Improving Wi-Fi in an apartment: the step-by-step guide that works.
In Lisbon, Porto, and areas with dense buildings, Wi-Fi suffers for two reasons: interference (many neighbors) and propagation (walls, corridors, doors). The solution is rarely "buying the most expensive router." Usually, it's about optimizing and only then expanding correctly .
Step 1: Positioning (this is the cheapest upgrade)
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Place the router high up and as centrally as possible.
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Avoid: inside closed cabinets, behind TVs, near microwaves
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If you have an ONT/box in the corner of your house, consider running a cable to place the main router in the center.
Step 2: You choose the right band (2.4 vs 5 vs 6 GHz)
2.4 GHz
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Greater reach, penetrates walls better.
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Slower and more congested
5 GHz
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Better balance for most apartments.
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It may suffer from obstacles and DFS (we've already discussed this below).
6 GHz (Wi-Fi 6E/7)
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Less congested and great for high performance.
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Shorter range; generally designed for indoor use. LPI
Step 3: 2.4 GHz channels (the classic solution that works)
In the 2.4 GHz band, channels overlap. Therefore, the common recommendation is to use "non-overlapping" sets. There are classic references such as 1/6/11 (often cited) and also European domain recommendations with 1/7/13 .
Practical rule for apartments:
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Define 2.4 GHz at 20 MHz (avoids 40 MHz on the 2.4 GHz band in buildings)
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Test “clean” channels (1, 6, 11) — and if it makes sense in your domain/region, evaluate 1/7/13
Step 4: Understanding DFS in 5 GHz (why Wi-Fi "changes on its own")
Some 5 GHz channels are DFS , which means the access point (AP) needs to detect radar and, if detected, switch channels to avoid interfering with protected services.
If your Wi-Fi "drops" for seconds/minutes and then comes back, it could be DFS (Distributed Financial Switching) in action.
What to do:
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If you experience frequent instability, try non-DFS channels.
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If you need more available channels, DFS can be useful — but in areas with detections, it can be annoying.
Step 5: Repeater vs. Mesh (the most impactful decision)
Repeater (extend)
It works, but it comes at a cost: since you need to receive and retransmit on the same channel, the throughput can drop significantly (often by "half" per hop).
Mesh
A well-designed mesh network is better for coverage and roaming. However, when the backhaul is wireless, there is also loss per hop. In technical mesh documentation, it is common to see estimates of approximately 50% reduction per hop .
✅ The best solution for apartments/houses:
Mesh with Ethernet backhaul (cables between nodes). This way you gain coverage without significantly impacting speed.
Step 6: Channel width (it's not "the bigger, the better")
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2.4 GHz: typically 20 MHz
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5 GHz: 40/80 MHz depending on the environment.
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6 GHz: 80/160 MHz (or more in Wi-Fi 7), but only makes sense with a good signal and low noise.
In a building with many networks, a very wide channel can worsen the situation (more spectrum "collision").
Step 7: Safety that also improves stability.
In modern networks, security and compatibility matter. In 6 GHz, there are stricter requirements: for example, PMF is mandatory in certain contexts, and older configurations (such as WPA2) do not apply in 6 GHz.
Recommendations:
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WPA3 whenever possible
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Guest network for visits
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Separate network for IoT (if the router allows it)
Quick checklist (do this before buying hardware)
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Central and elevated router
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2.4 GHz at 20 MHz + suitable channel
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5 GHz: tests non-DFS channel if instability occurs.
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If you need range: Mesh (preferably with Ethernet backhaul)
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If you only need to "get to the room": an extra wired access point is better than a repeater.
FAQ
Is a repeater worth it?
It works as a cheap "patch," but it can reduce throughput because it needs to retransmit on the same channel.
Why does the 5 GHz network sometimes disappear and reappear?
It could be DFS switching channels when radar is detected.