Has anyone correlated GTEM measurements to 10 meter data with acceptable
accuracy?
Frank de Vall
HID Global Corporation
"Bill Stumpf"
<[email protected]
OM> To
Sent by: "Kunde, Brian"
[email protected] <[email protected]>, "Grace
Lin" <[email protected]>,
<[email protected]>
06/18/2007 02:05 cc
PM
Subject
RE: RE Measurement Distance per EU
We have an NSA compliant 3-meter chamber. We do not use it where 10-meter
compliance is called for.
Bill Stumpf
D.L.S. Electronic Systems, Inc.
166 South Carter Street
Genoa City WI, 53128
262-279-0120
From: [email protected] [mailto:[email protected]] On Behalf Of Kunde,
Brian
Sent: Monday, June 18, 2007 2:33 PM
To: Grace Lin; [email protected]
Subject: RE: RE Measurement Distance per EU
Grace,
Do they make a fully compliant 3 meter semi-anechoic chamber? I wasn't
aware that a 3 meter chamber passed the NSA requirements down to 30Mhz.
The purpose of having a Test Standard is to standardize on a method in
which testing is performed so the results can be repeated at other test
sites and hopefully have the same or similar results. When you stray from
what the standard calls out, then you take the risk of your results being
brought into question.
I think your biggest problem with testing at 3 meter is going to be with
near field below 100Mhz. Because of the common differences seen when
testing a product at 3 meter verses 10 meter, I think there will always be
a high level of doubt in your test results.
In my opinion, "compliance testing" can only be confidently done at a 10
meter OATS or equivalent.
BTW, the note in section 10.2.1 is a method to test signals that fall near
or on a high ambient. Most all OATS have at least a few areas with high
ambient and this section gives them a work around at only those
frequencies. It is not intended to allow full testing at distances than 10
meter. In a chamber you wouldn't have any ambient signals so you couldn't
use this section to justify 3 meter testing.
I am very curious to know the confidence level of 3 meter chambers are.
Maybe some who have such chambers will post.
The Other Brian.
From: [email protected] [mailto:[email protected]] On Behalf Of Grace Lin
Sent: Monday, June 18, 2007 1:43 PM
To: [email protected]
Subject: RE Measurement Distance per EU
Dear Members,
Is 3m measurement distance for radiated emission not accepted by EU?
I propose a 3m full compliant chamber. A chamber manufacturer informs me
that EU only accepts 10m measurement distance. I checked EN 55022: 1998
incorprating Corrigendum Nol 1 and A1 and A2. Clause 6 states:
"The EUT shall meet the limits of Table 5 or Table 6 when measured at the
measuring distance R in accordance with the methods described in Clause
10. ... "
The title of Table 5 is: "Table 5 - Limits for radiated disturbance of
class A ITE at a measuring distance of 10m". The title of Table 6 is:
"Table 6 - Limits for radiated disturbanc eof class B ITE at a measuring
distance of 10m". Subclause 10.2.1 states:
"
10.2.1 Antenna-to-EUT distance
Measurements of the radiated field shall be made with the antenna located
at the horizontal distance from the boundary of the EUT as specified in
Clasue 6.
NOTE If the field-strength measurement at 10m cannot be made because of
high ambient noise levels, or fo rother reasons, measurement of class B
EUT's may be made at a closer distance, for example 3m. An inverse
proportionality factor of 20 dB per decade should be used to normalize the
measured data to the specified distance for determining compliance. Care
should be taken in the measurement of large EUTs at 3m at frequencies near
30 MHz, due to near field effects.
"
I look forward to your comments.
Best regards,
Grace Lin
Crestron Electronics, Inc.
www.crestron.com
- ---------------------------------------------------------------- This
message is from the IEEE Product Safety Engineering Society emc-pstc
discussion list. Website: http://www.ieee-pses.org/
To post a message to the list, send your e-mail to [email protected]
Instructions: http://listserv.ieee.org/request/user-guide.html
List rules: http://www.ieee-pses.org/listrules.html
For help, send mail to the list administrators:
Scott Douglas [email protected] Mike Cantwell [email protected]
For policy questions, send mail to:
Jim Bacher: [email protected] David Heald: [email protected]
All emc-pstc postings are archived and searchable on the web at:
http://www.ieeecommunities.org/emc-pstc
Notice: This communication may contain confidential information intended
for the named recipient(s)only. If you received this by mistake, please
destroy it and notify us of the error. Thank you. -
---------------------------------------------------------------- This
message is from the IEEE Product Safety Engineering Society emc-pstc
discussion list. Website: http://www.ieee-pses.org/
To post a message to the list, send your e-mail to [email protected]
Instructions: http://listserv.ieee.org/request/user-guide.html
List rules: http://www.ieee-pses.org/listrules.html
For help, send mail to the list administrators:
Scott Douglas [email protected] Mike Cantwell [email protected]
For policy questions, send mail to:
Jim Bacher: [email protected] David Heald: [email protected]
All emc-pstc postings are archived and searchable on the web at:
http://www.ieeecommunities.org/emc-pstc
This e-mail is confidential and may be privileged and/or proprietary. If you
are not the intended recipient, any review, disclosure, copying, or use of
this e-mail is prohibited.
-
This message is from the IEEE Product Safety Engineering Society
emc-pstc discussion list. Website: http://www.ieee-pses.org/
To post a message to the list, send your e-mail to [email protected]
Instructions: http://listserv.ieee.org/request/user-guide.html
List rules: http://www.ieee-pses.org/listrules.html
For help, send mail to the list administrators:
Scott Douglas [email protected]
Mike Cantwell [email protected]
For policy questions, send mail to:
Jim Bacher: [email protected]
David Heald: [email protected]
All emc-pstc postings are archived and searchable on the web at:
http://www.ieeecommunities.org/emc-pstc
______________________________________________________________________
This email has been scanned by the MessageLabs Email Security System.
For more information please visit http://www.messagelabs.com/email
______________________________________________________________________
