Convert wavelength in hectometres to femtohertz [fHz] Online | Free frequency-wavelength Converter

Describing Very Low Frequency Radio Waves

A hectometre (hm) is a unit of length equal to 100 metres, and it is used to describe very long wavelengths in the Very Low Frequency (VLF) and Low Frequency (LF) bands of the electromagnetic spectrum. Wavelengths in the hectometre range correspond to frequencies between approximately 3 kHz and 3 MHz. These long wavelengths are typically used for maritime navigation, military submarine communication, AM radio broadcasting, and time signal transmissions.

For example, a signal at 300 kHz has a wavelength of 1 kilometre, or 10 hectometres, and a signal at 1 MHz corresponds to 3 hectometres. These long wavelengths have the unique ability to travel long distances and penetrate water and the ground, which is why they are used in submarine communications and emergency broadcast systems.

Using hectometres to express wavelength offers a practical scale for understanding wave propagation over great distances. It also aids in antenna design, where very large antennas—often hundreds of metres long—are needed to efficiently transmit or receive these frequencies. Understanding wavelength in hectometres is important in geophysics, radio astronomy, and large-scale communications infrastructure.

Exploring Extremely Low Frequency Phenomena

The femtohertz (fHz) is a unit of frequency equal to 10⁻¹⁵ hertz, representing one cycle per 1,000,000,000,000,000 seconds—which is about 31.7 million years. This incredibly low frequency scale is used primarily in astrophysics, cosmology, and geophysics to describe ultra-slow oscillations and waves occurring over vast cosmic timescales.

Frequencies in the femtohertz range are associated with phenomena such as primordial gravitational waves, oscillations in the cosmic microwave background radiation, and long-term magnetic or seismic cycles on Earth. These waves have correspondingly immense wavelengths, stretching over billions of kilometres or even larger cosmic distances.

Because femtohertz frequencies are far beyond everyday human experience, they are mostly relevant for understanding the deep-time evolution of the universe and large-scale cosmic processes. Studying such slow oscillations helps scientists learn about the formation of galaxies, the behavior of space-time, and fundamental physical laws governing the cosmos.

Using femtohertz as a measurement allows researchers to quantify these vast time periods and wavelengths, connecting tiny frequency values with the immense scale of astrophysical phenomena and Earth’s geological history.