My friend's network consists of a Wi-Fi router/access point and about 10 wireless devices.
Wireless client devices show good strength signal but the router's internal diagnostics indicates very poor reception. Devices drop out of session sporadically and have to reconnect, internet also is reportedly slow unless close to the router.
Router indicates 2 to 4 (of 5) bars of reception for closeby devices; farther away ones behind a drywall get 0 to 2; 5 bars only if almost touching antennas. The devices themselves show 3 to 5 (of 5) bars - as normally is expected in this situation.
This network encompasses a medium-sized single-floor apartment within a 10-floor building in densely populated city, internal walls are drywalls. Router is an oldish middle-class one. Devices are mostly iPhones and iPads of varying generations, but also couple of PCs and a network printer.
Wi-Fi configuration is on its defaults, automatic channel, 2.4GHz. This router also supports a 5GHz network but brief tests show similar situation with this network. There are about 10 to 15 other neighbor networks visible throughout the apartment.
GSM and UMTS signal reception is Ok as normally expected. No obviously-EM-intensive appliances or microwave ovens are plugged in. There should be no devices transferring huge amounts of data all the time. Security is WPA2-PSK, WPS was allowed.
The following did not cause any visible improvement:
- Rebooting router
- Shutting down some devices
- Updating firmware (it had latest one installed)
- Virus and intruder checks on devices or router
- Moving router a tiny amount and rotating antennas somewhat
- Unscrewing and reattaching antennas
- Using a known-good client device (results are same as other devices)
- Searching the internet for potential problems with this exact router model\
What was NOT tried because I was not able to physically visit the place yet:
- Shutting down all client devices except one
- Changing wi-fi settings including selecting a radio channel
- Moving router to a different room (due to short cables) or mounting it high
- Precisely measuring (or mapping) reception strength in varying spots
- Trying to determine exact composition of drywalls with a drill or metal detector
- Trying to use another router / repeater / booster
- Installing enthusiast firmwares such as OpenWRT
- Creating wi-fi networks on smartphones and measuring strength
- Measuring signal strength changes throughout the day
(if any of above could help in diagnostics feel free to add to your answer)
I am not sure what could cause this exact situation apart from, obviously, a malfunctioning router.
What tools or techniques would you use to diagnose a similar problem?
I am mostly interested in what an average system administrator could accomplish within few hours with a smartphone and a known-good router but professional diagnostic tools may be worth mentioning too. Links to in-depth wireless troubleshooting guides would likewise be appreciated.