APPLICATIONS Horn antennas are widely used as satellite dishes and radio telescopes. Antennas 6 2. PARABOLIC ANTENNAS A parabolic antenna is an antenna that uses a parabolic reflector, a curved surface with the cross-sectional shape of a parabola, to direct the radio waves.
Flu (influenza). Flu is usually infectious a day before symptoms start and remains infectious for about five to six days. Children and people with lowered immune systems may be infectious for a few days longer.
How long does it take to develop symptoms of . influenza after being exposed? The incubation period of influenza is usually two days . but can range from one to four days. What are the symptoms of influenza? Typical influenza disease is characterized by abrupt . onset of fever, aching muscles, sore throat, and non-productive cough.