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23 Cards in this Set
- Front
- Back
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What are the available ISM channels in the US, Europe, and Japan?
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US: 11
Europe: 13 Japan: 14 |
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What bands are the ISM bands located in?
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902 MHz
2.4 GHz 5.8 GHz |
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What how many UNII bands exist and what and how wide are they?
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3 UNII bands
each is 100 MHz wide |
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How wide are ISM channels?
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22 MHz
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How are each of the UNII bands divided?
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Each 100 MHz wide band has four non-overlapping channels, each channel is 20 MHz wide with 5 MHz separation between each band.
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What is the maximum antenna gain for UNII band point to multi point?
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6 db
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what is the maximum effective power for a point to point upper band UNII link?
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200 watts
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What is the maximum allowed intentional radiated power for point to multi point links in the UNII bands?
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Lower: 40 milliwatts
Middle: 200 milliwatts Upper: 800 milliwatts |
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_____ is linked to the linear milliwatts scale, making it an absolute reference of power.
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dBm
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_____ is used to reference the increase in power in a certain direction by an antenna.
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dBi
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What does the i stand for in dBi?
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isotropic
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A __________ is a theoretical transmitter that propagates RF energy in all directions.
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isotropic radiator
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_____ references the orientation of the electric field of the electromagnetic wave in relation to the earth.
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Polarization
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What orientations can polarization be?
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vertical
horizontal angled circular (left or right handed) |
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What generally determines the polarization of the radiated wave?
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the physical orientation of the antenna
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What can mismatched polarizations cause?
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up to a 3 dB signal strength reduction at the receiver
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_____ antennas propagate RF waves perpendicular to the antenna itself.
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Omni-directional
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What are some common form factors of semi-directional antenna?
And what gain do they offer? |
patch
panel yagi between 8-20 dBi |
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What are some common form factors of highly directional antenna?
And what gain do they offer |
parabolic dish
grid up to 30 dBi |
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In _____ systems the carrier changes frequency or hops according to a predefined pseudo-random sequence.
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Frequency Hopping Spread Spectrum (FHSS)
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How often do Bluetooth devices hop?
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1600 times per second
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In _____ systems the carrier frequency doesn't change; instead, redundant information is added to the signal prior to transmission (causing the signal to take up more bandwidth) and removed from the signal upon reception.
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Direct Sequence Spread Spectrum (DSSS)
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_____ achieves high data rates by squeezing a large number of communication channels into a given frequency band. This is achieved by placing adjacent channels very precisely in frequency space in such a way that the channels' harmonics exactly cancel each other out effectively leaving only the fundamental signals.
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Orthogonal Frequency Division Multiplexing (OFDM)
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