[RFI] 160 meters RFI caused by low voltage bookcase lights

Hare, Ed W1RFI w1rfi at arrl.org
Tue Sep 30 11:43:01 EDT 2014

ARRL has very few reports of these things that have specific model numbers, so yes, please, send the information on any that cause interference to rfi at arrl.org.

The rules require the following:

1. The manufacturer must meet the rules for emissions limits from the power supplies.  If these are switching supplies operating above 9 kHz internally, they need to meet conducted limits into the AC mains below 30 MHz and radiated emissions limits above 30 MHz.  There are two sets of limits, a limit for devices that can be marketed into residential environments (Class B) and a higher limit for devices marketed only into industrial environments (Class A).  

2. The end marketer of a product is responsible for selling industrial-limit devices only into commercial environments.

3. Even if a device meets the limits, the end user of the product is required to use it in a way that does not cause harmful interference to licensed radio services.

Even the consumer devices have limits that are pretty high. A "legal" device would typically result in S7 noise (+- quite a bit) from the house next door, and S9 noise from a device in the ham's own house, relatively close to his or her antennas.

If we get reports involving model numbers, if the devices appear to be operating above the limits, ARRL will buy one and test it and if we find either a device exceeding the limits, or commercial devices being marketed to consumer environments, we will file formal complaints with the FCC. 

Ed Hare, W1RFI

-----Original Message-----
From: RFI [mailto:rfi-bounces at contesting.com] On Behalf Of David Cole
Sent: Tuesday, September 30, 2014 8:04 AM
To: rfi at contesting.com
Subject: Re: [RFI] 160 meters RFI caused by low voltage bookcase lights


Look to the power supply for the lights...  This happens all the time...
I do RFI hunting for the local hams when they ask, and about 30% of the RFI I find is this sort of issue...  Just replace the supply, being careful to not expose yourself to a lawsuit in the process...  i.e. if your neighbors home burns down as a result of your home built PS you get sued...  One of my neighbors had this exact issue, a new light system removed the RFI.

You might ask W1RFI if the ARRL keeps a list of these sorts of things, and reports them to the FCC, if so, send him, or his designee the info on make and model, etc.  

Thanks and 73's,
For equipment, and software setups and reviews see:
for MixW support see;
for Dopplergram information see:
for MM-SSTV see:

On Mon, 2014-09-29 at 13:25 -0400, Don Kirk wrote:
> Late last week I encountered interference on 160 meters which was repeating
> at 41 khz intervals, and this morning I was able to track the problem down
> to low voltage bookcase lights at my neighbors home which is 430 feet
> away.  I created a website to document this case which includes a link to a
> youtube video that contains receive audio of the noise, and my simple
> website URL is http://sites.google.com/site/bookcaselightsrfi/
> The signal was S9 on 160 meters (approximately 15 dB above my noise floor
> when using a 500 hz receive filter), and it could be heard up into the 80
> meter band.
> We (my neighbor and I) will now dig into his low voltage lighting system to
> see what we can do to eliminate the interference.
> Just FYI,
> Don Kirk (wd8dsb)
> _______________________________________________
> RFI mailing list
> RFI at contesting.com
> http://lists.contesting.com/mailman/listinfo/rfi

RFI mailing list
RFI at contesting.com

More information about the RFI mailing list