CNM324 Exam One Questions And 100%
Correct Answers
What's wrong with most RF (radio frequency) setups? - ANSWER The most common
reason: RF propagation takes place in non ideal environments
Wavelength - ANSWER the distance between identical points in the adjacent cycles of a
waveform. In wireless systems, this length is usually specified in meters, centimeters, or
millimeters
Frequency - ANSWER the number of complete cycles per second in alternating current
direction. The standard unit of frequency is the hertz, abbreviated Hz.
Wavelength Formula - ANSWER speed of light (c)/frequency
What is Tx? - ANSWER Transmit power, amount of energy across a defined bandwidth.
Either measured in dBm or W
decibel (dB) - ANSWER a logarithmic unit of sound intensity
3 dB rule - ANSWER adding 3dB doubles the power, subtracting 3dB halves the power
Effective Isotropic Radiated Power EIRP - ANSWER measured in dBm = power at
antenna input [dBm] +
relative antenna gain [dBi]
Effective Radiated Power ERP - ANSWER measured in dBm = power at antenna input
[dBm] +
relative antenna gain [dBd]
, Three types of propagation frequency bands - ANSWER Very Low Frequency, High
Frequency, and Medium Frequency
Waves behave more like ____ at high frequencies and ____ at low frequencies - ANSWER
light, radio
Diffraction - ANSWER Radio path between transmitter and receiver is obstructed by a
surface with sharp irregular edges. Waves bend around the obstacle, even when LOS
does not exist
Scattering - ANSWER Objects smaller than the wavelength of the propagating
wave cause scattering of the wave to occur. E.g., foliage, street signs, lamp posts
Reflection - ANSWER Propagating wave impinges on an object which is larger than the
wavelength
Optical LOS - ANSWER is related to the ability to see one
site from the other
Radio LOS - ANSWER related to the ability of the receiver
to 'see' the transmitted signal
Fresnel Zone - ANSWER Quantifies Radio LOS, a football shaped tunnel
between the two sites which provides a path for the RF signals.
Tropospheric - ANSWER Is the lowest of the atmosphere - 10km. Reflection and
refraction happens because of moister in layers. Sometimes causes Ducting RF
propagation that occurs in anticyclonic weather
Correct Answers
What's wrong with most RF (radio frequency) setups? - ANSWER The most common
reason: RF propagation takes place in non ideal environments
Wavelength - ANSWER the distance between identical points in the adjacent cycles of a
waveform. In wireless systems, this length is usually specified in meters, centimeters, or
millimeters
Frequency - ANSWER the number of complete cycles per second in alternating current
direction. The standard unit of frequency is the hertz, abbreviated Hz.
Wavelength Formula - ANSWER speed of light (c)/frequency
What is Tx? - ANSWER Transmit power, amount of energy across a defined bandwidth.
Either measured in dBm or W
decibel (dB) - ANSWER a logarithmic unit of sound intensity
3 dB rule - ANSWER adding 3dB doubles the power, subtracting 3dB halves the power
Effective Isotropic Radiated Power EIRP - ANSWER measured in dBm = power at
antenna input [dBm] +
relative antenna gain [dBi]
Effective Radiated Power ERP - ANSWER measured in dBm = power at antenna input
[dBm] +
relative antenna gain [dBd]
, Three types of propagation frequency bands - ANSWER Very Low Frequency, High
Frequency, and Medium Frequency
Waves behave more like ____ at high frequencies and ____ at low frequencies - ANSWER
light, radio
Diffraction - ANSWER Radio path between transmitter and receiver is obstructed by a
surface with sharp irregular edges. Waves bend around the obstacle, even when LOS
does not exist
Scattering - ANSWER Objects smaller than the wavelength of the propagating
wave cause scattering of the wave to occur. E.g., foliage, street signs, lamp posts
Reflection - ANSWER Propagating wave impinges on an object which is larger than the
wavelength
Optical LOS - ANSWER is related to the ability to see one
site from the other
Radio LOS - ANSWER related to the ability of the receiver
to 'see' the transmitted signal
Fresnel Zone - ANSWER Quantifies Radio LOS, a football shaped tunnel
between the two sites which provides a path for the RF signals.
Tropospheric - ANSWER Is the lowest of the atmosphere - 10km. Reflection and
refraction happens because of moister in layers. Sometimes causes Ducting RF
propagation that occurs in anticyclonic weather
