ACMA Wireless Networking Fundamentals & Technologies 3 — Questions and Answers
Question 1: What type of antenna pattern radiates power equally in all directions in the horizontal plane?
- Directional
- Yagi
- Omni-directional (Correct answer)
- Patch
Correct answer: Omni-directional
An omni-directional antenna radiates RF energy equally in all horizontal directions, producing a donut-shaped 3D radiation pattern.
Question 2: In Wi-Fi, what does RSSI measure?
- The data rate negotiated between client and AP
- The relative received signal strength of a wireless signal (Correct answer)
- The ratio of signal to noise at the receiver
- The channel utilization percentage
Correct answer: The relative received signal strength of a wireless signal
RSSI (Received Signal Strength Indicator) is a relative measurement of the power level of a received radio signal, typically expressed in negative dBm values.
Question 3: Which Wi-Fi frame type is responsible for negotiating association between a client and an AP?
- Data frame
- Control frame
- Management frame (Correct answer)
- QoS frame
Correct answer: Management frame
Management frames handle administrative tasks such as authentication, association, and beacon transmission between clients and APs.
Question 4: What is the primary purpose of RTS/CTS in 802.11?
- To encrypt the data payload before transmission
- To mitigate the hidden node problem by reserving the medium (Correct answer)
- To negotiate the MCS rate between client and AP
- To fragment large frames into smaller ones
Correct answer: To mitigate the hidden node problem by reserving the medium
RTS/CTS (Request to Send / Clear to Send) reserves the wireless medium before a data transmission, reducing collisions caused by hidden nodes.
Question 5: When a wireless client moves between APs within the same ESS without losing its IP address, this is called:
- Layer 3 roaming
- Layer 2 roaming (Correct answer)
- Fast BSS Transition
- Band steering
Correct answer: Layer 2 roaming
Layer 2 roaming occurs when a client transitions between APs on the same subnet/VLAN, retaining its IP address without requiring DHCP renewal.
Question 6: Which modulation scheme is used by 802.11ax that was NOT available in 802.11ac?
- 64-QAM
- 256-QAM
- 1024-QAM (Correct answer)
- 512-QAM
Correct answer: 1024-QAM
802.11ax (Wi-Fi 6) introduced 1024-QAM, encoding 10 bits per symbol and providing approximately 25% higher throughput than 256-QAM when signal conditions allow.
Question 7: What is the frequency range of the 6 GHz band introduced for Wi-Fi use in the US?
- 5.925–6.425 GHz
- 5.925–7.125 GHz (Correct answer)
- 6.0–7.0 GHz
- 6.5–7.5 GHz
Correct answer: 5.925–7.125 GHz
The FCC opened 5.925–7.125 GHz (1200 MHz) for unlicensed Wi-Fi use in the US, enabling 802.11ax (Wi-Fi 6E) and 802.11be (Wi-Fi 7) deployments.
ACMA Wireless Networking Fundamentals & Technologies 3
What type of antenna pattern radiates power equally in all directions in the horizontal plane?