Upgraded from Pi2 to Pi3 - RFXCOM not seeing all thermometers


I’ve recently upgraded from a Raspberry Pi 2 to a Raspberry Pi 3.
The Pi is connected to a RFXCOM usb tranceiver.

On the Pi 2 I could receive updates from Thermometers all over the house, and even the garage. But on the Pi 3 I dont see receivers on the ground floor or in the garage. If I move them up near the Pi 3 then they appear again.

Does the Pi 3 have less power sent to the rfxcom? Should I get a powered USB hub?
Anyone have similar problems with the Pi 3?

Also, I’m on Openhab 2.