User's Manual

GBI Antenna Controller User Manual Ver. 1.00
Antenna Tuning
P/N 1100031 page b
4) Using the
ceramic screwdriver
, turn the antenna matching capacitor to
reach
maximum
capacity.
OEM
GND
SIG
Antenna
VCpCp
Ls
Matching
Capacitor
ANTENNA
MATCHING CIRCUIT
Cable
Z
0
=50 Ohm
Cable
Z
0
=50 Ohm
Figure 3-2: Antenna Matching Circuit
5) Turn the antenna matching capacitor slowly counter-clockwise (CCW)
until the maximum DVM reading is achieved (approximately
110 - 130 mV).
Note: If voltage is highest when the matching capacitor is at the position of its
maximum capacitance, replace existing Cp capacitor with one of the next
higher
value. If voltage is highest when the matching capacitor is at the
position of its minimum capacitance, replace the existing Cp capacitor
with one of the next
lower
value (see Table 4.1).
Next, repeat steps 4 & 5.
mV
Cap
Max.
reading
in
Max.
position
Cp Value
to o h igh
Cp Value
to o low
Cp Value
OK
Vcp
min.
pos.
Vcp
min.
pos.
Vcp
min.
pos.
Vcp
max.
p
os.
Vcp
max.
p
os.
Vcp
max.
p
os.
Cp+VcpCp+Vcp Cp+Vcp
Max.
reading
in
Min.
position
Max.
reading
in
Range
Figure 3-3: Choosing the Antenna Matching Capacitor (Cp)