Encompass 4 Reader System Guide
8-20
physically adjusting the Encompass 4 Reader or external ante
nna mounting orienta-
tion, reprogramming the actual RF power output (#6
44NN Set RF Attenuation), and/
or reprogramming the RF sensitivity range (#643NN Set ATA Operating Range and
#645NN Set eGo and eGo Plus Operating Range). The combination of these adjust-
ments allows you to confine the read zone to the area where tagged vehicles pass. This
opera
tion also minimizes reading unwanted vehicles in adjacent lanes or parking
areas.
See sections “643NN Select ATA Operating Range (Distance)” on page 7-38, “645NN
Set eGo and eGo Plus Operating Range (Distance)” on page 7-38, and “644NN Set RF
Attenuation” on page 7-38 for more information.
Note: As desc
ribed in “Marking the Read Zone” on page 4-38, marking the read pat-
tern using test tags that are not mounted
to vehicles give a general idea of the read
pattern but the pattern will vary somewhat when actual vehicles with tags are tested.
Final adjustments must be made with tags properly mounted on a variety of vehicles.
Physically Orienting the Encompass 4 Reader
You can manually adjust the location of the read zone by loosening the Encompass 4
Reader mounting brackets and pointing the reader in the desired direction. The unit
should be aligned to point directly at the tag as it enters the desired read zone.
Physically Orienting the Encompass 4 Reader Antenna
You can manually adjust the location of the read zone by loosening the antenna
mounting brackets and pointing the antenna in the desired direction. The unit should
be aligned to point directly at the tag as it enters the desired read zone.
Fine-Tuning the Read Zone by Lowering Output Power
You can make the read zone smaller by adjusting the Encompass 4 Reader RF power
output from a maximum of 2 watts to a minimum of 200 milliwatts using command
#644NN Set RF Attenuation. Lowering the RF power has the added benefit of reduc-
ing RF interference with adjacent lanes.
To adjust the read zone by lowering output power
1. Ensure that your PC is communicating with the Encompas
s 4 Reader using a
terminal emulation program as described in section “Verifying Communications”
on page 8-8.
2. Mark the current read zone as described in section “Marking the Read Zone” on
page 4-38.
Caution
Test tags should be compatible with your
Encompass 4 Reader. Test tags can be
ATA-protocol, ISO-compliant, or Inter-Agency Group tags affixed to a plastic or
wooden yardstick, or eGo or eGo Plus sticker-type tags affixed to a piece of nonme-
tallic windshield-type glass 0.190 to 0.230 in (4.82 to 5.84
mm) in thickness. The
sticker-type tags have a reduced read range when not attached to glass.
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