Hi,
I received about 5 Sennheiser ew 135 G3 handheld mics and I am about to use them for the first time.
After gathering some info in the manual, I found out how to scan for frequencies etc.

MY BIG QUESTION IS:
I will be using the mics in a school with roughly 900 Students, how can I ensure a stable RF transmission
(with all those cellphones in the room) and Walkie-talkies (with run on 2.4 GHz so not a problem).
The scanning for frequencies will be done long before the 900 Students are in the hall, so I can't really check if the RF connection
is indeed stable or if there is any interference from cell phones.

I hope you guys can understand this problem, please tell me what I should do to get the best possible reception.
(I am just really nervous as this is the first time they are being used).


Cheers.