Wireless Site Survey Engineer Exam Practice Test

Many PoE VoIP telephones connected to the same Ethernet switch can cause problems because the switch might not have enough power to provide PoE to all the devices simultaneously. This can lead to unstable connections or devices not receiving power at all.

If a classification signature is not provided, the device is considered to be in class 0. This means that the device does not have any specific classification and is not categorized into any particular class.

The total power needed will be 694 watts. This is because the switch requires 500 watts for its basic switching functions. Additionally, there are 10 Class-1 VoIP phones and 10 Class-0 access points, which will require additional power. However, the exact power requirements for these devices are not specified in the question, so we cannot determine the exact amount of power needed. Therefore, the total power needed is 500 watts (for the switch) plus an unspecified amount for the phones and access points.

An endpoint PSE that provides power by using Alternative B is capable of providing power to devices using 10BaseT and 100BaseT Ethernet technologies. These technologies are both capable of carrying power over Ethernet (PoE) and can support the power requirements of devices connected to the PSE. 1000BaseT and 100BaseFX are not capable of carrying power over Ethernet, so they are not applicable in this scenario.

A measuring wheel can be used in an indoor site survey to measure distances accurately. A ladder can be used to access higher areas and inspect them properly. A battery pack can be used to power equipment and tools during the survey. GPS, microwave oven are not relevant tools for an indoor site survey.

During a 2.4GHz site survey, potential sources of interference that might be found include a nearby 802.11 FHSS access point, which operates on the same frequency and can cause interference; a plasma cutter, which can emit electromagnetic interference; a Bluetooth headset, which operates on the same frequency and can cause interference; and a 2.4 GHz video camera, which can also operate on the same frequency and cause interference.

Multiple antennas, client adapter, access point, and floor plan map can be used in an indoor 802.11 site survey. Multiple antennas are used to measure signal strength and coverage. A client adapter is used to connect to the wireless network and test the performance. An access point is used to create the wireless network and can be used to measure signal strength and coverage. A floor plan map is used to plan and visualize the coverage areas and signal propagation in the indoor environment.

An 802.3-2005 Clause 33 midspan PSE (Power Sourcing Equipment) can be used with both a 10BaseT repeater and a 100BaseT layer 2 switch. These devices are compatible with the power requirements and standards of the midspan PSE. However, a 1000BaseT layer 2 switch and a 1000BaseT layer 3 switch are not compatible with the midspan PSE as they operate at higher data rates and may have different power requirements.

A 24-port PoE Ethernet switch must be able to provide a maximum of 15.4 watts of power to each PoE device connected to all ports. Since there are 24 ports, the total power required would be 15.4 watts multiplied by 24, which equals 370 watts.

Based on the information provided, the switch requires 1000 watts to perform its basic switching functions. Additionally, there are 10 Class-2 cameras and 10 Class-3 access points connected to the switch. Each Class-2 camera requires up to 4.5 watts of power, while each Class-3 access point requires up to 15.4 watts of power. Therefore, the total power needed can be calculated by adding the power requirements of the switch, cameras, and access points: 1000 + (10 * 4.5) + (10 * 15.4) = 1000 + 45 + 154 = 1199 watts. Since none of the given options match this calculation, the correct answer is not available.

The site survey engineer should be looking for medical equipment interference, safety glass, and elevator shafts that might cause a loss of communication over the WLAN. Medical equipment interference can disrupt the wireless signals and cause communication issues. Safety glass can block or weaken the wireless signals, leading to a loss of communication. Elevator shafts can also interfere with the wireless signals and cause communication problems.

A powered device (PD) must be capable of accepting up to 57 volts from either the data lines or the unused pairs of the Ethernet cable. This means that the PD should be able to handle a maximum voltage of 57 volts to ensure proper functioning and compatibility with the power source.

Directional antennas would be the most important site survey tool in this scenario because they can provide focused and concentrated wireless coverage in specific areas. In a warehouse with long corridors and metal racks, directional antennas can help overcome obstacles and interference by directing the wireless signal towards the desired areas, ensuring better performance and coverage for the bar code scanners. This would help optimize the wireless network and improve the overall quality of the connection in the warehouse environment.

In a clean RF environment with minimal reflections and low multipath, using a 400-nanosecond guard interval can be an effective PHY layer mechanism to increase throughput. The guard interval is a period of time inserted between symbols in a communication system to mitigate the effects of multipath fading. By increasing the guard interval to 400 nanoseconds, the system can better handle any remaining multipath interference, leading to increased throughput.

Lightning and wind can both adversely affect an outdoor wireless bridge link. Lightning can cause electrical surges that can damage the equipment, while strong winds can cause the bridge to sway or move, potentially disrupting the signal. Both of these factors should be taken into consideration during an outdoor site survey to ensure the stability and reliability of the wireless bridge link.

The major types of coverage analysis site surveys are Assisted, Manual, and Predictive. Assisted site surveys involve the use of specialized tools or equipment to analyze and optimize wireless coverage. Manual site surveys require a technician to physically visit the site and conduct measurements and analysis. Predictive site surveys use software and mathematical models to simulate and predict wireless coverage based on various factors such as building materials and layout. These three types of surveys provide different approaches to analyzing and improving wireless coverage in different scenarios.

