ETSI EN 302 454-1 V1.1.1 (2007-07)
Electromagnetic compatibility and Radio spectrum Matters (ERM); Meteorological Aids (Met Aids); Radiosondes to be used in the 1 668,4 MHz to 1 690 MHz frequency range; Part 1: Technical characteristics and test methods
Electromagnetic compatibility and Radio spectrum Matters (ERM); Meteorological Aids (Met Aids); Radiosondes to be used in the 1 668,4 MHz to 1 690 MHz frequency range; Part 1: Technical characteristics and test methods
DEN/ERM-TG25-024-1
Elektromagnetna združljivost in zadeve v zvezi z radijskim spektrom (ERM) - Meteorološki pripomočki (Met Aids) - Radiosonde za uporabo v frekvenčnem območju od 1 668,4 MHz do 1 690 MHz - 1. del: Tehnične karakteristike in preskusne metode
General Information
Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.YHQþQHPElectromagnetic compatibility and Radio spectrum Matters (ERM) - Meteorological Aids (Met Aids) - Radiosondes to be used in the 1 668,4 MHz to 1 690 MHz frequency range - Part 1: Technical characteristics and test methods33.100.01Elektromagnetna združljivost na splošnoElectromagnetic compatibility in general33.060.99Druga oprema za radijske komunikacijeOther equipment for radiocommunications07.060Geologija. Meteorologija. HidrologijaGeology. Meteorology. HydrologyICS:Ta slovenski standard je istoveten z:EN 302 454-1 Version 1.1.1SIST EN 302 454-1 V1.1.1:2007en01-december-2007SIST EN 302 454-1 V1.1.1:2007SLOVENSKI
STANDARD
ETSI ETSI EN 302 454-1 V1.1.1 (2007-07) 2
Reference DEN/ERM-TG25-024-1 Keywords radio, SRD, testing, UHF ETSI 650 Route des Lucioles F-06921 Sophia Antipolis Cedex - FRANCE
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Important notice Individual copies of the present document can be downloaded from: http://www.etsi.org The present document may be made available in more than one electronic version or in print. In any case of existing or perceived difference in contents between such versions, the reference version is the Portable Document Format (PDF). In case of dispute, the reference shall be the printing on ETSI printers of the PDF version kept on a specific network drive within ETSI Secretariat. Users of the present document should be aware that the document may be subject to revision or change of status. Information on the current status of this and other ETSI documents is available at http://portal.etsi.org/tb/status/status.asp If you find errors in the present document, please send your comment to one of the following services: http://portal.etsi.org/chaircor/ETSI_support.asp 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 2007. All rights reserved.
DECTTM, PLUGTESTSTM and UMTSTM are Trade Marks of ETSI registered for the benefit of its Members. TIPHONTM and the TIPHON logo are Trade Marks currently being registered by ETSI for the benefit of its Members. 3GPPTM is a Trade Mark of ETSI registered for the benefit of its Members and of the 3GPP Organizational Partners. SIST EN 302 454-1 V1.1.1:2007
ETSI ETSI EN 302 454-1 V1.1.1 (2007-07) 3
Contents Intellectual Property Rights.6 Foreword.6 Introduction.7 1 Scope.8 2 References.8 3 Definitions, symbols and abbreviations.9 3.1 Definitions.9 3.2 Symbols.10 3.3 Abbreviations.10 4 Technical requirement specifications.10 4.1 Presentation of equipment for testing purposes.10 4.1.1 Choice of model for testing.11 4.1.2 Definitions of Switching Range, Alignment Range and Operational Frequency Range.11 4.1.2.1 Definition of Tuning Range (TR).11 4.1.2.2 Definition of Operating Frequency Range (OFR).11 4.1.2.3 Allocated Frequency Range.11 4.1.2.4 Number of samples for testing.11 4.1.3 Testing of equipment with alternative power levels.11 4.1.4 Testing of equipment that does not have an external 50 Ω RF connector (integral antenna equipment).12 4.1.4.1 Equipment with an internal permanent or temporary antenna connector.12 4.2 Mechanical and electrical design.12 4.2.1 Controls.12 4.2.2 Transmitter shut-off facility.12 4.2.3 Marking.12 4.2.3.1 Regulatory marking.12 4.3 Declarations by the manufacturer.12 4.4 Auxiliary test equipment.12 5 Test conditions, power sources and ambient conditions.12 5.1 Normal and extreme test conditions.12 5.2 Test power source.13 5.2.1 External test power source.13 5.2.2 Internal test power source.13 5.3 Normal test conditions.13 5.3.1 Normal temperature and humidity.13 5.3.2 Normal test power source.13 5.4 Extreme test conditions.13 5.4.1 General.13 5.4.2 Procedure for tests at extreme conditions.14 5.4.2.1 Procedure for equipment designed for continuous operation.14 5.4.2.2 Procedure for equipment designed for intermittent operation.14 5.4.3 High temperature test.14 5.4.4 Low temperature tests.14 5.4.5 Special Radiosondes.15 5.4.6 Extreme test source voltages.15 5.4.6.1 Power sources using batteries.15 5.4.6.2 Other power sources.15 6 General conditions.15 6.1 Test signals and modulation.15 6.2 Artificial antenna.16 6.3 Test fixture.16 6.4 Test sites and general arrangements for radiated measurements.16 SIST EN 302 454-1 V1.1.1:2007
