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if you're using an 802.11 network there
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are a number of technical specifications
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that you need to be aware of one is the
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frequency in use you may have already
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seen in the 802.11 standards video that
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there are many standards that use the
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2.4 gigahertz range and other standards
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that use the 5 gigahertz range and some
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of them use both of those ranges to be
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able to communicate you also have to
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keep in mind that there are separate
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channels within those frequency ranges
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that can be used these are groups of
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frequencies and the ieee has assigned
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numbers to these frequencies so that we
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can much easier refer to which channel
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we happen to be using that's why we
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often say if you're using multiple
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access points in a particular area you
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may want to make sure each of the access
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points is running on a different
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wireless channel
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and depending on where you are in the
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world there's probably a governmental
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agency that's responsible for managing
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the wireless spectrum or the frequencies
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that you would use for these 802.11
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networks these regulations often dictate
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exactly which frequency should be used
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they'll specify the maximum amount of
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power that can be used on those networks
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and they'll set requirements and limits
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over how much interference can be caused
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by these 802.11 networks
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we often see the 2.4 gigahertz and 5
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gigahertz networks compared with 802.11
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but i thought it'd be nice to see a
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visual representation of why the 5
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gigahertz networks are so popular let's
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start with 2.4 gigahertz networks these
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are the networks commonly seen as ieees
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channels 1 6 and 11 and these are three
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separate 20 megahertz bandwidths that
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range from 2412 megahertz through 24.82
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megahertz and that's where we get the
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2.4 gigahertz band information these are
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the only channels available in 2.4
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gigahertz as you can see there are three
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to choose from and if you're in an
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apartment complex with mini 802.11
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wireless networks you'll easily find a
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lot of activity on all three of those
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channels because of these limitations
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for 2.4 gigahertz we had to find some
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other available frequencies to use so we
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started using the 5 gigahertz spectrum
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everything that is on this 5 gigahertz
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list that is not red can be used to
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communicate so you can see there are
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many more 20 megahertz channels
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available
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on a 5 gigahertz spectrum than there
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ever was on 2.4 gigahertz this allows
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you to easily find some available
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spectrum in your area especially if
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there are a lot of access points being
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used simultaneously you may be using
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larger bandwidths than 20 megahertz to
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communicate because you can get much
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better throughput that way so it may not
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be 20 megahertz channels that you're
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choosing it may be a 40 megahertz
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bandwidth and 80 megahertz bandwidth or
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the current largest
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160 megahertz bandwidth you can see when
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you get to 160 megahertz that there are
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really two separate non-contiguous areas
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available to be able to communicate at
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such a large bandwidth
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not only do we often use these 802.11
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wireless networks we also extensively
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use bluetooth networks this effectively
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removes the wires from our peripherals
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that we connect to our mobile devices so
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if you're using a headset if you have a
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set of external speakers or you have an
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external keyboard that you use on your
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computer it's probably using bluetooth
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to communicate bluetooth also uses the
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2.4 gigahertz band the part of 2.4
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gigahertz it uses is the unlicensed ism
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part of the band that stands for
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industrial scientific and medical this
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is an area of the 2.4 gigahertz band
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that doesn't require you to get any
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special licensing from the government
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anyone can use these particular
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frequencies and that's why bluetooth and
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802.11 commonly use the 2.4 gigahertz
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band bluetooth devices generally only
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communicate in a small area around you
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we often refer to this as a personal
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area network because of that so most of
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the headsets and other devices you'll
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use will probably operate to about 10
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meters in distance
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if you're an environment that uses
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industrial bluetooth there are
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additional standards available that can
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increase that distance to over 100
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meters but if you're using consumer
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devices you're probably not using a 100
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meter distance between you and your
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headset instead we can use the bluetooth
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standards that limit that to about 10
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meters
