Submegahertz

Submegahertz is a term used to describe frequencies that are below one megahertz (MHz), which is one million cycles per second. This range is often referred to as the "low frequency" or "very low frequency" (VLF) band in the context of radio frequency communication. The submegahertz range is typically divided into several sub-bands, including the extremely low frequency (ELF) band, which extends from 3 Hz to 30 Hz, and the super low frequency (SLF) band, which covers frequencies from 30 Hz to 300 Hz. These frequencies are used for various applications, such as communication with submarines, power line carrier communication, and certain types of navigation systems. The submegahertz range is also significant in the study of the Earth's ionosphere and magnetosphere, as well as in the analysis of natural phenomena such as lightning and seismic activity. Due to their long wavelengths, submegahertz signals can travel long distances and penetrate obstacles such as buildings and foliage, making them useful for certain types of communication and sensing applications. However, the use of submegahertz frequencies is limited by their relatively low data transmission rates and the need for large antennas to achieve sufficient signal strength.