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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