RCDD Wireless Systems Design and Infrastructure 1 — Questions and Answers
Question 1: According to ANSI/TIA-4965, what is the recommended maximum distance between wireless access point (WAP) mounting locations and the nearest telecommunications outlet in a distributed antenna or WAP deployment?
- 15 meters (49 ft)
- 30 meters (100 ft) (Correct answer)
- 50 meters (164 ft)
- 100 meters (328 ft)
Correct answer: 30 meters (100 ft)
ANSI/TIA-4965 recommends WAP locations be served by cabling no longer than 30 meters (100 ft) from the telecommunications outlet to ensure adequate PoE delivery and signal quality.
Question 2: Which IEEE standard defines Power over Ethernet (PoE) at a maximum of 15.4 watts of power delivered to a powered device (PD)?
- IEEE 802.3af (Correct answer)
- IEEE 802.3at
- IEEE 802.3bt
- IEEE 802.3az
Correct answer: IEEE 802.3af
IEEE 802.3af (PoE) delivers a maximum of 15.4 W at the PSE (12.95 W at the PD), which is the original PoE standard.
Question 3: When designing in-building wireless (IBW) systems, a Distributed Antenna System (DAS) is primarily used to:
- Increase internet bandwidth by aggregating multiple ISP links
- Improve cellular and wireless coverage in areas with weak or no signal (Correct answer)
- Replace structured cabling in telecommunications rooms
- Reduce RF interference from neighboring access points
Correct answer: Improve cellular and wireless coverage in areas with weak or no signal
A DAS distributes RF signals from a central source through remote antenna units to improve wireless and cellular coverage throughout a building.
Question 4: In wireless LAN design, what term describes the overlapping coverage area between two adjacent access points, typically set at 15–20% overlap, to enable seamless roaming?
- Dead zone
- Cell overlap (Correct answer)
- RF handoff margin
- Co-channel interference zone
Correct answer: Cell overlap
Cell overlap (15–20%) between adjacent WAPs ensures a client device can roam seamlessly without dropping the connection before associating with the next AP.
Question 5: Which frequency band is most susceptible to absorption by walls and physical obstructions in an indoor wireless deployment?
- 900 MHz
- 2.4 GHz
- 5 GHz (Correct answer)
- 6 GHz
Correct answer: 5 GHz
The 5 GHz band has shorter wavelengths that are more readily absorbed and attenuated by walls and obstructions compared to 2.4 GHz, reducing range indoors.
Question 6: When documenting a wireless site survey for an RCDD project, which measurement is used to quantify the ratio of the desired signal strength to the background noise level?
- RSSI (Received Signal Strength Indicator)
- SNR (Signal-to-Noise Ratio) (Correct answer)
- EIRP (Effective Isotropic Radiated Power)
- BER (Bit Error Rate)
Correct answer: SNR (Signal-to-Noise Ratio)
SNR (Signal-to-Noise Ratio) measures the difference between the desired signal level and the noise floor, directly indicating link quality for wireless communications.
Question 7: Per BICSI TDMM guidelines, what minimum cable category is recommended to support IEEE 802.3bt (Type 4, 90W) PoE for high-power WAP installations?
- Category 5e
- Category 6
- Category 6A (Correct answer)
- Category 7
Correct answer: Category 6A
Category 6A is recommended for IEEE 802.3bt 4-pair PoE because its larger conductors and lower DC resistance reduce heat buildup during high-power delivery.
RCDD Wireless Systems Design and Infrastructure 1
According to ANSI/TIA-4965, what is the recommended maximum distance between wireless access point (WAP) mounting locations and the nearest telecommunications outlet in a distributed antenna or WAP deployment?