Just In Case You Ever Wondered What Frequency Your Communication Devices Operate At

The following are the band frequencies that our various communication devices operate at. I hope you find them interesting or maybe even useful.

Aeronautical/Maritime	9 KHz - 535 KHz
AM radio	535 KHz - 1,700 KHz
Shortwave radio	5.9 MHz - 26.9 MHz
Citizen's Band (CB)	26.96 MHz - 27.41 MHz
TV stations 2-6	54 MHz - 88 MHz
FM radio	88 MHz - 108 MHz
TV stations 7-13	174 MHz - 220 MHz
Cell phones CDMA	824 MHz - 849 MHz
Cell phones GSM	869 MHz - 894 MHz
Air Traffic Control	960 MHz - 1,215 MHz
GPS	1,227 MHz - 1,575 MHz
Cell phones PCS	1,850 MHz - 1,990 MHz

Definitions:

CDMA = Code Division Multiple Access describes a communication channel access principle that employs spread-spectrum technology and a special coding scheme (where each transmitter is assigned a code). In communications technology, there are only three domains that can allow multiplexing to be implemented for more efficient use of the available channel bandwidth and these domains are known as time, frequency and space. CDMA divides the access in signal space. By contrast, time division multiple access (TDMA) divides access by time, while frequency-division multiple access (FDMA) divides it by frequency. CDMA is a form of "spread-spectrum" signaling, since the modulated coded signal has a much higher bandwidth than the data being communicated.

An analogy to the problem of multiple access is a room (channel) in which people wish to communicate with each other. To avoid confusion, people could take turns speaking (time division), speak at different pitches (frequency division), or speak in different directions (spatial division). In CDMA, they would speak different languages. People speaking the same language can understand each other, but not other people. Similarly, in radio CDMA, each group of users is given a shared code. Many codes occupy the same channel, but only users associated with a particular code can understand each other.

Interestingly, CDMA is based on a patent granted in 1942 to two people-one of which was world famous actress Hedy Lamarr. Lamarr, probably best known for doing one of the first nude scenes in a major motion picture, worked with a partner-composer George Antheil-on a system that would make radio controlled torpedoes more difficult to detect through an early version of frequency hopping. Their system was inspired by the mechanical rolls that make self playing pianos work.

CDMA is also the current name for the cellular technology originally known as IS-95. Developed by Qualcomm and enhanced by Ericsson, CDMA is characterized by high capacity and small cell radius.

CDMA also refers to digital cellular telephony systems that use this multiple access scheme, as pioneered by QUALCOMM, and W-CDMA by the International Telecommunication Union (ITU), which is used in GSM’s UMTS.

CDMA has been used in many communications and navigation systems, including the Global Positioning System and the OmniTRACS satellite system for transportation logistics.

Source: http://en.wikipedia.org/wiki/CDMA

PCS = personal communications service) is a wireless phone service similar to cellular telephone service but emphasizing personal service and extended mobility.

The "personal" in PCS distinguishes this service from cellular by emphasizing that, unlike cellular, which was designed for car phone use and coverage of highways and roads, PCS is designed for greater user mobility. It generally requires more cell transmitters for coverage, but has the advantage of fewer blind spots. Technically, cellular systems in the United States operate in the 824-849 megahertz (MHz) frequency bands; PCS operates in the1850-1990 MHz bands.

Several technologies are used for PCS in the United States, including Time Division Multiple Access (TDMA), Code Division Multiple Access (CDMA), and Global System for Mobile (GSM) communication. GSM is more commonly used in Europe and elsewhere.

GPS = The Global Positioning System (GPS) is the only fully functional Global Navigation Satellite System (GNSS). Utilizing a constellation of at least 24 Medium Earth Orbit satellites that transmit precise microwave signals, the system enables a GPS receiver to determine its location, speed, direction, and time. Other similar systems are the Russian GLONASS (incomplete as of 2007) and the upcoming European Galileo positioning system.

Developed by the United States Department of Defense, GPS is officially named NAVSTAR GPS (Contrary to popular belief, NAVSTAR is not an acronym, but simply a name given by Mr. John Walsh, a key decision maker when it came to the budget for the GPS program).^[1] The satellite constellation is managed by the United States Air Force 50th Space Wing. The cost of maintaining the system is approximately US$750 million per year,^[2] including the replacement of aging satellites, and research and development.

Following the shootdown of Korean Air Lines Flight 007 in 1983, President Ronald Reagan issued a directive making the system available for free for civilian use as a common good.^[3] Since then, GPS has become a widely used aid to navigation worldwide, and a useful tool for map-making, land surveying, commerce, and scientific uses. GPS also provides a precise time reference used in many applications including scientific study of earthquakes, and synchronization of telecommunications networks.

Source: http://en.wikipedia.org/wiki/GPS