures must also resist oxidation during long-term exposure to any negative weather-based evolution.
Large antennas can weigh more than 10 tons (depending on the diameter and structural mass of the central assembly). So to fully articulate a dish antenna throughout its full range of adjustments, enormous power must be applied. On the elevation side, large rotors produce several horsepower (again, depending on the weight of the dish itself). On the azimuth side, the user can accept a lower power, since all the antenna has to be moved left and right. However, even in the case of the latter movement, the unit should be "overbuilt" to deal with any power necessity.
Large antennas operate on the basis of 1- to 3-degree increments in azimuth, and from 45 to 75 degrees in elevation, depending on where the particular antenna is going to be physically located. This means the power of the motor drive must also produce fine adjustments on both axis, and this is where gearing becomes critical to an efficient communications system. The best dual-motor systems also produce highly refined gear sets to produce the most accurate antenna positioning.
Costs for industrial large antenna rotor systems are not inexpensive. Individual elevation and azimuth systems can range from $1,500 up to $10,000 per unit, depending on the size of the antenna. At the same time, fully integrated, dual-motor systems can also be acquired within the same price ranges. The value here will be entirely subjective to the user, and must be based on the system's engineering suitability of purpose.