Two-Way Radios Receive Radio Waves
Two-way radios, just like standard radios, receive radio waves over the air. The antenna in a two-way radio contains a set of electrons (if the radio features multiple channels, there is a separate set of electrons for each channel). When a radio transmission is received, the radio waves excite the electrons and cause them to produce electrical impulses. These impulses are fed to a small processor which, in turn, converts them to an electrical signal that can be played as sound through the radio's speaker. Because radio waves are always present in the air, a certain non-descript sound is always being processed by the radio and sent to the speaker; for this reason, many radios also offer a "squelch" setting that can be used to adjust the signal threshold at which the speaker is activated.
Two-Way Radios Convert Sound to Radio Waves
Radios convert radio waves into sound. The defining characteristic of a two-way radio, however, is the ability to also convert sound back into radio waves for transmission to another radio receiver. When a user speaks into the two-way radio microphone, the vibrations created by the person's voice cause a membrane within the microphone to vibrate. The radio's processor notes these vibrations and converts them into an electronic signal suitable for transmission to the radio transmitter. The transmitter forwards the signal on to the antenna where it is broadcast outward in the form of radio waves (the radio waves can then be received by another two-way radio and converted back into sound as described in Section One above).
Radios May Use Multiple Channels
With the proliferation of two-way radios, users may find others using the radio frequency and interfering with conversations. For this reason, most modern two-way radios allow use on several different channels. To broadcast on different channels, the transmitter of the radio must be able to generate radio waves in several different frequencies, with very minute fluctuations in each available frequency (the fluctuations are actually the voice being transmitted, a process known as "frequency modulation"). When the modulated frequency is sent to the antenna and the proper electrons are excited, outgoing radio waves are generated; these radio waves can then be picked up by other radios within a small area determined by such factors as the size of the antenna, the battery power of the radio, and atmospheric conditions. When the radio frequency is picked up, the receiving radio passes received signals through a an electronic filter (known to technophiles as a bandpass filter) and converted back into sound.
Tags: radio waves, radio waves, two-way radio, back into, into sound