°Û °Û ÞÜ ±Û °Û °Û ÜÛÛ ÛÜ ±Û ²Û°ÛÛÛÛß°Û ÜÜÜ ±Û ÜÜ ÜÛÛÛÜ°ÛßßßÛ°Û °Û ÛÛ ° ÛÛ±Û ±Û ÛÛ ±ÛÛßßßÛܱÛÛßß°ÛÜÜÜß °Û°ÛÛÛ ÛÛ ° ÛÛ±Û ±Û ÛÛ ±Û °Û±Û °ÛÜ °ÜÛßßÛ°Û °Û ßÛ ÛÛß °ÛÛÛ ßÛÛÜ°ÛßÛÛÛÛß±Û °ÛÛÛß°ÛÜÜÛ²°Û °Û Outbreak Magazine Issue #12 - Article 5 of 18 '~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~' Radio Radio Radio ================= By: Logik- One of the most widely ignored subjects (and one of the most exploitable) today is that of radio. Most people consider radio to be just an old way of transmitting data and music, but it's really a lot more complex. A lot of high-tech equipment is controlled by radio, such as cell phones, wireless networking, military radar, even satellites in space, such as those used for taking pictures in space (or on earth), and communications. In this article I'm going to cover some of the basics of electronics used to build transceiving equipment along with measuring the frequencies broadcasted. This isn't meant to be an in depth guide all about radio, nor electronics, that would span multiple books. Anyways, enough bullshit, I'm going to explain it. Anyone familiar with basic electronics is aware that in all ac electronic circuitry, you have electric and magnetic fields surrounding it, the electric fields running parallel (kinda) with the circuit, the magnetic fields perpendicular. We call this combination of fields "electromagnetic waves". Now, alternating current always has a "frequency", which is very important, seeing as how later this will let us know what radio frequency we are broadcasting on, seeing as how they go hand in hand. The frequency of an ac circuit is measured by the reciprocal of T (in seconds) of the circuit. (To actually measure T, you would need an oscilloscope). Say that we have an AC circuit alternating at intervals of 2 milliseconds, or .002 seconds. To find the frequency of that circuit, you would divide 1 by .002, giving you a frequency of 500hz, meaning the current alternates cycles per second. Now, most of the time when using charts for AC, it's plotted in wave format. A line is drawn through the center, and everything above that line is positive voltage, everything below negative. When we plot AC, we also have a wavelength, which is also important for radio. Since the velocity of radio waves is 300,000,000 meters per second (or 984,000,000 feet per second), The wavelength of the circuit is equal to 300,000,000 x (1/frequency) now, if we use our earlier frequency of 500hz, the wavelength would equal out to 300,000,000/500, or about 600,000 meters, which is equal to 1,968,000 feet. Now, radios are never, ever broadcasted on this frequency because to do so would take an antenna so ridiculously large that it would break under it's own weight more than likely, I'm just using 500hz as an example. Now when you are sending "radio signals" you are really shooting the electromagnetic fields of the circuit discussed previously in this article into space, which in turn hits an antenna and converts those electromagnetic waves back into normal AC waves. To broadcast you can use either a quarter wave antenna or a half wave. Quarter wave is 1/4 the wavelength, half wave 1/2 obviously. Now, I mentioned before that all electronic circuits send out electromagnetic waves, so why doesn't the part before the antenna send out interference? Well, to stop this from happening, lines used in radio are usually covered with either coaxial cables or dual transmission lines, which I'm not going to discuss (although the principles are not that difficult, just simple transformers). These are usually on the lines directly connected to the antenna, which has to be at least 1/4 or 1/2 the the wavelength of the frequency you intend to broadcast on, depending on which method you use. In receiving, it's as simple as hooking up an antenna either half the wavelength or full wavelength to a circuit, to tune into that particular frequency. And of course frequency can be changed without changing your antenna, but is usually done with ferrite bars and magnetic flux, which is also outside the scope of this article. So that's the basic gist of radio, the conversion of electric signals to electromagnetic fields, sent through space at the speed of light which induce an alternating current on the receiving antenna, converting it back to normal electricity. I planned to go more in depth on some stuff, but this article is already too fucking long, so if you want to learn more, then just go to fucking radio shack or find a good book on electronics and radio, and have a lot of fun.