Reference

The Electromagnetic Spectrum

From quasi-DC fields below one hertz to gamma rays beyond 10²⁴ Hz — every electromagnetic phenomenon is a different frequency of the same underlying field. This table gathers the bands, their boundaries, the technology that lives in each, and the propagation quirks that make them useful (or useless) for any given purpose.

How to use: jump between batches with the tabs, type into the search box to filter rows live, or click Show more on long cells to expand the full text. The table scrolls horizontally on narrow screens and the header stays pinned as you scroll.

8 batches 12 rows Last updated 2026-05-06

Frequency Range (Hz)	Band Name / Designation	Wavelength Range	Photon Energy	Common / Alternative Names & Sub-bands	Primary Applications & Uses	Example Technologies / Systems	Propagation / Atmospheric Notes	Regulatory / Allocation Notes	Special Notes / Fun Facts
0 Hz (DC / static fields) to ~0.001 Hz	Ultra-Low DC / Static Geomagnetic Fields	Effectively infinite (planetary / interplanetary scale)	< 4 × 10^{-18} eV (4 aeV)	Direct current (DC) geomagnetic field, Earth's core dynamo field, steady magnetospheric field	4 uses Show more Global navigation and compass orientation (historical and modern) Geomagnetic surveying for mineral/oil exploration Satellite attitude control and magnetometer calibration Space weather monitoring of quiet-time solar wind interaction	Fluxgate magnetometers (e.g., on Swarm satellites), ground-based observatories (INTERMAGNET network), paleomagnetic core sampling	Static fields penetrate the entire Earth and atmosphere with negligible attenuation. No wave propagation — purely magnetostatic.	No regulatory allocation (natural phenomenon). Used freely in scientific and geophysical research worldwide.	Generated by convective currents in Earth's molten outer core. Strength... Show more Generated by convective currents in Earth's molten outer core. Strength ~25–65 μT at surface. Reversals occur every ~200,000–300,000 years. Used to date geological records via paleomagnetism.
0.001 Hz – 0.01 Hz (1–10 mHz)	Ultra-Low Ultra-Low Frequency Micropulsations (Pc5 class)	~30,000,000 km – 3,000,000 km (planetary scale)	~4 × 10^{-18} eV – 4 × 10^{-17} eV (4–40 aeV)	Pc5 pulsations, global magnetospheric cavity modes, solar-wind-driven ULF waves	4 uses Show more Space weather forecasting and geomagnetic storm prediction Magnetospheric research (field-line resonances) Earthquake precursor studies (some anomalous ULF signals) Power-grid harmonic analysis (very low-frequency components)	SuperMAG global magnetometer array, GOES/ACE satellite magnetometers, USGS geomagnetic observatories	Magnetohydrodynamic (MHD) waves in the magnetosphere. Couple to ground via ionospheric currents. Extremely long wavelengths allow global propagation with minimal loss.	Natural signals only — no licensing required. Monitored by international geophysical networks.	Driven by solar-wind pressure pulses and Kelvin-Helmholtz instability at the... Show more Driven by solar-wind pressure pulses and Kelvin-Helmholtz instability at the magnetopause. Can induce GIC (geomagnetically induced currents) in power lines, causing blackouts (e.g., 1989 Quebec event).
0.01 Hz – 0.1 Hz (10–100 mHz)	Ultra-Low Ultra-Low Frequency Micropulsations (Pc4 class)	~3,000,000 km – 300,000 km	~4 × 10^{-17} eV – 4 × 10^{-16} eV (40–400 aeV)	Pc4 pulsations, compressional ULF waves	3 uses Show more Magnetospheric diagnostics and solar-wind/magnetosphere coupling studies Geophysical exploration (deep-Earth conductivity sounding) Monitoring of auroral electrojet activity	CARISMA magnetometer chain (Canada), IMAGE array (Europe), THEMIS spacecraft magnetometers	Primarily compressional and toroidal MHD waves. Reach ground through ionospheric Hall/Pedersen currents. Highly latitude-dependent.	Unregulated natural signals. Studied under international programs (IAGA, INTERMAGNET).	Period range 10–100 seconds. Often observed during geomagnetic storms. Can... Show more Period range 10–100 seconds. Often observed during geomagnetic storms. Can resonate with field lines, transferring energy from solar wind to the magnetosphere.
