Feig Electronic OBID ID ISC.ANT310310-A Montageanleitung Seite 41

®
OBID i-scan
In order to re-adjust the antenna on 50  and phase angle 0°, the jumper terminals J1, J2 and J3
may be used for re-tuning. See chapter 4.6 How to measure the voltage standing wave ratio
(VSWR).
The purpose of the tuning process is to tune the antenna, again, as close as possible to

Z = 50 +/- 3
Please proceed as follows:
1. Adjust jumper terminals J1, J2 and J3 according Table 2
2. Adjust capacities by using terminal J3 at the optimal value lying close to 50  (minimum value
VSWR).
3. Adjust capacities by using terminal J1 and J2 at the optimal value lying close to 50  (minimum
value VSWR).
5. Repeat step no. 2. and 3. till a impedance of 50  ± 1  and phase angle 0°± 3° is reached
(minimum value VSWR <=1:1.3)
Setting the capacity at the terminals J1, J2, J3 at the best matching point close to 50  and phase
angle 0° must be done by insert or remove the jumper. Thereby, the value at the analyser or
VSWR meter before and after the change has to be compare.
As first step, the small capacities should be changed. If this change get an improvement or if the
jumper is inserted already with the next larger value has to be continued
If the closing of Pin 1-2 improve the matching, the next step would be to close Pin 3-4 and open
Pin 1-2. This is because the capacitor at Pin 3-4 has approximately twice the value of the capacitor
at Pin 1-2.
The jumper configuration at terminal J1 and J2 should be put equal. Big capacities at terminal J1
and small values at J2 lead to asymmetry in the antenna. This can lead to performance losses
and/or damage of the components in the antenna
Note: Voltages as high as 1000V may be present on the antenna wire or on various compo-
nents of the tuning boards. Before starting your work first disconnect the antenna from the
Reader. When tuning the antenna make sure no components inside the housing are
touched.
FEIG ELECTRONIC GmbH
50 . maintain the following tolerances:
and phase angle Phi = 0° +/- 3° or R = 50 +/- 3
or VSWR <= 1:1.3
Page 41 of 46
Installation ID ISC.ANT310310-A
 +/- 5 
and X = 0
M90401-2de-ID-B.doc