IEC 60489-1:1983/AMD2:1999

Amendment 2 - Methods of measurement for radio equipment used in the mobile services - Part 1: General definitions and standard conditions of measurement

General Information

• Status: Published
• Publication Date: 26-May-1999
• ICS: 33.060.20 - Receiving and transmitting equipment
• ICS: 33.060.30 - Radio relay and fixed satellite communications systems
• Technical Committee: TC 102 - Equipment used in radiocommunications for mobile services and for satellite communication systems
• Drafting Committee: WG 7 - TC 102/WG 7
• Current Stage: PPUB - Publication issued
• Start Date: 27-May-1999
• Completion Date: 31-May-1999

Overview

IEC 60489-1:1983/AMD2:1999 is Amendment 2 to Part 1 of the IEC series on "Methods of measurement for radio equipment used in the mobile services – General definitions and standard conditions of measurement." This amendment adds a normative Annex A that provides a practical guide for test sites and radio‑frequency coupling devices (RFCDs), expands test‑site evaluation and calibration methods, and clarifies measurement procedures (substitution method) for radiated emission and receiver sensitivity testing.

Key topics and requirements

• Test site types: definitions, advantages and limitations of Open Area Test Site (OATS), Low Reflection Test Site (LRTS), Anechoic Chamber (AC), Random Field Measurement (RFM) sites, and RFCDs (stripline, TEM, GTEM, test fixtures).
• Measurement methods: use of the substitution method (EUT replaced by calibrated auxiliary antenna and RF signal generator) for emission testing; calibration procedures for field strength and RFCDs.
• Site characteristics and construction:
  • Measuring distances commonly 3 m and 30 m for OATS, with useful frequency ranges and nominal site attenuation bands given per configuration.
  • OATS platform height 1.50 m, ground screen requirements (metal sheet or wire mesh with openings ≤ 10 mm), antenna booms of non‑conductive material and adjustable heights (1–4 m).
  • 30 m OATS minimum boundary ellipse (major axis 60 m, minor axis 52 m); limits on nearby conducting objects and cable filtering/grounding recommendations (e.g., burial depth ~300 mm for mains cables).
• RFCDs and calibration: overview of narrowband vs wideband RFCDs, size examples and frequency capability (e.g., GTEM cells for wide frequency ranges), and the expectation that RFCDs be calibrated to relate device voltages to equivalent field strengths.
• Practical measurement procedures: step‑by‑step guidance for transmitter emission and receiver sensitivity measurements, antenna alignment, and substitution/calibration steps.

Applications and users

This amendment is directly useful to:

• Test laboratories and EMC/EMI engineers performing radiated emission and receiver sensitivity tests on mobile radio equipment.
• Manufacturers of mobile radio and ancillary RF equipment preparing products for certification and compliance.
• Regulatory and certification bodies that reference IEC measurement methods in type‑approval or conformity assessment.
• Design engineers who need to understand practical measurement constraints and calibration practices.

Keywords: IEC 60489-1, radio equipment measurement, mobile services, RFCD, OATS, anechoic chamber, GTEM cell, TEM cell, LRTS, substitution method, calibration, radiated emissions, receiver sensitivity.

Related standards

• IEC 60489-8:1984 - Methods of measurement for radio equipment used in the mobile services – Part 8: Antennas (added by this amendment).

Standards Content (Sample)

INTERNATIONAL IEC
STANDARD
60489-1
AMENDMENT 2
1999-05
Amendment 2
Methods of measurement for radio equipment
used in the mobile services –
Part 1:
General definitions and standard conditions
of measurement
Amendement 2
Méthodes de mesure applicables
au matériel de radiocommunication
utilisé dans les services mobiles –
Partie 1:
Définitions générales et conditions
normales de mesure
 IEC 1999  Copyright - all rights reserved
International Electrotechnical Commission 3, rue de Varembé Geneva, Switzerland
Telefax: [phone] e-mail: [e-mail] IEC web site http://www.iec.ch
Commission Electrotechnique Internationale
PRICE CODE
XA
International Electrotechnical Commission
For price, see current catalogue

– 2 – 60489-1 Amend. 2 © IEC:1999(E)
FOREWORD
This amendment has been prepared by IEC technical committee 102: Equipment used in radio
communications for mobile services and for satellite communication systems.
The text of this amendment is based on
FDIS Report on voting
102/41/FDIS 102/49/RVD
Full information on the voting for the approval of this amendment can be found in the report on
voting indicated in the above table.
A bilingual version of this amendment may be issued at a later date.
___________
Add the following reference to the list of "Other IEC publications quoted in this standard":
IEC 60489-8:1984, Methods of measurement for radio equipment used in the mobile services –
Part 8: Antennas
Page 54
Add the following Annex A after figure 3.
Annex A
(normative)
Guide for the use of test sites and radio-frequency
coupling devices (RFCDs)
A.1 General
Test sites are basic means to perform radiation measurements. Radio-frequency coupling
devices (RFCDs) are means generally designed to perform many equipment radiation
measurements economically, using the same measuring method as equipment with antenna
terminals.
This annex describes low reflection test sites (LRTS) and anechoic chambers (AC) for upper
frequency limit extension and interference-free measurements, as well as random field
measurement sites for measurements similar in the real field and for measurement equipment
with a diversity antenna. TEM cells and GTEM cells are also described for wideband upper-
frequency limit extension and interference-free measurements.
The evaluation measurement of a test site is the method to judge whether a test site
construction satisfies the required conditions and is introduced for LRTS, AC and RFM sites in
this annex. The evaluation measurement for OATS was studied, but not introduced because
the available evaluation measurement required important measurement condition changes.

