Here is follow up to my Oct 14th posting about RFI tracked down to my
neighbors house. My neighbors house is on an adjacent street and her
backyard backs up to the side of my backyard.
Today I was able to go into my neighbors basement with my laptop based SDR
receiver and a 1 foot diameter untuned shielded loop and we quickly
determined the RFI (3.5 to 28 MHz repeating every 10 KHz) was generated by
LED string lights that she purchased on Amazon.com. Her bedroom is in the
basement and she ran the string lights around the entire perimeter of the
ceiling (probably 25 feet x 20 feet). I replaced the 24 Vdc 1 amp wall
wart power supply with my linear bench top power supply and that did not
eliminate the RFI so my guess is that the little LED controller box that
the power supply plugs into is the real culprit.
Note: My neighbors basement is approximately 120 feet from my antennas.
My neighbor is very concerned about EMF as her daughter who also sleeps in
the basement bedroom with her had a brain tumor removed earlier this year
and she had already been reading about the possible ill effects of EMF even
though I did not mention medical concerns with her related to the RFI her
house was generating.
My neighbor does not plan to use the lights anymore but I’m going to
investigate possible solutions.
Just FYI, and this case once again proves that I should never guess the
source as I would have guessed wrong.
Don (wd8dsb)
On Mon, Oct 14, 2024 at 11:08 AM Don Kirk <wd8dsb@gmail.com> wrote:
> I've been encountering new RFI this year every 10 KHz on 80 through 10
> meters and quickly (within minutes) tracked the RFI down to my neighbors
> house using my Portable Flag with DX engineering preamp connected to my
> laptop based SDR receiver. My neighbor lives on an adjacent street and his
> backyard butts up to the side of my backyard.
>
> I finally approached my neighbor yesterday who I get along with just
> great, and using my small 1 1/8 inch sniffer loop with the DX Engineering
> preamp connected to my SDR receiver we (my neighbor and I) were able to
> identify what circuit breaker in his main panel was suspect. We then
> turned on and off this circuit breaker and sure enough the RFI at my house
> as well as at the homeowners house can be turned on and off via this
> circuit breaker. The circuit breaker is identified as "basement" and
> therefore will have to schedule another time to enter the basement to
> investigate what device is generating the RFI as 3 generations of family
> live in the house and the person who has a bedroom in the basement was not
> home at the time.
>
> I have some suspicions on what's causing the RFI based on some other
> pieces of information I have about recent equipment installations
> and repair at my neighbors home but I need to keep an open mind as always
> and will let the data talk.
>
> For those interested, here is a link to a youtube video I just uploaded
> that shows the sniffer loop at the suspect circuit breaker and our turning
> on and off the RFI via the circuit breaker.
>
> Youtube video link: https://youtu.be/2fJav77AVok
>
> Just FYI, and 73.
> Don (wd8dsb)
>
>
>
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