[RFI] LED lighting

[Roger (K8RI)]

I worked in a double walled screen room quite often.  All leads were 
filtered. The door used a cam to finish closing.  A 10W signal outside 
the door was not detectable inside.  You could watch the signal go down 
as the cam was closed.  Well before the cam was closed the signal was 
gone.  I can't imagine needing more than a standard screen room for 
measuring RFI from LEDs and their switching supplies.

In my case the screen room was for isolation of very sensitive 
measurements in an area with a lot of RF. OTOH  I did a lot of RF 
monitoring to make sure those 200 KW and up, induction heating units 
could not be heard.

73

Roger (K8RI)

On 7/27/2015 11:25 AM, Hare, Ed W1RFI wrote:
> Actually, we don't.  We have the screen room to do receiver and transmitter testing, and a room set up in compliance with ANSI C63.4 to do conducted-emission measurements, but not an anechoic chamber. Outdoor testing should suffice, being a good approximation to a calibrated open-area test site.  If we find devices a few dB above the limits, we don't file complaints, but the things we have found to be bad have been WAY above the limits, so close enough is close enough.
>
>
> Ed Hare, W1RFI
> ARRL Laboratory Manager
> 225 Main St.
> Newington, CT 06111
> Tel: (860) 594-0318
> Fax: (860) 594-0259
> Email: W1RFI at arrl.org
> Member: IEEE Connecticut Section
> Member: IEEE EMC Society, Board of Directors
> Member: IEEE EMC Society Standards Development and Education Committee
> Primary representative:  ANSI ASC C63 EMC Committee, Vice Chair Subcommittee 5 (Immunity)
> Member: QRP Amateur Radio Club International, Board of Directors
>
>
>
> From: David Robbins [mailto:k1ttt at verizon.net]
> Sent: Monday, July 27, 2015 11:19 AM
> To: Hare, Ed W1RFI
> Cc: rfi at contesting.com
> Subject: Re: Re: [RFI] LED lighting
>
> what?  you don't have an anechoic shielded chamber to do that kind of stuff???
>
>
> Jul 27, 2015 11:05:16 AM, w1rfi at arrl.org<mailto:w1rfi at arrl.org> wrote:
> I bought one multi-LED bulb that came from China. It was dead quiet. My guess is that it simply put the LEDs in series and connected them to the line. Not all of them will have a switcher in them.
>
> ARRL tested a number and found them to be below the conducted emissions limits. I want to test them above 30 MHz too, for radiated emissions, though we'd need to set up outdoors to prevent scatters from throwing off the readings.
>
>
> Ed Hare, W1RFI
> ARRL Laboratory Manager
> 225 Main St.
> Newington, CT 06111
> Tel: (860) 594-0318
> Fax: (860) 594-0259
> Email: W1RFI at arrl.org<mailto:W1RFI at arrl.org>
> Member: IEEE Connecticut Section
> Member: IEEE EMC Society, Board of Directors
> Member: IEEE EMC Society Standards Development and Education Committee
> Primary representative: ANSI ASC C63 EMC Committee, Vice Chair Subcommittee 5 (Immunity)
> Member: QRP Amateur Radio Club International, Board of Directors
>
>
>
> -----Original Message-----
> From: RFI [mailto:rfi-bounces at contesting.com] On Behalf Of David Robbins
> Sent: Sunday, July 26, 2015 11:37 AM
> To: 'Phil Snyder'; rfi at contesting.com<mailto:rfi at contesting.com>
> Subject: Re: [RFI] LED lighting
>
> They could just be led bulbs in a standard 120v socket also... in those there is a switching supply in the base of each bulb.
>
> David Robbins K1TTT
> e-mail: mailto:k1ttt at arrl.net
> web: http://wiki.k1ttt.net
> AR-Cluster node: 145.69MHz or telnet://k1ttt.net
>
>
> -----Original Message-----
> From: RFI [mailto:rfi-bounces at contesting.com] On Behalf Of Phil Snyder
> Sent: Sunday, July 26, 2015 14:51
> To: rfi at contesting.com<mailto:rfi at contesting.com>
> Subject: [RFI] LED lighting
>
> Well after a 4 year period the local electric company found the offending lightning arrester and voila no more noise! Unfortunately, the neighbor behind me just remodeled the outside of their house and in the process added about 6 LED lighting fixtures in the soffit across the front and after a few days of watching and listening it appears that they are causing way more RFI then the faulty arrester ever did.
>
> I am hoping to learn a little more here before approaching them to make sure all my facts are straight. I am assuming that there is a switching power supply running the lights and that the power is cut to the supply when they are not on since the noise is gone when they are off. Is it possible to try and suppress the noise on the leads coming out of the power supply? Does he need to contact the manufacturer to replace the supply? Unfortunately they are mounted into the soffit like a can type light you would have inside your house and I hope the power supply is accessible.
>
> Thanks
> Phil
> N9LAH
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