What are radio waves?

Electromagnetic radiation is a wave that combines electric and magnetic fields, moving out from its source as an expanding sphere and having waves as the feilds alternate in value. Its formal name is Transverse Electro Magnetic wave, or TEM. This kind of radiation has different utility as its wavelength changes. Waves of a very long wavelength, such as thousands of meters, tend to travel along the surface of the earth and even penetrate into the water. These are useful for communication with submarines, and for broadcasting time signals. Broadcast radio, short-wave radio, television, cellular telephones, walky-talkies, 2-way police radios, satellite television, and other such communication/broadcast systems all use electromagnetic radiation, or "Radio Frequency Waves". Each communication service uses a part of the spectrum that is suitable for its needs. Light, infra-red heat, ultra-violet (black light), and even X-rays and Gamma-rays are all forms of electromagnetic waves. All of ...  more

Exhibit #1 Concept: A moving charge like a spark produces EM radiation This exhibit will use a spark plug, receiver and spectrum analyzer to approximate Hertz's experiment in which he discovered radio waves. A spark plug is set up to give off a spark when the visitor pushes a button. A receiver positioned at some distance away will audibly register the signal. The spectrum analyzer will show spikes occurring at many different frequencies indicating radio emission. Spark plugs are a source of man-made radio waves which interfere with the radio telescopes at NRAO. We prohibit most vehicles with spark plugs from driving on the site. Because this exhibit could really cause interference at the telescopes, the exhibit will have to be shielded in a Faraday cage. Thus, this exhibit can be used to teach visitors that interference is important and needs to be controlled at the NRAO. Outcome: An accelerated charge like a spark from a spark plug produces radio waves. Radio waves cannot pass ...  more

Electric and magnetic fields are fundamental forces in nature. Together they create invisible electromagnetic waves which pass through the environment - like ripples on the surface of water. Eletromagnetic waves have different properties and uses, depending on their wavelength. Radio waves occur within a specific range of wavelengths, and are useful for transmitting sound and digital signals. • Electricity and radio waves can be used to power man-made devices • We see different frequencies of visible light waves as different colors • X-rays can show inside some solid objects Lower frequency waves such as microwaves cannot change the structure of biological material, but can have a heating effect. This is called non-ionizing radiation. Higher frequency waves like x-rays can change the structure of biological material. This is called ionizing radiation. Radio devices emit non-ionizing radiation. Find out more about other sources of electromagnetic waves.  more

Objects in space (planets, comets, stars, galaxies, or clouds of dust for instance) emit electromagnetic waves. The full range of radiation emitted by an object is called its electromagnetic spectrum.  more

Radio waves (or radio frequency - RF) are an invisible yet essential part of our modern life. Radio waves were discovered more than 100 years ago and we often take today's technology for granted. Scientists have been studying the health effects of radio waves for more than 50 years. Radio waves are part of the electromagnetic spectrum which also includes light and heat and is used by all electrical equipment including television and radio stations as well as mobile phones. Radio waves are not radioactive. RF is a form of non-ionising radiation. It is not the same as radiation associated with X-rays or gamma-rays and its biological effect on humans is quite different. The energy emitted is insufficient to disrupt molecules in the body. At high powers, RF can cause heating - exposure guidelines protect against heating and all other known health effects. We always aim to inform our customers accurately on RF exposure and comply with international exposure limits.  more

Radio, like optical light, is a band of wavelengths in the Electromagnetic Spectrum. The Electromagnetic Spectrum characterizes all light by its wavelength or frequency. Objects in the universe radiate electromagnetic waves in all the bands of the Electromagnetic Spectrum, not just optical light. Hence we have radio, IR, optical, UV, X-ray and gamma-ray telescopes in order to study the universe in all of its emissions.  more

Radio waves are an invisible form of electromagnetic radiation that varies in wavelength from around a millimeter to 100,000 km, making it one of the widest ranges in the electromagnetic spectrum. "Radio" is a catch-all term describing all forms of electromagnetic radiation with a wavelength longer than a millimeter and a frequency above 300 GHz. Frequency refers to how long the measured time is between the "crest" and "trough" of a wave arriving at the source. For visible light, the frequency is in the 450-750 terahertz range, meaning in a single second of waves, 450-750 crests and troughs pass through a detector. Radio is most famously utilized to send audio, images, and text in the form of signals. Guglielmo Marconi and Nikola Tesla are both credited with being early pioneers in the area of radio. Radio's long wavelength allows it to circumvent obstacles and travel long distances, unlike visible light and other spectra of higher frequencies.  more