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Re: [RFI] LED lighting

To: rfi@contesting.com
Subject: Re: [RFI] LED lighting
From: "Roger (K8RI)" <k8ri@rogerhalstead.com>
Date: Tue, 28 Jul 2015 22:35:06 -0400
List-post: <rfi@contesting.com">mailto:rfi@contesting.com>
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@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@verizon.net]
Sent: Monday, July 27, 2015 11:19 AM
To: Hare, Ed W1RFI
Cc: rfi@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@arrl.org<mailto:w1rfi@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@arrl.org<mailto:W1RFI@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@contesting.com] On Behalf Of David Robbins
Sent: Sunday, July 26, 2015 11:37 AM
To: 'Phil Snyder'; rfi@contesting.com<mailto:rfi@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@arrl.net
web: http://wiki.k1ttt.net
AR-Cluster node: 145.69MHz or telnet://k1ttt.net


-----Original Message-----
From: RFI [mailto:rfi-bounces@contesting.com] On Behalf Of Phil Snyder
Sent: Sunday, July 26, 2015 14:51
To: rfi@contesting.com<mailto:rfi@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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