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Author Topic: Bluetooth speaker RFI  (Read 191 times)

N2QLT

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Bluetooth speaker RFI
« on: March 27, 2022, 08:10:10 AM »

I have one neighbor, about 100 yards away. He has an outdoor bluetooth speaker that is always powered up. The switching power supply was creating tremendous buzzsaw style RFI. I bought him a nice power supply with a transformer in it and that solved the problem. The power supply probably cost more than the speaker. The speaker itself is emitting a somewhat low level screaming sound between about 3 and 21 mhz. I also hear it on FM broadcast band. I'm guessing that the RFI is being introduced into the power lines. I have a big core of type J material, I was thinking of trying to make a choke with an extension cord to plug the power supply into. Any other ideas? Thanks.
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KH6AQ

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Re: Bluetooth speaker RFI
« Reply #1 on: March 29, 2022, 11:55:15 AM »

I recommend wrapping the power supply input and output cables each with 12 turns through an FT240-31 or FT240-43 ferrite core.

  https://www.qrz.com/db/N6VNO
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N2QLT

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Re: Bluetooth speaker RFI
« Reply #2 on: March 30, 2022, 05:36:52 PM »

Thanks. I found some cores on Amazon for about $13. I will try those. I'm not really sure what type J is, but I will just hold on to it. Don't want to keep going back to the neighbor's place more than I have to, ha ha.
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KH6AQ

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Re: Bluetooth speaker RFI
« Reply #3 on: April 04, 2022, 06:44:53 PM »

It is very nice that your neighbor is working with you on this.
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