60489-1 Amend. 2 © IEC:1999(E) – 3 –
The calibration method for a test site is the process for determining the numerical relationship
between equipment radiation power and the observed output of a radio-frequency signal
generator which replaces the EUT during the substitution measurement, or the numerical
relationship between the field strength where the EUT is placed and the indication of the
selective measuring device with the calibration antenna.
RFCDs were originally used only for ratio measurement of equipment receiving radio-frequency
electromagnetic energy. The radiation sensitivity measured in the RFCD was called "the
reference sensitivity (RFCD)" and defined as the level of RFCD input signal in microvolts (μV).
This annex also describes calibration methods. Calibration is the procedure for determining the
numerical relationship between RFCD input or output voltage and the equivalent field strength
where the EUT is placed, or the radiated power of the EUT. RFCDs should be principally
calibrated. Therefore, RFCDs need no evaluation measurement.
Test site overview and overview of RFCDs are shown in tables A.1 and A.2 respectively.
Table A.1 – Test site overview
Test sites Advantages Disadvantages
OATS: Open area test site Low construction cost Needs a lot of space
Available for large size EUT Interference from others
Includes ground reflection effects Weather dependency
Measurement fluctuation is
relatively high at frequencies higher
than 1 GHz
LRTS: Low reflection test site Clear and flexible evaluation Does not reflect reality
criterion
Is affected by absorber size
Possible to reduce error
Interference from others
Wide frequency range
Available for large size EUT
No influence of ground reflections
AC: Anechoic chamber No interference Limited lower frequency
No weather dependency Limited EUT size
No influence of ground reflections Expensive, especially for low
frequency
RFM: Random field measurement Few construction site requirements Needs many measurement values
site (anywhere) and their calculation
Evaluation of real world antenna
efficiency
Clear and flexible evaluation
criterion
Available for the evaluation of
diversity antenna
– 4 – 60489-1 Amend. 2 © IEC:1999(E)
Table A.2 – Overview of radio-frequency coupling devices (RFCDs)
RFCDs Maximum size of EUT [mm] Features
Narrowband RFCD ---------- Available in small size
Test fixture (Only for specific EUT) Not expensive
Only for specific EUT
Only for specific or approximate
frequency
Wideband RFCDs More than twice frequency range
Stripline arrangement 200 l × 200 b × 250 h for maximum Can be constructed with detailed
frequency of 200 MHz information
400 l × 400 b × 500 h for maximum Influence of surroundings
frequency of 100 MHz
Limited frequency range
TEM cell 100 l × 150 b × 50 h for maximum No influence from surroundings
frequency of 500 MHz
Limited frequency range
200 l × 300 b × 100 h for maximum
frequency of 250 MHz
GTEM cell 300 l × 300 b × 200 h to greater No influence from surroundings
than 5 GHz
Wide frequency range
or 1 000 l × 1 000 b × 500 h to
greater than 5 GHz
NOTE – A certain manufacturer specifies d.c. to 17 GHz for the frequency range of a GTEM cell.
A.1.1 Abbreviations:
AC Anechoic chamber
ETSI European Telecommunication Standards Institute
EUT Equipment under test
GTEM GHz TEM
LRTS Low reflection test site
OATS Open area test site
RFCD Radio-frequency coupling device
RFM Random field measurement
TEM Transverse electromagnetic mode
A.2 Test sites
A.2.1 Introduction, outline and selection of test sites
The radiation characteristics of equipment are measured at test sites. Both equipment emitting
radio-frequency electromagnetic energy and equipment receiving it can be measured. Emission
measurements can be made for all radio-frequency parameters pertaining to radiated radio-
frequency electromagnetic energy, for example, transmitter radiated power, transmitter
radiated spurious power, receiver radiated spurious power. Receiver measurements can be
made for all radio-frequency parameters pertaining to received radio-frequency electro-
magnetic energy, for example, receiver radiation sensitivity.
OATSs are the classic test sites and have been left as before. ACs are already widely used,
and the new evaluation measurement has been introduced. LRTS and RFM site are newly
introduced test sites. Both LRTS and RFM sites have clear and flexible evaluation criteria
which allow for easy appraisal of conformity to construction requirements.

