Radiated emissions (typically what causes hams interference) is regulated
and levels specified only at and above 30 MHz. Below 30 MHz, 150 kHz
through 29.99999.... MHz, conducted energy is specified and measured. The
reason for the latter is that it is very difficult place a receiving
antenna for measurement of RE in the far field on a test site at these low
frequencies. The reasoning is that at these low frequencies (HF, MF, LF,
VLF,...) the house wiring is 'long enough' to radiate energy coupled onto
the wiring. The house wiring becomes the 'antenna' for the generated RF
noise. Therefore, the regulatory agencies chose to specify and limit the
level of conducted energy coupled onto the wiring.
You are correct in that the levels set and to which any product must pass
before it is marketed do not assure the absence of interference. They
assume a relatively strong signal level against which the interference does
not interfere. In dealing with weak DX signals, yes, even an item which
has been tested and passed all the applicable regulatory requirements will
cause interference. I've been doing this for some 35 years and, believe
me, the limit of 30 dBuV (the EU limit for RE between 30 and 230 MHz) is a
relatively strong 'signal'. FCC is a bit different in the range above
roughly 100 MHz, but will accept the EU limits.
Another distinction: An item can be manufactured and put in service
legally, SO LONG AS *MONEY IS NOT EXCHANGED* for the product. Once money
is exchanged for the item, it is required that the item pass all regulatory
laws in place for the specific market. Universities are generally exempt
and Uncle runs his own show.
Another disgusting fact of budgets: At present, FCC doesn't give a rip
about Part 15 unless there is a large bucket of $$$$ for them. We are just
a grain of sand on the beach. These days, Part 15 is only addressed if it
is the whole beach of sand. Suggest you read the last paragraph on my QRZ
page - its from experience.
Dave - WØLEV
On Sat, Nov 23, 2019 at 3:30 AM Eddie Edwards <eddieedwards@centurylink.net>
wrote:
> We just did a kitchen remodel here that replaced our ceiling lights with
> new Lithonia wafer-thin LED lighting with external SMPS boxes that created
> strong RF noise strongest on 30 meters. I didn't like the way they were
> physically installed (made replacement messing and difficult) so rather
> than adding ferrites I had them removed and replaced with standard recessed
> cans for standard flood lights (LED or incan.) with plenty of room for
> adding ferrite filters latter myself if needed.
>
> I could not talk the contractor's electrician into installing or inserting
> my pre-wired ferrites while he was installing them because they were "not
> UL listed" devices but home-brewed instead. Perhaps Brad's neighbor has
> run into the same problem if he tried hiring an electrician to add
> ferrites? Perhaps the electrician told him they weren't safe to use? It
> could be something like this that made the neighbor change his mind.
>
> I have one question related to Mike Martin's comment what is legal to
> manufacture and what is not. My understanding is it's a Part 15 violation
> if it causes harmful interference, but not necessarily a violation if it
> has a poor design without what we consider proper filtering. Am I
> incorrect?
>
> I know there are RF noise level limits that are set by the FCC (probably
> in Part 15 and other regs), but devices that are able to meet those levels
> can still cause harmful interference especially in the HF bands with higher
> allowed limits. The reason for higher HF limits is probably similar to the
> old TVI problems back in the pre-cable TV era. TV manufacturers were not
> required to added high pass filters to all TVs was because not every TV set
> would be located near a ham radio station.
>
> FCC didn't want to force TV makers to all spend possibly millions of
> dollars on millions of TV sets to resolve a small number of problems that
> are not happening in every TV set location. However, if the ham did cause
> TVI back then, FCC forced quiet RF hours until the TVI was resolved by
> adding the high pass filters to TV set and low pass filter to the ham
> station.
>
> With TVI fading into history, now the RFI is in the other direction. But
> the FCC lawyers probably see it the same way: why force the costs of
> additional RF filters on all lights that probably meet Part 15 limits
> without filters and when 99.999% of them are not located near a radio
> station receiver?
>
> In this case we need Part 15 enforcement today just like we had in the TVI
> days: RF quiet periods until filters are added! Unfortunately, the FCC
> lawyers today don't respond the same for hams as it did for TV viewers
> probably because of the lower numbers of hams or the lower financial
> impact.
>
> 73, de ed -K0iL
>
>
> -----Original Message-----
> From: RFI <rfi-bounces@contesting.com> On Behalf Of Michael Martin
> Sent: Friday, November 22, 2019 07:59
> To: n8gls@arrl.net
> Cc: rfi@contesting.com
> Subject: Re: [RFI] FCC Complaint Filing
> Importance: High
>
> Hello Brad,
> Well it sounds like you've proven the cause. One of the things I like to
> do when approaching the owner of the offending source, is to have a radio
> in my hand that will display the noise. In your case I would approach the
> door with a clear radio station, maybe FM, and at a very low levels and as
> I'm talkin turn the volume up just slightly so they can hear the clear
> radio station. Then say this is a really clear station but let me show you
> this and hopefully through a memory channel in the radio or just tune to
> the am frequency where the noise is being displayed and say quote this is
> the noise I get on my equipment well your lights are on and then turn it up
> slightly so he can hear it so they get a better example as to what you're
> dealing with sometimes it's very convincing actually most of the time it's
> very convincing. Saying that all I'm interested in is being able to use my
> equipment without interference. It's unfortunate that he has the originator
> and source of the interference an
> d you understand it isn't his fault that he has that but the manufacturer
> that built it build it without filtering and that is a violation of FCC
> rules and regulations and you're willing to help him install those filters
> to get rid of it that they should have installed.
> I'd still like to know what area you are in?
> Best wishes
>
>
> _______________________________________________
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> RFI@contesting.com
> http://lists.contesting.com/mailman/listinfo/rfi
>
--
*Dave - WØLEV*
*Just Let Darwin Work*
*Just Think*
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