When using FM systems, remember that the receiver and transmitter MUST be set to the same channel. Color code receiver-transmitter pairs with indelible ink or nail polish, or record matching numbers on them. Have a pile of them in a drawer that you inherited when you got the job? Put fresh batteries in them, speak into one of the mics and have some one tell you which receiver is picking it up. Then mark the pairs.
Interference will come from other devices that also use FM. Even though certain channels are set aside for ALDs, devices sometimes ‘drift’ off their channels and must be recalibrated. Some interference will be short term, some long term. If the student is picking up construction worker’s directions in their Art History 201 course, you can try just switching channels on both the receiver and transmitter and see if that takes care of the problem. If not, you may need to get together with the construction folks, and maybe the company, to set up different channels for use.
