prEN IEC 62037-7:2026

SLOVENSKI STANDARD
01-marec-2026
Pasivne radiofrekvenčne (RF) in mikrovalovne naprave, meritve
intermodulacijskega nivoja - 7. del: Terenska merjenja pasivne intermodulacije
Passive RF and microwave devices, intermodulation level measurement - Part 7: Field
measurements of passive intermodulation
Dispositifs RF et à micro-ondes passifs, mesure du niveau d’intermodulation - Partie 7:
Mesures de l’intermodulation passive sur le terrain
Ta slovenski standard je istoveten z: prEN IEC 62037-7:2026
ICS:
33.120.01 Komponente in pribor na Components and
splošno accessories in general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

46/1075/CDV
COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 62037-7 ED2
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2026-01-16 2026-04-10
SUPERSEDES DOCUMENTS:
46/1053/CD, 46/1069A/CC
IEC TC 46 : CABLES, WIRES, WAVEGUIDES, RF CONNECTORS, RF AND MICROWAVE PASSIVE COMPONENTS AND ACCESSORIES
SECRETARIAT: SECRETARY:
United States of America Mr David Hess
OF INTEREST TO THE FOLLOWING COMMITTEES: HORIZONTAL FUNCTION(S):
SC 46A, SC 46F
ASPECTS CONCERNED:
Electromagnetic Compatibility
SUBMITTED FOR CENELEC PARALLEL VOTING NOT SUBMITTED FOR CENELEC PARALLEL VOTING
Attention IEC-CENELEC parallel voting
The attention of IEC National Committees, members of CENELEC, is
drawn to the fact that this Committee Draft for Vote (CDV) is
submitted for parallel voting.
The CENELEC members are invited to vote through the CENELEC
online voting system.
This document is still under study and subject to change. It should not be used for reference purposes.
Recipients of this document are invited to submit, with their comments, notification of any relevant patent rights of which t hey are aware
and to provide supporting documentation.
Recipients of this document are invited to submit, with their comments, notification of any relevant “In Some Countries” clau ses to be
included should this proposal proceed. Recipients are reminded that the CDV stage is the final stage for submitting ISC c lauses. (SEE
AC/22/2007 OR NEW GUIDANCE DOC).

TITLE:
Passive RF and microwave devices, intermodulation level measurement – Part 7: Field measurements of passive
intermodulation
PROPOSED STABILITY DATE: 2030
NOTE FROM TC/SC OFFICERS:
electronic file, to make a copy and to print out the content for the sole purpose of preparing National Committee positions.
You may not copy or "mirror" the file or printed version of the document, or any part of it, for any other purpose without
permission in writing from IEC.

IEC CDV 62037-7 © IEC 2026
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms, definitions and abbreviated terms . 5
3.1 Terms and definitions . 5
3.2 Abbreviated terms . 6
4 General considerations . 6
4.1 Test environment . 6
4.2 Test frequencies . 6
4.3 Safety . 8
5 Field PIM test equipment . 8
6 Test procedure . 8
6.1 General . 8
6.2 Equipment verification . 8
6.2.1 General . 8
6.2.2 Clean and inspect RF connections . 8
6.2.3 Residual PIM test . 8
6.2.4 PIM standard test . 9
6.3 VSWR verification . 9
6.4 Interference verification . 9
6.5 Static PIM test . 9
6.6 Dynamic PIM test . 10
6.6.1 General . 10
6.6.2 Coaxial cable assemblies . 10
6.6.3 Coaxial connectors . 10
6.6.4 Splitters, combiners, filters and receive low noise amplifiers . 10
6.6.5 Antennas . 10
7 Guidelines for minimizing generation of passive intermodulation. 11
8 Test specification . 12
9 Report . 12
Annex A (informative) Distance-to-PIM measurements . 13
Annex B (informative) Inbuilding distributed antenna systems . 15
Annex C (informative) Method to estimate system noise rise based on PIM test
measurements . 22

Figure 1 – Example of poor test frequency selection . 6
Figure 2 – Example of good test frequency selection . 6
Table 1 – Guide for the design and installation of indoor and outdoor networks to minimize
generation of passive intermodulation . 10
Figure A.1 – Internal vs. external PIM sources . 13

IEC CDV 62037-7 © IEC 2026
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
PASSIVE RF AND MICROWAVE DEVICES,
INTERMODULATION LEVEL MEASUREMENT –

Part 7: Field measurements of passive intermodulation

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all
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6) All users should ensure that they have the latest edition of this publication.
