Based on the post here are few things to look for and some publicly available open source tools. 

When you are setting up a wireless network it is important to know surrounding in your case for the bridge router. There are many obstacles that can attenuate the wireless signal. Some of these are furniture, walls, metal objects etc. 

I use wireshark as my wifi analyzer. Tool is a can be overwhelming. Below is image of the tool

[![enter image description here][1]][1] 

Another tool to take a look at is wifi analyzer. 

[![enter image description here][2]][2]

Take a look at these and let us know if these were helpful. 


  [1]: https://i.sstatic.net/i1qcX.png
  [2]: https://i.sstatic.net/LvEhU.png