Unfortunately, you haven't provided enough information to really diagnose the issue, and you already recognize that this is going to be related to specific hardware, and thus specific hardware issues. In other words, since you are seeing that nothing visible to your WiFi adapter in your computer seems to be producing a very strong signal, your issue could specifically be the WiFi adapter in your computer.
It could be that you are using a Macbook Pro with a metal case, which will actually reduce WiFi signal strength (in and out). It could be that one of the two WiFi antenna connections on the WiFi card in the laptop (assuming you have a notebook) is loose or damaged or not connected. If you are using a desktop with a wireless card that has an external antenna, the mini coax connection to the antenna could be damaged.
You would need to obtain a USB WiFi dongle, and test the signal strength with that. Why? Well, although not all USB WiFi dongles are created equal, it would be a second independent WiFi adapter to compare the signal strengths to. If the problem was in no way related to the first adapter in your computer, then you would see little to no difference in the signal strengths. However, if you used a second, USB dongle and you saw greatly increased signal strengths, that would tell you where the problem most likely was.
Again, this is all guess work, considering we don't know what kind of computer you have, what kind of wireless adapter you are currently using, what condition that adapter is in, what condition the antenna connections are in, etc. So, you really need to perform more diagnostics on your end (AKA, the second wireless adapter). You also need to provide more information on your hardware. Although that would make the solution a lot more specific to your situation, it also might shed light on others with your same hardware that are experiencing similar issues.