What is a VLF antenna?

ELF/VLF stands for Extremely Low Frequency and Very Low Frequency, and refers to the range 300 Hz to 30 kHz. We’re talking about radio waves, like the AM/FM signals you get, just at an even lower frequency.

How far can VLF transmit?

Therefore, VLF transmissions are very stable and reliable, and are used for long-distance communication. Propagation distances of 5,000–20,000 km have been realized. However, atmospheric noise (“sferics”) is high in the band, including such phenomena as “whistlers”, caused by lightning.

Can humans hear VLF?

VLF (Very Low Frequency) radio waves vibrate at frequencies that overlap the human hearing range, although we can’t directly hear them.

What does VLF sound like?

Types of VLF Signals. Sferics, short for “atmospherics”, are the impulsive signals emitted by lightning. The sound of sferics consists of sharp crackling noises like twigs snapping or sizzling noises like bacon frying. Sferics are caused by lightning strokes within a couple of thousand kilometers of the receiver.

What is VLF method?

The VLF-EM technique is a passive method that uses radiation from ground-based military radio transmitters (used for navigation, of which there are about 42 worldwide) operating in the VLF band (15–30 kHz) as the primary EM field.

What frequency do submarines use?

Very Low Frequency (VLF) communications transmitters use digital signals to communicate with submerged submarines on at frequencies of 3-30 kHz. The eighteen Trident submarines constitute about half the US strategic nuclear capability.

What is low frequency used for?

The Low Frequency (LF) band is mostly used for AM broadcasting in Europe as well as in areas of Northern Africa and Asia. Similar to VLF, LF can also be used for navigational radio beacons. It can also be used for maritime ship-to-shore communication, as well as transoceanic air traffic control.

What frequency is VLF?

VLF electromagnetic technology is used in the frequency range of 15–30 kHz. VLF utilizes the carrier waves of distant powerful communications transmission of military organizations also.

What can you hear on VLF?

You can hear sferics, tweeks, whistlers and other VLF radio sounds at any time of the day, but the hours around dawn and dusk are generally best. Nighttime is also better than daytime.

How does VLF testing work?

Very low frequency (VLF) diagnostic testing is the application of an AC sinusoidal waveform, generally applied at 0.1 Hz or lower, to assess the quality of electrical insulation in high capacitive loads, such as cables.