In an outdoor site survey used to provide outdoor coverage, several tools can be used. A spectrum analyzer is used to analyze the frequency spectrum and identify any interference or congestion in the area. A NEMA grade access point is designed to withstand outdoor conditions and provide wireless coverage in outdoor environments. Outdoor blueprints or topography maps are used to understand the layout and terrain of the outdoor area, helping in planning the coverage. Mesh routers can be used to extend the wireless coverage in a mesh network configuration. GPS can be used to accurately determine the location coordinates of the survey points.

The two potential sources of interference in the 5 GHz UNII band are cordless phones and radar. Cordless phones operate in the same frequency range as the 5 GHz UNII band, which can cause interference and degrade the performance of wireless networks. Radar systems, especially military or weather radars, can also operate in the 5 GHz frequency range and cause interference. It is important to be aware of these potential sources of interference when deploying or troubleshooting wireless networks in the 5 GHz UNII band.

During a passive manual site survey, two measurements that are taken are SNR (Signal-to-Noise Ratio) and dBm (decibel-milliwatts). SNR measures the ratio of the signal power to the background noise power, indicating the quality of the signal. dBm is a unit of power measurement that represents the power level in decibels relative to one milliwatt. These measurements help in assessing the signal strength and quality of the wireless network during a passive manual site survey.

To qualify as compliant with 802.3-2005, Clause 33, a powered device (PD) must be able to accept power in either of two ways: over the data pairs or over the unused pairs. It must also reply to the PSE with a detection signature and accept power with either polarity from the PSE.

The PSE (Power Sourcing Equipment) will provide 15.4 watts of power to the 802.3-2005 Clause 33 access point equipped with two radios. This is the maximum power that can be provided by the PSE.

The correct answer is 44 to 57, 48. This means that the PSE (Power Sourcing Equipment) is capable of providing power within a range of 44 to 57 volts. However, the nominal power, or the average or standard power output, is 48 volts. This suggests that the PSE typically operates at 48 volts, but can provide power within a wider range if necessary.

Bob should consider other tenants' WLANs during the planning and implementation stages of the site survey because they can cause interference and affect the performance of his WLAN. He should also ensure that the cell coverage of each access point extends to only one floor above and one floor below to create a three-dimensional channel reuse pattern. This helps to minimize interference between neighboring access points and optimize the overall performance of the WLAN in the 20-story building.

An indoor site survey kit is used to assess the wireless coverage and performance within a building or indoor space. A digital camera can be used to capture images of the physical layout and obstacles that may affect signal propagation. Colored electrical tape can be used to mark specific areas or identify potential signal interference sources. Temporary mounting gear is necessary to temporarily install access points or antennas in different locations for testing purposes. Therefore, these three tools are commonly included in an indoor site survey kit.

The PSE (Power Sourcing Equipment) applies a voltage of 10.1 volts while trying to identify the detection signature. This voltage is used to determine if a connected device is a valid powered device and to establish communication with it.

Class 2 devices are determined by measuring the resulting current when a voltage is applied. The current range that represents Class 2 devices is 17 - 20 mA.

The correct answer is three because in a 3x4 MIMO radio, there are three transmit antennas and four receive antennas. Each transmit antenna can send one spatial stream of unique data, so there are a total of three spatial streams of unique data being transmitted.

A modulation and coding scheme (MCS) uses several factors to define data rates for an HT radio. The modulation method refers to the technique used to encode information onto the carrier signal, such as BPSK, QPSK, or 16-QAM. Equal/unequal modulation refers to whether all spatial streams use the same modulation or if they can use different modulations. The number of spatial streams indicates the number of simultaneous data streams transmitted over different antennas. The guard interval (GI) is the duration of a cyclic prefix inserted between symbols to mitigate multipath interference. Channel size refers to the bandwidth allocated for transmission. All these factors are considered by an MCS to determine the data rates for an HT radio.

Active coverage analysis requires a radio card to be associated with an access point. This type of analysis involves actively sending and receiving signals to measure and analyze the coverage and performance of a wireless network. By associating the radio card with an access point, it can actively transmit and receive signals to determine the strength and quality of the network's coverage in different areas. This allows for real-time analysis and optimization of the wireless network's coverage.

The likely cause of the layer 2 retransmissions is multipath. Multipath refers to the phenomenon where the wireless signal takes multiple paths to reach the receiver due to reflections, diffraction, and scattering. In some areas of the facility, the signal may encounter obstacles such as walls or other objects that cause reflections and create multiple paths for the signal. This can lead to interference and signal degradation, resulting in layer 2 retransmissions.

If the VoIP telephone does not provide a classification signature, the PSE (Power Sourcing Equipment) will not recognize it as a powered device (PD). Therefore, the PSE will not provide any power to the telephone, resulting in 0 watts of power being supplied.

The guard interval is used as a buffer to compensate for intersymbol interference. Intersymbol interference occurs when the symbols of a digital signal overlap due to channel distortion or other factors. The guard interval allows for a small amount of time between symbols, which helps to reduce the interference and ensure accurate signal transmission.