60489-1 Amend. 2 © IEC:1999(E) – 5 –
All test sites use the substitution method for emission measurements and this reduces
measurement error. The EUT is to be substituted with a half-wave dipole antenna and a radio-
frequency signal generator. The field strength in receiver measurements is to be measured by
the calibration antenna and the selective measuring device.
A guide for the selection of test sites is shown in table A.1.
A.2.2 Open area test site (OATS)
A.2.2.1 General
Open area test sites are applicable to all kinds of measurements on mobile radio equipment in
areas where no interfering radio services are operating, and no other radio services may
interfere with the propagation of the measuring frequencies power used on the test site. In
other cases indoor test sites are recommended.
On an OATS, the measuring antenna or the calibration antenna receives the combination of a
direct wave and a ground reflected wave. By contrast, the measuring antenna or the calibration
antenna on the LRTS receives only a direct wave, while the ground reflection is suppressed.
Measuring distances of 3 m and 30 m are applied for OATS.
Emission measurements can be made on any measuring distance for all radio parameters
concerning radiated electromagnetic energy, for example, transmitter radiated power,
transmitter radiated spurious power, receiver radiated spurious power. The shorter measuring
distance test site can measure low power. The longer one can measure a large size of EUT
and lower frequency.
Receiver measurements can be made only on 30 m test site for all radio parameters
concerning received electromagnetic energy, for example, receiver radiation sensitivity. The
3 m test site has great field gradient in higher frequencies.
A.2.2.2 Test site characteristics
Characteristics Limits for a 3 m test site
Useful frequency range 100 MHz to 1 000 MHz
Nominal site attenuation 12 dB to 38 dB for 100 MHz
Nominal site attenuation 32 dB to 58 dB for 1 000 MHz
Equipment size limits 0,6 m maximum, including the antenna
NOTE - The nominal attenuation of the test site for a half-wave dipole is 18 dB for
100 MHz and 38 dB for 1 000 MHz. The actual attenuation may vary due to ground
reflections.
Characteristics Limits for a 30 m test site
Useful frequency range 25 MHz to 1 000 MHz
Nominal site attenuation 20 dB to 46 dB for 25 MHz
Nominal site attenuation 52 dB to 78 dB for 1 000 MHz
Equipment size limits 6 m, including the antenna
NOTE - The nominal attenuation of the test site for a half-wave dipole is 26 dB for
25 MHz and 58 dB for 1 000 MHz. The actual attenuation may vary due to ground
reflections.
– 6 – 60489-1 Amend. 2 © IEC:1999(E)
A.2.2.3 Basic measuring procedure
A.2.2.3.1 Transmitter emission measurements
a) Place the transmitter under test on the platform. Orientate the measuring antenna so that it
has the same polarization as the transmitter. Orientate the transmitter so that an intended
direction is perpendicular to the direction of the measuring antenna and operate the
transmitter.
b) Tune the selective measuring device to the radiated power component.
c) Raise and lower the measuring antenna to obtain the maximum indication on the selective
measuring device. Note the maximum indication.
d) Substitute the auxiliary antenna and the radio-frequency signal generator for the transmitter
under test. Adjust the measuring antenna height to the maximum point where reading in the
selective measuring device can be obtained.
e) Adjust or calculate the radio-frequency signal generator output level to the level obtained in
step c). This level is the radiated power of the transmitter under test for an intended
direction.
NOTE 1 – The selection of the measuring distance and the connection of the equipment in the test site are not
included in the above steps.
NOTE 2 – The measuring antenna height in step c) and step d) may vary. The measuring antenna height in step c)
for another intended direction may differ from the original.
A.2.2.3.2 Receiver measurement receiving radio-frequency electromagnetic energy
a) Calibrate the radio-frequency signal generator level to the electromagnetic field strength
received by the calibration antenna and the selective measuring device. It should be
confirmed that the transmitting antenna is less dependent upon small changes in antenna
height before the calibration.
b) Replace the calibration antenna and the selective measuring device by a receiver under
test. Orientate the receiver so that an intended direction is perpendicular to the direction of
the transmitting antenna and operate the receiver.
c) Adjust the signal generator level to the level which just satisfies the receiver radiation
sensitivity according to the sensitivity measurement procedure.
d) Read or calculate the average of signal generator level and convert it to the calibrated
level. This level is the radiation sensitivity of the receiver in an intended direction.
NOTE – Connection of the equipment in the test site is not included in the above steps. The measuring distance is
30 m.
A.2.2.4 Construction of a radiation test site
The measuring arrangement for equipment emitting radio-frequency electromagnetic energy is
shown in figure A.1. The measuring arrangement for equipment receiving electromagnetic
energy is shown in figure A.2.
The radiation test site shall be on ground level having uniform electrical characteristics and
being free from reflecting objects over an area as wide as possible, to ensure that the
extraneous electromagnetic fields do not affect the accuracy and repeatability of the test
results.
A.2.2.4.1 3 m test site
A continuous ground screen (either sheet metal or wire mesh having openings no greater than
10 mm, which should maintain good electrical contact between the wire) shall be used to
establish a uniformly conducting earth over part of the test site. The turntable shall be metallic
and shall be flush with the ground screen. The minimum ground screen area is shown in
figure A.3.
60489-1 Amend. 2 © IEC:1999(E) – 7 –
A.2.2.4.2 30 m test site
The minimum boundary of the test site shall be an ellipse having a major axis equal to 60 m
and a minor axis equal to 52 m. The EUT and the measuring antenna or the transmitting
antenna shall be located at the foci.
No extraneous conducting objects having any dimensions in excess of 50 mm shall be in the
immediate vicinity of either the EUT or the antennas.
The test site shall have a turntable and a support for the measuring antenna. The measuring
distance is the distance in the horizontal plane between the central vertical axis of the turntable
and the central vertical axis of the measuring antenna. A shelter may be provided for the whole
or a part of the test site. All such constructions having any dimensions greater than 50 mm
should be of wood, plastic, or other non-conducting material. Wood shall be impregnated to
ensure minimum water absorption.
All test equipment, if located above ground, shall be powered preferably by batteries. If the
equipment is powered by mains, each of the supply cables shall be provided with a suitable
radio-frequency filter. The cable connecting the filter and the measuring equipment shall be as
short as possible and shielded. The cable connecting the filter and mains shall either be
shielded and grounded, or buried to a depth of approximately 300 mm.
A.2.2.5 Position of the EUT
The equipment with its cabinet or housing in which it is normally operated shall be placed on a
horizontal platform, the upper side of which is 1,50 m above the ground. The platform and its
support shall be made of non-conductive material.
For equipment with an integral antenna, the equipment shall be placed on the platform in a
position which is closest to that in normal use.
Equipment having a rigid external antenna shall be mounted so that the antenna is in a vertical
position. Equipment having a non-rigid external antenna shall be mounted vertically, using a
non-conducting support.
It shall be possible to rotate the equipment around the central vertical axis of its antenna. It is
recommended that a turntable, preferably remotely controlled, be used for this purpose. If the
equipment has a power cord, it should extend down to the turntable, and any excess should be
coiled on it.
For information on the use of alternative test mounting arrangements for equipment which is
hand-carried or carried on a person in normal operation, see clause A.4.
A.2.2.6 Measuring antenna
The measuring antenna shall be suitable for the reception of linearly polarized waves. It may
consist of a half-wave dipole, the length of which is adjusted for the frequency concerned. For
practical reasons, however, to increase the sensitivity and to attenuate remaining reflections, a
more complex antenna, having high directivity and broad bandwidth, is preferred. For low
frequencies short dipoles are recommended.
The measuring antenna shall be mounted at the end of a horizontal boom supported by a
vertical pole, both made of non-conducting materials. The boom shall project at least 1 m from
the pole in the direction to the EUT and shall be arranged so that it may be raised and lowered
from 1 m to 4 m. The mounting shall permit the antenna to be positioned for measuring both
horizontal and vertical components of the electric field. The mount shall permit the antenna to
be tilted so as to permit simultaneous inclusion of both the direct and reflected rays. The lower
end of the antenna, when oriented for vertical polarization and placed at its lowest position,
shall be at least 0,3 m above the ground.

