This is by no means an exhaustive list of possible scenarios however in our many years of experience in the wireless world this guide will solve 99% of issues with wifi in the home. The enviroment your wifi router lives in is an ever changing world of radio frequencies, your wifi system may work fine today however this could all change tomorrow.
Some common causes of no connectivity:
Can see WiFi name in scan but unable to connect
Most common cause is incorrect wifi security key (password), remove (forget) the wifi network if your devices has it saved, reboot both wifi router and the connecting device, try setting up the connection again paying attention to the security key, they are case sensitive.
Can not see WiFi name in scan
Most likely cause is the router has been set back to factory defaults. If you see a name in the list of networks that has a good signal and contains the name of the router manufactuer like Tenda or Tp Link for example, then this is definately the case, sometimes however the router simply needs to be rebooted
Connected to WiFi router but no Internet
First check all the cables are firmly in place in the back of the router, check both ends of each cable. Reboot wifi router, if still no internet contact Compusurf to check you have Internet available at the property
Connected but poor performance
A common causes of poor performance is the routers location. Ideally any device connecting to a wireless router should have line of sight, however this is often not possible, luckily the frequency used by most wifi routers is 2.4ghz and can penetrate objects like walls, plastic, wood and many other things, however each object the signal has to pass through reduces the strength considerably and lowers performance, if you have a 5ghz router, this effect is even more dramatic, a single wall, depending on construction, can be enough to cause problems
Check wifi router antenna
All wifi routers have antennas, some are internal, some are external, external antennas should be in an upright vertical position, with internal antennas the router should be placed on its feet or stand if it has one, the routers antennas are designed to send the signal outwards horizontially and not upwards vertically, although you will get some signal upwards it is very much weaker. Trying to connect a device to a router on a different floor in a building is not ideal.
Remove interference sources
The single most common cause of problems is interference from other devices in or near the wifi router or its path to the connecting device. All electronic devices give of some form of electromagnetic radiation. Make sure the WIFI router is not located behind a TV set or on top of a Sat TV box. Sat TV boxes and TVs can knock out WIFI as they can emit a large amount of RF radiation. Other non wifi wireless systems like alarms or doorbells in the house can effect your wifi signal, the worst culprit is a Wireless TV sender that sends a TV picture from one TV to another wirelessly. Wireless CCTV systems and security systems can also have an effect. Turn off all non wifi wireless systems, before starting to troubleshoot.
If the earthing system in a property is less than perfect, rf radiation from electrical devices will be more likely as any built in shielding will not be effective. Compusurf recommends that any earthing system in a property should be checked every few years by a qualified electrician, this not only ensures electrical safety in the home but may also solve many interference issues.
Reboot the wifi router
Before you can do any troubleshooting the wifi router must first be rebooted by unplugging from the power for at least one minute. DO NOT PRESS ANY RESET BUTTONS.
All wifi routers will from time to time require rebooting to maintain optimal performance. The internal workings of a wifi router are software based utilising a cpu and memory just like a PC but on a much smaller scale, wifi routers also suffer from overheating so its important not to block any vents and never position in the sun.
Disconnect all devices
Disconnect all wifi devices from the wifi router like phones tablets and pc’s by powering them off or turning thier wifi off, do not forget things like TV boxes, firesticks and cameras. Once this is done and your sure nothing is connected wirelessly to your router move to the next stage
Connect testing device
Choose one device, reboot it and reconnect it to the wifi router, position the device no closer than 1 metre and no further than 5 metres from the router, there must be clear line of site between the testing device and the wifi router.
Do initial test
Using your chosen testing device, open a browser and go to www.compusurf.es/speed ,do a test, make a note of the results, if all is good go to the next stage. if their is still an issue at this stage then it is possible there is some external interference like a nieghbours router, skip the next stage and go to the section ” external Interference”
Non wifi wireless systems
If applicable, turn on one of the non wifi wireless system, mentioned in the interference section, that were turned off and do another test, repeat this process for every non wifi wireless system you turned off, if all remains good then we know all the non wifi wireless systems in the house are not causing a problem. If it is discovered one of the systems is causing a problem then you should change the wifi router operating channel and test again, repeating until you find a channel that sits comfortably with all the non wifi wireless systems in the house.
External interference can be the hardest nut to crack, sometimes the only solution is to move the router to a new location in the property away from the interference. The source of the interference could be any of the above mentioned things in a neighbours property,
Detecting other wifi routers
The most common cause of external interference is another wifi router transmitting on the same channel as yours, simply scanning for wifi signals with your device will not help as you are not normally able to see the channel the wifi signal is using. To discover the channels that other wifi routers are operating on you will need a wifi scanner app, the one I use is free and called “Wifi Analyzer” Once you know the channels your nieghbours are using, you can move your channel to somewhere else that is free from other wifi routers.
Another cause of under performance is too many devices connected, home wifi routers are generally not very powerful devices and cheaper devices will start to struggle once 3 or more connected devices are using a lot of bandwidth at the same time, this effect is dramatically amplified if one of the devices has a poor connection, one poorly connected device will slow down all devices connected to the same wifi router regardless of how good their connection is.
Other external interference
If all the above fails to resolve the issue, it is possible the wifi router is faulty or there is some non wifi external rf interference, to detect the latter you need a spectrum analyzer, these are very expensive to purchase, so you could to ask a professional wireless company like Compusurf to come and do a spectrum analysis for you,