SIST ETS 300 457 E1:2006

SLOVENSKI STANDARD
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Satellite Earth Stations and Systems (SES); Test methods for Television Receive Only
(TVRO) operating in the 11/12 GHz frequency bands
Ta slovenski standard je istoveten z: ETS 300 457 Edition 1
ICS:
33.060.30 Radiorelejni in fiksni satelitski Radio relay and fixed satellite
komunikacijski sistemi communications systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN ETS 300 457
TELECOMMUNICATION November 1995
STANDARD
Source: ETSI TC-SES Reference: DE/SES-04011
ICS: 33.060.30
TVRO, testing
Key words:
Satellite Earth Stations and Systems (SES);
Test methods for Television Receive Only (TVRO)
operating in the 11/12 GHz frequency bands
ETSI
European Telecommunications Standards Institute
ETSI Secretariat
F-06921 Sophia Antipolis CEDEX - FRANCE
Postal address:
650 Route des Lucioles - Sophia Antipolis - Valbonne - FRANCE
Office address:
c=fr, a=atlas, p=etsi, s=secretariat - secretariat@etsi.fr
X.400: Internet:
Tel.: +33 92 94 42 00 - Fax: +33 93 65 47 16
Copyright Notification: No part may be reproduced except as authorized by written permission. The copyright and the
foregoing restriction extend to reproduction in all media.
© European Telecommunications Standards Institute 1995. All rights reserved.
New presentation - see History box

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ETS 300 457: November 1995
Whilst every care has been taken in the preparation and publication of this document, errors in content,
typographical or otherwise, may occur. If you have comments concerning its accuracy, please write to
"ETSI Editing and Committee Support Dept." at the address shown on the title page.

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ETS 300 457: November 1995
Contents
Foreword .7
1 Scope .9
2 Normative references.9
3 Definitions and abbreviations .10
3.1 Definitions .10
3.2 Abbreviations .10
4 General test arrangements .11
4.1 General .11
4.2 Outdoor far-field test site .11
4.2.1 General.11
4.2.2 Description .11
4.3 Anechoic chamber .12
4.3.1 General.12
4.3.2 Description .12
4.3.3 Parasitic reflections .14
4.4 Reverberating chamber .15
4.4.1 General.15
4.4.2 Description .15
4.5 Open area test site.15
4.5.1 General.15
4.5.2 Description .16
4.6 Compact antenna test range .16
4.6.1 General.16
4.6.2 Description .17
4.7 Semi-anechoic chamber.18
4.8 TEM cell.18
4.9 Power supplies.18
4.9.1 Test power supplies .18
4.9.2 LNB power supply .18
4.10 Test equipment .18
4.10.1 General.18
4.10.2 Substitution antenna.19
4.10.3 Measuring and test antenna.19
4.10.4 Measuring receiver/Spectrum analyser.19
4.10.5 Screening .19
4.11 Environmental conditions.20
4.11.1 General.20
4.11.2 Standard conditions for measurement .20
4.11.3 Non-standard conditions for measurement.20
4.12 Test results and test report.20
4.12.1 Test results.20
4.12.2 Test report.20
5 Safety .21
5.1 Mechanical safety .21
5.1.1 Specification .21
5.1.2 Test method .21
5.2 Mechanical construction - wind speed.21
5.2.1 Specification .21
5.2.2 Test methods .21
5.2.2.1 General.21
5.2.2.2 Wind tunnel.22
5.2.2.3 Numerical analysis and load applications.22

