I moved here last summer and I assumed as it was a 50 year old block of flat the walls were affecting signal as if I tried my dongle or mobile none of my laptops or desktops picked up wifi signal even with phone/dongle less than a foot away or if it did connect signal would keep appearing and disappearing at random and get speeds like 1 meg, I used dongle a few times in bedroom too because the main router seemed to get no signal in bedroom despite it being like 20-30 feet from router but stopped by the time I wired in ethernet under carpets so no need for wifi.
Around christmas time there was a block of burned out flats right across from mine that were knocked down, I did notice at the time my living room wifi seemed a little more stable(always got 5 bars on it but only 1 or 2 meg speed) but as I used wired I never really checked it.
I have used my dongle a few times recently as having problems accessing some websites on landline internet and suddenly noticed I can leave dongle anywhere in house and get 5 bars on laptop, though bedroom desktop is a little iffy still(have aerials pointing up I get 5 bars, move a millimeter or to left or right and get nothing but that is next to a wardrobe and desk so maybe blocking signal)
I am just confused as I am thinking did the flats that were knocked down affect my wifi? Also not sure if related but after flats were knocked down had many problems with Sky tv signal being weaker than before.