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the publication, use of, or reliance upon, this IEC Publication or any other IEC Publications.
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) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent
rights. IEC shall not be held responsible for identifying any or all such patent rights.
IEC 62037-7 has been prepared by IEC technical committee 46: Cables, wires, waveguides, RF
connectors, RF and microwave passive components and accessories. It is an International
Standard.
IEC CDV 62037-7 © IEC 2026
This second edition cancels and replaces the first edition published in 2022. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
a) revised specification to accommodate multi-path field installations as might be found in
distributed antenna systems;
b) added examples to clarify how to adjust test frequencies to avoid interference;
c) revised specification to allow static, fixed frequency tests as might be required in distributed
antenna systems;
d) added informative Annex B to address unique test requirements of distributed antenna
systems.
e) Added informative Annex C providing guidance on how to estimate noise rise in a wide
bandwidth systems based on narrow bandwidth PIM tests.
The text of this International Standard is based on the following documents:
Draft Report on voting
46/XXX/XX 46/XXX/XX
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 International Standard 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/standardsdev/publications.
A list of all parts of the IEC 62037 series, under the general title: Passive RF and microwave
devices, intermodulation level measurement, 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,
• replaced by a revised edition, or
• amended.
IEC CDV 62037-7 © IEC 2026
1 PASSIVE RF AND MICROWAVE DEVICES,
2 INTERMODULATION LEVEL MEASUREMENT –
4 Part 7: Field measurements of passive intermodulation
8 1 Scope
9 This part of IEC 62037 defines test methods for reverse measurement of passive intermodulation
10 (PIM) in systems of RF components deployed in the field. Field PIM measurements can be
11 conducted on RF systems terminated into low PIM loads or on antenna feed systems that broadcast
12 the test signals into the environment.
13 2 Normative references
14 The following documents are referred to in the text in such a way that some or all of their content
15 constitutes requirements of this document. For dated references, only the edition cited applies. For
16 undated references, the latest edition of the referenced document (including any amendments)
17 applies.