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ETS 300 457: November 1995
5.3 Mechanical construction - interface loads. 23
5.3.1 Specification . 23
5.3.2 Test method. 23
5.4 Mechanical construction - adverse conditions . 24
5.4.1 General . 24
5.4.2 Corrosion resistance. 24
5.4.2.1 Specification. 24
5.4.2.2 Test method. 24
5.5 Fire hazard . 24
5.5.1 Specification . 24
5.5.2 Test method. 24
5.6 Electrical shock by access . 24
5.6.1 Specification . 24
5.6.2 Test method. 24
5.7 Lightning protection. 24
5.7.1 Specification . 24
5.7.2 Test method. 24
6 Radio frequency. 25
6.1 LNB downconverter. 25
6.1.1 Definition. 25
6.1.2 Test site . 25
6.1.3 Power supply . 25
6.1.3.1 General . 25
6.1.3.2 Specification. 25
6.1.3.3 Method of measurement. 25
6.1.4 Input range. 26
6.1.4.1 Specification. 26
6.1.4.2 Method of measurement. 26
6.1.5 Local oscillator frequency . 26
6.1.5.1 Frequency spectrum . 26
6.1.5.1.1 Specification. 26
6.1.5.1.2 Method of verification . 26
6.1.5.2 Frequency conversion. 26
6.1.5.2.1 Specification. 26
6.1.5.2.2 Method of measurement . 27
6.1.6 Output range. 27
6.1.6.1 Specification. 27
6.1.6.2 Method of measurement. 27
6.1.7 Noise figure (noise temperature) . 28
6.1.7.1 Specification. 28
6.1.7.2 Method of measurement. 28
6.1.8 Image frequency rejection . 28
6.1.8.1 General . 28
6.1.8.2 Specification. 29
6.1.8.3 Method of measurement. 29
6.1.9 Unwanted signals immunity . 30
6.1.9.1 Specification. 30
6.1.9.2 Method of measurement. 30
6.1.10 Small signal gain. 31
6.1.10.1 Specification. 31
6.1.10.2 Method of measurement. 31
6.1.11 Linearity . 32
6.1.11.1 Amplitude-frequency characteristic. 32
6.1.11.1.1 Specification. 32
6.1.11.1.2 Method of measurement . 32
6.1.11.2 Group delay characteristic . 33
6.1.11.2.1 Specification. 33
6.1.11.2.2 Method of measurement . 33
6.1.11.3 Output level (multicarrier intermodulation ratio test) . 34
6.1.11.3.1 General. 34
6.1.11.3.2 Specification. 34
6.1.11.3.3 Method of measurement . 34

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ETS 300 457: November 1995
6.1.12 LNB interfaces.35
6.1.12.1 Input.35
6.1.12.1.1 Specification.35
6.1.12.1.2 Method of measurement.35
6.1.12.2 Output impedance .35
6.1.12.2.1 Specification.35
6.1.12.2.2 Method of measurement.35
6.1.12.3 Output connector .36
6.1.12.3.1 Specification.36
6.1.12.3.2 Method of verification.36
6.1.12.4 Output return loss .36
6.1.12.4.1 Matched load .36
6.1.12.4.2 Specification.36
6.1.12.4.3 Method of measurement.36
6.2 On-axis spurious radiation .37
6.2.1 Definition .37
6.2.2 Specification .37
6.2.3 Method of measurement .37
6.2.3.1 General.37
6.2.3.2 Test site .37
6.2.3.3 Method of measurement.38
6.2.3.3.1 Conducting method.38
6.2.3.3.2 Reverberating chamber method .39
6.3 Spurious radiation.40
6.3.1 General.40
6.3.2 Specification .40
6.3.3 Method of measurement .40
6.3.3.1 Test method.40
6.3.3.2 Identification of frequencies of spurious radiation .40
6.3.3.2.1 Test site .40
6.3.3.2.2 Procedure .40
6.3.3.3 Measurement of power levels of identified spurious
radiation.41
6.3.3.3.1 Test site .41
6.3.3.3.2 Procedure .41
6.3.3.4 Measurement of spurious radiation radiated through the
antenna.42
6.3.3.4.1 Test site .42
6.3.3.4.2 Procedure (antenna flange) .42
6.3.3.4.3 Procedure (primary feed).43
6.4 Immunity .44
6.4.1 General.44
6.4.2 Test site.44
6.4.3 Definition .44
6.4.4 Ambient fields.44
6.4.4.1 Specification .44
6.4.4.2 Method of measurement.44
6.4.5 Currents.45
6.4.5.1 Specification .45
6.4.5.2 Method of measurement.46
6.5 Antenna sub-system .46
6.5.1 Co-polar on-axis gain .46
6.5.1.1 Definition.46
6.5.1.2 Specification .46
6.5.1.3 Test site .46
6.5.1.4 Method of measurement.46
6.5.2 Antenna receive radiation patterns.47
6.5.2.1 General.47
6.5.2.2 Specification .47
6.5.2.3 Design objectives.48
6.5.2.4 Test site .48
6.5.2.5 Method of measurement.48
6.5.2.6 Computation of results.49