– 8 – 60489-1 Amend. 2 © IEC:1999(E)
The antenna cable shall be routed along the horizontal boom for at least 2 m, preferably at
ground level. Suitable antenna clearance is recommended. Alternatively, the cable may be
routed underground.
A.2.2.7 Transmitting antenna
The transmitting antenna shall be suitable for the radiation of linearly polarized waves. It may
consist of a half-wave dipole, the length of which is adjusted for the frequency concerned. For
practical reasons, however, to increase the sensitivity and to attenuate remaining reflections, a
more complex antenna having high directivity and broad bandwidth is preferred. For low
frequencies short dipoles are recommended.
The transmitting antenna shall be mounted at the end of a horizontal boom supported by a
vertical pole, both made of non-conducting material. The boom shall project at least 1 m from
the pole in the direction of the equipment under test and shall be arranged so that the centre of
the antenna is 3 m ± 0,2 m above the ground. The mounting shall permit the antenna to be
positioned for the same polarization as that of the receiver antenna.
The antenna cable shall be routed along the horizontal boom for at least 2 m, preferably at
ground level. Suitable antenna clearance is recommended. Alternatively, the cable may be
routed underground.
At some frequencies, an appreciable variation of signal level occurs for a small change in
antenna height due to ground reflections. Where this occurs, the transmitting antenna should
be moved up or down by an amount that will place the antenna in a region of small height
sensitivity and make the test site calibration less dependent upon small changes in antenna
position.
A.2.2.8 Auxiliary antenna
The auxiliary antenna substitutes for the equipment under test during calibration. The auxiliary
antenna shall be a half-wave dipole and shall be arranged in a manner similar to that of the
measuring antenna, except that the centre of the auxiliary antenna should coincide
approximately with the normal position of the centre of radiation of the equipment under test. A
broadband antenna also may be used as the substitution antenna.
At frequencies below about 60 MHz, the above condition may be impossible to achieve for
vertical polarization. In this case, the lower end of the antenna should be placed 0,3 m above
the ground, and the EUT shall be positioned to satisfy the above listed conditions.
A.2.2.9 Calibration antenna
The calibration antenna replaces the EUT during calibration of the receiver receiving
electromagnetic energy measurement. The calibration antenna shall be an antenna for which
the available power output has been calibrated in field strength. The centre of the calibration
antenna is located so that this point coincides with the centre of the radiation centre of the
EUT.
The antenna, including the cable, shall be matched to the input impedance of the selective
measuring device.
At frequencies below about 60 MHz, the above condition may be impossible to achieve when
the antenna is arranged for vertical polarization. In this case, the lower end of the antenna
should be placed 0,3 m above the ground and the EUT shall be positioned to satisfy the above
conditions.
60489-1 Amend. 2 © IEC:1999(E) – 9 –
A.2.2.10 Radio-frequency signal generator
A well-shielded radio-frequency signal generator, with a matching or combining network (if
required) and its associated output cable, shall be placed so that it will not affect the accuracy
of the results, and shall be connected to and matched to the auxiliary antenna.
A.2.2.11 Selective measuring device
The selective measuring device should be a calibrated field strength meter or a spectrum
analyzer (with preselector), and shall be placed, together with its associated input cable, in a
position where it will not affect the accuracy of the test results.
A.2.2.12 Calibration method for OATS
A.2.2.12.1 General
The test site calibration is the procedure for determining the numerical relationship between
the EUT radiated power and the selective measuring device indication in an emission
measurement site, or the field strength where the EUT is placed, and the radio-frequency
signal generator equivalent output voltage in a receiver measurement site.
Measurement distance is not so important for the substitution method. Only the adjustment of
the radiation centre of the EUT at the measurement distance to that of the auxiliary antenna for
substitution is meaningful.
The radiation centre of the receivers is not recognized and the radiation centre of the
calibration antenna may differ from that of the receivers. This means that the field strength
measured by the calibration antenna might be different from the field strength at the radiation
centre of the receivers.
A.2.2.12.2 Calibration for measurement of equipment emitting radio-frequency
electromagnetic energy
This method is applicable to the radiated radio-frequency power of transmitters and the
radiated spurious components of receivers.
a) Connect the equipment as illustrated in the chosen test site with the auxiliary antenna and
the measurement antenna oriented to provide the polarization intended for the
measurement.
b) Adjust the auxiliary antenna (if applicable) to the correct length for the frequency to be
measured and adjust the frequency of the radio-frequency signal generator to the same
frequency.
c) Adjust the measurement antenna (if applicable) to the correct length for the frequency to be
measured and tune the selective measuring device to the operating frequency of the radio-
frequency signal generator.
d) Adjust the output level of the radio-frequency signal generator to –10 dBm (103 dBμV).
e) Raise and lower the measuring antenna to obtain the maximum indication on the selective
measuring device. Record the indication level of the selective measuring device.
f) The radiated radio-frequency power for other values of the selective measuring device
indication is given by:
radiated power = (new indication level in decibels (dB)) – (indication level in step e) in
decibels (dB)) – 10 dBm
NOTE – The calibration is only valid for the frequency, antennas, polarization, and antenna position used in the
calibration procedure. If any of these change, the site should be recalibrated.

