Why is wireless printing prone to problems

Solve puzzling WiFi problems and crashes

Thomas Rau

Often enough, your wireless network amazes you with strange behaviors and unfathomable errors. Then you won't get any further with basic tips for WiFi. We take care of the complex problems and help people to help themselves.

EnlargeHow to Solve Mysterious Wireless Router Problems.
© Photo: © maxsim - AdobeStock

Some WLAN problems are simply mysterious: The connection in the wireless network between two devices that previously understood each other perfectly breaks off again and again. Or suddenly there is no connection at all. A device appears to be in contact with the router via WLAN, but still cannot access the Internet. And so on.

Solving WLAN problems quickly is often difficult because in this case there are no cables, no connection sockets and no PC interfaces that you can control at a glance. The problem lies somewhere in the radio waves that travel invisibly and connect devices - or they don't. Many of these problems are particularly puzzling because you actually know the basics of WiFi and have taken appropriate precautions: the distance between router and WiFi devices is not too great, no thick walls on the radio path, and if there is no other way, you have one Repeater used.

In order to come up with a solution anyway, we have compiled common WiFi puzzles from practice - and of course a solution with which you can solve these problems in the wireless network. There is often a technical explanation for the behavior of the WLAN devices: If you know this, you can work around the problem before the connection in the future. A changed setting in the router, repeater or WLAN driver usually brings you to your destination. And sometimes you need special tools for this, with which you can see more than in the menus of the WLAN devices.

See also:10 tips for a fast and stable WiFi

Despite the dual-band devices, no 5 GHz WLAN is active

EnlargeAfter a restart, the 5 GHz band is not available because routers with DFS first have to check whether other services are using this frequency.

The riddle: You definitely want to connect your notebook to the dual-band router using the faster 5 GHz frequency. Because you need a high speed for video streaming to the laptop. That should actually work without any problems, because the notebook and router are not very far apart. Now check in the Windows network settings whether the 5 GHz connection currently exists. But the operating system indicates that the notebook is connected via 2.4 GHz. You disconnect the WLAN connection and reconnect the laptop to the router - but the problem does not change for the time being.

The solution: You actually did everything right. Because in this situation there is no 5 GHz WLAN that the notebook can connect to. This happens, for example, after restarting the router, which you either triggered yourself to install new firmware or to repair an unstable Internet connection. However, this problem can also occur after you have changed the WLAN settings in the router, for example when setting a specific radio channel.

Most dual-band routers switch off the 5 GHz frequency for a short time after restarting or changing the WLAN settings. This is legally stipulated in the event that the router wants to use all radio channels above 5 GHz - including those in the frequency range from 5.26 GHz (channel 52). The so-called “primary users” of these frequencies also work there: These are services such as radar systems for the military, air traffic control or the weather service. These must not be disturbed during operation, which is why the router must first check whether a corresponding service is active in its vicinity after it has activated the 5 GHz WLAN.

In this case, you cannot do anything other than wait for the period of this test to then connect to the operational 5 GHz WLAN. Because if you change something in the router settings to shorten this waiting time, it starts all over again. Incidentally, this behavior does not occur with a router that lacks the DFS (Dynamic Frequency Selection) function, because it is only allowed to use the lower radio channels up to and including 48 over the 5 GHz frequency, which the radar systems do not use.

A dual-band-capable Fritzbox with Fritz-OS 7 or higher can shorten the waiting time by switching to a channel between 36 and 48 in the meantime in order to generally enable a connection via the 5 GHz frequency. After the waiting time has elapsed, it then changes back to the originally set higher channel.

Two dual-band devices do not connect at 5 GHz

EnlargeIf a dual-band client does not support the DFS function, you must set a radio channel below 52 for a connection in the router.

The riddle: You have a dual-band router and a dual-band stick on the USB port of your PC. You also want to connect the computer via the 5 GHz frequency in order to avoid interference in the 2.4 GHz frequency range. To do this, you have set up two different SSIDs on the router for 2.4 GHz and 5 GHz WLAN. But the connection doesn't work: The 5 GHz WLAN does not appear on the PC, it only recognizes the wireless network for the 2.4 GHz range. Even after restarting the router nothing changes: Even after a long wait, no 5 GHZ WLAN is visible.

The solution: DFS also plays a role in this problem. Because the router can do it - but not the WLAN USB stick. This is why the router can use a channel 52 or more for the 5 GHz WiFi, but the WiFi stick can only use one less. The result: The PC cannot receive the network ID of this WLAN at all and therefore does not even find out that this wireless network exists.

So you have to set a fixed channel in the router for the 5 GHz frequency that the stick can receive - in this case between 25 and 48. With a Fritzbox, go to "WLAN -› radio channel ". Select “Adjust radio channel settings” there. In the drop-down menu behind "Radio channel in the 5 GHz frequency band", select a suitable channel instead of the "Auto channel" setting. With a model from TP-Link you will find the corresponding option under "Wireless -› Basic Settings - ›Channel". The connection should now work over 5 GHz.

At a glance: WLAN settings

The first step in any WLAN problem: Get an overview of the current settings for the wireless network in the router and client. Many basic questions about connection and security can be answered immediately. In the table you will find the way to the corresponding menus in the router, computer and smartphone.

In…

you can find the WLAN settings under ...

Android

Settings - ›Network and Internet -› WLAN

AVM Fritzbox

WLAN - ›radio network / WLAN -› radio channel / WLAN - ›security

iOS

Settings - ›WLAN

Linux Mint

Menu - ›Settings -› Network

Telekom Speedport

Home network - ›Basic WLAN settings

Windows 10

Settings - ›Network and Internet -› WLAN