Wi-Fi strength intermittent

[Westy250]

The strength of my Wi-Fi is intermittent and is gradually worsening.  The router is in the same position it's been for at least 10 years, there are no new devices that have been added recently. Total devices number around 15, mainly smart plugs. There is no heavy bandwidth use, the strength drops even when the devices are not in use and in line of site of the router. It's a two bed flat with plasterboard walls. The bedroom fartherest from the router has always had a slightly reduced strength, around 80-90% but this has always been enough even when streaming a movie. Due to the fluctuations I've bought an extender which has increased the strength but the signal still drops enough to make this pointless. I've rest the router and gone through all the steps in the Sky instructions. Can anyone help?

[Chrisee]

@Westy250 from the description it is likely the issue is increased interference from your neighbours' WiFi networks. While you maynot have made changes it is prettycertain they have upgraded their systems. In flats you can have 8 or more networks with sufficent power to cause issues.There are a linited number of WiFi channels available and in practice interferencecin blocks of flats is inescapable. Reboiting your hub will cause it to find the least congested channels to use but any improvement may bectemporary. 

Amore modern wifi systems might help but Inam not confident.