18 IEC 62037-1:2025, Passive RF and microwave devices, intermodulation level measurement –
19 Part 1: General requirements and measuring methods
20 IEC 62037-2:2021, Passive RF and microwave devices, intermodulation level measurement –
21 Part 2: Measurement of passive intermodulation in coaxial cable assemblies
22 IEC 62037-3:2025, Passive RF and microwave devices, intermodulation level measurement –
23 Part 3: Measurement of passive intermodulation in coaxial connectors
24 IEC 62037-5:2021, Passive RF and microwave devices, intermodulation level measurement –
25 Part 5: Measurement of passive intermodulation in filters
26 IEC 62037-6:2021, Passive RF and microwave devices, intermodulation level measurement –
27 Part 6: Measurement of passive intermodulation in antennas
28 3 Terms, definitions and abbreviated terms
29 3.1 Terms and definitions
30 No terms and definitions are listed in this document.
31 ISO and IEC maintain terminological databases for use in standardization at the following
32 addresses:
33 • IEC Electropedia: available at https://www.electropedia.org/
34 • ISO Online browsing platform: available at https://www.iso.org/obp
IEC CDV 62037-7 © IEC 2026
35 3.2 Abbreviated terms
37 DAS Distributed antenna system
38 DTP Distance to PIM
39 DUT Device under test
40 IM Intermodulation
41 MIMO Multiple input multiple output
42 OFDM Orthogonal Frequency Division Multiplexing
43 PIM Passive intermodulation
44 RF Radio Frequency
45 TMA Tower mounted amplifier
46 VSWR Voltage standing wave ratio
47 4 General considerations
48 4.1 Test environment
49 When a field PIM measurement is conducted on an antenna feed system that allows the test signals
50 to broadcast into the environment, it is important to ensure that government regulations pertaining
51 to the maximum authorized RF radiation levels are met. This applies to all fixed frequency PIM
52 tests, swept PIM tests and distance-to-PIM (DTP) tests described in this document. See Annex A
53 for information on distance-to-PIM measurements.
54 Field PIM measurements conducted on antenna feed systems measure the linearity of the entire
55 RF path including the site RF infrastructure (coaxial cables, filters, antennas, etc.) and the
56 environment where the antenna is installed (mounting hardware, cable support brackets, metal
57 objects in front of or in the vicinity of the antenna). Technicians performing field PIM tests through
58 an antenna shall avoid placing objects with non-linear PIM behaviour such as keys, cell phones,
59 ladders and tools in locations in front of or in the vicinity of the antenna that might impact results.
60 4.2 Test frequencies
61 The f , f and IM product frequency selected for testing a RF path shall fall within the operating
1 2
62 bandwidth of the path under test. The f and f test frequencies shall be able to pass through the
1 2
63 entire system and the IM product frequency being measured shall be able to return to the PIM
64 analyzer for measurement. If devices are present in the RF path that block the f and/or f test
1 2
65 frequency or prevent the desired IM product frequency from returning to the PIM analyzer, bypass
66 these devices with short, low PIM jumper cables while testing. See Annex B for test frequency
67 suggestions for inbuilding distributed antenna system (DAS) testing.
68 The f and f test signals shall be spaced far enough apart in frequency to place the IM product
1 2
69 being measured in the receive band of the PIM analyzer. To meet this requirement, one or both
70 test signals will likely be outside of the spectrum owned by the operator commissioning the test.
71 While it is unlikely that PIM test signals will cause harmful interference to other operators, it is good
72 practice to select f and f test frequencies that fall in the guard bands between operators.
1 2
73 When PIM testing through an antenna, interfering signals can be received from user equipment
74 operating at the IM product frequency. A survey of frequencies locally in use should be conducted
75 prior to testing. If interfering signals are detected, change the f and/or f test frequency to move
1 2
IEC CDV 62037-7 © IEC 2026
76 the IM product frequency to unused spectrum, such as a guard band frequency between active
77 channels.
78 Figures 1 and 2 demonstrate the concept of adjusting the f and/or f test frequencies to
1 2
79 intentionally place the IM3 frequency being measured into a guard band frequency between
80 operators. The f and f test frequencies shown in Figure 1 generate an IM3 frequency that falls
1 2
81 in operator 2’s uplink. User equipment transmitting in operator 2’s spectrum will interfere with PIM
82 measurements made using these test frequencies. This interference can be eliminated by changing
83 the f test frequency as shown in Figure 2 to move the IM3 frequency to the guard band frequency
84 between operator 1 and operator 2.
86 Figure 1 – Example of poor test frequency selection
89 Figure 2 – Example of good test frequency selection
IEC CDV 62037-7 © IEC 2026
94 4.3 Safety
95 Performing field PIM tests through antennas can be dangerous. Potentially high voltages and high
96 levels of RF energy can be present near the antenna. Technicians performing field PIM tests shall
97 remain at a safe distance from the antenna and minimize exposure to electromagnetic fields in
98 order to not exceed the acceptable levels specified by government agencies.
99 PIM tests require technicians to disconnect the coaxial cables at the radio output ports. Make sure
100 that all radios feeding the line under test are locked-off and non-transmitting to prevent RF burns.
