[RFI] RFI from LED light fixture in garage 0.14 miles away from my house.

[Pete Smith N4ZR]

Jim, your report reminded me of the strangest RFI I have seen - a heated 
dog dish next door that totally took out 160M on my shunt fed tower a 
couple of hundred feet away

73, Pete N4ZR

On 11/2/2023 1:28 PM, AA5CT via RFI wrote:
>   Lesson learned on my part (year back now) - the higher frequency also means shorter wavelengths yielding 'plane waves'/freely radiating wave from a source closer in, having E and H fields normal to each other and then a DF apparatus will indicate correctly WHILE it is in the "far field" region" and outside the influence of noise coupling via magnetic of electric fields only in the near field ...
> My DF apparatus consisting of a marine direction finder using both a ferrite loop and a 'sense' antenna work well when respecting the near vs the far fields .. and going up in frequency sometimes I can see the direction indicated change, if I am not quite far enough away from the near field and into the plane-wave far field.
> Like you I've located down to a choice of two houses on the lower bands (160 meters in particular). Fortunately my noise went away after awhile so I didn't have the opportunity of going deeper. One of those sources was a (presumed) wireless dog collar that used a low freq but created wandering 'dirty' carriers below and in the 80 meter band.
>
> Good to know the results of your RFI-xpedition, Don.
> de AA5CT Jim
>
> -------------------------------
>
>
>      On Thursday, November 2, 2023, 12:01:36 PM GMT-5, Don Kirk<wd8dsb at gmail.com>  wrote:
>   
>   I had a very interesting case involving RFI on 160 and 80 meters and
> actually a little bit on 40 meters at my QTH which I was able to resolve
> yesterday.  For those interested here is a link to a youtube video I just
> uploaded that documents the case:
> https://youtu.be/Ktl-GNxq1C8?si=uUue8aG5asoC7_1B
>
>
> *Details*
> While I hate to admit mistakes I did make one while tracking down the RFI.
> Originally I tracked the RFI down using a frequency high in the AM
> broadcast band and all of my MF antennas (portable flag, tuned loop, and
> untuned loop) agreed on what house the RFI was coming from.  Well I was
> wrong by one house and when I later switched to higher frequencies (2 MHz
> and above) all of my antennas now indicated the RFI was actually coming
> from one house North of the first house I suspected.
>
> The two houses and their electric meters are only 14 feet apart from each
> other and their underground utility feeds run right between the two
> properties and it appears they get fed from the same ground mounted
> pedestal.  The first homeowner was kind enough to work with me and her
> house wiring was swamped with RFI even when we killed the main breaker to
> her house.  She then gave me permission to access her backyard during
> daylight hours so I could get better headings on the RFI.  I came back over
> with all my gear and quickly determined I was off by one house.
>
> Yesterday I worked with the second homeowner and within minutes of sniffing
> his circuit breaker panel with my sniffer loop we determined the RFI was
> originating from his garage circuit breaker circuit and that the source of
> the RFI was his indoor garage 3 panel LED light fixture that had been in
> service for a very long time (many years).  We replaced the LED light
> fixture with a new one he just happened to have still in its box and this
> cured the RFI problem (same light fixture manufacturer but different
> model).  I suspect something had failed in the old fixture that caused the
> RFI to suddenly appear this year.
>
> What was interesting about this entire case is that the RFI would typically
> come on around 8 or 9am and stay on until around 8pm but occasionally the
> RFI would not turn off at night.  It turns out that the homeowner's wife
> likes to leave the garage light on continuously during the day so it's not
> dark when she goes in the garage as the garage has no windows but sometimes
> they forget to turn the light switch off at night (light switch is in the
> hall that leads to the garage).  Initially I had to cancel a couple of
> visits to the house because for some reason the RFI was magically not
> present on the first 2 days I was scheduled to go there, but after we
> cancelled my visits due to lack of RFI the RFI would magically appear
> (within a half hour both times) and this had me thinking the homeowner was
> playing games with me.  I started to think I was dealing with a grow light
> because of the typical 12 hour on time of the RFI.  *What this experience
> once again taught me is to keep an open mind and don't jump to conclusions.*
>
> Well it's now time for me to bake a couple of batches of brownies and
> deliver them to both houses.
>
> Just FYI, and 73.
> Don (wd8dsb)
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