Stid TeleTag System Implementation Manual page 3

Vehicle identification: TeleTag UHF
Optimum
Given the constraints described above, it is important to identify the conditions that will give the best
possible system performance. This means ensuring the optimum antenna and tag positions.
Performance will depend on the position of the tag relative to the antenna. Maximum range and
optimised detection will be achieved if the tag is directly opposite the antenna, parallel to it, and with the
correct polarisation.
For optimum performance, the tag should be straight opposite the antenna.
The range values given in technical specifications for the readers are measured in straight-on distances,
with the tag parallel to the antenna.
When the tag is at an angle from the antenna, the effective range is reduced.
Reduced range
Nominal range
The angle in question may be a horizontal or vertical angle, depending on the comparative height of the
antenna compared to the vehicle and the lateral offset of the antenna, compared to the lane of traffic.
0° / 100%
30° / 87%
45° / 70%
© STid 2014 – No unauthorised reproduction | General principles of UHF technology 3
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