CISPR TR 16-4-6:2024

CISPR TR 16-4-6 ®
Edition 1.0 2024-10
TECHNICAL
REPORT
INTERNATIONAL SPECIAL COMMITTEE ON RADIO INTERFERENCE

Specification for radio disturbance and immunity measuring apparatus and
methods –
Part 4-6: Uncertainties, statistics and limit modelling – Statistics on radio
frequency interference (RFI) and verification by measurements in the field
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CISPR TR 16-4-6 ®
Edition 1.0 2024-10
TECHNICAL
REPORT
INTERNATIONAL SPECIAL COMMITTEE ON RADIO INTERFERENCE

Specification for radio disturbance and immunity measuring apparatus and

methods –
Part 4-6: Uncertainties, statistics and limit modelling – Statistics on radio

frequency interference (RFI) and verification by measurements in the field

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 33.100.10; 33.100.20 ISBN 978-2-8322-9798-8

– 2 – CISPR TR 16-4-6:2024 © IEC 2024
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms, definitions and abbreviated terms . 7
3.1 Terms and definitions . 7
3.2 Abbreviated terms . 10
4 Acquisition and organization of data on RFI incidences . 10
4.1 Basic interference model and conditions for undisturbed radio reception . 10
4.2 Occurrence of interference . 11
4.3 Accumulation of statistical data on interference and preparation for reporting
to CISPR. 12
4.3.1 General . 12
4.3.2 First data set – RFI incidences not necessarily indicating insufficiencies
in CISPR standards . 12
4.3.3 Second data set – RFI incidences possibly indicating insufficiencies in
CISPR standards . 12
4.4 Accumulation of data on interference and preparation for reporting to CISPR . 13
4.4.1 General . 13
4.4.2 Data to be collected . 13
5 Root-cause-analysis of the reported RFI incidences . 14
6 Reporting. 15
6.1 General . 15
6.2 Indications on the reporting format for traditional statistics of complaints . 15
Annex A (informative) Guidance for collation of statistical data on interference
complaints and classification of interference sources . 16
A.1 General . 16
A.2 Example of how to use the XML input form . 16
Annex B (informative) Value of statistics on radio frequency interference observed in
the electromagnetic environment . 20
B.1 Background and history . 20
B.2 Towards the loss of a precious indicator: interference complaints . 20
Annex C (informative) Field strength measurements in the electromagnetic
environment . 21
C.1 General . 21
C.2 Use of measurement frequencies . 21
C.3 Measurement arrangement for field strength measurements in the local
electromagnetic environment . 21
C.4 Target levels for in-situ field strength measurements – Analysis of root
causes (a) and (c) in D.2.2 . 23
C.5 Target levels for the field strength of the wanted radio signal – Analysis of
root cause (c) in D.2.2 . 24
C.5.1 Use of national reference levels of the wanted signal field strength . 24
C.5.2 Use of target levels for the wanted signal field strength recommended
by CISPR. 24
Annex D (informative) Root-cause-analysis of the reported RFI incidences . 25
D.1 General . 25
D.2 Matrix of root causes and identification procedure . 25

D.2.1 General . 25
D.2.2 Root causes of interest in maintenance of CISPR standards and limits . 26
D.3 Accumulation of statistical data on root causes . 28
D.4 Instructions for normalization of the absolute number/frequency of observed
interference incidences/scenarios into representative relative figures . 28
Annex E (informative) Cross-reference list of CISPR TR 16-4-4 [1] and this document . 31
Bibliography . 32

Figure 1 – Basic RFI model for source without radio module . 10
Figure 2 – Basic RFI model for source with radio module . 10
Figure C.1 – Conditions for coverage planning for different modes of radio reception . 22

Table A.1 – Information on reporting party . 16
Table A.2 – Data fields of one occurrence . 16
Table C.1 – Generic target levels for evaluation/analysis of the residual risk of
occurrence of individual interference incidences . 23
Table D.1 – Matrix for root cause analysis of a detected interference scenario . 26
Table E.1 – Cross-reference list of CISPR TR 16-4-4 [1] and this document . 31

