[RFI] LED Bulbs

Dale svetanoff at earthlink.net
Wed Feb 12 12:37:10 EST 2014


Gary,

Short answer to your question: NO.  "Hospital grade" is a SAFETY issue, not an RFI issue.  Those green dots on hospital grade electrical connectors and equipment means that the items have met certain specifications applicable to the hospital environment, including AC power leakage current - an important spec for anything that connects or touches a patient's body.  

Other than military specs, such as MIL-STD-461, the Part 15 Class B and A limits are what there is.  Period.  We would all be happier hams if all consumer electronics met the 461 levels of radiated and/or conducted emissions, which are designed to allow co-located systems on a common platform.  (Translation: multiple electronic systems on the same vehicle, in the same building, or on a person.)  Problem: no one could afford to buy anything.  Part 15 limits do reduce interference between Part 15 devices, but have little hope of reducing RFI to radio operations because of the allowable limits.  Note that Class B-rated devices are for home or office use, Class A-rated devices are for commercial and industrial use, and those limits are even higher.  That is why I can detect point of sale systems in gas stations, banks, and Walgreens Drug Stores at a block or more distant with my 2m/70cm mobile FM rig.  

As I have posted here before, one significant problem with some of the consumer grade garbage is the fact that some off-shore (you know who I mean) producers are prone to submitting an item for FCC approval testing, win approval, then alter the regular production units by leaving out the EMC components to save costs.  It is precisely those turkeys whose products need to be reported and confiscated.  BTW: Yes, I have personally seen altered equipment.  Easy to spot, but you have to usually cut them open or break their housings to see the pc boards inside.  You will find jumper wires in place of missing inductors and vacant solder pads where by-pass caps should have been placed.  A sickening sight.

With all of the weeping and wailing going on in this thread, I make one modest suggestion: before saying that a certain piece of consumer electronics is junk that needs to be tossed, you need to confirm if it actually does bear an FCC marking (meaning it passed Class B or A) AND then you need to determine if it is one of those altered products I described above.  Keep in mind that actual Class B limits are around 30 dB (or worse) above the MIL-STD-461F limits.  It can take a LOT of design technique and hardware implementation (all spelled "$$$") to get rid of those extra 30 or so dB of noise.  

Finally, keep in mind that YOU can not stop emissions from your neighbor's junk at your end.  The solution is to apply fixes at the source, as Jim, K9YC, has said so many times on this forum.  That means winning the cooperation of your neighbors and (probably) paying for the materials to make the fix.  The "good" news is that the farther you are from the neighbors, the less "fix" required.        


-----Original Message-----
>From: Gary Smith <wa6fgi at yahoo.com>
>Sent: Feb 12, 2014 10:52 AM
>To: rfi at contesting.com
>Subject: Re: [RFI] LED Bulbs
>
>Would it be a better idea if we hams suggested that our neighbors look 
>for "hospital grade" electronic and electrical devices?
>
>I have done my best to "educate' my neighbors, this has helped over the 
>long haul somewhat.
>
>Gary...wa6fgi
>
>
>
>On 2/12/2014 7:43 AM, CR wrote:
>> This may be a good one to complain about anyway given the broad 
>> spectrum of interference reported; it will affect broadcast, air to 
>> ground communications, police, fire and commercial radio reception as 
>> well.
>>
>> FWIW, Part 97 is not where you should look for illumination devices; 
>> look in Part 18. Harmful interference *is* unlawful.
>>
>>
>> Cortland Richmond
>>
>> PS: Apologies for mistaking you for the other Dale. He and I have been 
>> working in EMC for years.
>>
>> On 2/12/2014 10:25 AM, Dale J. wrote:
>>> Hi Roger,
>>>
>>> Now that statement I'll agree with.  I will too.
>>>
>>> Even if I were to call the FCC to complain would I talk to a live 
>>> human who knows what I'm talking about or would it be a robot that 
>>> directs me to a FAQ on how to deal with RFI.
>>>
>>> 73
>>> Dale, K9vuj
>>>
>>>
>>> On 12, Feb 2014, at 8:12, Roger D Johnson<n1rj at roadrunner.com>  wrote:
>>>
>>>> >Unfortunately, interference to amateur radio appears to be VERY low
>>>> >on the FCC priorities list. I'll probably be an SK long before they
>>>> >act on my complaint!
>>>> >
>>>> >73, Roger
>>
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