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 will the influenza last? Usually, influenza lasts three to five days. If it goes on for more than a week or if the symptoms are very severe, you are advised to consult your doctor. A bad case of influenza has the potential to develop into a more serious condition like pneumonia or sinus trouble, and in rare cases it can be life-threatening.