has anyone tried using mobile hotspot with an android tablet?

i am trying to decide whether to buy a motorola xoom tablet, so i went to best buy to check it out. i tried to connect to my n900 mobile hotspot, but the xoom kept indicating the network was out of range. a nook color similarly reports the network as out of range.

strangely, i can connect from my macbook and and an ipad 2 when i tested it last friday.

so what is causing xoom and nook color to be unable to connect?