Tagsys S.A. LIBSECPEDEST2 Manuale Utente
LIBRARY SECURITY PEDESTAL 2
Figure 30: Antenna Tuning (Isolation) with Impedance Analyzer
EAS Pedestal
Network Impedance Analyzer
Top
Antenna
Center
Antenna
Bottom
Antenna
Calibration Plane
(50 Ohms + 0j)
B
A
R
RF Out
Transmission/Reflexion Set
RG-58 Cables
Figure 31: Isolation Values using an Impedance Analyzer
Poor Isolation
Good Isolation
Note that the isolation adjustment process often requires repeating the procedure several times
between the top and center antennas and between the center and bottom antennas. This means
that it is normally more difficult to achieve good results of isolation between the center and bottom
antennas. Therefore, it is important to check and minimize the isolation between the center and
bottom antennas before moving to the top and center antennas. Typically, an isolation value equal
to or less than 100 mVpp should be obtained between the center and bottom antennas and also
between the top and center antennas.
between the top and center antennas and between the center and bottom antennas. This means
that it is normally more difficult to achieve good results of isolation between the center and bottom
antennas. Therefore, it is important to check and minimize the isolation between the center and
bottom antennas before moving to the top and center antennas. Typically, an isolation value equal
to or less than 100 mVpp should be obtained between the center and bottom antennas and also
between the top and center antennas.
Once the antennas have been correctly tuned for optimal impedance and isolation, it is best to
verify their synchronization with the mains power supply and the trigger threshold levels.
verify their synchronization with the mains power supply and the trigger threshold levels.
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Revision 1.0
December 2004