101 5 Field PIM test equipment
102 PIM test equipment used for field measurements shall be capable of performing a reverse (reflected)
103 PIM test in accordance with IEC 62037-1:2025, 6.2.2. Field PIM test equipment will experience
104 shock and vibration during transportation to a site and during use. In addition, field test equipment
105 will often be used in outdoor, uncontrolled thermal environments. For these reasons, field PIM test
106 equipment shall be ruggedized to perform reliably under typical test conditions.
107 6 Test procedure
108 6.1 General
109 Unless otherwise specified, test tones from the PIM analyzer will be injected into the system under
110 test through the same connector that transmit signals enter the system from the radio. When
111 multiple radio ports are present, each RF path shall be tested.
112 6.2 Equipment verification
113 6.2.1 General
114 Because field PIM test equipment can be exposed to mechanical and thermal stress between tests,
115 it is important to verify before testing that the equipment is in good operating condition. In addition
116 to good operating condition verification, the following verification steps can be performed as
117 needed while testing to rule out equipment issues when unexpected results are encountered.
118 6.2.2 Clean and inspect RF connections
119 Clean and inspect all RF connectors in the test set-up using isopropyl alcohol and a lent-free wipe
120 prior to beginning verification tests. Mating surfaces inside the RF connectors should be clean and
121 free of oils, dirt or objects that will increase contact resistance. In addition, all metal flakes shall be
122 removed from inside the RF connector. Replace any worn or damaged components found during
123 visual inspection.
124 6.2.3 Residual PIM test
125 Measure the residual PIM of the test set-up including the PIM analyzer and any coaxial cables and
126 RF adapters used to connect the PIM analyzer to the system under test. Connect one end of the
127 coaxial cable test lead to the PIM analyzer and the other end to a low PIM termination. Flex the
128 test cable while measuring the test set-up. The test set-up maximum self-intermodulation (including
129 contribution of the load) should be at least 10 dB below the level to be measured on the system
130 under test as specified in IEC 62037-1.
IEC CDV 62037-7 © IEC 2026
131 6.2.4 PIM standard test
rd
132 A PIM standard is a device that consistently produces a known 3 order IM product level when
133 tested at a specified power level using specified f and f test signals. Some PIM standards include
1 2
134 an integrated RF termination while others are "in-line" standards that require a low PIM termination
135 to be connected to the output port of the standard. Connect the PIM standard plus termination
rd
136 directly to the output port of the PIM analyzer and measure the 3 order IM level. The value
137 measured should be within 3 dB of the expected value for that standard.
138 6.3 VSWR verification
139 Measure the VSWR of the system including the test lead and any RF adapters used to connect the
140 PIM analyzer to the system at the f , f and IM product frequencies. Unless otherwise specified,
1 2
141 the VSWR should be <1,92:1 (10 dB return loss). If higher reflected energy is detected, investigate
142 and repair the fault prior to performing a field PIM test.
143 6.4 Interference verification
144 Perform an external noise level measurement at the desired IM product frequency prior to
145 performing a field PIM test. The magnitude of external received signals at the IM product frequency
146 should be 10 dB lower than the IM level to be measured on the system under test. This test can be
147 performed using a spectrum analyzer attached to the system under test or by using the PIM test
148 equipment itself with the receiver active and the test signals turned off.
149 6.5 Static PIM test
150 "Static" means "without movement or stress". Perform a static PIM test to determine the lM product
151 level generated by the system. If the static IM product level is below the specified pass/fail threshold,
152 proceed to “dynamic” PIM testing when specified. If the IM product level is above the specified
153 pass/fail threshold, find and repair the PIM faults before proceeding. See Annex C for information
154 on how to estimate noise rise in a wide bandwidth communications system based on static PIM test
155 results.
