I am trying to improve my wireless speeds and signal by using an old router (TP Link AC1750) in AP mode connected to the main router BGW210-700. However devices dont seem to want to jump from the main Router to this AP.

I read that devices often have a minimum signal strength (~70db) before they decide to switch so I lowered the transmit power on the main router BGW210-700 but even with very poor signal (-90db) no devices would make the jump to the AP (-40db).

When I change the SSID of the AP to a different name, and connect I can see speeds of 300+, but with the same SSID devices wont make the jump over and I see speeds of only 20 Mbps. With the same SSID names and using ipconfig/all I see the DNS server is still the main router.

Any advice? Main router is ip 192.168.1.254 and AP is 192.168.1.154 neither is setup as static IP. The main router is placed poorly in a closet under the stairs so I am simply trying to make a poor mans mesh with what I have on hand.