They were not kidding about the range!
finally had time to test out one of my Xbee3 XB3-24Z8ST as an arrival sensor
I changed it to an end point and used an old Asus dual band wifi antenna (maybe 1-2 dbi could not find the specs)
set on the dash of my car.
and an old 2.4 wifi omnidirectional antenna (I think it is a 12 dbi) attached to another Xbee3 XB3-24Z8ST set as a router in the second floor corner of my house.
It picked picked up the Xbee3 arrival while driving 1/2 mile (600 meters) away.
I could likely do better with a better antenna in the car but 1/2 mile is plenty.
compared to the SmartThings arrival sensor which will only pickup at best when walking 2-3 houses away or in the car it is usually in the driveway before detected.
driver issue: (cosmetic)
The Xbee3 device display shows 2 sets of
"Minutes elapsed until sensor is not present *"
one says "click to set"
and the second says
I set both to one minute and they still display
"click to set"
but still functions with the selected 1 minute selection.
As far as powering the Xbee3 arrival in the car I am going to leave it only powered using USB so it is only present when the car is running. This way if any of the kids get out in the garage and keys happen to be within range of push to start or command start happens to start the car my garage door will open.
I updated the original post for end point settings (I didn't need to change SP settings)
AP = 0 (for an end device)
SM = 5 (has to be not 0 for end devices)
and I just pressed reset on the USB board to get it to change from router to end device.
Thanks Dan.t !