Help please! Strong Wi-Fi signal but some devices not connecting / connected but no internet

[#1]

Hi, we switched off our router for 4 days while we were on holiday, and when we returned and switched it back on, we experienced the above problems that we never had before.

On an Android smartphone, our wifi network is showing with full signal strength, but internet connection only works when the phone is right next to the router (even when standing elsewhere in the same room, the connection drops!). It takes a long time to connect, and even when it does connect successfully, it only lasts for a few seconds.

Our router is in the living room and when standing literally on the other side of the wall opposite from the router, there is no connection at all.

Other devices seem to be ok - Macbook is fine, other Android phone seems to be okay (albeit sluggish when loading websites).

We have tried these fixes already, but none work:

• Did a hard reset of the router
• Forget network on phone, reconnect
• Used static IP address
• Changed broadcast channel from 6 to 2

Our router is a Technicolor TG582n and never had any problems before! All devices were able to pick up a strong signal anywhere in our flat. It's been a day now and still no signs of improvement.

Greatly appreciate any help from the Plusnet tech team or other users!

[#2]

and while you were on holiday, did you connect these phones to other wifi/guest/free wifi etc etc?

If you have not already done so I'd be inclined to forget all the networks on one of the phones and start again. What's it like using mobile data?

You can also log in to the router and remove the connections for the phone from the dhcp table just to be thorough.

[#3]

I wonder if it's significant that you're in a flat? Could a neighbour's signal be swamping yours? We live in a flat, too, and our Wi-Fi environment is very congested, at least in the 2.4 GHz band, where, with neighbours above, below, and each side, we can sometimes see 16 or more access points. (The 5 GHz band is much quieter.)

We use the Wi-Fi Analyser app (https://play.google.com/store/apps/details?id=com.farproc.wifi.analyzer) to see what is going on. Might be worth trying this app (paid for by ads, but you can kill them for nothing for a few days - and there are other similar apps).

Hope this helps.

[#4]

@pschow

When choosing WIFi channels on the 2.4GHz range, you really need to pick only from channels 1, 6 or 11 as these are the only non overlapping channels, and give the best signal at all times. 

For an explanation and hints please read this article  http://www.metageek.com/training/resources/why-channels-1-6-11.html

[#5 · Accepted solution]

Thanks all for the suggestions! After speaking to someone from Plusnet Tech support and having my line tested on their end, it turns out the signal-to-noise ratio (SNR) on my line was too low, which affects the ability of devices to connect properly to the router. They adjusted this and now everything's fine.

Don't have to stand right next to the router to get a clear connection anymore!