[Wswss] PNWVHFS Thread: QRN From LEDs

[peter h]

N6zeLEDqrn  27nov18



QRNComments on PNWVHFS chat room by W7YOZ & others




 


Ihave just (finally) tracked down a broadband noise source which has hinderedreception on 144 Mhz. at W7YOZ.  It sounds like the typical buzz powerline noise on HF and can be seen  on my K3 IF radio spectrum display as anincrease in the base (grass) noise floor across the entire 200 KHzbandwidth.  After monitoring this and recording on/off times forseveral weeks it became apparent to only occur during the night darkhours.    With some newer neighbors installing motion actuatedflood lights etc. they seemed a likely source but their timing did notcorrelate withy my noise observations.   Further tests revealedit was a LED floodlight  on my own detached garage which houses myham shack.  This was installed some time ago in favor of theformer incandescent bulbs which frequently burned out (over 20 years)and were difficult to reach and replace. 




 


I nowhave made further on/off noise level comparisons with this LED lightand find a consistent 144 MHz base noise level of -113 dBm with the LEDlight off and -99 with it on  for a total degradation of 14dB!!   This was measured on an R-9500 receiver with a discone antennalocated about 20 ft. above the garage.   I will make further tests tosee what other bands are affected.  




 


Iam submitting this in hopes it may help others identify at least one of thenasty new noises that pop up with increasing frequency in ourbands.     




 


73,




 


MerleW7YOZ



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When I started switching over to LED bulbs in the house12yrs ago, I purchased one of each brand I could find in stores at the time,about a dozen as I recall, and tried them out for QRN, using an MFJ RF noisefinder in addition to monitoring band noise on my receivers (the MFJ doesn’t doVHF/UHV, but I used my Icom 910H to listen).  The majority of the brandsproduced significant QRN from their built-in switching power supplies, butthere were two exceptions: Creed and Energetic; I still have them in my houseand I can't detect RFI/EMI until the noise finder is close to the bulbbase.  Feit was the worst by far then, I recall, followed bySylvania  Now, with that said, the manufacturers are constantly changingtheir designs and these many year later I wouldn't be surprised if the list ofbest vs worst has changed completely.  BTW, I also found that I had toloop many AC cords through ferrite power cord chokes throughout the house, egrefrigerator, microwave oven, flat-panel TV...and I installed a line filter inmy shack for the radios.  Peace and quiet bands result.

Moral of the story: try a couple different brands to find a bulb that isacceptable to you.

I tried to get the ARRL Lab to do comparative testing of LED house bulbs for anarticle, since they have expensive lab-grade RFI/EMI measurement equipment anda supposed RFI/EMI engineering specialist, but they refused to do it despitethe rapid growth of LED house bulbs at the time presumably also in hamhomes/shacks & their neighbors.  This was one of the many, many thingsthat eventually led to me not renewing my ARRL membership in disgust.  Butit may be a new era, since we have a lot of new ARRL Division Directors electedthis month (Nov) to replace the incumbents and who are a new majority on theboard and are promising to effect transparency for members about the board andorganizations affairs, and make some needed changes to reverse decliningmembership (less than 20% of licensed USA hams are members).  Our own NWDivision Director is one of those change agents, Mike Ritz W7VO, who was justelected and will begin in January with the other new board directors. Based on the hope of such change, I signed up for membership again lastweek.  Maybe some day the Lab there will help hams understand how to dealwith LED QRN without them having to spend the time that I did on that issue.

Stephen W9SK



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Hi Merle, sameproblem here. My neighbor 2 houses away has 6 led floodlights in her diningroom and when she turns them on the 2 meter band get wipe out with 8+ noiselevel. I found out that some led lights sold by Costco( brand  Feitelectric) are the culprit. I haven't done anything yet since she is in badhealth and I don't want to bother her for now. This is one of the reasons I'mhaving a hard time participating on the weak signal group on Tuesday nights.



Cesar N7bus



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I guess Iwas lucky that I bought Creed LED's 
from (Home Depot) in the beginning.  No RFI on 
any band up to 1296.  I have no problem with 
florescent lights or even the low-psi sodium yard 
light.  I get into our subwoofer when I operate 
6m.  Tried ferrites but did not help.

New 6m yagi will be further from the house and 
amp located at tower base which might help?

73, Ed - KL7uW