Robert,
According to BS EN 55022 : 1995 cl. 11.2.1 Antenna-to-EUT distance I quote:
"Measurements of the radiated field shall be made with the antenna located at
the horizontal distance from the boudary of the EUT as specified in clause 6.
The boundary of the EUT is defined by an imaginary straight-line periphery
describing a simple geometric configuration encompassing the EUT. All ITE
inter-system cables and connecting ITE shall be included within this boundary
(see also figure2).
NOTE - If the field strength measurement at 10 m cannot be made because of
high ambient noise levels or for other reasons, measurement of Class B EUTs may
be made at a closer distance, for example 3m. An inverse proportionality factor
of 20 dB per decade sahould be used to normalize the measured data to the
specified distance for determining compliance. Care should be taken in
measurement of large EUTs at 3 m at frequencies near 30 MHz due to near field
effects."
Clause 6 says the EUT must meet the limits of tables 3 and 4. Tables 3 and 4
are the Class A and Class B limits at a measuring distance of 10 m. FIgure 2 is
labeled "Minimum alternative measurement site" and contains a 3 m dimension
between the EUT and the antenna.
Scott Douglas
Principal Compliance Engineer
ECRM Incorporated
Telephone: 1-508-851-0207
Facsimilie: 1-508-851-7016
e-mail: sdoug...@ecrm.com
_______________________________________________________________________________
From: Robert Macy on Thu, Jun 12, 1997 2:25 AM
Subject: Distance of Measurements
To: emc-p...@ieee.org
For measuring emissions per CISPR 22B what is the proper distance for
the placement of the antenna?
Is it 3m? or 10m?
[I'm running across reputable labs that claim there is nothing wrong
with measuring everything at 3m, just like FCC B.]
- Robert -
robert.m...@engineers.com
AJM Electronics
---
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From: robert.m...@engineers.com (Robert Macy)
Subject: Distance of Measurements
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Date: Wed, 11 Jun 1997 20:11:00 GMT
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