– 4 – CISPR TR 16-4-6:2024 © IEC 2024
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SPECIFICATION FOR RADIO DISTURBANCE AND IMMUNITY
MEASURING APPARATUS AND METHODS –

Part 4-6: Uncertainties, statistics and limit modelling –
Statistics on radio frequency interference (RFI) and
verification by measurements in the field

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and
in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports,
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preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with
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Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
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any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.
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6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). IEC takes no position concerning the evidence, validity or applicability of any claimed patent rights in
respect thereof. As of the date of publication of this document, IEC had not received notice of (a) patent(s), which
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the latest information, which may be obtained from the patent database available at https://patents.iec.ch. IEC
shall not be held responsible for identifying any or all such patent rights.
CISPR 16-4-6 has been prepared by CISPR subcommittee H: Limits for the protection of radio
services. It is a Technical Report.
The text of this Technical Report is based on the following documents:
Draft Report on voting
CIS/H/504/DTR CIS/H/513/RVDTR
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this Technical Report is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
A list of all parts in the CISPR 16 series, published under the general title Specification for radio
disturbance and immunity measuring apparatus and methods , can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn, or
• revised.
– 6 – CISPR TR 16-4-6:2024 © IEC 2024
INTRODUCTION
In 2018, work started in CISPR/H to undertake a fundamental review of CISPR TR 16-4-4:2007,
CISPR TR 16-4-4/AMD1:2017 and CISPR TR 16-4-4/AMD2:2020 [1] . As a result of this
review, it was decided to transfer the content on statistics of complaints in Clause 4 to a new
publication, as the content of this clause was quite disconnected from the limit modelling part
of CISPR TR 16-4-4 [1]. A cross-reference list of CISPR TR 16-4-4 [1] and this document is
given in Annex E. Note that with reorganization of CISPR 16 in 2003, the recommendations on
statistics of interference complaints were moved from CISPR TR 16-3:2002 (first edition) to
Clause 4 of CISPR TR 16-4-4:2003 (first edition).
In the past interference on analogue radio reception, for example television, was easy to detect.
With the shift to newer technologies the recognition of interference is more difficult.
Nevertheless, submission of statistical data on complaints is still considered an important
instrument to verify the suitability of CISPR publications, as they are widely adopted in various
regions and countries for market access of equipment.
The recommendations for reports on statistics of complaints in CISPR TR 16-4-4 were found
also to be outdated and not suitable to analyse and interpret the interference complaints that
are often reported within CISPR and its subcommittees. Therefore, it was decided also to add
additional recommendations in this new CISPR publication to enable proper analysis of these
complaints and subsequently to implement appropriate changes in the CISPR publication
concerned. With these additions, this CISPR publication on statistics of radio frequency
interference serves as a more meaningful feedback loop on how effective the limits and test
methods in CISPR publications are.
This CISPR publication is intended for any party having an interest in aggregation and
subsequent submission of statistical data to CISPR, either as a CISPR liaison, or via the
respective National Committee. It addresses radio frequency interference incidences and
reported cases which could be traced back to having been caused by use as intended in the
given category of electromagnetic environment, of any kind of electric/electronic equipment,
system or installation being conformant with the provisions of CISPR standards.
This document provides a methodology for the systematic collation, aggregation and verification
of interference in the given environment, or in general any investigations into reported radio
frequency interference cases.
The latter more administrative activity incorporates the aggregation of statistical data on
interference complaints. These could be traced back to having been caused by operation and
use of any kind of closely co-located and well-maintained or also defective electric/electronic
equipment, systems or installations and radio receivers in the field or also by other
shortcomings in the local conditions of use of such equipment, radio receivers, or by lack of
service coverage or other reasons. This document can be used to prepare reports on the
statistics of interference complaints in line with the provisions set out in Chapter IV, Article 15,
Section VI of the ITU Radio Regulations 2020 [2], see also Appendix 10 of these ITU Radio
Regulations [2].
___________
Numbers in square brackets refer to the Bibliography.

