OBID
®
Installation
ID ISC.ANT300/300-A
FEIG ELECTRONIC GmbH
Page 33 of 43
M01001-2de-ID-B.DOC
E N G L I S H
5.4 The influence of the noise level on the antenna’s working range
Interferences have to be largely avoided, so that the smart label may be read by the receiver even
at low signal levels. The amplitude of the interference levels can be found out at reader
ID ISC.LR200 with the help of the noise levels. Critical are not the absolute measured values, but
rather the difference between Umax-Umin.
This has been simulated at 4W and represented graphically in the following figure.
Figure 18: reading range* in dependance on the noise levels
*Label 46 x 75 mm
2
, over the centre of the antenna, sensitivity / minimum operating field
H
min
=85mA/m rms, parallel orientation to the antenna,. transmitting power 4 W.
The difference of the noise levels (U
max
- U
min
) should be less than 20 mV.
Possible reasons for excessive noise levels:
•
Bad (HF-)connections between reader and antenna.
•
Improper cable layout between antenna and reader
•
Badly tuned antenna
•
Interfering signals of other electronic appliances or transmitting stations.
•
Interfering signals on the reader’s power supply line.
•
Interfering signals coming from other cables close to the cables leading to and away from the
reader.
•
Metal parts close to the antenna
20
25
30
35
40
45
50
55
60
0
100
200
300
400
500
Noise Level Umax-Umin
reading range [cm]