0.1 Hz – 1 Hz (100 mHz – 1 Hz)	Ultra-Low Ultra-Low Frequency Micropulsations (Pc3 class)	~300,000 km – 30,000 km	~4 × 10^{-16} eV – 4 × 10^{-15} eV (0.4–4 feV)	Pc3 pulsations, upstream waves, foreshock waves	3 uses Show more Solar-wind monitoring and space weather alerts Ionospheric and magnetospheric research Seismic-electromagnetic precursor detection research	Ground magnetometer arrays (e.g., SAMBA, MACCS), Cluster and MMS spacecraft, Japanese geomagnetic observatories	Waves generated in the foreshock region travel sunward then couple into the magnetosphere. Reach ground with moderate attenuation.	Natural only. No spectrum allocation.	Often linked to 30-second upstream waves from the bow shock.... Show more Often linked to 30-second upstream waves from the bow shock. Strongest during high solar-wind speed periods.
1 Hz – 3 Hz	Ultra-Low Upper Ultra-Low / Lower Extremely-Low Frequency Micropulsations	~30,000 km – 10,000 km	~4 × 10^{-15} eV – 1.2 × 10^{-14} eV (4–12 feV)	Pc2 pulsations (border), sub-ELF geomagnetic variations, power-grid sub-harmonics	4 uses Show more Advanced geophysical sensing (Earth conductivity profiling) Research into earthquake electromagnetic precursors (some studies report anomalies in this range) Laboratory simulation of natural ULF fields Biological research (weak field interaction studies)	High-sensitivity SQUID magnetometers, induction coils at remote observatories, Schumann-resonance-adjacent monitoring stations	Still dominated by magnetospheric/ionospheric coupling. Wavelengths comparable to Earth radius — global-scale standing waves possible.	No allocation. Overlaps with the very bottom edge of the ITU ELF band (3–3000 Hz) but remains natural-signal dominated.	This range marks the transition into the official ELF band... Show more This range marks the transition into the official ELF band (ITU defines ELF starting at 3 Hz). Some studies link ultra-low geomagnetic fluctuations to subtle effects on human brain alpha waves or animal navigation, though evidence remains debated.
EXAMPLE: 3 Hz – 30 Hz	ELF/SLF/ULF EXAMPLE: ELF (Extremely Low Frequency)	EXAMPLE: 100,000 km – 10,000 km	EXAMPLE: 1.24 × 10⁻¹⁴ – 1.24 × 10⁻¹³ eV	EXAMPLE: ELF, Schumann band	3 uses Show more EXAMPLE: Submarine communication EXAMPLE: Geophysical research EXAMPLE: Schumann-resonance studies	EXAMPLE: Project ELF / ZEVS transmitters, large loop antennas	EXAMPLE: Earth–ionosphere waveguide; very low attenuation in seawater	EXAMPLE: Mostly military / scientific use; not commercially allocated	EXAMPLE: Schumann resonances peak near 7.83 Hz. Show more EXAMPLE: Schumann resonances peak near 7.83 Hz.
EXAMPLE: 3 kHz – 30 kHz	VLF/LF/MF EXAMPLE: VLF (Very Low Frequency)	EXAMPLE: 100 km – 10 km	EXAMPLE: 1.24 × 10⁻¹¹ – 1.24 × 10⁻¹⁰ eV	EXAMPLE: Myriametric waves, Band 4	3 uses Show more EXAMPLE: Submarine communication EXAMPLE: Navigation (Omega, Alpha) EXAMPLE: Time-signal broadcast	EXAMPLE: Massive grounded antennas, ferrite-loop receivers	EXAMPLE: Stable Earth–ionosphere waveguide; penetrates ~20 m of seawater	EXAMPLE: ITU Band 4; mixed military / aeronautical / time-signal allocations	EXAMPLE: Replace with real data. VLF transmitters have antennas measured... Show more EXAMPLE: Replace with real data. VLF transmitters have antennas measured in kilometres.