156 Static PIM tests can be conducted using fixed f , f and IM product frequencies to avoid external
1 2
157 interference at the IM product frequency and to minimize the probability of harmful interference by
158 the test signals on other operators. Fixed frequency testing can occasionally report a passing PIM
159 test result at the specified IM product frequency when there are multiple PIM sources present in
160 the system under test. If multiple PIM sources are physically separated in such a way that the
161 signals arrive at the PIM test equipment receiver 180º out of phase, the PIM signals will cancel,
162 indicating low PIM in the system under test.
163 Static PIM tests can also be conducted using swept PIM measurements where one test frequency
164 is fixed while sweeping the second test frequency across a range of spectrum. Changing the test
165 frequencies changes the phase relationship between multiple IM product signals on the line.
166 Sweeping across multiple test frequency combinations provides a range of IM product data points
167 to help ensure that poor system PIM performance is not reported as good performance due to an
168 unfortunate selection of test frequencies.
169 PIM measurements on antenna feed systems can broadcast one or both test signals outside the
170 licensed spectrum owned by the operator commissioning the test. The test signals are short
171 duration and are typically transmitted in the downlink range of licensed spectrum holders . As a
172 result, this test is unlikely to cause harmful interference to other users.
IEC CDV 62037-7 © IEC 2026
173 6.6 Dynamic PIM test
174 6.6.1 General
175 "Dynamic" means "with movement and/or with stress". When a dynamic PIM test is specified,
176 perform a PIM test on the system while applying a dynamic stimulus to all components and
177 connections in the system. The maximum IM product level measured during the dynamic PIM test
178 shall not exceed the specified pass/fail level for the system.
179 The purpose for applying a dynamic stimulus while PIM testing is to verify that all connections are
180 tight and to identify any components with unstable PIM performance. The stimulus does not have
181 to simulate environmental conditions to identify loose connections and unstable components. In
182 addition, the stimulus does not have to exactly replicate the stimulus specified for factory PIM
183 testing. The field dynamic stimulus shall not, however, be more severe than the stimulus defined
184 in the relevant IEC 62037 specification for the component under test.
185 Fixed frequency PIM tests shall be used for maximum responsiveness while performing dynamic
186 PIM tests. Multiple dynamic stimuli are required at each component and connection as described
187 below to increase the probability of detection of PIM events.
188 6.6.2 Coaxial cable assemblies
189 Hold the cable at a distance of 4× the specified repeated bending radius of the cable and rotate
190 the cable in either a clockwise or counterclockwise direction for 3 cycles. The radius of rotation
191 should be equal to the cable diameter plus approximately 10 mm as specified in
192 IEC 62037-2:2021, 4.2.
193 6.6.3 Coaxial connectors
194 Strike the connector with an instrument that will not damage the surface of the connector such as
195 the plastic end of a screwdriver or the rubberized end of an adjustable wrench. Be careful not to
196 strike the coaxial cable. Apply 5 impacts per connector with an impact energy less than or equal to
197 the level specified in IEC 62037-3:2025, Table 1 for the connector type under test.
198 6.6.4 Splitters, combiners, filters and receive low noise amplifiers
199 Strike the device body with an instrument that will not damage the surface of the device such as
200 the plastic end of a screwdriver or the rubberized end of an adjustable wrench. Two impacts shall
201 be applied as close as possible to each connector on the device while still impacting the device
202 body. For any side of the device that has no connectors, apply 3 impacts along each side. Impact
203 energy shall be less than or equal 0,14 J per impact as specified in
204 IEC 62037-5:2021, 4.2.
205 6.6.5 Antennas
206 For directional panel antennas, strike the rear surface of the antenna with an instrument that will
207 not damage the surface of the antenna such as the plastic end of a screwdriver or the rubberized
208 end of an adjustable wrench. Strikes should not be applied to AUT accessories or other fragile
209 parts of the antenna. Two impacts shall be applied as close as possible to each coaxial connector
210 on the device while still impacting the antenna rear surface. Additional impacts will be applied every
211 30 cm along the height of the antenna. Impact energy shall be less than or equal 1 J per impact as
212 specified in IEC 62037-6:2021, 7.3.
