When multiple backpack readers are used in a group the charge pulses all need to be synchronized to go on and off at the same time. This can be done by enabling wireless synchronization. In this mode, after the reader listens for the tag message it also listens for other charge pulses. If one is heard then the reader extends the listen time a little longer to try and get in step with the other reader.
In a group of mobile readers it is useful to have one central reader be the master with synchronization mode turned off. All other readers will synchronize to that signal.
Wireless synchronization is also good for using a mobile reader passing through the scan zone of a stationary antenna. The stationary antenna does not need synchronization enabled, just the mobile one.