EXAMPLE: 3 MHz – 30 MHz	HF EXAMPLE: HF (High Frequency)	EXAMPLE: 100 m – 10 m	EXAMPLE: 1.24 × 10⁻⁸ – 1.24 × 10⁻⁷ eV	EXAMPLE: Short wave, decametric waves, Band 7	4 uses Show more EXAMPLE: International short-wave broadcasting EXAMPLE: Amateur (ham) radio EXAMPLE: Aviation HF, maritime HF, military comms EXAMPLE: Over-the-horizon radar	EXAMPLE: SSB transceivers, dipole / Yagi / log-periodic antennas, NVIS	EXAMPLE: Skywave via F-layer; strongly diurnal and solar-cycle dependent	EXAMPLE: Densely allocated by ITU; amateur sub-bands (80m–10m); WARC bands	EXAMPLE: Replace with real data. Maximum Usable Frequency (MUF) tracks... Show more EXAMPLE: Replace with real data. Maximum Usable Frequency (MUF) tracks the solar cycle.
EXAMPLE: 30 MHz – 300 MHz	VHF/UHF EXAMPLE: VHF (Very High Frequency)	EXAMPLE: 10 m – 1 m	EXAMPLE: 1.24 × 10⁻⁷ – 1.24 × 10⁻⁶ eV	EXAMPLE: Metric waves, Band 8	4 uses Show more EXAMPLE: FM broadcast (~88–108 MHz) EXAMPLE: Aviation comms / VOR / ILS EXAMPLE: Marine VHF EXAMPLE: Amateur 2 m / 6 m bands	EXAMPLE: Yagi antennas, vertical whips, FM transceivers, SDRs	EXAMPLE: Mostly line-of-sight with slight diffraction; sporadic-E and tropo-ducting possible	EXAMPLE: ITU Band 8; nationally licensed broadcast and safety services	EXAMPLE: Replace with real data. Tropospheric ducting can carry VHF... Show more EXAMPLE: Replace with real data. Tropospheric ducting can carry VHF hundreds of km on rare nights.
EXAMPLE: 3 GHz – 30 GHz	SHF/EHF/µwave EXAMPLE: SHF (Super High Frequency) / Microwave	EXAMPLE: 10 cm – 1 cm	EXAMPLE: 1.24 × 10⁻⁵ – 1.24 × 10⁻⁴ eV	EXAMPLE: Centimetric waves; IEEE C / X / Ku / K bands	5 uses Show more EXAMPLE: Satellite communications (C, Ku, Ka) EXAMPLE: Wi-Fi 5/6/6E (5 GHz, 6 GHz) EXAMPLE: Weather and air-traffic radar EXAMPLE: Microwave point-to-point backhaul EXAMPLE: 5G FR2 (mmWave) lower edge	EXAMPLE: Parabolic dishes, phased arrays, GaN/GaAs HEMTs, waveguides	EXAMPLE: Strict line-of-sight; rain fade above ~10 GHz; atmospheric absorption peaks	EXAMPLE: ITU Region allocations; ISM at 2.4 / 5.8 / 24 GHz; auctioned 5G bands	EXAMPLE: Replace with real data. 60 GHz suffers ~15 dB/km... Show more EXAMPLE: Replace with real data. 60 GHz suffers ~15 dB/km O₂ absorption — useful for short-range security.
EXAMPLE: 300 GHz – 3 THz	THz / IR EXAMPLE: Terahertz / Sub-millimetre	EXAMPLE: 1 mm – 100 µm	EXAMPLE: 1.24 meV – 12.4 meV	EXAMPLE: T-rays, sub-mm waves, far-IR boundary	4 uses Show more EXAMPLE: Body / package security scanners EXAMPLE: Molecular and rotational spectroscopy EXAMPLE: Radio astronomy (e.g. ALMA) EXAMPLE: Experimental high-bandwidth wireless	EXAMPLE: Quantum-cascade lasers, photoconductive antennas, bolometers, HEB mixers	EXAMPLE: Heavy water-vapour absorption; non-ionising; cannot penetrate metal or water	EXAMPLE: Largely unallocated above ~275 GHz; ITU footnote 5.565 lists passive services	EXAMPLE: Replace with real data. Historically called the 'terahertz gap'... Show more EXAMPLE: Replace with real data. Historically called the 'terahertz gap' due to lack of compact sources.
EXAMPLE: 430 THz – 770 THz	Visible → γ EXAMPLE: Visible Light	EXAMPLE: 700 nm – 380 nm	EXAMPLE: 1.65 eV – 3.26 eV	EXAMPLE: Optical, VIS, light	4 uses Show more EXAMPLE: Human vision EXAMPLE: Photography, imaging, displays EXAMPLE: Free-space optical communication, LiFi EXAMPLE: Photosynthesis (PAR ≈ 400–700 nm)	EXAMPLE: LEDs, lasers, CMOS/CCD sensors, optical fibres (near-IR / vis)	EXAMPLE: Line-of-sight; scattered by aerosols; absorbed strongly in water at red end	EXAMPLE: Not radio-regulated; eye-safety covered by IEC 60825 laser classes	EXAMPLE: Replace with real data. Visible band is roughly one... Show more EXAMPLE: Replace with real data. Visible band is roughly one octave wide — frequency doubles violet → red.