The necessary calculations for an outdoor bridging survey under five miles include the link budget, free space path loss, Fresnel zone, and fade margin. The link budget calculation helps determine the overall gain and loss in a communication system. Free space path loss calculates the signal attenuation over a distance in free space. The Fresnel zone calculation ensures that there is minimal interference due to obstacles in the transmission path. The fade margin calculation provides a buffer for any potential signal fading or loss. The height of the antenna beamwidth is not directly related to the necessary calculations for an outdoor bridging survey under five miles.

The correct answer is PSE and PD. PSE stands for Power Sourcing Equipment, which refers to devices that provide power to other devices over Ethernet cables. PD stands for Powered Device, which refers to devices that receive power from PSEs over Ethernet cables. PPE and PT are not types of PoE devices defined by the standard.

The two best choices for coverage analysis in this scenario are to install the thin access points in a grid and conduct an assisted site survey for both networks, and to conduct manual coverage analysis for the 5GHz network first and then conduct manual coverage analysis for the 2.4 GHz network based on the AP placement of the 5GHz APs. These choices ensure that both networks are properly analyzed and optimized for coverage and performance. The first choice allows for a comprehensive analysis of both networks using an assisted site survey, while the second choice prioritizes the 5GHz network and uses the placement of the 5GHz APs as a guide for the coverage analysis of the 2.4 GHz network.

PCO mode stands for Partial Channel Offload mode. In this mode, the device uses time slices to alternate between transmitting on a 20 MHz channel and a 40 MHz channel. This allows for more efficient use of the available spectrum and can help improve overall network performance.

When a powered device is first connected to a PSE (Power Sourcing Equipment), it presents itself as having a resistance level of 25k-ohms.

The maximum power used by a PD Class 0 device is 12.95 W. This means that the device can consume up to 12.95 watts of power.

PCO mode is not recommended when VoWiFi phones are deployed because it stands for Power Save Mode with Coexistence. In this mode, the access point and client devices take turns transmitting data, which can cause delays and interruptions in voice calls. VoWiFi requires a continuous and stable connection, so using PCO mode can negatively impact the quality of the calls. Therefore, it is not recommended to use PCO mode in this scenario.

Sounding frames are used in transmit beamforming to analyze the MIMO channel before transmitting directed paths of data. These frames help in determining the channel characteristics, such as signal strength and interference, which are crucial for optimizing the beamforming process. By analyzing the MIMO channel using sounding frames, the transmitter can adjust the beamforming parameters and direct the data along the most favorable paths, improving the overall transmission performance.

Passive manual coverage analysis does not require a radio card to be associated with an access point. This type of analysis involves monitoring and collecting data from existing network traffic without actively participating in the network. It is a non-intrusive method that allows for the assessment of coverage and signal strength without the need for additional hardware or active involvement in the network.

Predictive site surveys use modeling algorithms and attenuation values to create visual models of RF coverage cells. This type of survey does not require physically visiting the site, as it uses software to predict and simulate the RF coverage based on various factors such as building materials, obstacles, and antenna placements. By analyzing these models, network planners can determine the optimal placement of access points and predict the expected RF coverage and performance in different areas of the site.

The correct answer is Clause 33. The IEEE 802.3af amendment, which deals with power over Ethernet, has been incorporated into the IEEE Std. 802.3-2005 revised standard. This amendment is defined in Clause 33 of the standard.

The correct answer is Single-port power injector, Multiport power injector, Midspan PSE, Endpoint PSE. These devices are capable of providing power over the spare pairs of the Ethernet cable.

Clause 20 HT radio transmissions are defined for frequencies in the range of 2.4–2.4835 GHz and 5.15–5.25 GHz. These frequencies are commonly used for high-throughput wireless communication, such as Wi-Fi networks. The range of 2.4–2.4835 GHz is part of the 2.4 GHz ISM band, which is widely used for various wireless applications. The range of 5.15–5.25 GHz is part of the 5 GHz UNII band, which is also used for high-speed wireless communication.

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SM power save is a power-management method defined by the 802.11n amendment that conserves power by powering down all but one radio. This method allows devices to enter a power-saving mode where only one radio remains active, reducing power consumption while still maintaining connectivity.

During manual coverage analysis, it is important to record the power settings and channel setting of the access point. Power settings determine the strength of the signal, which can affect the coverage range. Channel setting refers to the specific frequency channel used by the access point, which can also impact coverage and interference. Recording these settings helps in analyzing and optimizing the coverage area of the access point. The other options, such as encryption settings, authentication settings, and IP address, are not directly related to coverage analysis and may not have a significant impact on it.

The powered device accepts power on conductors/wires 1, 2, 3, and 6.

A MIMO system can increase throughput at the Physical layer through spatial multiplexing, transmit beamforming, and the use of 40 MHz channels. Spatial multiplexing allows multiple data streams to be transmitted simultaneously on different antennas, increasing the overall data rate. Transmit beamforming focuses the transmitted signal towards the intended receiver, improving signal strength and reducing interference. The use of 40 MHz channels allows for wider bandwidth, enabling higher data transmission rates.