Question: In a Base Station (BS) using antenna arrays, what condition does NOT alone meet the criteria for applying the special testing considerations outlined for antenna arrays?
Option 1: The transmitter output signals from one or more TRX appear at more than one antenna port.
Option 2: There is more than one receiver antenna port for a TRX or per cell, with an input signal required at more than one port for correct operation.
Option 3: A BS operates in conjunction with an external antenna system containing necessary filters or active elements for UTRA compliance.
Option 4: Diversity reception is utilized, where multiple antennas are used to improve signal quality.
Explanation: According to the provided context, diversity reception (where multiple antennas are used to enhance signal quality) does not meet the condition for applying special testing considerations for antenna arrays. This is because the criteria specifically exclude diversity reception as a qualifying factor, emphasizing instead scenarios where signals are directly connected to and combined from/to multiple antennas or when transmitter outputs appear at more than one antenna port.