I need a tag that can be interrogated from more than 500 feet away. Is this possible—and, if so, what are the requirements for the tag and receiver or scanner device?
Yes, they can. Active RFID tags have a read range of 1,000 feet or more. These are battery-powered tags that broadcast a signal, rather than harvesting energy from a reader and reflecting back a signal. The requirements depend on what your application is and what you are trying to track. Typically, active tags are based on the Dash-7 air-interface protocol, but there are proprietary systems as well.
Active tags are pricey (they can cost more than $20 apiece). If you are tracking large numbers of items and cannot recycle the tags, this can be a big cost. There are passive ultrahigh-frequency (UHF) systems that employ phased-array antenna systems to obtain a read range of up to 500 feet, but you would need to get a device close to the tag to power it up.
If you are interested in discussing your needs, you can e-mail email@example.com to arrange a free, unbiased phone consultation.
—Mark Roberti, Founder and Editor, RFID Journal
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