SLZB-MR1U - Range settings?

Hello,

I just started using any home smart products and am doing everything though the SLZB-MR1U over POE.

I have only setup radio 2 as a zigbee coordinator and basically nothing else other than firmware updates. I have noticed the range is not great. I was wondering if there are any tweaks I can do to increase range on this or if I need to just get some repeaters?