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The earliest radio transmitters, including the Alexanderson alternator , were all longwave transmitters.
In Europe, North Africa and Asia, longwave radio frequencies between 153 and 279 kHz are used for domestic and international broadcastingInternational broadcasting is broadcasting deliberately aimed at a foreign, rather than a domestic, audience. It usually is broadcast by means of longwave, mediumwave, or shortwave radio, but in recent years has used direct satellite broadcasting and the. In the Americas, frequencies between 200 and 430 kHz are used for non-directional radio beacons, and do not necessarily follow the same 9 kHz spacing that other areas do.
The frequency of 60 kHz is used by several nations, such as the USAWWVB is a special NIST time signal radio station in Fort Collins, Colorado, co-located with WWV. WWVB is the station that radio-controlled clocks throughout North America use to synchronize themselves. The signal transmitted from WWVB is a continuous 60 k, UKThe MSF time signal is a broadcast from Rugby, Warwickshire based on time standards maintained by the British National Physical Laboratory. The transmitted signal has an ERP of 15 kW, on a frequency of 60 kHz, the same frequency used by WWVB. MSF is a rad, and JapanJJY is the callsign of a longwave time signal radio station similar to WWVB. The station is located in Japan, operated by a branch of the Japanese government known as the. JJY broadcasts a 50 kW signal on 40 kHz from a transmitter site on Mount Otakadoya,, for extremely accurate time and precision frequency signals. (77.5 kHz is used in GermanyDCF77 is a longwave time signal radio station. The callsign stands for D Deutsche (German), C long wave signal, F Frankfurt, 77 frequency: 77. It is run by The Physikalisch-Technische Bundesanstalt. DCF77 radio signals (set by an atomic clock) are broadca.) Many commercial applianceThe term Appliance refers to two classes of objects: One class of objects includes items that are custom-fitted to an individual for the purpose of correction of a physical problem, such as prosthetic and orthotic appliances. The other class of objects ins (such as self-setting clocks) sold since approximately 2000 have a VLF receiver capable of receiving these signals, which penetrate indoors more effectively than mediumwave or shortwave signals.
Radio signals below 50 kHz are capable of penetrating ocean depths to approximately 200 meters. The United States, Russian, British, Swedish, and Indian navies communicate with submarines on these frequencies.
In addition, Royal Navy nuclear submarines carrying ballistic missiles are allegedly under standing orders to monitor the BBC Radio 4 transmission on 198 kHz in waters near the U.K. It is rumoured that they are to construe a sudden halt in transmission as an indicator that the U.K. is under attack, whereafter their sealed orders go into place.
Longwave transmitting antennas take up large amounts of space, and have been the cause of controversy in the United States and Europe due to fears over proximity to high-power radio waves.