Siemens SIMATIC RF600 System Manual page 166

Antennas
6.2 Guidelines for selecting RFID UHF antennas
Antenna cable loss
In order to be able to transmit the available UHF power from the SIMATIC RF660R reader to
the antenna(s), the antenna cable loss must not exceed a value of approx. 4 dB.
Dependency of the cable loss
The cable loss depends on two important factors:
● External characteristics of cable. These includes the cable length, diameter and design.
● As a result of the physical principle, the cable loss is also frequency-dependent, i.e. the
Cable vendors usually provide tables or calculation aids for their types of cable which usually
include the transmitter and receiver frequencies as well as the cable length. Therefore
contact your cable vendor in order to determine the appropriate type of cable using the
approximate value referred to above.
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cable loss increases at higher transmitter frequencies. Therefore the cable loss must be
specified in the frequency band from 860 to 960 MHz.
System Manual, 10/2009, J31069-D0171-U001-A8-7618
SIMATIC RF600