tálantenna

tálantenna, commonly known as a dish antenna or parabolic dish, is a type of high-gain radio antenna that uses a parabolic reflector to collect or focus electromagnetic signals. It is widely used for satellite communications, radio astronomy, and radar due to its directional characteristics and sensitivity.

The core of a tálantenna is a reflective parabolic surface, typically made of metal, which reflects incoming radio waves toward a feed antenna located near the dish’s focus. For reception, signals from distant sources arrive as nearly parallel waves and are reflected to the feed, where they are processed by a receiver. For transmission, the feed emits radio waves that are reflected by the dish into a narrow, directed beam. The geometry of the parabola ensures that waves from the feed are collimated into or from a specific direction.

There are different configurations. Prime-focus dishes place the feed at the focal point in front of the dish, while offset dishes position the feed off-center to avoid obstructing the reflected beam. Dishes range from small terrestrial models used for TV to large installations for scientific research and long-range links.

Key performance factors include dish diameter, surface accuracy, and operating frequency. Larger diameters or higher surface precision yield higher gain and narrower beamwidth, at the cost of increased size and wind loading. Materials are usually aluminum or other metals, with mounting hardware and anti-corrosion treatments. Tálantenna systems require careful alignment and weather considerations but offer substantial directional gain and interference rejection.

See also: satellite dish, parabolic reflector, radio telescope.