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.
And donât forget to get a good specimen sample. Influenza has a typical incubation period of 1-4 days. In other words, patients may not have flu symptoms for several days after they have been infected. When patients develop symptoms, the symptoms usually last 3-7 days, but the cough can last for up to 2 weeks.