WiFi Lab

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WiFi Lab
Physics & Lab Event
Forum Threads 2018 (Trial)
There are no tests available for this event
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This event was not held recently in Division B
Division C Champion Merrimack High School


WiFi Lab (also known as Radio Lab) is a Division C that was a trial event at the 2017 Ohio state tournament, the 2017 Boyceville Invitational, the 2018 Texas state tournament, the 2017 and 2018 Virginia state tournaments and the 2018 National Tournament. Competitors are asked to build an antenna that transmits a signal at 2.4 GHz and complete a written test about electromagnetic waves. Teams may bring a three ring binder and two computational calculators, and are required to provide graphs and tables showing the relationship between power and distance for different configurations of the antenna.

Building an Antenna

Types of Antennas

Electromagnetic Spectrum

A diagram of the electromagnetic spectrum

The electromagnetic spectrum is the range of frequencies of electromagnetic radiation, including radio waves. The frequencies of these waves are measured in hertz (Hz). The frequency range is divided into separate bands, and the waves within these bands have different names. From the largest wavelength to the shortest wavelength these bands are radio waves, microwaves, infrared and visible light, ultraviolet, x-rays, and gamma rays.

X-rays and gamma rays are known as ionizing radiation and can be dangerous if an organism is exposed to them for too long. X-rays are defined as electronic transitions and gamma rays are generated from nuclear processes such as decay. Both gamma and X-rays have many uses in medicine and occasionally gamma rays are used in the sterilization of foods and seeds. Ultraviolet (UV) rays are not ionizing, but can still break chemical bonds causing sunburn and even potentially skin cancer. Some UV rays in the middle of the range also have a strong potential to cause mutation. Most damaging UV rays emitted by the sun are absorbed by the atmosphere, being blocked by the ozone layer or being absorbed by oxygen or nitrogen in the air.

Visible light occupies a very small portion of the electromagnetic spectrum. Different visible colors are the result of differing electromagnetic wavelengths, with red having the longest wavelength and purple the shortest. Electromagnetic radiation between 400–790 terahertz (THz) is visible to the human eye, but sometimes infrared and ultraviolet rays can be referred to as light. Infrared rays are useful in thermal imaging and occasionally in data transmission. Television remotes transmit signals using infrared light, which is why if the front of the remote is blocked the signal will not be received. Some infrared light can also be detected by photograph film.

Microwaves and radio waves have the lowest frequency of the electromagnetic spectrum, and are most well known for their use in microwave ovens. They can also be used in industrial heating and radar systems, as well as transmitting information. However, at that intensity microwaves do not have the same heating effects.

Radio Waves

Radio waves are the focus of the event, as WiFi is transmitted over radio waves. Radio waves are transmitted and received by antennas and are widely used to transmit information. They are also used for GPS systems and locating distant objects with radars. To generate radio waves, a transmitter generates an AC current which is applied to the antenna and generates an electric and magnetic field.

WiFi is most commonly transmitted over the 2.4 GHz and 5.8 GHz bands which are divided into multiple channels. These channels can be shared by multiple networks, making WiFi much more vulnerable to attack than wired connections. Security protocols have been created so that WiFi access is secure as possible, including the WEP and WPA protocols.

Bandwidth

Impedance

Wave Propagation

Gain Patterns

Antenna Noise

Resources