Mutual Interference Of Readers (Antennas) - Siemens SIMATIC RF600 System Manual

RF600 system planning
4.3 Antenna configurations
4.3.5

Mutual interference of readers (antennas)

Using more than one reader
When several RFID readers are used, there is a danger that RFID tags can also be read by
other readers. It must be ensured that the tag can only be identified by the appropriate
reader.
Technical disruptions between readers then occur particularly when they transmit on the
same channel (on the same frequency). You will find more detailed information in the section
"The response of electromagnetic waves in the UHF band (Page 72)".
To prevent this, readers used in Europe and China must operate on different channels with
"frequency hopping" activated. "Frequency hopping" is permanently set in the USA.
Antenna alignment and antenna spacing with an external antenna
The minimum distance required between antennas that use the same frequency and that are
connected to different readers depends on the maximum radiated power set (RF670R with
RF660A = 2000 mW ERP; RF640R with RF660A = 2000 W ERP; RF620R/RF630R =
500 mW ERP) and the antenna alignment.
Figure 4-5
48
Antenna distances for different readers and identical frequencies
System Manual, 05/2012, J31069-D0171-U001-A13-7618
SIMATIC RF600