Strength and corrosion testing of satellite dishes

Satellite dishes are one of many important components of an antenna system. This type of antenna provides reception of the signal that is transmitted by telecommunications satellites providing access to hundreds of foreign programs that are broadcast from even the most remote places in the world. However, few users and installers of satellite dishes pay attention to the quality of the dish itself as well as its suspension. These are two elements that must ensure the stability of the antenna set and safety. High-end satellite dishes are subjected to state-of-the-art testing that simulate: gusty winds, acid rain, the burden of freezing rain, the impact of salt spray (coastal areas), high and low temperatures.
Due to its shape, a satellite dish is susceptible to wind which can shift or bend it and thus disrupt reception. Thunderstorms, tornadoes and hurricanes can completely break the antenna from its mounts and cause danger to people and property in the area. Some antenna manufacturers recommend using a reinforced mounting system in areas with adverse wind conditions.
One of the many parameters for satellite dishes that manufacturers test, especially for large dishes, is wind resistance. According to IEC1114-2, we can distinguish three states of antenna operation:
  • allowable wind speed (72 km/h = 20m/s) – wind speed the electrical characteristics of the antenna being tested cannot be degraded without changing its direction. The typical value of antenna gain reduction is 1 dB.
  • maximum wind force (144km/h=40m/s) – the speed at which permanent degradation of the tested antenna cannot occur, but it is necessary to readjust the antenna to restore its electrical characteristics.
  • destructive wind force (216km/h=60m/s) – the speed at which permanent degradation of the electrical properties of the tested antenna can occur. For safety reasons, no part of the antenna will disintegrate mechanically.
The following pictures show the data for the DPL-120 A9682, A9684 dish test according to the wind resistance standard.
The acceptable wind force of 72 km/h (20 m/s)
To simulate the loading of the dish with wind blowing at 72 km/h (20 m/s), bags of loose material weighing 43.7 kg were placed on the front and then on the back of the antenna. After removing them, the deformation of the dish was checked and the received signal level of the antenna was measured.
The manufacturer guarantees that the received signal drop across the band does not exceed 1 dB and no antenna adjustment is required.
Satellite dish loading DPL-120 with 43.7 kg which corresponds to the pressure of the wind force of 72 km/h.
The maximum wind force of 144 km/h (40 m/s)
To simulate the loading of the dish with wind blowing at 144 km/h (40 m/s), bags of loose material weighing 175 kg were placed on the front and then on the back of the antenna. After removing them, the deformation of the dish was checked and the received signal level of the antenna was measured.
The manufacturer guarantees that the received signal drop across the band does not exceed 1 dB and the antenna position may need to be readjusted.
Satellite dish loading DPL-120 with 175 kg which corresponds to the pressure of the wind force of 144 km/h.
Destructive wind force of 216 km/h (60m/s)
The manufacturer guarantees that, the antenna will maintain its integrity – the antenna will remain on the mount and no part of the antenna will be detached from the rest. However, the antenna will not be suitable for further use and must be replaced with a new one.
Salt resistance test (NBR 8094)
The DPL-120 dish resistance to corrosion of steel components has been tested in accordance with NBR 8094 (salt spray corrosion test of coated and uncoated metallic materials). According to it, the dish and the supporting elements were subjected to salt mist with a concentration of 5% in a special chamber capable of simulating precipitation. The tests lasted respectively: 500 h for the dish and mounting elements and 750 h for connecting elements (bolts, nuts). The tests showed no signs of corrosion on any of the components.
Verification of zinc coating thickness (NBR 7937)
The DPL-120 dish is zinc coated to 8.5 μm. This thickness has been verified with test methods described in NBR 7937.