SPECIFICATION FOR RADIO DISTURBANCE AND IMMUNITY
MEASURING APPARATUS AND METHODS –

Part 4-6: Uncertainties, statistics and limit modelling –
Statistics on radio frequency interference (RFI) and
verification by measurements in the field

1 Scope
This part of CISPR 16, which is a Technical Report, applies to the acquisition, processing and
preparation of statistical data of radio interference cases to facilitate the evaluation of the
effectiveness of CISPR standards with respect to their potential to prevent radio frequency
interference (RFI).
This document also provides a method for the analysis and evaluation of the residual risk of
occurrence of the incidence of RFI in the electromagnetic environment.
This document also provides guidance for how an interested party can verify the root cause of
RFI. This can be applied to either a reported RFI case or a case otherwise suspected of
constituting an “RFI scenario”, by inspection and field strength measurements at the local site
in the given electromagnetic environment.
Acquisition of statistical data according to this document only encompasses RFI incidences
which affect radio reception by radio receivers or respective receiver components.
2 Normative references
There are no normative references in this document.
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1.1
complaint
report containing information on radio frequency interference (RFI) observed on radio receiving
equipment
EXAMPLE Report received by a national RFI investigation service from a citizen containing information on an RFI
incident including or not including a request for assistance.

– 8 – CISPR TR 16-4-6:2024 © IEC 2024
3.1.2
RFI investigation service
entity investigating reported cases of radio frequency interference (RFI)
EXAMPLE Examples of institutions include regulatory authorities and special interest groups.
3.1.3
source
any electric or electronic equipment, system, or (part of an) installation generating
electromagnetic emissions in the radio frequency (RF) range which can cause radio frequency
interference to radio receiving equipment
Note 1 to entry: Electric and electronic equipment can be a source of electromagnetic energy when they contain
active components or modules, such as switched mode power supplies, power electronic components, electric motors
and thermostats.
3.1.4
electromagnetic disturbance
any electromagnetic phenomenon that can degrade the performance of a device, equipment or
system, or adversely affect living or inert matter
Note 1 to entry: An electromagnetic disturbance can be an electromagnetic noise, an unwanted signal, or a change
in the propagation medium itself.
Note 2 to entry: In this document, the phrase “propagation medium” is taken as the propagation mechanism or
means, an example being leakage from a coaxial cable or by mode conversion in a balanced pair cable.
[SOURCE: IEC 60050-161:2018, 161-01-05, modified – Notes 2 and 3 have been removed and
a new Note 2 has been added.]
3.1.5
radio frequency disturbance
RF disturbance
RF interference
RFI
electromagnetic disturbance having components in the radio frequency range
Note 1 to entry: In accordance with IEV 701-02-12, the radio frequency range comprises by convention all
frequencies which are lower than 3 000 GHz.
Note 2 to entry: The disturbance can also present the accumulation of disturbance components from more than
one, i.e., from multiple disturbance sources.
Note 3 to entry: The English words "interference" and "disturbance" are often used indiscriminately.
Note 4 to entry: The word interference is used short term for radio frequency interference in this document.
[SOURCE: IEC 60050-161:2018, 161-01-13, modified – In the terms, “radio disturbance” has
been removed, RF interference is no longer a deprecated term, and “RFI” has been added; in
addition, the original Note 2 has been renumbered as Note 1 and Notes 2 and 3 have been
added. A Note 4 for clarification of the short term use has been added.]
3.1.6
root cause of RFI
local conditions and circumstances in the electromagnetic environment causing a radio
frequency interference case
