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Wireless Business Network (Radio Frequency (A frequency is the number of…
Wireless Business Network
Radio Frequency
A way of sending digital information (1's & 0's) through the air
Amplitude = Strength of the wireless signal
There are licensed radio frequencies and they can be reserved for certain organisations to use or available for anyone to use
A frequency is the number of occurrences of a repeating event per period of time
Radio frequency is measured in Hertz
On Hertz (Hz) = one cycle
Radio frequency time is traditionally one second
mHz is million cycles per second
gHZ is billion cycles per second
kHZ is thousand cycles per second
Therefore the higher the frequency, the more data can be sent.
Wavelength = How far apart the radio waves are
A higher frequency means a shorter wavelength
RSSI = Simplifed way of describing the power level or amplitude of a radio signal
Radios & Antennas
Radios are the transmitters and receivers of wireless signal
Antennas are the radiators and catchers of wireless signal
A Radio Chain is the combination of a radio and an antenna
Modern wifi often uses multiple radio chains (MIMO)
Battle of the Bands
The 2.4 & 5 Ghz bands are are a range of frequencies
5 Ghz
Shorter
Doesn't travel as far, which isn't always a disadvantage
Higher frequency
Carries more data per wave cycle
2.4 Ghz
Farther
Can travel farther as it is not as affected by obstructions such as walls
Lower frequency
Carries less data per wave cycle
Wireless channels simply describe a range of frequencies. Each is around 20-22 MHz wide
The only non-overlapping channels in the 2.4 Ghz band are 1, 6, & 11
In the 5 Ghz band each channel has its own frequency space and it is even possible to enable channel bonding to achieve high speeds
Many people use the UNII-1 & UNII-3 channels to avoid the possibility of using the already allocated UNII-2 weather system channels.
Wireless Speed Reality
There are many factors that affect Wifi performance
Due to overhead of DIFS consider speed to be cut immediately in half
Add in multiple clients
Distance and interference
MIMO
Wifi driver differences
Wifi data rates are deceptive