Electronic – How to prevent PA system from interference of 4G signal

interferencesignal

I apologize if this is not the right place to post this.

I am working on a small PA system for a weekly gathering. It catches the signal from wireless mics and output it to the speakers. I am pretty sure that the machine itself is not damaged.

Recently, I've found that there are very sharp digital noise coming out from the speakers and it is so annoying that it masks the voices and songs. I've done some investigation and found out that it could be caused by 4G cell phone signal. So I tried some experiments and the observations seem proved the theory.

I've learned from my online research that I can either ask everyone to turn off the 4G signal (which is unlikely since the population is around 100), or replace my PA system.

Is there another way out? Such as a 4G signal filter or jammer? If so, my concern is, will these filters and jammers also get rid of the signal from the wireless mics?

Thanks.

Update 1:

Thank you all for your advice. Unfortunately, I cannot get access to the equipment until this weekend. I'll mark the models of the gears and post them here then. I'll also try to upload a sample noise for your analysis.

Best Answer

I've worked on small PA systems for weekly gatherings for about 20 years. The problem you describe is common, but usually fixable, and usually indicates a design issue with the wiring of the PA system. I've never had any success with filtering, every success was from changing the wiring.

Describe the wiring totally; the type of connectors, the number of wires in cables (balanced, or unbalanced), where the cables come from and go to, and the type of amplifier. Photographs of the amplifier would help.

You may be able to shorten this effort by testing one channel of the system at a time, with other channels disconnected.

If a particular channel is sensitive to the problem, change to balanced cabling and test again.

Check the earth of the system exists in only one place.

If the wireless receiver unit is separate from the PA, disconnect it and use another device to listen for the noise. If you truly have noise arriving with the wireless signal, you'll probably have to replace the wireless receiver.

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