When choosing a new antenna, diameter and gain may no longer be the most important parameters. Side-lobe rejection is also now important. Many antennas were sold with a “two degree compliant” sales pitch. This indicates that the side-lobe rejection curve for this antenna meets section 29.205 of the FCC’s Rules. This specification alone may not be good enough for reliable operation in a real-world two degree spaced environment.
Solid dishes offer many advantages over mesh or perforated dishes. Solid dishes are sturdier, they hold their shape better and they flex less in the wind. They are more expensive, but have a better value for the dollar. Expect solid dishes to have a useful life of 7 to 15 years. Westwood One recommends using only solid dishes.
Mesh or perforated dishes are more flexible than solid dishes. They move more in the wind and are less durable. Mesh dishes are less expensive, but need more frequent replacement. Expect mesh or perforated dishes to have a useful life of 4 to 6 years. Other disadvantages of mesh or perforated dishes include poor side lobe rejection of adjacent satellites and the rejection is not consistent from year to year.
Offset dishes are another type of dish seen on the market. “Offset” means the feed element is purposely kept outside of the “main beam” between the dish and satellite. Offset dishes reduce terrestrial interference and improves the beam shape slightly, but they are more complex to set up and adjust.
Diameter choices come down to one statement: “Bigger is better”. Bigger dishes offer higher gain, they have a narrower “beam” that has better side lobe rejection of adjacent satellites and better rejection of terrestrial interference. Westwood One recommends a minimum dish diameter of 3.7 meters. A dish as large as 4.5 meters virtually guarantees headache-free operation for 15 years or more.
Mounting choices are several and you must select very carefully. An improperly mounted dish will move in the wind. Inexpensive mounts, often sold separately, may be less durable than the dish manufacturer’s own mounting structure. Single pole mounts work best when braced with diagonal members also anchored to the foundation. Purchase a high-wind brace kit if it is available for your dish. What follows is a listing of mounting choices.