User's Manual
September 2013 63-70-076-DOC-1 31
MARS-24ATRUser Manual
5. WORKING WITH ANTENNAS
The MARS-24ATR requires special installation and tuning of external antennas. Refer to the ReaderManager User Guide
(40-01-006-DOC) for the antenna matching, tuning and testing instructions using the Reader Setup Wizard tool.
MARS’ external antennas are suitable for applications where one or many reading points are required. They are designed
to be used as free standing antennas, integrated into non-metallic (preferably plastic) housings, or even embedded
into desk tops or shelves.
Once antennas are placed in the position they are to be used, it is essential that they are xed in place and tuned.
The tuning is to be done only once at installation. All antennas have an adjustable capacitor that allows for
tuning.
5.1 mAteriAls
The material upon which an antenna is mounted and the positioning of the antenna itself can have a signicant eect
on antenna performance.
The eect of materials and antenna position on antenna operation may be determined as follows:
Place an antenna on a styrofoam block and tune for maximum voltage at the antenna center using an
Antenna Tuning Probe, digital voltmeter and a trimming tool. Then place the antenna on/into the installation
position, retune and measure the maximum voltage again. Compare the voltage values.
A difference of 10% or less is acceptable. If the voltage reduces by more than 10%, this indicates that
the material is adversely affecting the antenna. The user should determine if the reduction in operation is
acceptable by measuring read range and stacking operation. If the reduction is not acceptable the antenna
must be relocated.
Alternatively the use of a plastic spacer of 5 mm minimum thickness between the mounting material and the
antenna is recommended where the mounting material is adversely affecting the antenna.
Antenna performance may be aected by conductive and metallic materials in the immediate vicinity of the antenna.
Metal, metallic or metallized objects placed next to the reader antenna may change the characteristics of the antenna
aecting the tuning operation and reducing the read range.
It is recommended that the antenna should not be placed closer than 35 cm to any metallic object that is of a similar
or larger size to the antenna.
Small metallic objects such as jewelry or coins put on the antenna will have almost no aect on the antenna
performance.
If metallic conveyor rollers are a part of an application it is recommended that they be replaced with plastic parts if
possible or apply shielding techniques as required.
Materials such as wood, laminated MDF, HDF or plywood have a limited conductivity. If an antenna is mounted into
these materials some reduction in the read range can be expected.
Plastics are the best materials on which to mount an antenna provided that they are graphite/carbon free.
•
•
•