– 10 – 60489-1 Amend. 2 © IEC:1999(E)
A.2.2.12.3 Calibration for measurement of equipment receiving radio-frequency
electromagnetic energy in a 30 m test site
a) Connect the equipment as illustrated in the chosen test site with the transmitting antenna
and the calibration antenna oriented to provide the polarization intended for the receiver
under test.
b) Adjust the frequency of the radio-frequency signal generator to the operating frequency of
the receiver.
c) Adjust the calibration antenna (if applicable) to the correct length for the frequency to be
measured and tune the selective measuring device to the operating frequency of the radio-
frequency signal generator.
d) Adjust the output level of the radio-frequency signal generator to produce a reading of
100 μV/m (40 dBμV/m) on the selective measuring device. Record the output of the radio-
frequency signal generator in microvolts.
e) The field strength for other values of the radio-frequency signal generator output is given
by:
new output level
field strength = × 100 μV/m
output level recorded in step d)
or
field strength in dBμV/m = 40 + 20 lg (new output level in microvolts)
–20 lg (output level in microvolts recorded in step d).
NOTE 1 – The calibration is only valid for the frequency, antennas, polarization, and antenna position used in the
calibration procedure. If any of these change, the site should be recalibrated.
NOTE 2 – Measurement distance is not so important for the substitution method, but the radiation centre
coincidence between calibration antenna and the receiver under test is very important because the radiation centre
difference between them means a calibration error. To reduce this error, a longer measurement distance is
recommended because it has a lesser degree of field strength variation than a shorter measurement distance.
Especially at high frequency, this becomes severe, for example an 8 dB variation with 100 mm height difference is
observed at 900 MHz at a measurement distance of 3 m. Therefore, a 3 m test site for equipment receiving radio-
frequency electromagnetic energy is not recommended.
A.2.3 Low reflection test sites (LRTS, reduced ground reflections)
A.2.3.1 Introduction
The open area test sites (OATS) are widely used and popular test sites. Recently, upper
frequency limitation improvement became necessary and some studies were made. One of the
effective improvement methods is to suppress the ground-reflected waves. It also improves the
measurement repeatability.
On an OATS, the measuring antenna or the calibration antenna receives the combination of a
direct wave and a ground reflected wave. By contrast, the measuring antenna or the calibration
antenna on the LRTS receives only a direct wave, while the ground reflection is suppressed.
The suppression of ground-reflected waves makes the characteristics of the test site similar to
those of anechoic chambers and not to those of OATS.
LRTS have simple and clear evaluation criteria which can be adapted to any level of measuring
error or repeatability requirements. LRTS require no specific construction requirements and
can be applied to any measuring distance, for example, 3 m, 5 m, 10 m or 30 m.
For suppression of ground-reflected waves, use of a high directivity antenna and any other
means are recommended. However, the quality of the construction is to be judged only by the
evaluation criterion. (see A.2.3.4 and A.2.3.5)
NOTE – ETSI indoor test site is involved in LRTS. It requires a specific construction and a specific evaluation
criterion.
60489-1 Amend. 2 © IEC:1999(E) – 11 –
A.2.3.2 Test site characteristics
Measuring distances of 3 m to 30 m can be used in combination with ground-reflected wave
suppression described in A.2.3.4. Longer distance sites are unusual. Only the lowest frequency
to be used and the largest dimension of the equipment under test require a longer measuring
distance. LRTS characteristics are very similar to those of an anechoic chamber. The anechoic
chamber can be used as an LRTS. The useful frequency range is extended to 18 GHz
(depending on site performance).
As an example, a measuring distance of 3 m is shown below.
Characteristics Limits for a distance of 3 m
Useful frequency range 100 MHz to 18 GHz
Nominal site attenuation 32 dB to 44 dB for 1 000 MHz
Equipment size limits 0,6 m maximum
A.2.3.3 Basic measuring procedure
A.2.3.3.1 Transmitter emission measurements
a) Place the transmitter under test on the platform. Orientate the measuring antenna so that it
has the same polarization as the transmitter. Orientate the transmitter so that an intended
direction is perpendicular to the direction of the measuring antenna and operate the
transmitter.
b) Tune the selective measuring device to the radiated power component.
c) Raise and lower the measuring antenna around the same height as the transmitter under
test, to obtain the maximum indication on the selective measuring device. Note the
maximum indication.
d) Substitute the auxiliary antenna and the radio-frequency signal generator for the transmitter
under test. Adjust the auxiliary antenna height to the maximum reading point in the
selective measuring device.
e) Adjust or calculate the radio-frequency signal generator output level to the level obtained in
step c). This level is the radiated power of the transmitter under test for an intended
direction.
NOTE 1 – Selection of the measuring distance, connection of the equipment in the test site and the evaluation
measurements are not included in the above steps.
NOTE 2 – The measuring antenna height, the transmitter radiation centre and the auxiliary antenna will be the
same.
A.2.3.3.2 Receiver measurement receiving radio-frequency electromagnetic energy
a) Calibrate the radio-frequency signal generator level to the electromagnetic field strength
received by the calibration antenna and the selective measuring device.
b) Replace the calibration antenna and the selective measuring device by a receiver under
test. Orientate the receiver so that an intended direction is perpendicular to the direction of
the transmitting antenna and operate the receiver.
c) Adjust the signal generator level to the level which just satisfies the receiver radiation
sensitivity according to the sensitivity measurement procedure.
d) Read or calculate the average of the signal generator level and convert it to the calibrated
level. This level is the radiation sensitivity of the receiver in an intended direction.
NOTE – Selection of the measuring distance, connection of the equipment in the test site and the evaluation
measurements are not included in the above steps.

