Encompass 4 Reader System Guide
2-10
• Low antenna profile
Note: D
o not use an AA3152 Universal Toll Antenna for side-fire application.
AA3153 Toll Antenna
Appropriate for installations with the following requirements and conditions:
• 902 to 928 MHz operation
• Exposure to harsh environments
• Broadcast pattern with virtually no side or back lobes, which helps confine cover-
age to a single lane width
• Low antenna profile
Antenna and Tag Alignment
The position of the antenna connected to the Encompass 4 Reader and placement of
the tag on the vehicle must be compatible. Also, consider any existing tagged vehicles
now using the facility to determine the optimal Encompass 4 Reader antenna location
and orientation at the site.
Note: If any of
the vehicles using your facility already have tags, such as those used
in toll applications, contact TransCore for information about mixed-tag installations
before you plan tag type, location, and programming.
Three primary criteria must be satisfied to
achieve the highest read reliability:
• Polarization of the tag and the Encompass 4 Reader antenna must be aligned hori-
zontally.
• The installed tag must be in a direct, unobstructed line of sight to the Encompass 4
Reader antenna.
• Tags designed to be mounted in a vehicle windshield must be mounted in the vehi-
cle’s windshield, and tags designed to be mounted on the exterior surface of the
ve
hicle must be mounted on the exterior surface of the vehicle.
Caution
A tag may not be reliably read unless the preceding criteria are met.
Polarization
The polarization of the tag must be aligned in the same direction as the antenna con-
nected to the Encompass 4 Reader.
Note:
Matching the tag and antenna polarization is critical to obtain optimal system
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