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Sound Waves

Measuring terms:1,000,000 cycles per second = Megahertz (MHz)
1,000 cycles per second = Kilohertz (KHz)

1 cycle per second = Hertz (Hz)

These frequency numbers are in Hertz, which are cycles per second:

1 Approx. beginning of brain waves

6.66 Theta brain waves

7.85 Alpha brain waves

15.7 Beta brain waves

30-30.56 Government VLF stations

32-33 Government VLF stations

34-42 Government VLF stations

50 Approx. Upper limits of brain wave frequencies

60 Produces an audible sound

ELF – Extremely Low Frequencies (30 to 300 Hertz):

A great deal of attention is paid by the scientific and experimenter communities to the frequencies below 9 kHz. Here you can monitor, and actually hear, a wide range of “natural radio” phenomena. Events such as “whistlers”, which are believed to be the sound of the energy pulse of a lightning bolt following the earth’s magnetic field, can be heard with special radio receivers. These radios (which are surprisingly easy to build) are capable of tuning down to 300 cycles and below, where these signals are heard. There are many other sounds from known and unknown sources that are being investigated as well. Many who assist the scientific communities in such studies do not even listen to the sounds produced, but monitor such things as the changes to background noise using pen traces on paper tape, or computer sampling of variations in measured voltages. Through this activity, further knowledge is being developed about the radio propagation in this region, which still contains many mysteries.

FREQUENCY is a measure of the rate at which electromagnetic waves are generated. Frequency is measured in cycles per second, called hertz (Hz) after the German scientist who first discovered radio waves. (1 Hz equals one cycle per second.) The field around power lines, for example, is predominantly 60 Hz. Radio wave frequencies range from 300 Hz to billions of hertz. Electromagnetic waves with similar frequencies can be grouped together. These groupings form the ELECTROMAGNETIC SPECTRUM, with low-frequency waves (sometimes called ELF for “extremely low frequencies”) at one end and high-frequency waves at the other. Radio waves, microwaves, and infrared light can be found at the lower end of the spectrum. Ultraviolet light, X-rays, and gamma rays occupy the upper end. Visible light, including sunlight, occupies the middle region. Microwaves are used in the transmission of telephone and telegraph messages, in communications between earth and orbiting satellites, and in relaying certain television broadcast signals.

ELF/VLF radio waves penetrate deeply beneath the surface of the earth and interact with the geologic structure of the earth. This interaction induces secondary fields with measurable effect upon and above the surface of the earth. Proper understanding of the physics of the generation and propagation of ELF/VLF waves and their interactions with earth materials will allow these waves to be used for applications such as sub-surface communications and exploration of the subsurface geological structure. (Source)

Electromagnetic radiation with a high frequency carrier wave (e.g., radio wave) and an extremely low frequency (ELF) modulation is considered amplitude modulated (e.g. TDMA mobile phone systems). The modulation can also be pulsed where the carrier wave is switched on and off very rapidly in the rate of about 100 pulses per second (e.g., GSM mobile phone systems), while continuous wave (CW) radiation is generated essentially at a single frequency (e.g., analog mobile phone systems).

Natural ELF/VLF Radio – also called “Natural Radio” – is audio-frequency radio signals of Earth in the approximately 200 Hz to beyond 10,000 Hz (10 kHz) spectrum which are not man-made but occur naturally. Most of the best phenomena are heard between 400 Hz and 5 kHz. Interest in naturally-occurring ELF/VLF radio phenomena such as “whistlers” and “chorus” has enjoyed a rapid resurgence during the past 10 years on the part of academic research via orbiting space-probes and ground-based monitoring efforts, and also notably amongst amateur hobbyists world-wide, thanks to easy availability of sensitive receiving equipment.

Sferics – Mainly the ubiquitous snap, crackle and pop of lightning all over the earth, this can be heard anytime, anywhere, on frequencies from 1 Hz to beyond 100 MHz. Just tune your AM radio to an empty frequency.

The ELF frequency range is critically important to the Navy because of its value in providing a way to communicate with submerged submarines. As a result of the high electrical conductivity of sea water, signals attenuate (or decrease) rapidly as they propagate downward through it. In effect, the seawater “hides” the submarine from detection while simultaneously preventing it from communicating with the outside world through normal radio transmissions.

We record wideband ELF/VLF (~200 Hz to 20 kHz) data at Palmer Station, Antarctica. Extremely Low Frequency (ELF, 30-3000 Hz) and Very Low Frequency (VLF, 3-30 kHz) are frequency bands to denote where the signals we measure are in the electromagnetic spectrum. Our signals happen to be in the audio range, so that if they were sound waves, you could hear them.

The degree to which a signal is attenuated depends on its frequency, however. The lower the frequency, the more deeply a signal can be received in seawater. In order to receive conventional radio transmissions a submarine must travel at slow speeds and be near the surface of the water. Both of these situations make a submarine more susceptible to enemy detection.

FCC rules allow unlicensed stations to operate between 160 to 190 kHz providing that:

1. The power input to the final amplifier does not exceed one watt.

2. All emissions below 160 kHz or above 190 kHz are suppressed by 20 dB.

3. The total length of the transmission lines plus the antenna does not exceed 50 feet.

HAARP is a project funded by the US Senate and operated by the US Navy & Air Force.

HAARP or “High Frequency Active Auroral Research Program,” was supposedly started to communicate with submarines deep in the ocean using ELF radio waves, which can penetrate the ocean as well as the earth’s surface. With the power HAARP has, it can focus all its radio waves into a single beam in the sky, which effectively exceeds its 3.6 million-watt power status. Still, to get a better idea, it’s 72,000 times more powerful than the US’s most powerful radio station. With this much power the possibilities for use are endless; of course activists, conspiracy theorists, and environmentalists all have their own ideas for applications of this weapon / utility, both good and bad.

“Natural Radio” describes naturally occurring electromagnetic (radio) signals emanating from lightning storms, aurora (The Northern and Southern Lights), and most importantly, the Earth’s magnetic-field (The Magnetosphere). This is a presentation of Earth’s natural radio emissions that occur in the extremely low frequency to very-low-frequency (ELF-VLF) radio spectrum–specifically, at AUDIO frequencies between approximately 100 to 10,000 cycles-per second (0.1 – 10 kHz). Unlike sound waves, which are vibrations of air molecules that our ears are sensitive to, natural radio waves are vibrations of electric and magnetic energy (electromagnetic waves) which-though occurring at the same frequencies as sound–cannot be listened to without an audio-frequency ELF-VLF radio receiver to convert the natural radio signals directly into the same sound frequencies. Another amazing realm of nature is thus ready to be explored and observed.