[PPRAANet] source of interference

[Greg Beeley]

Hi all,

Interestingly, if you read some of the FCC's publicly-posted warning 
notices, some of them specifically tell people that the source is most 
likely a light fixture, so this can indeed get bad enough to elicit 
complaints and FCC actions in the worst cases.  The recommendation is 
indeed to walk around the building with a handheld AM radio to find the 
source of the problem.

LED bulbs have problems not only in their power supplies, but also with 
internal arcing esp. with age, which of course creates broad spectrum 
interference.

73,

- Greg AK6B


ken at k0kwh.me wrote on 10/4/22 18:55:
> Hi Jim,
>
> Good information, glad you shared.
>
> In my opinion, LED replacement light bulbs are all terrible when it comes to interference.  Some are better than others (kind of a get what you pay for type deal), but none are great.
>    
> It gets exponentially worse if they are installed in fixtures that have dimmer switches which were dimming a standard bulb.  Most all the LED replacements say they are dimmable, but if you read the fine print, the good ones will say what dimmer switch(s) they have been tested with, which is probably not what was installed for the standard bulb.   Having a dimmer switch that has been tested and compatible with the LED helps, but at the end of the day, LED replacement bulbs are usually made with cheap parts to keep the cost down.
> Going one step further - newer light fixtures that are LED (i.e. you cannot replace the bulb) run the gamut of good to bad when it comes to interference.  Again, it is mostly due to the manufacturer and what they are using for the housings, driver and LEDs.  This is definitely a get what you pay for deal, dimming can be problematic with these also.
>
> I could get into dimming protocols (forward phase, reverse phase, 0-10V, etc.) and LED drivers but that’s a deep rabbit hole.  Moral of the story, for the best results I would encourage anyone with any LED bulbs/fixtures to have them shut off when operating on any frequency.
>
> Ken - K0KWH
>
> Sent from my iPhone XS
>
>> On Oct 4, 2022, at 2:35 PM, K3ILC <je_madsen at comcast.net> wrote:
>>
>> For the past few months, I've been receiving interference on the 2-meter band -- it sounds like power-line interference, and is strong enough to interfere with some of the weaker 2-meter FM signals.
>> Today, I finally got off my butt and tracked down the source.  It is coming from two 8.8 watt LED bulbs I used to replace old ones in the kitchen (regular bulbs, not like the fluorescent tubes).  They are Feit brand -- think I bought them at Ace Hardware.
>>
>> So if they want to sell you Feit, put up a fight (or something like that).
>>
>> BTW tracking the source was simple.  Since it was on the 2-meter band, I switched my Yaesu FT60 HT to the AM mode, and walked around until I located the source.
>>
>> 73
>> Jim
>> K3ILC
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