Note 1 to entry: Such conditions and circumstances can relate to phenomena in the electromagnetic environment
(e.g., very high ambient noise), to the equipment with the radio receiving function incorporated (e. g. insufficient
immunity), or to the equipment producing the unwanted radio frequency energy (e. g. via a special coupling
mechanism).
3.1.7
interference incidence
event, detected as degradation in the quality of radio reception, that drops below the necessary
quality of service or quality of experience
Note 1 to entry: The quality of experience can be defined in ITU documents.
Note 2 to entry: The probability of an interference incident is binary either there is or there is not an interference
incidence.
Note 3 to entry: Interference incidence does not by itself state the severity of the incidence.
3.1.8
incidence distance
shortest distance between the particular disturbance source and the antenna of the disturbed
radio receiver
Note 1 to entry: If a machine or installation causing interference is in a dedicated building/premises, the distance
can be measured from the boundary of that premises/building.
3.1.9
protection distance
distance between the source of a radiated disturbance and the victim receiver at the
edge-of-service area used for the derivation of a specific CISPR limit for radiated disturbance
Note 1 to entry: The edge-of-service area is defined by the minimum value of the wanted field strength of a radio
service or application derived from ITU-R specifications.
Note 2 to entry: This definition can vary in other publications, when conducted disturbances are concerned.
Note 3 to entry: Every limit has an associated protection distance; the protection distance can vary with frequency.
[SOURCE: CISPR 16-2-3:2016/AMD1:2019 [19], 3.1.34]
3.1.10
target
figure, value, ratio or the like of a given parameter recommended by CISPR as criterion for the
assessment as to whether or not a detected RFI incidence can be considered a case of harmful
interference
Note 1 to entry: Target figures are recommended by CISPR for use as reference, guideline and measure for the
overall evaluation of reported RFI cases or results of survey measurements aiming at data gathering for indication
of the residual risk of radio frequency interference, in the electromagnetic environment.
3.1.11
residual risk
remaining risk of an interference incidence when the requirements of the applicable CISPR
standards are met
3.1.12
harmful interference
Interference which endangers the functioning of a radionavigation service or of other safety
services or seriously degrades, obstructs, or repeatedly interrupts a radiocommunication
service operating in accordance with Radio Regulations
[SOURCE: ITU Radio Regulations:2020 [2], 1.169]
3.1.13
radio function
function that provides either a radiocommunication interface, or a radiodetermination interface,
or both
– 10 – CISPR TR 16-4-6:2024 © IEC 2024
3.1.14
radio appliance
appliance in which the radio function is incorporated in a fixed and permanent way
3.2 Abbreviated terms
EE Electromagnetic environment
EMC Electromagnetic compatibility
E minimum level of usable field strength
u
ISM Industrial, scientific and medical (electrical equipment, system or installation)
RF Radio frequency
RFI Radio frequency interference
4 Acquisition and organization of data on RFI incidences
4.1 Basic interference model and conditions for undisturbed radio reception
RFI relates to the disturbance source, coupling path and victim as shown in Figure 1 and
Figure 2. In addition, the wanted RF radio signal at the antenna of the radio receiver is provided
with at least the minimum level of usable field strength E .
u
NOTE The conducted cable is not necessarily connected to the victim as for example in telecommunication lines,
where only the radiation coupling (path B2) exists.
Figure 1 – Basic RFI model for source without radio module

NOTE The conducted cable is not necessarily connected to the victim as for example in telecommunication lines,
where only the radiation coupling (path B2) exists.
Figure 2 – Basic RFI model for source with radio module