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ETS 300 457: November 1995
6.5.3 Cross-polarisation discrimination. 49
6.5.3.1 General . 49
6.5.3.2 Specification. 49
6.5.3.3 Design objective. 49
6.5.3.4 Test site . 49
6.5.3.5 Method of measurement. 49
6.5.4 Pointing accuracy. 50
6.5.4.1 Specification. 50
6.5.4.2 Test site . 50
6.5.4.3 Method of verification. 50
6.5.5 Polarisation plane alignment. 50
6.5.5.1 General . 50
6.5.5.2 Specification. 50
6.5.5.3 Test site . 50
6.5.5.4 Method of verification. 50
6.5.6 Mechanical stability. 51
6.5.6.1 Specification. 51
6.5.6.2 Method of measurement. 51
6.5.7 Output interface and impedance matching. 51
6.5.7.1 Test site . 51
6.5.7.2 Interface . 51
6.5.7.2.1 Specification. 51
6.5.7.2.2 Method of measurement . 51
6.5.7.3 Impedance matching. 51
6.5.7.3.1 Specification. 51
6.5.7.3.2 Method of measurement . 52
6.6 Figure of merit . 52
6.6.1 General . 52
6.6.2 Specification . 52
6.6.3 Test site . 52
6.6.4 Method of measurement. 53
6.7 Supplementary requirements . 54
6.7.1 General . 54
6.7.2 Commands . 54
6.7.2.1 Specification. 54
6.7.2.2 Test site . 54
6.7.2.3 Method of measurement. 55
7 Documentation. 57
7.1 Basic specification . 57
7.2 Information leaflet . 57
7.3 Method of verification. 59
Annex A (normative): Test report summary. 60
Annex B (normative): Test report result forms . 64
Annex C (normative): Waveguide flanges . 103
C.1 Rectangular waveguide flange dimensions . 103
C.2 Circular waveguide flange dimensions . 103
History. 104

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ETS 300 457: November 1995
Foreword
This European Telecommunication Standard (ETS) has been produced by the Satellite Earth Stations and
Systems (SES) Technical Committee of the European Telecommunications Standards Institute (ETSI).
Transposition dates
Date of adoption of this ETS: 15 September 1995
Date of latest announcement of this ETS (doa): 28 February 1996
Date of latest publication of new National Standard
or endorsement of this ETS (dop/e): 31 August 1996
Date of withdrawal of any conflicting National Standard (dow): 31 August 1996

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ETS 300 457: November 1995
Blank page
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ETS 300 457: November 1995
1 Scope
This European Telecommunication Standard (ETS) covers the test methods for TeleVision Receive Only
(TVRO) outdoor units used for reception of audio-visual signals from satellites within the 11/12 GHz
frequency bands. These TVROs are defined and their characteristics are specified in the reference ETSs,
ETS 300 158 [1] or ETS 300 249 [2]. This ETS specifies the test methods for demonstration of
compliance with the specifications of the reference ETS, and also with those for which the reference ETS
allows verification at the manufacturers' discretion.
The TVROs are classified into two different types according to the corresponding services:
- Type A for collective reception;
- Type B for individual reception.
2 Normative references
This European Telecommunication Standard (ETS) incorporates by dated or undated reference,
provisions from other publications. These normative references are cited at the appropriate places in the
text and the publications are listed hereafter. For dated references subsequent amendments to or
revisions of any of these publications apply to this ETS only when incorporated in it by amendment or
revision. For undated references the latest edition of the publication referred to applies.
[1] ETS 300 158: "Satellite Earth Stations (SES); Television Receive Only
(TVRO-FSS) Satellite Earth Stations operating in the 11/12 GHz FSS bands".
[2] ETS 300 249: "Satellite Earth Stations (SES); "Television Receive-Only (TVRO)
equipment used in the Broadcasting Satellite Service (BSS)".
[3] IEC 510-1 (1975): "Methods of measurement for radio equipment used in
satellite earth stations; Part 1: General".
[4] IEC 1079-2 (1992): "Methods of measurement on receivers for satellite
broadcast transmissions in the 12 GHz band; Part 1: Electrical measurements
on DBS tuner units".
[5] CISPR 16-1 (1993): "Specification for radio disturbance and immunity
measuring apparatus and methods: Part 1: Radio disturbance and immunity
measuring apparatus".
[6] ETS 300 019: "Equipment Engineering (EE); Environmental conditions and
environmental tests for telecommunications equipment".
[7] HD 444.2 (1983): "Fire hazard testing: Part 2: Test methods".
[8] EN 60950 (1992): "Safety of information technology equipment including
electrical business equipment".
[9] EN 50083-1 (1993): "Cabled distribution systems for television and sound
signals. Part 1: Safety requirements".
[10] EN 50081-1 (1991): "Electromagnetic compatibility - Generic emission standard.
Part 1: residential, commercial and light industry".
[11] EN 50082-1 (1991): "Electromagnetic compatibility - Generic immunity standard.
Part 1: residential, commercial and light industry".
[12] EN 50140: "Electromagnetic compatibility - Basic immunity standard - Radiated,
radio-frequency electromagnetic field - Immunity test".
[13] EN 50141: "Electromagnetic compatibility - Basic immunity standard -
Conducted disturbances induced by radio-frequency fields - Immunity test".

