Search results
Results From The WOW.Com Content Network
During the 1920s and 1930s, radio engineers and government regulators investigated the characteristics of transmitting frequencies higher than those currently in use. In the United States, by 1930 the original AM broadcasting band consisted of 96 frequencies from 550 to 1500 kHz, with a 10 kHz spacing between adjacent assignments.
Since 1934 U.S. frequencies above 1500 had been allocated only to four experimental stations that broadcast with a signal 20 kHz wide for "high fidelity." The stations were converted to regular broadcasting with the NARBA frequency move, having already been allowed to choose normal call signs in 1936. [22] W9XBY to KITE (now dark) up 20 1550 1550
As a matter of convention, the ITU divides the radio spectrum into 12 bands, each beginning at a wavelength which is a power of ten (10 n) metres, with corresponding frequency of 3×10 8−n hertz, and each covering a decade of frequency or wavelength. Each of these bands has a traditional name.
Wide band Frequency modulation radio originated in the United States during the 1930s; the system was developed by the American electrical engineer Edwin Howard Armstrong. However, FM broadcasting did not become widespread, even in North America, until the 1960s. Frequency-modulated radio waves can be generated at any frequency.
Radio amateurs may engage in satellite and space craft communications; however, the frequencies allowed for such activities are allocated separately from more general use radio amateur bands. Under the International Telecommunication Union 's rules, all amateur radio operations may only occur within 50 kilometres (31 mi) of the Earth's surface.
high frequency (HF) Very long range through "skipping". Standard time frequencies can be heard here. VHF low 54–88 MHz: vestigial sideband modulation for analog video, and FM for analog audio; 8-VSB or OFDM for digital broadcast very high frequency (VHF) band I: Channels 2 through 6 are from 54–88 MHz (except 72–76 MHz). FM radio: 87.5 ...
The 27 MHz CB27/81 Bandplan is a list of the channel frequencies for FM CB radio in the United Kingdom. Unlike CB usage in the United States , and subsequently elsewhere in the world, the original UK 40 channels progress in order with 10 kHz spacing.
Unlicensed Personal Communications Services or UPCS band is the 1920–1930 MHz frequency band allocated by the United States Federal Communications Commission (FCC) for short range Personal Communications Services (PCS) applications in the United States, such as the Digital Enhanced Cordless Telecommunications (DECT) wireless protocol.