Very Low Frequency (VLF) Stations

T he Very Low Frequency (VLF) radio spectrum extends from 3 to 30 kHz. Standard communications receivers do not receive signals that low in frequency. Furthermore, most antennas used with standard communications receivers are optimized for higher frequencies and perform poorly in the VLF spectrum. Because of that, few Radio Amateurs or shortwave listeners have ever heard VLF signals and most know very little about the large number of stations in that part of the spectrum, what those stations are used for, or the nature of VLF radio signal propagation.

However, because VLF receivers and receiving antennas are easy to construct, the VLF spectrum attracts a small number of curious and sometimes very dedicated VLF listeners who want to learn more about this little-known and somewhat secretive part of the radio spectrum. The guide below is provided to assist them in identifying stations they receive.

Signals from powerful VLF stations can be received worldwide. They penetrate deep into the earth and deep into the sea (especially in the lower portion of the VLF spectrum) and therefore can be received by submerged submarines. Though some VLF stations have other purposes, the primary function of most VLF stations is to communicate with submerged military submarines or help them navigate underwater.