le light, ultra- violet, X rays, and gamma rays. By briefly studying each type of wave and its potential utilization, we can begin to understand the potential use of light transmission within a fiber. RADIO WAVES Radio waves have the longest wavelength and lowest frequencies of all waves within the frequency spectrum. Such waves can have wavelengths ranging from hundreds of meters at low frequencies to less than a centimeter at higher frequencies. In fact, if you stayed up late one night and watched a military-type movie where a submarine had to communicate with a base station while submerged, you probably heard the captain order the antenna to be deployed. Because a submerged sub- marine uses very-low-frequency (VLF) communications, the resulting radio waves are quite long, requiring the submarine to deploy a spool of wire that can extend a distance of a mile or more to function as an antenna. Team-Fly® Understanding Light As we move up the frequency spectrum we encounter AM, VHF TV, FM, and UHF (ultra-high-frequency) TV. AM radio uses the 550- to 1650- kHz band, while FM radio occurs in the 88- to 108-MHz band. Concern- ing television, in the United States VHF TV resides in the 54- to 216- MHz band; UHF TV, in the 220- to 500-MHz band. Although not shown in Figure 2.3, wireless communications that occur in the 800- and 1900- MHz bands results in relatively short wavelengths, which explains why the handset in your purse or connected to your belt has a relatively short antenna. MICROWAVES Microwaves are shorter than radio waves but longer than infrared. Two of the more popular uses for microwaves are for cooking and radar. Because water and fat molecules absorb energy in the form of waves generated at approximately 2.45 GHz, a microwave oven generates waves at that frequency. To do this, the oven uses a small metal box with sever- al ridges that are sealed in a vacuum to generate electromagnetic waves at a frequency of 2.45 GHz. That box, referred to as a magnetron, repre- sents the most costly component in a mic