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ETS 300 457: November 1995
[14] EN 55020 (1994): "Electromagnetic immunity of broadcast receivers and
associated equipment".
[15] EN 55022 (1994): "Limits and methods of measurement of radio interference
characteristics of information technology equipment".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of this ETS, the following definitions apply.
open air: Transparent to electromagnetic waves at the frequencies under consideration. Any covering or
environmental protection used must therefore also be transparent to electromagnetic waves at the
frequencies under consideration.
outdoor unit: That part of the TVRO installed in a position within line of sight to the satellite(s) to be
received. This normally comprises the antenna, LNB(s) and the LNB mounting.
Type A equipment: For collective reception, in particular:
Community Antenna TeleVision (CATV) equipment;
Master Antenna TeleVision (MATV) equipment.
Type B equipment: For individual reception, that is:
Direct To Home (DTH) equipment.
Other definitions are generally included in the subclause in which they occur. The definitions have been
taken, where possible, from "International Electrotechnical Vocabulary (2nd Edition), Group 60,
Radiocommunications" published by the International Electrotechnical Commission. Other sources
include, but are not limited to, documentation produced by IEC, ETSI and CISPR.
3.2 Abbreviations
For the purposes of this ETS the following abbreviations apply:
ac alternating current
BSS Broadcast Satellite Service
CATV Community Antenna TeleVision
MATV Master Antenna TeleVision
DBS Direct Broadcast by Satellite
dc direct current
EIRP Equivalent Isotropically Radiated Power
emf electro-motive force
EUT Equipment Under Test
FSS Fixed Satellite Service
IF Intermediate Frequency
LNB Low Noise Block downconverter
LO Local Oscillator
RF Radio Frequency
TEM Transverse ElectroMagnetic
VSWR Voltage Standing Wave Ratio

