Modifying Antenna Range
78
750.001.003
Revised June 1999
© 1999 AXCESS
TM
Inc.
Note: Each Reader is shipped from the factory with the voltage level
adjusted to its highest level.
Required Materials
The following materials are necessary for successful adjustment of
the transmission field:
•
A very small flathead screwdriver
Adjusting the Transmission Field
The output voltage is controlled by the blue adjustable pot on the
transmitter card. This pot is a thirty-turn pot -- it can rotate in one
direction 30 times. After it has been rotated 30 times, it will make a
soft clicking sound as it is turned, indicating that the pot can no
longer be turned in this direction and have an effect. When you hear
this sound, the transmitter card has been adjusted to one extreme or
the other.
IMPORTANT!
There are four blue adjustable pots in the card stack.
Refer to Figure 34 to ensure that you tune the correct one.
To lower the voltage level and reduce the transmission field
-
Rotate the pot
clockwise
. The volume of the chirping will also be
reduced. Constantly check the field to ensure that it has the range
that you want.
IMPORTANT!
The system will stop functioning if the voltage is
turned down too low. To fix this, turn the pot counter-clockwise until
the pot clicks and the chirping from the transmitter card can be
heard. Then back the field down again without turning off the voltage
to the system.
To increase the voltage level and enlarge the transmission field
- Rotate the pot
counter-clockwise
. The volume of the chirping will
also increase. When the pot makes a clicking noise it has been
turned up as high as possible.
When you have adjusted the field,
retune the ATU. See the
chapter
Maximizing Antenna Performance with the ATU
, page 73.