How to build a "Fox Hole" radio

Steps to Building a Fox Hole Radio

Materials:

• wood block
• wire
• pipe
• razor blade
• safety pin
• paper clip
• screws
• headphone jack
• pencil

1. Wrap a magnet wire around a piece of pipe 120 times 
2. Attach the pipe to a wood block with a couple screws
3. Put a couple screws on the outsides of the pipe
4. Attach a copper wire to one of them and hook it to another metal object like a radiator
5. Hook another wire around the other screw and make sure it's long and use this as an antenna and put it out a window.
6. Connect another wire to the wire connected to the ground wire and hook it up to one side of the headphone jack
7. Connect another wire to the other side of the headphone jack and connect it to a paper clip used as a tuner
8. Connect 2 wires to the wire used as an antenna and hook one to a razor blade set on the wood block and the other to a safety pin with a pencil attached to it

How Radios Work

Radios have been used for a very long time as a means of communication. The process of how this communication gets to its destination can be confusing sometimes but also easy.
First, a radio station picks something that needs to be transmitted and they convert the sound waves into electromagnetic waves. The reason behind this is because sound waves cannot travel through a vacuum, whereas electromagnetic waves can so they convert them into these electromagnetic waves so they can travel great distances through any kind of matter or atmosphere is little disruption. Once the wave is sent it is then picked up by a radio and the radio decodes these electromagnetic waves and then uses a speaker to convert them back into sound waves and output the sound for our ears to hear. The sounds that we hear depend on the changes that were made to a waves frequency and amplitude. Which also brings about the AM and FM radio modulations.

Sources:
"NRAO: National Radio Astronomy Observatory." How Radio Communication Works. National Science Foundation, n.d. Web. 18 Feb. 2013.

Radios and the history of them

Radios have been around for a very long time. They are a way of transmitting a message through the sound waves and them being picked up and converted so they can be heard through speakers to the receiver.
Radios were developed as the wireless telegraphy. Guglielmo Marconi used the radio in commercial, military and marine communication. He also transmitted the first successful message through radio waves in 1902.
The invention of the radio intrigued many people and researchers, but it also sparked arguments as to who actually invented the radio. In most cases they just give the birth of the radio credit to two other inventions, which are the telegraoh and the telephone.
Radios work through the transmission of "radio waves" which are part of the electromagnetic spectrum. These waves can pass pictures, music, speech, and other data through the air invisibly.
In the 1860s, Heinrich Rudoph Hertz, who was a Germand physicist showed how rapid vibrations could be put into the air in the form of waves like heat and light.
The first person to call it the "radio" was Lee Deforest and as the result of some of his work the AM radio was born. The FM was then created from the AM later.



Sources:
"History of Radio." Wikipedia. Wikimedia Foundation, 17 Feb. 2013. Web. 18 Feb. 2013.
http://en.wikipedia.org/wiki/History_of_radio
Bellis, Mary. "The Invention Of Radio." About.com Inventors. N.p., 2013. Web. 18 Feb. 2013.
http://inventors.about.com/od/rstartinventions/a/radio.htm

How sinusoids apply to radios

Radios work through the transmission of sounds waves as everyone pretty well knows. A sinusoid would look very much like a sound wave as they both have a certain frequency and amplitude making them sound the way they do and they both have a certain period that it takes to complete one cycle or sound transmission. The key points that would be used to graph a sound wave would look similar to the ones used to graph a sinusoid. To visually see a sound wave is the form of a sinusoid. Here are a few pictures of sound waves showing how they are visually showed as sinusoids. The second picture is of a real trig function for the note A and how it would be graphed.




Sources:
graphsofsineandcosine.weebly.com

 Rogness, Jonathan. "Soundwaves." Soundwaves. N.p., n.d. Web. 18 Feb. 2013. http://www.math.umn.edu/~rogness/math1155/soundwaves/

The difference in AM and FM

The first difference is what the definition of each uses. AM is amplitude modulation, while FM is frequency modulation.
The AM modifies the amplitude of a wave of the carrier to be received, but the FM modifies the frequency of the wave of the carrier to be received.

AM is simplest of the two. An AM radio picks up the changes in the carrier frequency's amplitude and heightens is to put it through a speaker. The downfall with the AM radios was that it was easily affected by the weather conditions. Also, the AM radio was only able to output one audio channel, but the signal can travel much farther than that of an FM radio.

The FM Radio can output more than one audio channel at a time and it actually stores the actual voice signal so it can not be easily affected or distorted like the AM. FM can also relate easier to stereo so it makes it ideal for music whereas the AM is more of a mono sound making it more ideal for talk radio.

In summary:
FM:                                                                                AM:

• modifies frequency                                                 - modifies amplitude
• shorter distance traveled                                         - travels long distance
• output more than one audio channel                        - easily affected or distorted
• stores actual voice signal to prevent distortion         - only puts out one audio channel
• ideal for music                                                        - ideal for talk radio

Sources:
"The Difference Between AM and FM." The Difference Between AM and FM. N.p., 2013. Web. 18 Feb. 2013. <http://www.differencebetween.net/technology/the-difference-between-am-and-fm/>.

How to graph sinusoids

First you must determine all the necessary information to begin graphing a sinusoid.
The elements you will need to graph these are:
Amplitude - the distance from the center points to the minimum or maximum values.
Period - The amount of time it takes to complete one cycle.
Key Point Interval - The intervals you will go by on the axis of your graph.
Frequncy - The amount of cycles that pass in one second
Parent Functions
y=sinx                                                          y=cosx
Period: 2π                                                                       Period: 2π
Key Pt. Int.: 2π/4 = π/2                                               Key Pt. Int.: 2π/4 = π/2

                                              Frequency=b/2π

                                            



Sources:

www.intmath.com

graphsofsineandcosine.weebly.com

www.daviddarling.info