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ETS 300 457: November 1995
4 General test arrangements
4.1 General
Seven possible test sites are described in this clause: outdoor far-field test sites, anechoic chambers,
reverberating chambers, open area test sites, compact antenna test ranges, semi-anechoic chamber and
a TEM cell. The test sites used for the measurements shall be validated and, where appropriate,
calibrated, so as to reduce measurement uncertainty and the probability of measurement error. Other test
sites may be used provided that they are proven to produce results consistent with those produced by the
appropriate test site described in this clause.
Any measurement involving either antenna gain patterns or polarisation measurements shall be
performed in the far field obtainable on an outdoor far-field test site, through a compact antenna test
range or any other recognised method that can be proved to give the same results over the concerned
frequency range.
An open air test site shall be on a reasonable level surface or ground and it shall be free from reflecting
objects so that the measurement results are not unduly affected. Sufficient precautions shall be taken to
ensure that reflections from objects adjacent to the test site do not degrade the measurement methods.
The ambient noise of the test site shall be at least 6 dB lower than the lowest limit to which the
measurements need to be compared. All test cables shall be as short as possible and shall be adequately
screened.
In the case where the outdoor unit is manufactured without an accessible interface between the antenna
sub-system and the LNB, it is impossible to carry out the tests to verify compliance with the specifications.
In this case the manufacturer shall provide suitable fixtures.
4.2 Outdoor far-field test site
4.2.1 General
This test site shall be such that any covering or environmental protection as well as the site itself shall be
transparent to electromagnetic waves at the frequencies under consideration. The distance between the
measuring and measured antennas shall be such that they are each in the far-field region of the other
antenna. Reflections from both natural and artificial objects shall be at a minimum and of known amplitude
and effect.
4.2.2 Description
The far-field distance of an antenna is defined as:
R ≥ 2D / λ
where:
R is the distance;
D is the largest dimension of the antenna under test;
λ is the free space wavelength at the test frequency.
Even at this minimum distance, the path difference between the ray from the source to the centre of the
aperture and the ray from the source to the edge of the aperture is λ/16 and the resulting phase deviation
of the incident wave-front is 22,5° which corresponds to an error of about 0,1 dB in antenna gain.
The structure supporting the EUT shall have means of adjustment in polarisation, elevation angle and
azimuth angle so that the received signal can be maximised.
If the near-field scanner technology to convert near-field measurements to far-field results is proven to be
accurate by reference to tests taken in both regions, then antenna measurements may be taken in the
near-field.
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ETS 300 457: November 1995
4.3 Anechoic chamber
4.3.1 General
An anechoic chamber is a well shielded chamber covered inside with radio frequency absorbing material
and simulating a free space environment. Absolute or relative measurements can be performed, absolute
measurements of field strength require the anechoic chamber to be calibrated. This is the type of chamber
often used for immunity measurements.
4.3.2 Description
An anechoic chamber shall meet appropriate requirements for shielding effectiveness and wall return loss.
Figure 1 shows an example of such requirements. Figure 2 shows an example of the construction of an
anechoic chamber having a base area of 5 m by 10 m and a height of 5 m, usually used for EMC
measurements. The ceiling and walls are coated with pyramidal-formed absorbers approximately 1 m
high. The base is covered with special absorbers which form the floor. The available internal dimensions
of the chamber are 3 m by 8 m by 3 m, so that a maximum measuring distance of 5 m in the middle axis
of this chamber is available. The floor absorbers reject floor reflections so that the measuring antenna
height need not be changed during the calibration procedures. Figure 3 shows an example of a chamber
that can be used for higher frequencies. Anechoic chambers of other dimensions may be used.
a (dB)
Minimum shielding effectiveness
Limit of the return loss
f (Hz)
0 / /
10k 100k 1M 10M 30M 100M 300M 1G 4G 10G
Interfering Field strength 0,1 μA/m
Interfering Field strength
30 μV/m
0,5 μV/m
where: a is attenuation;
f is frequency.
Figure 1: Example of an anechoic shielded chamber for simulated free-space measurements

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ETS 300 457: November 1995
10 m
Measuring
Equipment
Measurement distance
antenna
under test
5 m
- Non-conductive turntable
Non-conductive surface
Side view 1 m
Ground plan
Measurement distance
5 m
- Non-conductive turntable
Absorbers
Room without absorbers
Filter blocks
for the test instrumentation
and coaxial
(shielded recommended)
feedthrough
Figure 2: Example of an anechoic shielded chamber for simulated free-space
measurements below 3 GHz
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ETS 300 457: November 1995
Test
EUT
Antenna
Side view
Ground plan
Test
EUT
Antenna
Absorbers
Room without absorbers
Filter blocks
for the test instrumentation
and coaxial
(shielded recommended)
feedthrough
Figure 3: Example of an anechoic shielded chamber for simulated free-space
measurements above 3 GHz
4.3.3 Parasitic reflections
For free-space propagation in the far-field the relationship between the field strength and the distance is
given by:
X = X x (R /R),
o o
where:
X is the field strength;
X is the reference field strength;
o
R is the reference distance;
o
R is the distance.
This relationship allows relative measurements to be made as all constants are eliminated within the ratio
and neither cable attenuation nor antenna mismatch or antenna dimensions are of importance.

