Hertzian waves travel through the Universe

The airwaves are undoubtedly the form of terrestrial intelligence have been further travels through the universe. Radio waves (named after its discoverer) is sprayed into the air at the speed of light (300 thousand kilometers per second). But there is a process before the signal is transformed into "waves.

The transmission of waves depends on the frequency assigned to each station. Channel frequency separation between AM is 30 kilohertz, while F.M. this separation is 800 kilohertz. In Mexico City there are at least a case that does not respect the distance between frequencies, so its signal can be received clearly. In later time we'll talk about this often. According to experts, the best frequencies are the center of the dial.

There are also differences between the transmission bands AM and F.M. In the first case, electromagnetic waves travel along the ground control, so, can "deliver" obstacles such as mountains. And although there is a relationship between the power-kilowatts-and frequency-kilohertz AM and FM-megahertz in the transmission of the signal depends primarily on the topographical conditions of the location of the station. A curious fact is that at night (ah, the magic night!) By atmospheric conditions, electromagnetic waves of the AM band travel greater distances, and its signal can be captured in unforeseen places.

The electromagnetic waves of the band F.M. ranging from 88 to 108 megahertz, with a channel separation greater than in AM -So there are fewer FM stations, have no capacity to fight these barriers. Although the reception is clearer, and less susceptible to "dirty" with industrial noises or atmospheric (LEHA year played on the radio you hear a flash in the night?) As this happens more frequently in the amplitude modulation stations. But, the AM. has a wider range and it seems that its stations have been earmarked to "talk radio" (programs, not just programming), while in FM very few stations that include programs in their format. About seven people are tuned out the signal "on air" and can be clearly captured by listeners, speaking only of the broadcast signal.