Search results
Results from the WOW.Com Content Network
Radio propagation is the behavior of radio waves as they travel, or are propagated, from one point to another in vacuum, or into various parts of the atmosphere. [1]: 26‑1 As a form of electromagnetic radiation, like light waves, radio waves are affected by the phenomena of reflection, refraction, diffraction, absorption, polarization, and scattering. [2]
A radio band is a small frequency band (a contiguous section of the range of the radio spectrum) in which channels are usually used or set aside for the same purpose. To prevent interference and allow for efficient use of the radio spectrum, similar services are allocated in bands.
Radio waves are more widely used for communication than other electromagnetic waves mainly because of their desirable propagation properties, stemming from their large wavelength. [12] Radio waves have the ability to pass through the atmosphere in any weather, foliage, and through most building materials.
In radio communication, used in radio and television broadcasting, cell phones, two-way radios, wireless networking, and satellite communication, among numerous other uses, radio waves are used to carry information across space from a transmitter to a receiver, by modulating the radio signal (impressing an information signal on the radio wave ...
Small errors in the detection process greatly affect the pitch of the received signal. As a result, single sideband is not used for music or general broadcast. Single sideband is used for long-range voice communications by ships and aircraft, citizen's band, and amateur radio operators. In amateur radio operation lower sideband (LSB) is ...
When single-sideband is used in amateur radio voice communications, it is common practice that for frequencies below 10 MHz, lower sideband (LSB) is used and for frequencies of 10 MHz and above, upper sideband (USB) is used. [12] For example, on the 40 m band, voice communications often take place around 7.100 MHz using LSB mode.
A trunked radio system is a two-way radio system that uses a control channel to automatically assign frequency channels to groups of user radios. In a traditional half-duplex land mobile radio system a group of users (a talkgroup) with mobile and portable two-way radios communicate over a single shared radio channel, with one user at a time ...
HeyPhone and Nicola operate single (upper) sideband on 87 kHz in the LF band, while Cave-Link uses different frequencies between 20-140 kHz depending on the expected distance at 30 W power. [ 7 ] Systems like Molefone and HeyPhone operate as single-sideband (USB) 87 kHz radio with earthed electrodes of 25–100 metres (80 to 330 feet) length. [ 8 ]