The following gives information on the conditions required to ensure that there is compatibility
between disturbance source, system or installation operated in the field and radio receivers in
the neighbourhood of these sources.
a) Source related:
1) Emissions from the source in Figure 1 or Figure 2, along path A or paths B1/B2 do not
exceed limits specified in the EMC standard applicable for that type of source.
2) In addition to 1) if the source has a radio component, intentional, out-of-band and
spurious emissions from the source comply with the relevant radio performance
specifications, i. e. with RF spectrum-related and associated supplementary EMC
requirements (coupling path C);
NOTE 1 Radio requirements are typically not considered by CISPR.
b) Victim related:
1) The victim (i. e. the antenna of the radio receiver) is in a position where it could receive
sufficient signal.
2) The victim radio equipment has sufficient immunity to unwanted emissions from the
source arriving through paths A/B in Figure 1 and Figure 2.
3) In addition to 2), the victim has sufficient immunity to any intentional, out-of-band and
spurious emissions from the source’s radio transmitter/transceiver component (if any),
arriving through radiation coupling paths C/D.
4) The radio receiver or radio communication equipment being the victim complies with the
relevant radio performance specifications, i. e. with RF-spectrum-related requirements
(coupling path C).
c) Coupling-path-related:
1) The distance between source and victim is sufficient.
NOTE 2 Conditions a)1) through c)1) are used to determine the root cause of RFI incidents in 4.4.
4.2 Occurrence of interference
If one of the conditions above is not met, interference is likely. And even if all of the above
conditions are met, interference can occur, as follows:
– any specified emission limits as well as immunity levels in CISPR and IEC standards are
derived on a statistical basis enabling EMC to prevail for a very large number of
configurations and installations operated in the given electromagnetic environment, but not
preventing interference in all configurations;
– specified coverage and reliability figures for radio services in national planning standards
are based on statistical assumptions for the tolerable probability of instantaneous
interference caused by unfavourable local coverage conditions;
– the current emissions/immunity requirements fail to provide adequate protection for radio
and need review.
That means that compliance of products with requirements in EMC or radio performance
standards, or both, does not prevent the appearance of occasional interference cases, but
where they appear, although all conditions listed in 4.1, a)1 through c)1) are met, then they will
be included in the total number of observed interference incidences too. Due to the first two
reasons mentioned above, there remains a residual (and to a certain extent tolerable) risk of
interference anyway, and it is one of the purposes of this document to provide guidelines for
evaluation of whether the number of reported or otherwise observed RFI incidences is still below
the residual risk of RFI. If statistics indicate that this is not the case anymore, then this can
induce a review of the CISPR limits and standards with regards to their ability to fulfil the target
of the CISPR scope of protection of radio reception.

