User Manual

ThingMagic Nano User Guide 63
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• Fluorescent lighting fixtures are a source of strong electromagnetic interference and, if possible, should
be replaced. If fluorescent lights cannot be replaced, keep the reader cables and antennas away from
them.
• Coaxial cables leading from the reader to antennas can be a strong source of electromagnetic radiation.
These cables should be laid flat and not coiled.
Tag Considerations
There are several variables associated with tags that can affect reader performance:
• Application Surface: Some materials, including metal and moisture, interfere with tag performance. Tags
applied to items made from or containing these materials may not perform as expected.
• Tag Orientation: Most tags have folded dipole antennas. They read well when facing the antenna and
when their long edge is oriented toward the antenna, but very poorly when their short edge is oriented
toward the antenna.
• Tag Model: Many tag models are available, each with its own performance characteristics.
Antenna Considerations
• Use a circularly polarized antenna. Linear antennas can only be used if the tag orientation to the antenna
is consistent, or if not in the ideal orientation the antenna or tag can be rotated for best reading.
• Use an antenna whose design naturally presents a short to DC. This will help eliminate ESD issues.
• Use an antenna with a return loss of 17 dB or greater (1.33 VSWR) in the transmission band of the region
the module is using.
• Use an outdoor-rated antenna if there is a chance that water or dust could get into the antenna and
change its RF characteristics.
• Ensure that the antenna is mounted such that personnel do not stand in the radiation beam of the
antenna unless they are more than 21 cm away from the face of the antenna (to adhere to FCC limits
for long term exposure). If the application calls for personnel to work in the antenna beam and they will
be less than 21 cm from the face of the antenna, Nano power should be reduced, or a lower gain antenna
must be used (21 cm assumes a 27 dBm power level into an 8.15 dBi antenna).
Multiple Readers
• The reader adversely affects performance of 900 MHz devices. These devices also may degrade
performance of the reader.
• Antennas on other readers operating in close proximity may interfere with one another, thus degrading
performance of the readers.
• Interference from other antennas may be eliminated or reduced by using either one or both of the
following strategies:
• Affected antennas may be synchronized by a separate user application using a time-
multiplexing strategy.
• Antenna power can be reduced by reconfiguring the RF Transmit Power setting for the reader.
NOTE: Performance tests conducted under typical operating conditions at your site are recommended
to help optimize system performance.