Maximizing Antenna Performance with the
ATU
Because the antenna transmits by inductive coupling at low
frequency, it is subject to environmental detuning, due to where the
antenna is mounted, what material it is mounted on, etc.
For this reason, it is impossible to factory pre-tune antennas for
optimized generation of the
wakeup
signal.
Currently, ATUs have one of two methods of adjustment - toggle
switch or jumper. While the methods for adjusting performance are
different, the ATUs are functionally the same.
Adjusting Antenna Performance
Step 1:
Apply power to the Reader.
Step 2:
Open the Reader. Ensure that the card stack has four
LEDs lit and is emitting a ticking sound.
Step 3:
Open the ATU cover. NOTE! You will see
either
a toggle
switch and rotary dial (Figure 30) or a series of 11 jumpers
(Figure 33). To tune an ATU with jumpers, see page 75.
TX
A
n
tenn
a
RX
A
n
tenna
RX
R
eade
r
TX
Re
ader
1
0
2
Rotary Switch
3-Position Toggle Switch
P
R
IM
AR
Y T
U
N
IN
G
S
E
CO
N
D
A
R
Y
T
U
NI
NG
H1
1
1
Header
0
5
10
15
0
D.
C
. VO
LT
S
Figure 30 ATU with toggle and rotary switches