– 12 – CISPR TR 16-4-6:2024 © IEC 2024
RFI can occur if either the source or victim is defective (e.g., due to component failure, damage,
ageing, end of life, etc.) or in case of abused use of products or illegal product modifications. If
this is the case, then the radio or EMC performance of either the source or victim can be
jeopardized. In practice this can also be a rather obvious cause of RFI, even though the
conditions listed in 4.1 are apparently met.
4.3 Accumulation of statistical data on interference and preparation for reporting to
CISPR
4.3.1 General
The number of reported or otherwise observed RFI incidences is part of the statistical data of
interest to CISPR. This data can also be expressed as a relative figure for the same environment
category of representative and well defined reference size.
A percentage of the overall number of RFI incidences (scenarios) detected locally in a given
electromagnetic environment can be used for comparison with a tolerable residual risk of
interference (which can be set during the limit derivation process using the alpha factor, see [1]).
For further more detailed analysis, any registered RFI incidence needs to be attributed either
to the subset of cases covering conditions that do not necessarily indicate insufficiencies in
CISPR standards or to subsets that do.
4.3.2 First data set – RFI incidences not necessarily indicating insufficiencies in
CISPR standards
This subset consists of cases where any of the conditions a)2), b)1), b)2), b)3) or b)4) of 4.1
are not met.
The number of reported or otherwise observed interferences in the first set, attributed
individually (and separately) to one of the conditions a)2), b)1), b)2), b)3) or b)4) represents the
traditional way of reporting to CISPR and indicates among other things, up to which extent the
involved sources and victim radio equipment comply with the provisions of the relevant EMC
standards or radio performance specifications, or both.
It can be seen that statistical information derived from data in the first set has less direct
relevance for CISPR. However, this data can be an important indicator for many interested
stakeholders. This could include for instance certain parties such as administrations, countries
with special national conditions, or manufacturers of products with specific needs who might
decide on the non-applicability of a standard to their situation.
4.3.3 Second data set – RFI incidences possibly indicating insufficiencies in CISPR
standards
The number of RFI incidences in the second set provides information of much more substantial
interest for CISPR, in respect of possibly pending needs for maintenance of CISPR standards
and review of CISPR limits as well.
In respect of reporting statistical data on the frequency of occurrence of RFI incidences or
otherwise seemingly RFI scenarios, only data accumulated for condition a)1) to c)1) in 4.1 carry
content of interest which is related to the residual risk of RFI and which accompanies the “use-
as-intended” of any electric/electronic equipment (inclusive radio equipment) in the local
electromagnetic environment.
4.4 Accumulation of data on interference and preparation for reporting to CISPR
4.4.1 General
Not meeting a condition in 4.1 is a possible root cause of an RFI incident. Therefore information
on all conditions is gathered.
Guidance for collation of statistical data on interference complaints and preparation of reports
to CISPR are set out in Annex A of this document.
Annex B gives general information on the value of statistics on radio frequency interference
observed in the electromagnetic environment.
Annex C gives guidance on field strength measurements in the electromagnetic environment.
4.4.2 Data to be collected
Upon reception of an RFI complaint, it is convenient to collect and pre-process as much as
possible of the following information for subsequent reporting. The letters in front define
classification codes.
1) General information
a) an index number or reference;
b) state in which country the RFI case occurred.
2) Source-related:
a) short description of the product (e.g. toaster);
b) state which EMC standard was applied to demonstrate compliance of the product;
c) state if the source was individually tested for compliance with the relevant standard and
its outcome: not tested, compliant, not compliant.
NOTE 1 Whilst it is better if the source can be individually tested to assess compliance with the relevant
standards it is recognised that this is not always possible and interference situations can still be included in
statistics where further testing has not been possible.
d) if c) was performed state the margin to the limit at the frequency relevant to the RFI
incident;
e) state whether the source equipment is predominantly moving or static;
f) assessment as to whether the (type of) source is (predominantly) used with connection
to the LV AC mains, to a DC (power) supply network or fed by batteries;
g) report all ports of the source equipment with cables connected to them;
h) state the length of every attached cable connected to the ports reported in g);
i) assessment as to whether the received complaint belonged to an interference caused
by a single RFI source or by multiple items of the same type, as e. g. found in an
installation;
3) Source-related – supplement for sources with radio modules:
a) state whether the interference was caused by intentional, out-of-band or spurious
emissions of the radio module;
NOTE 2 This can be verified by switching off the radio function of the source, if possible.
b) state whether the radio module or part/component of the source was found to be
compliant with the applicable radio standard(s) (noting 2)c) above).

