Frequencies Supported
Radio waves are classified according to their frequency band. Each of these frequency bands has its own characteristics and their applications differ according to frequency. DKK supplies products supporting all frequency bands.
About Frequency
Radio waves travel at the speed of light (300,000 km/s). Frequency is the number of radio waves that can travel during a single second, and is expressed in terms of Hertz (Hz). Since the speed of radio waves is constant, low frequencies have long wavelengths while high frequencies have short wavelengths.
Very Low Frequency (VLF): Under 30kHz
Very low frequencies have extremely long wavelengths and travel long distances along the Earth’s surface. They can go over low mountains and can travel in water.
Very large transmission equipment is required for VLF transmission and DKK can design, manufacture, construct, and service extremely large antennas of several hundred meters in length.
Low Frequency (LF): 30-300kHz
Low frequency waves have little linearity and can go around obstacles traveling great distances. They are used primarily for public service applications such as the radio wave transmission stations for frequency and time standard which transmit Japan standard time around the country and the radio beacons which provide locational information to assure safety in maritime transport.
The Hagane-yama LF Standard Time and Frequency Transmission Station
There are two radio wave transmission stations for frequency and time standard which transmit standard time in Japan. Both of these transmission stations make use of DKK’s antenna design, manufacturing, installation, and maintenance services.
Medium Frequency (MF): 300-3000kHz
Because medium frequencies afford stable transmission of radio waves over long distances, they are used primarily for medium wave broadcasting (AM radio), ship communications, LORAN (radio navigation), and other applications.
Medium Wave Radio Broadcasting Stations
DKK has built medium wave radio broadcasting stations not only in Japan, but in many locations around the world. From site studies to design, manufacturing, installation, and maintenance, DKK provides end-to-end services for the construction of these broadcasting stations.
High Frequency (HF): 3-30MHz
High frequencies waves are reflected repeatedly between the ionosphere, which envelops the Earth, and the Earth’s surface and can travel great distances. These frequencies are used widely for short wave radio broadcasting, maritime communications, aircraft on international routes, international broadcasting, and ham radio.
Shortwave Radio Broadcasting Antennas
Using the characteristics of short waves, DKK draws on its experience and knowledge to provide antennas for the high-frequency band, including curtain and doublet antennas for various applications such as shortwave radio broadcasting antennas for radio transmission abroad.
Very High Frequency (VHF): 30-300MHz
Very high frequency waves have linearity, yet they can go around obstacles to some extent. Since signals in the VHF band can carry more data than high frequency signals, they find wide application in television and FM radio broadcasting, as well as ship and aircraft communications, disaster prevention and administration radio, police and fire radios, ham radio, and so on.
VHF Television Broadcasting Antennas
DKK provides many twin loop antennas and dipole antennas across Japan used in television broadcasting. From site area reviews to site studies, design, and installation, from planning to station opening, DKK provides an end-to-end service. And not just antennas: from antenna steel towers to radio station structures, DKK can handle all your requirements.
Disaster Prevention Radio Relay Facilities
In addition to VHF broadcasting, very high-frequency radio waves are widely used for ship and aircraft communications, disaster prevention and administration radio, police and fire radios, ham radio, and other applications.
Ultra High Frequency (UHF): 300-3000MHz
This is currently the most commonly used frequency band. The linearity of UHF is still higher than VHF, but this bandwidth can carry even more data and, given its adaptability to compact antennas and receivers, it finds wide use in mobile telephones, digital terrestrial broadcasting, police radios, taxi radios, aircraft and weather radar, ham radio, and so on.
Mobile Communications Base Stations
From the fabrication of antennas, steel towers, and peripheral equipment to aftermarket services, DKK has a full line of products and services for the base stations used as relay facilities for mobile communications of cellular telephones and the like.
Television Broadcasting Stations (Master Stations)
In television broadcasting, there is a shift underway from analog to digital broadcasting. With this shift, television broadcasting facilities are going digital, as well. We provide a full range of services for master stations in various locations, including antennas, steel towers, and construction services.
*Master station: A representative transmission station that receives broadcasting signals.
Television Broadcasting Transmission Stations (Relay Stations)
Broadcasting is done via relay stations for areas that cannot receive broadcast signals for master stations. DKK will survey the area to be served by the relay station, providing an end-to-end service that includes antenna fabrication, installation, and on-site tuning, as well as steel tower strength assessment and design, fabrication, and maintenance.
Super High Frequency (SHF): 3-30GHz
Given their ability to carry enormous amounts of data, super high frequency waves are used for relaying broadcast programs (STL/TSL/TTL), radar (weather, etc.), satellite communications and satellite broadcasting, and other applications. DKK provides parabolic antennas of each diameter and FPU rotating equipment, as well as reflector panels and other equipment essential for microwave communications circuits.
Microwave Communication Antennas
Broadcasters depend on FPU rotators to transmit images and audio data recorded in the reporting of news and coverage of events. DKK has a full line of these devices and provides them not only in Japan but for export overseas, as well.
FPU Rotators
To relay broadcast programs, FPU rotators perform microwave transmission to broadcasting stations and FPU base stations. DKK can recommend FPU rotators which are essential to the reception of broadcast signals that meet various requirements.
Satellite Communication Antennas
In satellite communications, there are VSAT and Ku-Band offset compact antennas that exchange image, audio, and data communications.
Extremely High Frequency (EHF): 30GHz and higher
Extremely high frequency (EHF) waves can carry an enormous amount of data and find wide application in radar, simple-type terrestrial communications, and satellite communications. DKK studies and develops Extremely High Frequency antennas that meet our customers’ diverse requirements.
FWA(Fixed Wireless Access) Parabolic Antenna
This is a 0.3 m parabolic antenna which DKK has prototyped for 37 GHz applications. We design and manufacture antennas that meet our customers’ requirements.
FWA(Fixed Wireless Access) Flat Antenna
This is a flat antenna which DKK has prototyped for the 60 GHz band. We can propose antennas for a wide range of requirements.
