802.11a coverage at lowest rate: Indoors, what is the typical maximum distance for an 802.11a link operating at its lowest fallback data rate?

Introduction / Context:
As Wi-Fi lowers its data rate, it can hold a connection at longer distances because the required SNR drops. For 802.11a (5 GHz), the “low-rate” coverage is shorter than comparable 2.4 GHz due to higher path loss and DFS constraints.

Given Data / Assumptions:

• Standard: 802.11a at 5 GHz, indoors.
• Lowest rate (for many profiles: 6 Mbps).
• Typical office attenuation and multipath.

Concept / Approach:
Common planning figures show roughly ~150 ft for lowest-rate 5 GHz indoor coverage. This is shorter than 2.4 GHz at the lowest rates (often ~300 ft), yet still considerably longer than the highest-rate coverage area at 54 Mbps.

Step-by-Step Solution:

Verification / Alternative check:
Site survey experiences and vendor reference designs corroborate this order of magnitude for 5 GHz low-rate distances.

Why Other Options Are Wrong:

• 100 ft: Often too conservative for the lowest rate.
• 175/300/350 ft: Either optimistic for 5 GHz or more aligned with 2.4 GHz (11g) low-rate reach.

Common Pitfalls:
Assuming 5 GHz and 2.4 GHz reach the same distances; ignoring building construction, which can alter results substantially.

Final Answer:
About 150 feet