Installation Manual

Modifying Antenna Range: Adjusting the
Transmitter Card
Introduction
Each Reader contains a card stack that has five sub-boards, each of
which has a specific function. The transmitter card controls the
voltage output to the transmit antenna. If the Reader’s connectors are
at the bottom, then the transmitter card is on the bottom of the stack
(Figure 34). This card also can be identified by the faint chirping
sound it makes and the cable that goes to the TX connector on the
outside of the Reader.
Conduit
Chase
Terminal Block (TB1)
Ground Lug
RXRS-232
Unilon TX Card
Transmitter Card
Unilon Output Card
RF Card
TX
Unilon RX Card
RJ-45
Cabling Label
Reader Case
Figure 34 Reader – Internal View
The transmitting antenna puts out a “wakeup” field that activates
Tags entering that field. The area of Tag activation can be controlled
by adjusting the size of the transmit field. By turning down the voltage
to the transmit antenna, you shrink the transmit field. This is useful
when a transmission field extends beyond its desired area. For
example, you may want to shrink a transmission field for a Road
Loop so that the size of the field is only a lane wide. This prevents
accidental activation of Tags in another lane – for instance, a parking
garage with entrance and exit gates right next to each other.