– 12 – 60489-1 Amend. 2 © IEC:1999(E)
A.2.3.4 Construction of a radiation test site
The measuring arrangement for equipment emitting radio-frequency electromagnetic energy is
shown in figure A.4. The measuring arrangement for equipment receiving electromagnetic
energy is shown in figure A.5.
For the ground reflected wave suppression, use of a high directivity antenna and any of the
measures in figure A.6 are suggested.
If a radio-wave screening curtain is used for the suppression of ground-reflected waves, the
height of the curtain should be adjusted to be the optimum clearance as shown in figure A.6a.
The optimum clearance will be 80 % to 100 % of the first Fresnel zone, which is calculated by
the following formula. The output of the measuring antenna or the calibration antenna becomes
a maximum at the optimum clearance.
dd
H =
dd+
If a radio-wave absorber is used for the suppression of the ground-reflected wave, the width of
the absorber area projected circle on the perpendicular plane to the ground-reflected wave
path should be more than the circle with the same radius as the first Fresnel zone (see figure
A.6d).
The other side area of the high directive measuring antenna or transmitting antenna should be
as wide as possible to avoid extraneous reflected waves.
No extraneous conducting objects shall be in the immediate vicinity of either the equipment
under test or antennas. It is also not recommended to use high permittivity dielectric in the
immediate vicinity of either the equipment under test or the antennas. It may affect field
distribution in the 800 MHz band or a higher frequency band.
The extraneous reflected waves increase the standing wave ratio in the evaluation
measurement and this means an increase of the measurement error.
The test site shall have a turntable. The measuring distance is not critical in substituting a
measurement if the centre of the equipment under test and the centre of the measuring
antenna are placed in the same position.
A.2.3.5 Evaluation measurements
The evaluation measurement is the procedure to judge whether the test site construction
satisfies the required conditions.
The reflected waves cause standing waves. The ratio value in decibels (dB) between a peak
and an adjacent valley measured field strength means the maximum measuring value variation
in decibels (dB). The maximum value measured in the volume of EUT is to be the maximum
measuring error or the repeatability of the test site. The standing waves should be measured at
least in two directions, in the three perpendicular directions of the measuring antenna or the
calibration antenna. Measurement should be made by moving the measuring antenna or the
calibration antenna continuously.
The length of the standing-wave measurement should be greater than the size of the EUT or a
half-wave length, whichever is longer. The centre of the standing-wave measurement should be
almost the same point to the radiation centre of the EUT.
Any value of the evaluation criterion could be used if both the purchaser and the manufacturer
agree. However, ±1 dB to ±3 dB would be realistic.

