Electromagnetic radiation has been around for centuries. The technological improvements have tremendously evolved in the technical revolution. The basis of wave propagation, frequency, and decibels are the basis for anything geolocation. There are some definitions that you will also need to know and understand.
- [Instructor] So just a review of some basic stuff. Electromagnetic radiation is the radiant energy released by certain electromagnetic processes. Visible light is electromagnetic radiation, as is invisible light, such as radio, infrared, and X-rays. It consists of electromagnetic waves and becomes complex fairly quickly. Started in the early 19th century, before electromagnetic radiation was understood, it was also called magic.
A guy named James Maxwell developed some theory equations in the 1860s. Alexander Bell and Charles Tainter used light beams to transmit a conversation in the 1880s. Another guy name Heinrich Hertz actually made some radio waves in the 1880s too. Then G. Marconi actually transmitted signals across the Atlantic in 1902. His technology was actually used 10 years later during the attempted rescue of the Titanic.
While the ship still sunk, those who were saved were credited as being saved through his invention. Then again, there are two sides to every story, and the other side says that his technology was outdated and technically conservative. Had a more modern radio been installed, it could have had a better outcome. Over 30 years ago in 1982, TRON was released. It was named after electronic. Wink wink.
Number conspiracy theorists would say this is not a coincidence. So TRON, coming out in 1982, if you look at Bell and Tainter's photophone, that came out in 1880. You take the eight from the 80, and you add it into the 1902 from G. Marconi's radio transmission, and you get 1982. So electromagnetic radiation are waves of electronics.
The waves look like these in motion, the ones on the screen. They're polarized and propagating. They also travel at the speed of light. Well, almost. In a vacuum they do. In the real world, there's some affects that kind of change that number. To put the speed into context, it is roughly 670 million miles per hour. The speed at which the waves oscillate is called frequency. There's some things that can change this, but primarily it will be the antenna length proportionately.
The longer the wavelength, the longer the antenna. Anything wireless uses this kind of stuff. What was magic back then, is still magic to some people. To others, it's just science, physics, and math. Decibels, sometimes referred as dB, are logarithmic units used to express the ratio of two values of a physical quantity, dB isotropic, or dBi. So first off, I'm sorry for the crazy words here.
Isotropic means that it is having a physical property that is the same value when measured in different directions. In other words, in a perfect world. So dBi is the forward gain of an antenna, compared with a hypothetical isotropic antenna, which uniformly distributes energy in all directions. Linear polarization of the electromagnetic field is assumed, unless noted otherwise. Bigger the gain, bigger the signal amplification.
Basically, the signal gets stronger. So lets get into the application of it, starting with war driving.
Note: This course was recorded and produced by Mentor Source, Inc. We're pleased to host this training in our library.
- Access points
- Reviewing the concept of geolocation
- Reviewing available products for geolocation
- Use cases