213 For omnidirectional antennas, the test technician must remain outside of the antenna beam while
214 performing dynamic PIM tests. Strike the antenna mounting surface using a fiberglass rod as close
215 as possible to the coaxial connectors. Strikes should not be applied to any fragile part of the
IEC CDV 62037-7 © IEC 2026
216 antenna. Impact energy shall be less than or equal 1 J per impact as specified in IEC 62037-
217 6:2021, 7.3.
219 7 Guidelines for minimizing generation of passive intermodulation
220 IEC 62037-1:2025, 7.2 provides guidelines for minimizing internal passive intermodulation in RF
221 components. Table 1 provides additional guidelines for preventing both internal and external
222 passive intermodulation interference that should be considered and adhered to whenever possible
223 when deploying systems of RF components in indoor and outdoor networks.
224 Table 1 – Guide for the design and installation of indoor and outdoor networks to minimize
225 generation of passive intermodulation
Component, design PIM type Recommendation
parameter or procedure
RF connectors Internal Use 4.3-10 series or equivalent connectors when possible due
to their superior intermodulation performance vs. 7-16 series
or Type-N connectors
RF connections Internal Clean RF connections with lint-free wipe moistened with
alcohol to remove dirt, grease and metallic debris prior to
assembly. Torque RF connections using a calibrated torque
wrench to achieve manufacturer’s recommended assembly
torque.
RF connector attachment to Internal Use factory terminated cable assemblies when possible.
coaxial cable When field termination is required be sure to use the correct
cable preparation tools for the cable in use. Cutting tools
should be kept clean and sharp. Use knives or blades to cut
conductors where possible rather than saws to avoid creation
of metal flakes. Hold cables in a downward position when
cutting to avoid metal debris falling inside the cable. Carefully
remove metal burrs from cut metal surfaces. Remove all metal
residue, dielectric material and adhesive residue from mating
surfaces using wipes moistened with alcohol and non-metallic
scrapers prior to assembly. Torque or compress retaining
hardware according to manufacturer’s specification.
RF components Internal Use low PIM RF components (antennas, filters, combiners,
terminations, etc.) that have been factory tested to verify low
PIM performance in accordance with the applicable IEC 62037
test specification. Properly handle RF components to prevent
mechanical damage during transportation and installation.
Leave protective caps installed on RF connectors prior to
assembly.
RF and mechanical equipment External Any RF or mechanical equipment installed within 3
wavelengths of an antenna (component mounting brackets,
installed near antennas
cable support brackets, antenna support frames, radio
equipment, etc.) should be low PIM by design. PIM
performance of this equipment should be verified using a near
field radiated PIM test in accordance with IEC 62037-8.
Prevent galvanic corrosion by avoiding stainless steel
mounting brackets in contact with galvanized steel support
IEC CDV 62037-7 © IEC 2026
Component, design PIM type Recommendation
parameter or procedure
frames. Tighten all mechanical fasteners to manufacturer’s
specifications to prevent loose metal-to-metal contacts.
Site hygiene External Eliminate obvious sources of loose metal-to-metal contact or
corrosion within 3 wavelengths of installed antennas. Remove
metal trash or debris. Insulate or mechanically isolate lightly
touching metal brackets or antenna support frame members.
Remove un-used metal hardware. Remove rust from metal
surfaces and coat with rust inhibiting primer / paint.
Antenna placement / External Eliminate antenna skew with respect to antenna mounting
orientation (outdoor sites) frame or building surface (if mounted on side of building.)
Provide a minimum of 2 wavelengths horizontal separation
between adjacent directional panel antennas. For rooftop
installations, minimize set-back from the edge of the building
to reduce roof area illuminated by the antennas. Avoid metal
objects of any kind in the main beam (+/- 45 degrees) of
directional panel antennas (power lines, adjacent buildings,
rooftop equipment, adjacent towers, etc.)