60489-1 Amend. 2 © IEC:1999(E) – 13 –
A.2.3.6 Position of the EUT
The position of the EUT is recommended to be as high as possible because the higher position
makes larger incident angle difference between the ground-reflected wave and the direct wave.
Consequently, the received power of the ground-reflected wave is reduced by the increased
directivity of the measuring antenna. The higher position also increases the propagation loss of
the ground-reflected wave which reduces the power of the reflected wave.
Some examples of higher positions are shown in figure A.7.
The equipment in the cabinet or housing in which it normally operates shall be placed on a
platform. The platform and its support shall be made of non-conducting materials. Equipment
having an integral antenna shall be placed on the platform in a position which is closest to its
normal use. If dielectric material is used for supporting the stand position of the equipment, low
permittivity material is recommended.
It shall be possible to rotate the equipment about the vertical axis through the centre of the
antenna of the EUT. It is recommended that a platform in the form of a turntable, preferably
remotely controlled, should be used for this purpose. If the equipment has a power cable, it
should extend down the turntable.
For information on the use of alternative test mounting arrangements on this test site for
equipment which is hand-carried or carried on a person while in normal operation, see clause
A.4.
A.2.3.7 Measuring antenna
The measuring antenna shall be suitable for the reception of linearly polarized waves and shall
be a high directive antenna for suppressing the receiving power of the ground-reflected wave
and other extraneous reflected waves.
The mounting shall permit the antenna to be positioned for measuring both horizontal and
vertical components of the electric field.
NOTE – EUT is generally designed for vertical polarization. However, it may have other stronger polarizations in
higher frequency spurious components.
A.2.3.8 Transmitting antenna
The transmitting antenna shall be the same as the measuring antenna except that the
transmitting antenna height and direction shall be adjusted so that the received power of the
calibration antenna becomes maximum.
A.2.3.9 Auxiliary antenna
The auxiliary antenna replaces the EUT during part of the emission measurement. The
auxiliary antenna shall be a half-wave dipole (see A.7.1).
The auxiliary antenna height shall be adjusted so that the received power of the measuring
antenna becomes maximum after the measuring antenna height has been adjusted to the
maximum point of the received power from the EUT. This procedure makes the radiation centre
of the auxiliary antenna coincide with the radiation centre of the equipment under test.
A.2.3.10 Calibration antenna
The calibration antenna replaces the equipment under test during calibration of the receiver
receiving electromagnetic energy measurement. The calibration antenna shall be an antenna
for which the available power output has been calibrated in field strength. The centre of the
calibration antenna shall be located so that this point coincides with the centre of the radiation
centre of the EUT. The antenna, including the cable, shall be matched to the input impedance
of the selective measuring device.

