[RFI] LED fish tank light noise.

[Dave (NK7Z)]

Hi,

I had a similar problem with a wall SMPS, (switching mode power supply). 
  I used a single 240/31, with 7 or 8 turns of the power cord, wrapped 
such that the ferrite was as close to the power supply as I could get it.

The problem ended.  I also tried 5 snap on Mix31 ferrites, and the 
problem persisted...  The blocking ability for RFI goes up dramatically 
when you wrap turns on a ferrite.

See:

http://k9yc.com/2018Cookbook.pdf

73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist, RFI
ARRL Asst. Director, NW Division, Technical Resources

On 4/22/22 07:20, Mike Fatchett wrote:
> This morning the noise is back.  Same light.  Tried a snap on on the 
> other side of the controller which did not work.
> 
> W0MU
> 
> On 4/21/2022 11:36 PM, Mike Fatchett wrote:
>> I ran into a new noise here.  It started on 15m through 40m on 
>> antennas close to the house.  The noise seemed to come on in the late 
>> afternoon or evening.  It was very evident when I turned the antenna 
>> toward the house.
>>
>> The noise almost sounded like an am signal in the noise.  KOA radio 
>> with 50k watts is about 5 miles away so they can get into lots of 
>> things.  There were distinct mounds about every 20kcs and an overall 
>> hash on the flex that took the noise floor from -120 to around -110.
>>
>> The only thing in the house that I could think of are my fish tank 
>> lights.  I have 3 tanks all with the same light or similar style and 
>> design.  I pulled the plug and the noise is gone.   I narrowed it down 
>> to the tank that is in the shack.
>>
>> The brand is Hygger and I bought it from Amazon.  It is an led light 
>> bar.  I wrapped a number of turns through a snap on ferrite and 
>> plugged it back in.  So far so good!  The cord is a wall wart that 
>> plugs into the control unit which turns the light on, timer etc.    42 
>> watts  215 led bulbs.
>>
>> I can attempt to detail this further with recordings and screen shots 
>> if needed.
>>
>> I just thought I would pass this along.
>>
>> Mike W0MU
>>
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