Which is not correct about the air interface utilization?

What does the key indicators of the combiner include? (Multiple choice)

What is the type of radio frequency interface in the picture?

Good grounding is also an important means to ensure the normal operation of communication equipment, what are its functions? (Multiple choice)

According to the working principle of the wireless air interface competition mechanism (CSMA/CA), it is recommended that the number of nodes participating in the competition should not exceed ______, because when the competition point reaches ________, air interface conflicts will rise sharply. In actual business, to ensure the effective bandwidth of users, it is recommended that the number of concurrent users under each P AP does not exceed _______.