PSA (granted, doesn't apply to OP):
Anyone looking for tools to test wifi signal strength around their home will doubtlessly come across Android-only solutions like Wifi Analyzer. Buried in just one forum after hours of looking was the tool for iPhones. It's an Apple app but it needs to be downloaded from the app store - AirPort Utility. Once installed, find it in settings to enable Wi-Fi Scanner and you're golden. Updates the -dbm every 3 seconds.
This is the one that got me to realize that even if I was paying, I was still the product.