This article describes the difference between the Main and Aux antenna’s negotiation.
Scope
FortiExtender 2XX Series.
Solution
The main RF channel and antenna handle both TX and RX functions, supporting multiple RF bands.
The Diversity (AUX) RF channel and antenna are used for RX only. They must be paired with the main RF channel/antenna for transmitting to the base station and enabling MIMO reception. Using the Diversity (AUX) antenna alone will not establish a proper connection with the base station, as there is no TX from FEXT to the base station.
If installation constraints allow for only one antenna, it must be the main antenna. Otherwise, there will be no uplink.
Without the Diversity (AUX) antenna, MIMO reception is not available, resulting in lower RX throughput, but the LTE connection will still function
