Which 2.4 GHz Channel Width Minimizes Interference in Dense Environments?
Short answer
B 20MHz
Question
Key Takeaways
This question tests knowledge of 802.11 channel widths and band-specific limitations: 20 MHz is the only safe, standard channel width for 2.4 GHz in dense deployments, while wider channels (40, 80, 160 MHz) apply mainly to 5 GHz and increase interference risk.
For overlapping Wi-Fi coverage in dense environments, 20 MHz channels minimize interference in the 2.4 GHz band. Community consensus strongly supports 20 MHz, noting that wider channels increase risk of interference and are unsuitable for the crowded 2.4 GHz spectrum.
Common mistake: Choosing 160 MHz (E) is a common trap because it offers the highest throughput, but it is not supported in 2.4 GHz and would be unusable in dense environments; 80 MHz and 40 MHz similarly cause excessive interference and overlapping coverage.
Expert Analysis
Why the Answer Is Correct
20 MHz is the standard baseline channel width for 802.11 networks in the 2.4 GHz band. In dense environments, narrow channels reduce the chance of overlapping signals interfering with each other because they occupy less spectrum. The 2.4 GHz band has only three non-overlapping 20 MHz channels (1, 6, 11), making 20 MHz the only practical choice when many access points must coexist.
Why the Other Options Are Wrong
Option A (11 MHz) is not a standard 802.11 channel width; 802.11b used 22 MHz, but modern Wi-Fi uses 20 MHz minimum. Options C (40 MHz), D (80 MHz), and E (160 MHz) are wider channel widths that are primarily used in the 5 GHz band. In 2.4 GHz, such widths are either unsupported (80/160 MHz) or cause severe overlap and interference, especially in dense installations.
Community Comment Notes
One highly-rated comment (4 likes) explains that "20 MHz is absolutely correct. The wider the channel, the higher the risk that somewhere in its frequency range it will be hit with interference." It also correctly notes that 2.4 GHz is crowded and choosing 20 MHz avoids interference even at the cost of per-client bandwidth. Another commenter asks for explanation, but the consensus remains clear: 20 MHz is the correct answer for minimizing interference in dense 2.4 GHz environments.
Official Reference
These links open the official vendor documentation in a new tab.
Exam Strategy
When asked about minimizing interference in the 2.4 GHz spectrum, always look for the narrowest standard channel width that is actually available. Remember that 20 MHz is the baseline and that 40/80/160 MHz are wider channels mainly used in 5 GHz, so they will not help in 2.4 GHz dense deployments.
Community Votes
50% of anonymous learners picked answer B. Votes are pick records left by other test-takers — they are not the verified answer.
Discussion 3 contributions
Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.
From public community threads 3
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chrys 👍 420 MHz is absolutely correct. The wider the channel, the higher the risk that somewhere in its frequency range it will be hit with interference. Since 2.4 GHz is an especially crowded band, you want to avoid the risk of interference, even though it means that each mobile client will be stuck with less overall bandwidth for their connection
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cdozier2 👍 1 Answered Esomebody please explain
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HeatSquad77 👍 1 Answered B20 MHz
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