Xfinity hotspot

My mac is able to connect to xfinity hotspot but the speed is very slow and signal very weak while my iphone has very strong signal with fast speed. Somehow my mac probably connects to the furthest hotspot location in a different building vs connecting to hotspot  provided by my router. In wifi settings signal shows as very strong but after connecting it drops to 1-2 bars. Tried to speak to xfinity tech support but they are useless and clueless