– 14 – CISPR TR 16-4-6:2024 © IEC 2024
4) Victim-related:
a) short description of the product (e.g. toaster);
b) state any EMC or radio standards, or both, applied to demonstrate compliance of the
product;
c) state if the victim was individually tested for compliance with the relevant standards and
its outcome: not tested, compliant, not compliant;
NOTE 3 Whilst it is better if the victim can be individually tested to assess compliance with the relevant
standards it is recognised that this is not always possible and interference situations can still be included in
statistics where further testing has not been possible.
d) state whether the victim equipment was located in an environment with sufficient wanted
field strength at the antenna;
e) if possible provide measurement data on the wanted field strength at the location of the
antenna;
f) state whether the victim equipment is predominantly moving or static;
g) report all ports of the victim equipment with cables connected to them;
h) state the length of every attached cable connected to the ports reported in g);
i) State the reason(s) for filing the complaint (e.g. audible or visible distortions,
malfunction, damage, etc.);
j) state how often and for how long the observed interference occurred (e.g. occurrences
per day, per hour, permanently or repetitively, periodically, occasionally, etc.).
5) Coupling-path-related:
a) state in which environment the source is located (i.e. residential, commercial, light
industrial or industrial area);
b) state in which environment the victim is located (i.e. residential, commercial, light
industrial or industrial area);
c) state the distance between the RFI victim and the source.
6) With relation to other causes:
a) state whether the victim or source is defective (e. g. due to component failure, damage,
aging, end of life);
b) state whether the victim or source is not installed or used in accordance with the user
manual or installation guideline, or used with illegal product modifications.
Annex A gives guidance on how to report to the CISPR.
5 Root-cause-analysis of the reported RFI incidences
In case of RFI incidences assigned to the second data set (as described in 4.3.3) the root cause
of the incidence has to be investigated further.
The main possible root causes for second-data-set-RFI-incidences are:
– No applicable limit in the affected frequency range, for the affected port or the affected mode
of operation exists.
– The disturbance field strength value of the source is in between the limit of the existing
applicable EMC standard and the worst case CISPR limit resulting from derivation based on
the parameters in the IEC Radio Services Database (RSD).
– Disturbance field strength exceeds the limit in the applicable EMC standard.
– Incidence distance falls short of the protection distance.
– Some of the systematic factors in the related derivation procedure based on
CISPR TR 16-4-4 [1] were not chosen accurately (attenuation by obstacles, polarization
decoupling) to reflect real situations.

– Summation effects by multiple sources.
Frequent and repeated observation of such incidents can be an indicator for insufficiencies in
CISPR standards and therefore will be investigated carefully.
For more details on root-cause-analysis see Annex D.
6 Reporting
6.1 General
Any party with interest in collecting reliable information and statistical data on RFI is encouraged
to provide this information to CISPR. Annex A can be followed for guidance on how to structure
this information.
Reports intended for CISPR can be prepared, in line with the recommendations and advice in
this document, either as results of case studies, other kinds of spectrum survey or monitoring
measurements in the field (e. g. as results of measurement campaigns), or, preferably on an
annual basis, as traditional reports on statistics of complaints (see 6.2).
Parties being liaisons to CISPR can submit their contributions and reports directly to CISPR or
CISPR/H. For other interested parties such reports can be submitted to CISPR and the relevant
CISPR subcommittee via the respective National Committee being a member of CISPR. Both
paths of providing information to CISPR will ensure that the reports will find the appropriate
attention in CISPR.
The reports cover any relevant statistical data, but preferably also other information of general
interest, as regards possible needs for maintenance of CISPR standards and limits.
6.2 Indications on the reporting format for traditional statistics of complaints
RFI investigation services which would like to issue reports on statistics of radio-interference
complaints can report as described in Annex A. For a possible classification of root causes
guidance is given in Annex D. Use of classifications will facilitate comparison of RFI situations
observed in different countries.
Data and statistics preferably cover a complete calendar year. They are whenever possible
presented in XML format, without employing more detailed categories than those listed in
Table A.2. It is however not intended to exclude further material, which can be submitted as
separate documents in addition to the data in XML format.

– 16 – CISPR TR 16-4-6:2024 © IEC 2024
Annex A
(informative)
Guidance for collation of statistical data on interference complaints
and classification of interference sources
A.1 General
Interference reports come in many different shapes. For easy evaluation it is desirable to have
a common data exchange format. The information from 4.4.2 has been encoded in an XML
schema which will be available on the IEC EMC zone.
A.2 Example of how to use the XML input form
The data structure is in XML format. Each interference case can be a separate occurrence
within a single XML message. Table A.1 shows how information on the reporting party is
gathered, Table A.2 describes the data fields of one occurrence in line with 4.4.2.
Table A.1 – Information on reporting party
No Heading Datatype
1 Name of person string
or organization
submitting
report
2 Contact details string (address, Email)

Table A.2 – Data fields of one occurrence
No Description Heading Datatype Note
1) General information
a) An index number or ind
...