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BASIC TELECOMMUNICATIONS

BASIC TELECOMMUNICATIONS . WiFi Network standards. BASIC TELECOMMUNICATIONS . We are now going to take a look at the different WiFi standards that have been released since 1999 to present day

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BASIC TELECOMMUNICATIONS

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  1. BASIC TELECOMMUNICATIONS WiFi Network standards

  2. BASIC TELECOMMUNICATIONS • We are now going to take a look at the different WiFi standards that have been released since 1999 to present day • There are four 802.11 networks currently in operation today operating in two different frequency ranges • These standards are constantly under development and are evolving to increase interoperability with other wireless devices

  3. BASIC TELECOMMUNICATIONS The four wireless standards are: • 802.11a • 802.11b • 802.11g • 802.11n Let’s take a closer look at these standards………

  4. BASIC TELECOMMUNICATIONS 802.11a: • The first WiFi standard to be released • Used mostly in corporate applications • Operates in the 5GHz range • Offers 54 Mbps of bandwidth speed • Has a range of 100’ • Not implemented anymore

  5. BASIC TELECOMMUNICATIONS 802.11b: • The second WiFi standard to be released • Utilized by corporations and the public • Operates in the 2.4GHz frequency range • Offers 11Mbps of bandwidth speed • Has a range of 150’ • No longer implemented anymore

  6. BASIC TELECOMMUNICATIONS 802.11g: • The third WiFi standard to be released • Gained a lot of popularity and found in many hot spots • Operates in the 2.4GHz frequency range • Offers 54Mbps of bandwidth speed • Has a range of 150’ • Still widely used and available

  7. BASIC TELECOMMUNICATIONS 802.11n: • The latest standard to be released • Widely available and implemented everywhere • Operates in the 2.4GHz and 5GHz frequency range • Offers 70 to 300Mbps (still under development and bandwidth varies depending on manufacturer) • Has a range of 200’ to 400’ (depending on manufacturer) • Current

  8. BASIC TELECOMMUNICATIONS Ranges and bandwidth will vary depending on the environment and placement of the wireless router or access point Some factors that affect range and bandwidth are: • Mirrors • Walls, sheetrock 1dBi loss, plywood 2dBi, concrete 3dBi • Mechanicals in the walls, HVAC ducts, conduits etc. • Ceramic walls • Large appliances • Trees will affect outdoor performance

  9. BASIC TELECOMMUNICATIONS • The most popular wireless network is 802.11g though the 802.11n is gaining ground • Wireless routers operating in the 5GHz range are more susceptible to interference than the 2.4GHz routers • Every new release of a 802.11 wireless standard is backward compatible with previous version, however if you have an “n” card in your laptop and you connect to a “b” network your surfing at the “b” rates

  10. BASIC TELECOMMUNICATIONS • In the U.S. there are 11 channels that WAPs broadcast on, in Japan and Europe they are a total of 14 channels • Each channel is 22MHz wide with a top, center and bottom frequency • Remember that these channels operate in the 2.4GHz frequency range

  11. BASIC TELECOMMUNICATIONS In the U.S. the 802.11 standard calls for the 2.4GHz frequency to be split into 11 overlapping channels, channel 1, 6 and 11 are considered non-overlapping

  12. BASIC TELECOMMUNICATIONS • Another way to increase performance of your wireless router is to set it on a non-overlapping channel • inSSIDer is a utility you can download for free and it will show all wireless routers in your vicinity, the channel it’s on and the SSID of the router • It will also show the channel frequency allocation in real time

  13. BASIC TELECOMMUNICATIONS Here’s a screen shot of inSSIDer

  14. BASIC TELECOMMUNICATIONS • The wireless coverage area and signal can be increased by installing amplifiers and high gain antennas • Most APs and wireless routers come out of the box with your standard monopole or “rubber duck antenna” with about a 3dBi gain

  15. BASIC TELECOMMUNICATIONS • There are many different styles of antennas for both indoor and outdoor applications • In some cases the antenna can be extended away from the AP with a coax cable and placed 3’ to 30’ away • There are two categories for AP antennas: • Omni-directional • Directional

  16. BASIC TELECOMMUNICATIONS The basic omnidirectional antenna is either a monopole or a dipole antenna Let’s look a the dipole first

  17. BASIC TELECOMMUNICATIONS • A dipole antennais a radio antenna that can be made of a simple wire, with a center-fed driven element • It consists of two metal conductors of rod or wire, oriented parallel and collinear with each other (in line with each other), with a small space between them

  18. BASIC TELECOMMUNICATIONS • The radio frequency voltage is applied to the antenna at the center, between the two conductors • The antenna pattern of a dipole

  19. BASIC TELECOMMUNICATIONS • A monopole antennais a class of radio antenna consisting of a straight rod-shaped conductor, often mounted perpendicularly over some type of conductive surface, called a ground plane • The driving signal from the transmitter is applied, or for receiving antennas the output voltage is taken, between the lower end of the monopole and the ground plane

  20. BASIC TELECOMMUNICATIONS The monopole antenna is very similar to a dipole antenna however, instead of two wires there is only one wire and a metal base (plane) that serves as the second conductor

  21. BASIC TELECOMMUNICATIONS • Omni directional antennas provide 360 degree coverage and the antenna pattern resembles a donut as opposed to a sphere • Longer rubber duck antennas typically provide higher gain hence broader coverage Omni-directional ant. patterns

  22. BASIC TELECOMMUNICATIONS • Dipole antennas are typically used on TVs such as rabbit ears • Monopole antennas are used in APs and walkie-talkies • Both antennas have similar propagation patterns • Now we’ll look at directional antennas

  23. BASIC TELECOMMUNICATIONS • A directional antennais an antenna which radiates greater power in one or more directions allowing for increased performance on transmit and receive and reduced interference from unwanted sources • Directional antennas like Yagiantennas provide increased performance over dipole antennas when a greater concentration of radiation in a certain direction is desired

  24. BASIC TELECOMMUNICATIONS Yagi antennas are similar to the old TV antennas that you can still find on the roofs of homes all across the country OLD TV ANTENNA YAGI ANTENNAS

  25. BASIC TELECOMMUNICATIONS • A Yagi-Uda (the two Japanese inventors) antenna is essentially a dipole antenna set in a horizontal plane with additional elements added • Depending on the length and spacing of the elements they will increase overall gain and directional beam • There are other directional antennas that have completely different exterior designs that are more stream line but are internally built on the same principles

  26. BASIC TELECOMMUNICATIONS The directional antenna concentrates and propagates the signal in one direction and provides various degrees of angle coverage

  27. BASIC TELECOMMUNICATIONS Below is an example of different propagation patterns from a side view

  28. BASIC TELECOMMUNICATIONS • The RF industry utilizes dozens of different RG type coax connectors that connect antennas and cables for all types of applications • The cable industry (CATV) uses “F” connectors • The surveillance industry (CCTV) uses “BNC” • The WiFi industry uses many different connectors………

  29. BASIC TELECOMMUNICATIONS Below is a chart of RF connectors and the frequency range that they’re designed for

  30. BASIC TELECOMMUNICATIONS What two types of RG connectors do you think are the most commonly utilized for WAPs and wireless routers?

  31. BASIC TELECOMMUNICATIONS Most rubber duck antennas have either a SMA or TNC style connection These monopole antennas simply screw off and a higher gain antenna can be attached in place of the old one For even more gain an amplifier can be added to boost the signal 802.11N - Outdoor Amp -

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