Useful Wifi Analyser
If you have a smart phone I can really really really recommend Wifi Analyser from Keuwlsoft - in the Play Store.
It is ad free, tracking free, free, and very very good.
Within a few minutes I'd moved my HomeHub3 a couple of feet, switched off BT Wifi/Fon hotspot, confirmed channel and it even made a nice cup of tea
well maybe not the last, but it may be of help to folks struggling with wifi strength.