Would an RFID system be effective when set up outdoors?
Generally speaking, passive UHF RFID systems are used to determine if a tagged object is located within a specific zone or has passed through that zone. When a tagged object was in an antenna’s RFID read field, you would know its general location. If the object moved through a portal, you would know that the tagged item had arrived or had left, or that it was in a particular room.
You could set up read zones or portals outdoors. We have seen deployments in which cars coming off a production line are tagged (usually, a tag is placed on a hanger on each vehicle’s rear-view mirror). When a car is driven to an area of a large parking lot, its tag is then read and its general location is thus recorded. However, UHF radio waves are absorbed by water, so if it rained or snowed, the system would not work as effectively. You would need to conduct some testing in your environment to determine whether a passive UHF RFID system would meet your needs.
—Mark Roberti, Founder and Editor, RFID Journal