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ETS 300 457: November 1995
If the logarithm of the foregoing equation is used, the deviation from the ideal curve can be easily seen
because the ideal correlation of field strength and distance appears as a straight line. The deviations
occurring in practice are then clearly visible. This indirect method shows quickly and easily any
disturbances due to reflections and is far less difficult than the direct measurement of reflection
attenuation.
With an anechoic chamber of the dimensions given above at frequencies below 100 MHz there are no far
field conditions, but the wall reflections are stronger, so that careful calibration is necessary. In the
frequency range from 100 MHz to 1 GHz the dependence of the field strength to the distance meets the
expectations very well. Above 1 GHz, because more reflections will occur, the dependence of the field
strength to the distance will not correlate so closely.
It is for this reason that the size of the anechoic chamber in relation to the required frequency range and
the physical size of the equipment to be tested are of importance.
4.4 Reverberating chamber
4.4.1 General
The reverberating chamber is a small screened room or aluminium chamber (a reflecting chamber) with
mechanical stirrers driven by electric motors. This test site can be used for radiation measurements where
the antenna is of integral construction and where it is not possible to measure at the antenna flange but it
is either possible to remove the reflector or there is no reflector. The EUT would, in this case, include the
primary antenna.
4.4.2 Description
Uncertainties increase below a certain frequency thus setting a minimum usable frequency (maximum
wavelength). The maximum usable wavelength is one tenth (1/10th) of the chamber's smallest physical
dimension. There is no advantage in using a chamber which is much larger, and in fact greater sensitivity
would be required in the receiver in such case.
Two stirrers are necessary to achieve an uniform electric field of ± 1 dB with a level of confidence of 95 %.
The stirrers should have as large a surface area as possible with no gaps or holes, but should have
irregularities with dimensions of at least one wavelength.
To maximise stirring the measuring antenna shall point to one stirrer and the EUT and substitution
antenna towards the other. The antennas and EUT should be close to a stirrer but not less than 0,1 m
from the walls or stirrers.
4.5 Open area test site
4.5.1 General
This test site shall be such that any covering or environmental protection as well as the site itself shall be
transparent to electromagnetic waves at the frequencies under consideration. Absolute or relative
measurements can be performed, absolute measurements of field strength require the open area test site
to be calibrated.
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ETS 300 457: November 1995
4.5.2 Description
2F
F = 10 or 30 m
3 F
Measuring
EUT
Antenna
Boundary of area defined by an ellipse
Figure 4: Open area test site arrangement
Figure 4 shows the arrangement of the test site which shall be void of buildings, electric lines, fences,
trees etc. and be level. A reflecting ground plane shall be installed, if required to assist the reflectivity of
the natural terrain and to avoid reflectivity changes due to environmental conditions or time. If an open
area test site is constructed of wire mesh or aluminium mesh then a solid metal ground plane of total
width at least 3 m and length 6 m towards the measuring antenna shall be placed from the centre of the
turntable for the measurement of frequencies above 1 GHz. The site shall have an obstruction-free area
surrounding it. This obstruction-free area shall be large enough so that scatterers from outside the
obstruction-free area will have little effect on the fields measured by the measuring antenna.
Measuring
Antenna
EUT
1 to 4 m
h
10 or 30 m
Figure 5: Schematic of equipment in relation to ground plane
Figure 5 shows the location of the equipment and ground plane. The height of the EUT (h) shall be as
specified for each test. The height of the measuring antenna can be changed to allow both the direct and
reflected waves to be combined.
4.6 Compact antenna test range
4.6.1 General
A compact test range is a large anechoic chamber in which, with the use of reflectors, it is possible to
simulate the far-field obtainable on an open air test site. These reflectors are very accurately profiled large
metal plates which are optically aligned with each other.

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ETS 300 457: November 1995
4.6.2 Description
Figure 6 shows the general arrangement of the test range which is one in which the receiving antenna is
illuminated by the collimated energy in the aperture of a larger point or line focus antenna. The linear
dimensions of the reflectors are usually chosen to be at least three times that of the antenna that they are
illuminating, or are being illuminated by, so that the illumination sufficiently approximates a plane wave.
To suppress any direct radiation from the feed antenna in the direction of the test region the reflectors are
designed with long focal lengths. The use of relatively long focal-length reflectors has the additional
advantage that for a given size reflector the depolarisation effect associated with curved reflectors is
reduced. Diffraction from the edges of the reflectors is reduced by designing the reflectors with serration
around the edges. High-quality absorbing material is placed between the two antennas to absorb the
unwanted radiation. The structure holding the measuring antenna can be moved both sideways and
forwards and backwards in order to further reduce any direct coupling between the antennas.
In order to obtain good results with a compact range the reflectors should be constructed with sufficient
accuracy. Small deviations in the fabricated reflector surface can result in significant variations in the
amplitude and phase distribution of the incident field at the receiving antenna. To assess the effect of
surface deviations not only their shapes and maximum deviations should be noted but, also very
importantly, their areas. For example, if the reflector has small deviations that do not exc
...