I’ve performed radio subsystem trace (TRX internal decoder ) to see those rach. Of course they could be generated by the bts itself but , from our last findings on phatom rach, there is an erratic behavior for these rach in our system . both TA and Cause are random. We also find a strange behavior of the system but only for LU and at TA=0 but nothing has been ever found on Rcah with emergency cause.
I’ve allready asked for frequency changed. waiting for an answer from customer. (and according to the crazy amount 1/2h should be enough 🙂 )
I’ve also checked rach time reception and they seems to be random. you can have 2 minutes without any rach then 2 in 15ms (which is not a racch repetition due to ccch_conf and tx_interger settings of the network)
I’m afraid antenna downtilt is not the solution because it should not really affect reception . i was thinking in intermodulation issue.