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              Outbreak Magazine Issue #12 - Article 5 of 18
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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.