– 14 – 60489-1 Amend. 2 © IEC:1999(E)
A.2.3.11 Calibration method for LRTS
A.2.3.11.1 General
The test site calibration is the procedure for determining the numerical relationship between
EUT radiated power and the selective measuring device indication in an emission measure-
ment site, or the field strength where the EUT is placed and the radio-frequency signal
generator equivalent output voltage in a receiver measurement site.
The measurement distance is not so important for the substitution method. Only the adjustment
of the radiation centre of the EUT at the measurement distance to that of the calibration
antenna for substitution is meaningful.
Radiation measurement directions in a vertical plane are almost always horizontal and may
differ from that of an OATS or an AC with ground plane.
A.2.3.11.2 Calibration for measurement of equipment emitting radio-frequency
electromagnetic energy
This method is applicable to the radiated radio-frequency power of transmitters and the
radiated spurious components of receivers.
a) Connect the equipment as illustrated in the chosen test site with the auxiliary antenna and
the measurement antenna oriented to provide the polarization intended for the measure-
ment.
b) Adjust the auxiliary antenna (if applicable) to the correct length for the frequency to be
measured and adjust the frequency of the radio-frequency signal generator to the same
frequency.
c) Adjust the measurement antenna (if applicable) to the correct length for the frequency to be
measured and tune the selective measuring device to the operating frequency of the radio-
frequency signal generator.
d) Adjust the output level of the radio-frequency signal generator to –10 dBm (103 dBμV).
e) Raise and lower, for example ±0,3 m, the measuring antenna to obtain the maximum
indication on the selective measuring device. Record the indication level of the selective
measuring device. The same height to the auxiliary antenna may be acceptable if the above
indication shows flatness or very little variation.
f) The radiated radio-frequency power for other values of the selective measuring device
indication is given by:
radiated power = (new indication level in decibels (dB)) – (indication level in step e) in
decibels (dB)) – 10 dBm
NOTE – Calibration is only valid for frequency, antennas, polarization, and the antenna position used in the
calibration procedure. If any of these change, the site should be recalibrated.
A.2.3.11.3 Calibration for measurement of equipment receiving radio-frequency
electromagnetic energy
a) Connect the equipment as illustrated in the chosen test site with the transmitting antenna
and the calibration antenna oriented to provide the polarization intended for the receiver
under test.
b) Adjust the frequency of the radio-frequency signal generator to the operating frequency of
the receiver.
c) Adjust the calibration antenna (if applicable) to the correct length for the frequency to be
measured and tune the selective measuring device to the operating frequency of the radio-
frequency signal generator.
60489-1 Amend. 2 © IEC:1999(E) – 15 –
d) Raise and lower, for example ±0,3 m, the calibration antenna to obtain the maximum
indication on the selective measuring device. The same height to the auxiliary antenna may
be acceptable if the indication shows flatness or very little variation.
e) Adjust the output level of the radio-frequency signal generator to produce a reading of
100 μV/m (40 dBμV/m) on the selective measuring device. Record the output of the radio-
frequency signal generator in microvolts (μV).
f) The field strength for other values of the radio-frequency signal generator output is given by
new output level
field strength = × 100 μV/m
output level recorded in step e)
or
field strength in dBμV/m = 40 + 20 lg (new output level in microvolts (μV))
–20 lg (output level in microvolts (μV) recorded in step e))
NOTE – Calibration is only valid for frequency, antennas, polarization, and the antenna position used in the
calibration procedure. If any of these change, the site should be recalibrated.
A.2.4 Anechoic chamber
A.2.4.1 General
The anechoic chamber is a well-shielded chamber which allows disturbing influences on the
measurements from outside to be avoided.
All inside surfaces are covered by electromagnetic absorption material which suppresses
reflections and simulates free-space conditions. However, the suppressing of reflections is
limited in reality by the frequency or the room to be used.
A.2.4.2 Characteristics of an anechoic chamber
Example of an anechoic chamber with the dimensions of 5 m × 5 m × 10 m.
Characteristics Limits for a 10 m chamber
Useful frequency range 100 MHz to above 1 000 MHz
Useful measuring distance 3 m to 5 m
Nominal site attenuation 5 m distance and 100 MHz 26 dB
Nominal site attenuation 5 m distance and 1 000 MHz 46 dB
Minimum shielding attenuation 100 dB
Minimum return loss of absorbers 10 dB
Maximum equipment size 1 m
A.2.4.3 Basic measuring procedure
The basic measuring procedure of the anechoic chamber is the same as that of the LRTSs
(see A.2.3.3).
A.2.4.4 Example of the construction of an anechoic chamber
An example of a chamber with dimensions of 5 m × 5 m × 10 m, which is shown in figure A.8,
has internal room dimensions of 3 m × 3 m × 8 m, so that a maximum measuring distance of
5 m in the middle axis of the room is available. The chamber consists of shielded walls, ceiling
and floor. The ceiling and walls of the chamber are coated with about 1 m high pyramid
absorbers. The floor can be covered with floor absorbers which can be walked on. The ground
reflections need not be considered and the antenna height has basically no influence on the
results.
– 16 – 60489-1 Amend. 2 © IEC:1999(E)
All measuring results therefore can be checked by simple calculations and the measuring
tolerances are as small as possible. When planning an anechoic chamber, two parameters are
very important: shielding loss and return loss. Shielding loss is the capability of the chamber to
attenuate radiated r.f. energy. The attenuation depends on the material and the construction of
the chamber and is normally specified by the manufacturer.
The return loss is a measure of its ability to suppress reflections and standing waves. The
value of the return loss depends on the material, the geometrical shape and the dimensions of
the absorbers applied.
Typical values of pyramid-shaped absorbers with a base of 600 mm × 600 mm and a height of
600 mm are 5 dB to 8 dB return loss. The attenuation varies, for example, with the height and
material of the absorber and the frequencies, as well as the installation practice.
The measuring arrangement for equipment emitting radio-frequency electromagnetic energy
and for equipment receiving electromagnetic energy are the same as those of the LRTSs
shown in figure A.4 and figure A.5 respectively.
A.2.4.5 Evaluation measurements
To meet the proposed specification, it is necessary to measure the quality of the anechoic
chamber which depends especially on the wall influences of the mounted chamber. The
evaluation measurement is the procedure to judge whether the test site construction satisfies
the required conditions.
The reflected waves cause standing waves. The ratio value in decibels between a peak and an
adjacent valley measured field strength means the maximum measuring value variation in
decibels. The maximum value measured in the volume of the equipment under test (EUT) is to
be the maximum measuring error or the repeatability of the test site. The standing waves
should be measured at least in two directions, in the three perpendicular directions of the
measuring antenna or the calibration antenna. The measurement should be made by moving
the measuring antenna or the calibration antenna continuously. The length of the standing
wave measurement should be greater than the size of the EUT or a half-wave length,
whichever is longer. The centre of the standing wave measureme
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