From the documentation and Decawave forum, I see that "stationary detection" may be turned off for the Tag, and this will cause the 10 Hz update rate to continue, and the Tag will not switch to the "energy conserving" 0.1 Hz update rate. This can be done under Tag settings on the Android App. I will try this next. It seems to have the "energy conservation" settings much too aggressive by default. That causes it to often run much too slowly. Updating position every 10 seconds would never work for a rover robot! Or for a flying robot, for that matter.
Thank you for the answer, yes, this made a great difference! Testing was much more successful.
However, sometimes the Tag shows in the ROS output, and at other times it isn't there. I see just two devices reporting through the ROS topics. What we need most of all is to be able to plug the USB into the active Tag and get it's location. This will be on the robot and assisting with location awareness. To listen to a passive device and then send that data to the robot will only slow down the process.
And I didn't see any output on the Rviz grid. It stays blank.