[RFI] RFI on 160 meters at WD8DSB from Hi-Fi Amp or its power supply 0.27 miles away.

[Hare, Ed, W1RFI]

ARRL is looking to do something about this problem, but we need help.  We can't do much about the eBay sellers, but if we can find the following information, we can start measuring devices and finding the worst of them.  The problem is that there are no radiated emissions limits <30 MHz and the conducted limits that do offer some protection apply only to the AC mains.

We did have one case of RFI from Class D amps, and it turned out to be the power supply.

We need the manufacturer and model number, an S meter reading, a distance and the name of the store or company selling them retail in the US.  From there, we can start trying to get the support of FCC, perhaps building on what we are doing with enforcement of noise issues. 

We get the help of the FCC from its Enforcements staff on the basis of harmful interference, but if we start alleging emissions-limit violations, this will be under the wing of the Office of Engineering and Technology.

Send any info you have to RFI at arrl.org and Steve and I will be on it.

Ed, W1RFI



-----Original Message-----
From: RFI <rfi-bounces+w1rfi=arrl.org at contesting.com> On Behalf Of David Eckhardt
Sent: Monday, April 11, 2022 8:05 PM
To: Jim Brown <jim at audiosystemsgroup.com>
Cc: Rfi List <rfi at contesting.com>
Subject: Re: [RFI] RFI on 160 meters at WD8DSB from Hi-Fi Amp or its power supply 0.27 miles away.

The largest EMC/RFI hole with the FCC these days is their lack of enforcing the regs. already on the books.  Part 15 is pretty much ignored and nothing much stops SMPS from China.  And not to mention the whole solar power industry.

But you've read all this from me before, many times.

Dave - WØLEV

On Mon, Apr 11, 2022 at 11:55 PM Jim Brown <jim at audiosystemsgroup.com>
wrote:

> The gaping hole in FCC EMC regs is that they fail to consider 
> conducted emissions on anything but the power line. Thanks to widespread "Pin One"
> problems at connectors for signal and control lines, common mode 
> current on these cables, usually on cable shields) is a primary cause 
> of EMC issues, both incoming and outgoing. The "Pin One Problem," 
> first identified by an engineer with a ham background working in pro 
> audio, is the failure to terminate cable shields to the shielding 
> enclosure at the point of entry. A similar problem often occurs when 
> the "green wire" of the power line fails to contact the shielding 
> enclosure directly at the point of entry. The first two links were 
> written for a newsletter for sound contractors. The third is my 
> tutorial for hams. The Pin One Problem is addressed beginning on Page 8.
>
> http://k9yc.com/Pin_1_Revisited.pdf
> http://k9yc.com/Pin_1_Revisited_Part_2.pdf
> http://k9yc.com/RFI-Ham.pdf
>
> Neil Muncy's original work on this was published in the June 1995 
> Journal of the Audio Engineering Society, which can be downloaded from 
> aes.org (modest fee). JAES is in the engineering libraries of most 
> universities.
>
> 73, Jim K9YC
>
> On 4/11/2022 3:39 PM, David Eckhardt wrote:
> > It was the ONLY product in my some 30+ years as an EMC/RFI engineer 
> > we had to install a 35 dB, yes, you read correctly, 35 dB attenuator 
> > (!!!) between the product connection to the AC power (LISN) and the 
> > conducted emission receiver.
>
> _______________________________________________
> RFI mailing list
> RFI at contesting.com
> http://lists.contesting.com/mailman/listinfo/rfi
>


--
*Dave - WØLEV*
*Just Let Darwin Work*
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