CWTS-6-Radio Frequency Fundamentals for Wireless LAN Technology

Two characteristics of RF signals are: A. Amplitude B. Reflection C. Phase D. Refraction E. Diffraction

A, C. Amplitude and phase are two characteristics of RF signals. Reflection, refraction, and diffraction are behaviors of RF.

Which are absolute measures of RF power? (Choose two.) A. Watt B. dB C. mW D. dBi E. dBd

A, C. Watt and mW are absolute measures of RF power. dB, dBi, and dBd are relative measures.

The capacity of an access point is dependent on which factors? (Choose two.) A. Number of users B. Channel reuse C. Co-location D. Software applications E. Frequency

A, D. The capacity of an access point is dependent upon the number of users and software applications in use. Too many users or too many bandwidth-intensive applications will affect the performance of an access point.

What two devices use RF to communicate? (Choose two.) A. Transmitter B. Transistor C. Reactor D. Reflector E. Receiver

A, E. RF communications require a transmitter and receiver. A transistor is an electronic component; a reactor does not exist in RF.

Which two channels are considered nonoverlapping in the 2.4 GHz band? A. 1 and 6 B. 2 and 6 C. 6 and 10 D. 11 and 13

A. Channels 1 and 6 are nonoverlapping. There must be a separation of fi ve channels (with the exception of channel 14) to be considered nonoverlapping in the 2.4 GHz band.

When an RF signal passes between media of different densities and may change speeds and bend, the behavior is known as: A. Refraction B. Reflection C. Scattering D. Diffraction

A. Refraction occurs when a signal changes speed and bends when passing between mediums of different densities. Refl ection bounces off a smooth surface, diffraction will pass around, and scattering bounces off an uneven surface.

As seen in a two-dimensional (X/Y) view, the amplitude of an RF signal is: A. Height B. Length C. Shift D. Width

A. The amplitude is the height of an RF signal. The length of one cycle is the wavelength, the shift is phase, and width is not a valid factor.

Which are relative measures of RF power? (Choose two.) A. mW B. dB C. dBm D. dBi E. Watt

B, D. dB and dBi are relative measures of RF power. mW, dBm, and watt are absolute measures of RF power.

An 802.11b channel is how wide in MHz? A. 5 MHz B. 22 MHz C. 25 MHz D. 30 MHz

B. A 2.4 GHz 802.11b signal is 22 MHz wide. 25 MHz is the distance required to be considered nonoverlapping.

When an RF signal bounces off a smooth nonabsorptive surface, the behavior is: A. Refraction B. Reflection C. Scattering D. Diffraction

B. An RF signal that bounces off a smooth surface is reflection. Refraction passes through, diffraction bends around, and scattering bounces off a non-smooth surface.

What is the term defining the number of times a cycle of an RF signal will oscillate in one second? A. Phase B. Frequency C. Amplitude D. Wavelength

B. Frequency is the number of times in one second a signal will oscillate. Phase is a shift, amplitude is height, and wavelength is a distance of one cycle.

Which item has an effect on RF line of sight? A. Phase B. Obstacles C. Interference D. Amplitude

B. Obstacles affect the RF line of sight. Phase and amplitude are characteristics of radio frequency, and interference affects the throughput.

The range of a 2.4 GHz signal is mostly dependent on which RF characteristic? A. Frequency B. Wavelength C. Amplitude D. Phase

B. The wavelength is the measurement of one complete cycle of an RF signal. The higher the frequency, the shorter the wavelength; therefore the shorter the range. Frequency is the number of times an RF signal cycles in one second, amplitude is the height from a 2D perspective, and phase is a shift.

How many nonoverlapping channels are available in the unlicensed 2.4 GHz ISM band? A. 1 B. 3 C. 6 D. 11

B. There are three nonoverlapping channels in the 2.4 GHz ISM band. Fourteen channels are available in this band. The locale will determine which channels can be used.

How many channels are available for wireless LANs to use in the unlicensed UNII-1 band? A. 2 B. 4 C. 6 D. 11

B. UNII-1 band has four channels available for wireless LAN use. Eleven channels are available in UNII-2e.

In the 2.4 GHz range, what distance between the center frequencies (in megahertz) is required for two channels to be considered nonoverlapping for HR/DSSS? A. 5 MHz B. 22 MHz C. 25 MHz D. 30 MHz

C. 25 MHz is required for channels to be considered nonoverlapping. 22 MHz is the width of a DSSS channel in the 2.4 GHz band.

What is the gain of an antenna measured in? A. dB B. dBc C. dBi D. dBm

C. The gain of an antenna is measured in dBi. This is a relative measure of power.

How many channels are available for wireless LAN use in the unlicensed middle UNII-2e band? A. 4 B. 6 C. 11 D. 14

C. There are 11 channels available for wireless LAN use in the unlicensed UNII-2e band. The other three 5 GHz bands have only 4 channels each.

When RF passes or bends around an obstacle such as a building or column, the behavior is: A. Reflection B. Refraction C. Scattering D. Diffraction

D. Diffraction passes or bends around an obstacle. Refl ection bounces off a smooth surface, refraction passes through, and scattering bounces off an uneven surface.

How many channels are available for wireless LAN use in the unlicensed 2.4 GHz ISM band? A. 8 B. 10 C. 11 D. 14

D. There are 14 channels available in the unlicensed 2.4 GHz ISM band. The channels used are determined by the locale.