Two bars in the bedroom while the kitchen shows full rarely means the internet package is too small. You can prove where a signal dies, and why, in about twenty minutes with a phone and a laptop. Most weak spots inside a flat or a two-storey house come down to one congested channel, a router lying on the floor behind a metal cabinet, or a single dense wall eating more signal than the rest of the floor plan combined.
Read the signal in dBm, not in bars
Bars are decorative. Strength is a negative number in dBm, and the practical thresholds are: about −55 dBm for a clean 4K stream, −67 dBm as the safe floor for a video call, and below −75 dBm packets drop as soon as anyone else on the network does anything heavy.
On Android, install a Wi-Fi analyser and walk the flat with the strength graph open — WiFi Analyzer (the open-source one, no ads) and WiFiman both report dBm live. Windows hides it in a command: run netsh wlan show interfaces in Terminal. The “Signal” percentage there maps 100% to −50 dBm and 0% to −100 dBm, so 60% is roughly −70 dBm. On a Mac, hold Option and click the Wi-Fi icon to see RSSI and the channel you are on. iPhones bury it in AirPort Utility: open the app, then its Settings, and switch on Wi-Fi Scanner.
Record the number in the three places you actually sit — bed, desk, sofa — and note which band the phone is on at each spot. A bedroom reading of −71 dBm on 2.4 GHz but −79 dBm on 5 GHz means the phone is clinging to the wrong band, which is a different repair from a room that is simply too far away.
When the fault is the channel, not the distance
The 2.4 GHz band carries thirteen channels across most of the world, but only 1, 6 and 11 avoid overlapping each other at 20 MHz width. If the analyser shows three neighbours parked on channel 6, joining them means sharing airtime with every one of their devices. Move to whichever of the three is emptiest, and force 20 MHz width: a 40 MHz setting on that band swallows most of the spectrum and slows your own devices down.
5 GHz has far more room and much shorter reach. Expect roughly 3–6 dB more loss per plasterboard wall than 2.4 GHz, and up to 15 dB through reinforced concrete. So a 5 GHz reading below about −72 dBm in the far room makes modern phones fall back to 2.4 GHz, meaning the “dead zone” is really band steering working against you. If your router only offers channels 36–48 and 149–165, a DFS channel in the 52–144 range may be clean spectrum — but some smart TVs refuse to use it, so test first.
Three router settings that quietly change coverage
Log in at the address printed on the router’s sticker — usually 192.168.1.1 or 192.168.0.1 — and look for these before you consider new hardware:
- Transmit power. Many ISP-supplied units ship at 50% or “auto”. Set 5 GHz to 100% and 2.4 GHz to about 50%: the cell shrinks, edge devices move to the faster band, and neighbours get less interference from you.
- Legacy and basic rates. If there is an option to disable 802.11b rates (sometimes “legacy rates” or “b/g protection”), disable it. One old device negotiating at 1–2 Mbps consumes airtime for everyone else, and the fix costs nothing.
- Band steering and airtime fairness. Turn band steering on if the router has it, and leave airtime fairness enabled. Where “MU-MIMO” and “OFDMA” appear, leave both on — they help the crowded-room case you are fixing.
Then update the firmware, over a cable rather than Wi-Fi. A router two years behind on updates can have a broken band-steering implementation, and the changelog usually names the fix.
Free physical fixes that beat a repeater
If the router has two screw-on antennas, set one vertical and tilt the second to about 45 degrees. A vertical antenna radiates in a flat doughnut, so a phone held upright in the same plane gets the strongest signal; two antennas pointing straight up inside a cabinet is worse than leaving the unit on a shelf. Get it 1.5 m off the floor, out of any enclosed metal or glass cabinet, and a metre away from the TV, microwave and cordless phone base.
Then look along the path between router and weak room. A mirror, a fish tank, a steel storage rack or a chimney breast costs more than a few extra metres. Shifting the router 60–80 cm sideways often takes the path off a structural column, and that one move is frequently the whole cure.
Know when to run a cable instead
If the far room still reads worse than −75 dBm after a channel change, a reposition and a power tweak, stop tuning. A repeater placed in a −75 dBm spot rebroadcasts a weak signal at half the throughput, so games stutter and calls still break. A 15 m Cat6 patch lead costs about 900 BDT, and a second-hand router used as an access point on the far end will outperform any repeater at the same price. If drilling is impossible, powerline adapters on the same circuit are the next best thing.
For the standards behind these band and channel limits, the Wi-Fi Alliance’s Wi-Fi 6 overview explains what changes with newer gear. If the dead zone is really about where the box sits, our router placement guide goes deeper, and reusing an old router as an access point covers the wired fix.