Antenna placement (inbuilding External Avoid loose metal-to-metal contacts of any kind within 1
sites) wavelength of inbuilding antennas (ceiling tile support frames,
metal pipes, metal cable trays, etc.) Relocate antennas to
avoid these objects. Avoid spraying fire retardant construction
foam on or near inbuilding antennas. This foam often contains
nano particles able to produce corona discharge / wideband
interference.
Inbuilding component Internal Plan and build the RF distribution network so that component
placement RF connectors (combiners, couplers, antennas, etc.) remain
accessible for measurements and repairs.
227 8 Test specification
228 Test specifications shall specify for each point of test:
229 a) test power level;
230 b) IM product order to be measured;
231 c) frequency band(s) or specific test frequencies within the band(s) to be measured ;
232 d) static or dynamic test;
233 e) fixed or swept frequency test
234 9 Report
235 The report shall document the following:
236 a) residual PIM of the measurement system for each band measured;
237 b) maximum PIM value measured over the test duration for each point of test.
IEC CDV 62037-7 © IEC 2026
IEC CDV 62037-7 © IEC 2026
239 Annex A
240 (informative)
242 Distance-to-PIM measurements
243 PIM test equipment can be equipped with a test mode that displays the electrical length between
244 the instrument and the PIM fault. A distance-to-PIM (DTP) test mode, also referred to as range-to-
245 fault (RTF) or distance-to-faulty PIM (DTFP), provides a static test tool for identifying the
246 approximate location of PIM faults, both inside the feed system as well as beyond the antenna.
247 PIM test equipment able to perform a DTP measurement includes additional hardware and signal
248 processing software needed to transform frequency information into time domain plots , for example
249 using inverse fast Fourier transform (FFT) or signal correlation methods.
250 NOTE When using the FFT method, DTP measurements are conducted by transmitting two PIM test signals into the
251 system under test. PIM test signals are swept over a range of frequencies to produce IM products in the receive band of
252 the PIM analyzer. The inverse FFT algorithm is used to reconstruct time domain range pulses by digitally summing the
253 quantized phase and amplitude components of each frequency involved in the computation. The more frequency
254 bandwidth available for analysis the sharper the mathematical pulse edges will be, providing improved resolution of
255 closely spaced PIM sources.
256 DTP measurements can require frequencies to be transmitted by the test equipment that are
257 outside the licensed spectrum owned by the operator commissioning the test. The test signals are
258 short duration and are typically transmitted in the downlink range of licensed spectrum holders. As
259 a result, this test is unlikely to cause harmful interference to other users.
260 DTP test modes do have limitations that should be considered by users. Accuracy is dependent on
261 selection of the correct cable velocity factor for the system under test, which can be difficult when
262 multiple cable types are used in the system. In addition, electrically long devices, such as filters
263 and TMA’s can create a large difference in electrical length compared to the device’s physical
264 length. DTP algorithms are not able to cope with large interfering signals or large variations in PIM
265 magnitude during the measurement window. If these conditions are present, DTP results can be
266 highly inaccurate, and therefore should not be used as a pass/fail test. However, even with these
267 limitations, DTP has proven to be a useful tool for identifying the location of static PIM sources in
268 the field.
269 DTP technology is useful when measuring antenna feed systems for determining if PIM sources
270 are inside the antenna feed system or beyond the antenna as shown in Figure A.1. The preferred
271 method is to place a strong PIM source, such as a bag of steel wool, on the antenna radome and
272 record the electrical distance to the antenna radiating aperture. Next, remove the strong PIM source
273 from the antenna radome and measure the electrical distance to the largest "site" PIM source. If
274 the site PIM source is electrically further away than the antenna aperture PIM, the site PIM source
275 is beyond the antenna. If the site PIM source is electrically closer than the antenna aperture PIM,
276 then the site PIM source is inside the antenna or inside the antenna feed system.
