FrequenciesThe Spectrum
Explore the electromagnetic spectrum from VLF to EHF — the frequencies that make all wireless communication possible.
Frequencies Topics
Navigate through the topics and technology of frequencies
Frequencies Overview
Explore the electromagnetic spectrum from VLF to EHF
The Electromagnetic Spectrum
Complete range from radio waves to gamma rays
Very Low Frequency (VLF)
3-30 kHz — submarine communication, natural radio
Low Frequency (LF)
30-300 kHz — maritime navigation, time signals
High Frequency (HF)
3-30 MHz — shortwave and ionospheric propagation
Russian Woodpecker
The Soviet Duga OTH radar that disrupted global shortwave radio — 10 Hz pulsing, STEEL WORK, 1976-1989
JORN — Australian OTH Radar
Australia's Jindalee Operational Radar Network — active HF over-the-horizon radar covering 37,000 km² from Western Australia
OTH Radars — Northern Hemisphere
US OTH-B, ROTHR, MADRE, UK's Cobra Mist, France's NOSTRADAMUS, Russia's Container and Podsolnukh — OTH radar systems of the Northern Hemisphere
OTH Radars — Southern Hemisphere
Australia's JORN, Brazil's OTH-0100, South Atlantic surveillance — OTH radar systems of the Southern Hemisphere
Very High Frequency (VHF)
30-300 MHz — FM radio, TV, aviation, public safety
Ultra High Frequency (UHF)
300 MHz - 3 GHz — TV, cellular, WiFi, GPS
Microwave Frequencies
3-300 GHz — satellite, radar, point-to-point links
Loran-C
Long-range navigation system at 100 kHz
Radar Systems
Pulse and CW radar across multiple frequency bands
Acoustic & Hydroacoustic Telemetry
Sound-based communication through water — the only viable long-range wireless link beneath the ocean surface
Waveguide
Hollow metal tubes for microwave transmission — rectangular and circular waveguides, mode propagation