Linear vertical or horizontal polarization is normally used in microwave transmission. Reasons: Circularly polarized antennas are more complex and more expensive, because they are actually double polarized antennas, i.e. a combination of horizontal and vertical polarizations. Rain attenuation is lowest when the polarization is vertical. Therefore longer hops can be built if circular polarization is avoided.
radio transmission can be heard in hilly areas because of diffraction
205
Radio waves were discovered before the radio was invented.
Do you mean 'Who made the first radio?'? Several people were experimenting with radio transmission, among them Marconi and Hertz.
guglielmo marconi
Polaroid filters in cameras and glasses; strain analysis (to measure the stress in objects such as seeing where the most stress occurs in a hip bone) and polarised radio waves are used for television transmission.
radio transmission can be heard in hilly areas because of diffraction
radio waves or radio frequency
I believe that communication is the backbone of civilization. But radio communication, hand signals, and smoke gernades are all vital to police work.
205
The Wikipedia article on radio is pretty comprehensive: http://en.wikipedia.org/wiki/Radio
There are no miracles of radio. It is a form of transmission of information using the electromagnetic spectrum
Radio waves were discovered before the radio was invented.
The analog method of signal transmission uses radio waves to carry signals. Digital transmission involves the use of satellites to transmit signals.
in 1901
Do you mean 'Who made the first radio?'? Several people were experimenting with radio transmission, among them Marconi and Hertz.
It can't. Radio transmission is inherently un-private. The only way to achieve privacy in radio communication is to encode, scramble, encrypt, etc., in a way that a random listener can't decode.