TransCore Amtech IT2200, Инструкция по установке, обслуживанию и ремонту

Страница: 69 / 204

4-3
Chapter 4
Installing the IT2200 Reader System
This chapter includes information on:
Assessing the Site — Instructions for conducting an RF survey of the
chosen site and formulating a frequency plan.
Preparing the Site — Checklist of tasks involved in preparing a site for
installation.
Installing the System — Checklist of required components and a
checklist of installation tasks. Description of where to mount the reader
system components for several typical site configurations. Step-by-step
instructions for installing the system.
Assessing the Site and Formulating a Frequency Plan
Perform an RF site survey to check for RF noise sources near the toll plaza or toll lane
being installed. Use a spectrum analyzer and a horizontally polarized whip antenna.
(TransCore recommends a Agilent Technologies Model 8523 spectrum analyzer.)
•
Set up the test equipment under the plaza canopy, if possible, or within a 15m (50-
ft) radius of the plaza.
•
Record any frequencies operating in the 902 to 904 MHz or the 909.75 to 921.75
MHz bands.
•
If you find frequencies within these bands, check the power level. Power levels
exceeding -10dBm could possibly alter the consideration of installing the system
at this site or the frequency plan for the system. Consult with Amtech
®
if you
encounter this problem.
Formulate a frequency plan for the plaza. There are two frequencies for each reader:
downlink (reader-to-tag communication) and uplink (tag-to-reader response). For this
system, all readers share the same downlink frequency, which is generally set to
918.75 MHz. Uplink frequencies should alternate between adjacent lanes. For exam-
ple, a four-lane plaza would have the frequencies shown in Table 4-1.