For our European friends, please note that all the frequencies referenced below are for the American and Canadian radio spectrum. The lowest frequencies are radio waves, that are actually the same as frequencies as the audio sound which comes out of your speakers. This called VLF, or Very Low Frequency. These waves have wavelengths measured in thousands of miles. They pass through the body without damage.
Commercial AM radio signals, use waves that are also quite long and pass through the body with relative ease. These are also waves, whose wavelengths are measured in hundreds of feet. Shortwave signals are also very long, and this part of the spectrum reaches up to a part of the miltary band, located below TV channel 2.
Decades ago, people could go to a doctor for aches and pains and be treated with a Diathermy machine. This machine was essentially a shortwave radio transmitter, and operated with a curved antenna that fits the human body. When placed against the skin, the antenna radiated energy that was absorbed deep in the body’s tissues. A sufficient power level of RF energy will cause currents of electricity to flow in these tissues, thereby creating warmth. These machines are probably outlawed by now and died a quiet death in America. RF energy causes molecules to collide with one another creating heat. This occurs in tisuues like muscles, as well as blood.
FM stations (located in the radio band near TV channel 6) and over the air television channels 2 through 13 are all in the VHF band. These signals can also pass through the human body without harm. These waves are measured in several feet.
When you look at any TV antenna, multiply the width of the antenna by four, and that will be the wavelength of the wave from the TV transmitter. Hence the term 1/4 wavelength, which is a design rule for most antennas.
Television channels 14 through 83 are in the UHF region. Channel 83 is actually just below analog cell phone frequencies. Progammable police scanners scan police channels that are very close to cell phone frequencies.
(Privacy laws force scanners to block the cell phone band. )
San Marino, San Marino,
City of Fairfield, Australia,
Cambodia, Phnom Penh,
City of Hawkesbury, Australia,
Peru, Lima, City,
Palmerston, Northern Territory
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