Hardware
Design notes
Antenna performance
Antenna location is important for optimal performance. The following suggestions help you achieve
optimal antenna performance. Point the antenna up vertically (upright). Antennas radiate and receive
the best signal perpendicular to the direction they point, so a vertical antenna's omnidirectional
radiation pattern is strongest across the horizon.
Position the antennas away from metal objects whenever possible. Metal objects between the
transmitter and receiver can block the radiation path or reduce the transmission distance. Objects
that are often overlooked include:
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metal poles
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metal studs
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structure beams
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concrete, which is usually reinforced with metal rods
If you place the device inside a metal enclosure, use an external antenna. Common objects that have
metal enclosures include:
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vehicles
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elevators
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ventilation ducts
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refrigerators
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microwave ovens
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batteries
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tall electrolytic capacitors
Do not place XBee devices with the chip or integrated PCB antenna inside a metal enclosure.
Do not place any ground planes or metal objects above or below the antenna.
For the best results, mount the device at the edge of the host PCB. Ensure that the ground, power,
and signal planes are vacant immediately below the antenna section.
Keepout area
We recommend that you allow a “keepout” area, which the following drawings show.
XBee/XBee-PRO S2C 802.15.4 RF Module User Guide
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ETC [ ETC ]