IEC CDV 62037-7 © IEC 2026
278 Figure A.1 – Internal vs. external PIM sources
279 To estimate the distance between the antenna and an external PIM source, repeat the process
280 described above with the velocity factor set to 1. Place the strong PIM source at the center of the
281 antenna array for the band under test. The center of the array under test will sometimes not be at
282 the physical center of the antenna since multi-band antennas can incorporate stacked antenna
283 arrays. Running the PIM analyzer in fixed frequency mode while moving the strong PIM source
284 over the face of the antenna will help identify the array location. Stronger PIM readings will be
285 measured when the PIM source is located over the array under test.
286 Distance measurements for PIM sources beyond an antenna are most accurate for PIM sources
287 located within the half-power beamwidth of the antenna. Inaccurate distances are often reported
288 for PIM sources located outside the half-power beamwidth. For example, a PIM source located
289 directly behind the antenna at a physical distance of 0,5 m can be reported to be 3,0 m away using
290 this process.
292 ___________
IEC CDV 62037-7 © IEC 2026
301 Annex B
302 (informative)
304 Inbuilding distributed antenna systems
305 To improve wireless network performance inside buildings, mobile operators often deploy
306 distributed antenna systems (DAS). Inbuilding DAS can be single or multi-operator systems using
307 a combination of active and passive components to transport signals between each mobile
308 operator’s radio and antennas distributed inside the building. This Annex will focus on PIM testing
309 methods associated with the passive sections of inbuilding DAS.
310 Figure B.1 shows a simplified diagram of a fully passive inbuilding DAS network. RF combiners
311 are used to combine signals from multiple radios and distribute these signals to different zones in
312 the building. A zone could be a single floor, a group of floors or a specific area such as a parking
313 garage. Hybrid combiners are often used to combine the signals and large diameter, low loss
314 coaxial cable is often used to transport the signals from the RF combiner to each floor. Within
315 each zone, tappers and splitters are used to divide the signals with the objective being to deliver
316 approximately equal RF power to each antenna in the zone. Smaller diameter coaxial cable is often
317 used at floor level to simplify cable routing. For multiple input, multiple output (MIMO) systems,
318 two passive networks are installed to serve each zone with spatially separated or dual polarized
319 antennas at each antenna location.
321 Figure B.1 – Passive inbuilding DAS
322 Figure B.2 shows a simplified diagram of a hybrid inbuilding DAS network. There are many
323 variations of this type of DAS with the common elements being that multiple radios are combined
324 at the head end of the system and fed to multiple remote radio units using an active distribution
325 network. Hybrid inbuilding DAS often use relatively high-power remote radio units to broadcast the
326 combined signals into a passive RF distribution network at the floor or zone level.
327 RF conditioners in this type of system receive signals from the mobile operator radios, provide
328 means for reducing RF power (when required) and separate uplink signals from downlink signals.
329 Small diameter, low-power coaxial cables transport the conditioned signals to the head end
330 equipment. The head end equipment converts the RF signals to a different media (optical fiber or
331 copper wire) to transport to the signals to multiple zones within the building. PIM testing in a hybrid
332 inbuilding DAS is limited to the high-power regions between the radios and the RF conditioner and
333 the distribution network beyond the remote radio units.
IEC CDV 62037-7 © IEC 2026
335 Figure B.2 – Hybrid inbuilding DAS
336 As in outdoor systems, inbuilding DAS often have a linearity requirement defined by the mobile
337 operator. Test tones from the PIM analyzers used to validate the system linearity are injected into
338 the DAS through the same connector that transmit signals enter the system from the radio . Due to
339 the large number of RF connections in an inbuilding DAS, it is highly recommended that PIM testing
340 be conducted throughout construction on smaller segments of the DAS, rather than waiting until
341 construction is complete to validate linearity.
342 A good practice is to start at the floor level and validate the linearity of each floor before moving
343 on to the next floor or coverage area. Once validated, install a protective cap on the RF connector
344 feeding the floor to prevent foreign materials from entering the validated section. Since many of
345 the problems found in inbuilding DAS are connector related issues (cleanliness, tor
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