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6.5 Modes of operation of the transmitter.16 6.6 Measuring receiver.17 7 Measurement uncertainty.17 8 Methods of measurement and limits for transmitter parameters.17 8.1 Frequency error.18 8.1.1 Definitions.18 8.1.2 Method of measurement.18 8.1.3 Limit.18 8.2 Carrier power (conducted).18 8.2.1 Definition.18 8.2.2 Method of measurement.18 8.2.3 Limits.19 8.3 Effective radiated power.19 8.3.1 Definition.19 8.3.2 Methods of measurement.19 8.3.3 Limit.20 8.4 Transmission power spectral density.20 8.4.1 Definition.20 8.4.2 Method of measurement.20 8.4.2.1 Method of measurement using a spectrum analyser.20 8.4.3 Limits.21 8.5 Spurious emissions.21 8.5.1 Definition.21 8.5.2 Method of measuring the power level in a specified load, clause 8.5.1 a) i).21 8.5.3 Method of measuring the effective radiated power, clause 8.5.1 a) ii).22 8.5.4 Method of measuring the effective radiated power, clause 8.5.1 b).22 8.5.5 Limits.23 8.6 Frequency stability under low voltage conditions.23 8.6.1 Definition.23 8.6.2 Method of measurement.23 8.6.3 Limits.23 Annex A (normative): Radiated measurement.24 A.1 Test sites and general arrangements for measurements involving the use of radiated fields.24 A.1.1 Anechoic chamber.24 A.1.2 Anechoic chamber with a conductive ground plane.25 A.1.3 Open Area Test Site (OATS).26 A.1.4 Test antenna.27 A.1.5 Substitution antenna.28 A.1.6 Measuring antenna.28 A.1.7 Stripline arrangement.28 A.1.7.1 General.28 A.1.7.2 Description.28 A.1.7.3 Calibration.28 A.1.7.4 Mode of use.28 A.2 Guidance on the use of radiation test sites.29 A.2.1 Verification of the test site.29 A.2.2 Preparation of the EUT.29 A.2.3 Power supplies to the EUT.29 A.2.4 Volume control setting for analogue speech tests.29 A.2.5 Range length.30 A.2.6 Site preparation.30 A.3 Coupling of signals.31 A.3.1 General.31 A.3.2 Signals.31 A.4 Standard test position.31 A.5 Test fixture.32 SIST EN 302 454-1 V1.1.1:2007
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A.5.1 Description.32 A.5.2 Calibration.32 A.5.3 Mode of use.33 Annex B (normative): Technical performance of the spectrum analyser.34 Annex C (informative): Bibliography.35 History.36
ETSI ETSI EN 302 454-1 V1.1.1 (2007-07) 6
Intellectual Property Rights IPRs essential or potentially essential to the present document may have been declared to ETSI. The information pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web server (http://webapp.etsi.org/IPR/home.asp). Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web server) which are, or may be, or may become, essential to the present document. Foreword This European Standard (Telecommunications series) has been produced by ETSI Technical Committee Electromagnetic compatibility and Radio spectrum Matters (ERM). For non-EU countries the present document may be used for regulatory (Type Approval) purposes. The present document is part 1 of a multi part deliverable, covering digitally modulated Radiosonde transmitters in the Meteorological Aids frequency band from 1 668,4 MHz to 1 690 MHz, as identified below: Part 1: "Technical characteristics and test methods"; Part 2: "Harmonized EN covering essential requirements of article 3.2 of the R&TTE Directive". Clauses 1, 2 and 3 provide a general description on the types of equipment covered by the present document and the references, definitions and abbreviations used. Clause 4 provides a guide as to the number of samples required in order that type tests may be carried out, and any markings on the equipment which the manufacturer should provide. Clauses 5 and 6 give guidance on the test and general conditions for testing of the device. Clause 7 gives the maximum measurement uncertainty values. Clause 8 specifies the spectrum utilization parameters, which are required to be measured. These are the maximum limits, which have been chosen to minimize harmful interference to other equipment and services. The clause provides details on how the equipment should be tested and the conditions, which should be applied. Annex A provides specifications concerning radiated measurements.
Annex B provides information on the spectrum analyser specification. Annex C provides related bibliography information.
National transposition dates Date of adoption of this EN: 29 June 2007 Date of latest announcement of this EN (doa): 30 September 2007 Date of latest publication of new National Standard or endorsement of this EN (dop/e):
31 March 2008 Date of withdrawal of any conflicting National Standard (dow): 31 March 2008
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Introduction Meteorological aids, Radiosondes, are mainly used for in situ upper air measurements of meteorological variables (pressure, temperature, relative humidity, wind speed and direction) in the atmosphere up to an altitude of 36 km. The measurements are vital to national weather forecasting capability (and hence severe weather warning services for the public involving protection of life and property). The Radiosonde systems provide simultaneous measurements of the vertical structure of temperature, relative humidity and wind speed and direction over the full height range required. The variation of these meteorological variables in the vertical contains the majority of the critical information for weather forecasting. These systems are the only meteorological observing systems able to regularly provide the vertical resolution that meteorologists need for all four variables.
The Radiosonde observations are produced by Radiosondes carried by ascending balloons launched from land stations or ships. Radiosonde observations are carried out routinely by almost all countries, two to four times a day. The observation data are then circulated immediately to all other countries within a few hours via the WMO (World Meteorological Organization) Global Telecommunications System (GTS). The observing systems and data dissemination are all organized under the framework of the World Weather Watch Programme of WMO. The observation stations are required, worldwide, at a horizontal spacing of less than or equal to 250 km, during the first decade of the twenty-first century, with a frequency of observation of from one to four times per day.
Remotely sensed measurements from satellites do not have the vertical resolution available from Radiosondes. Successful derivation of vertical temperature structure from these satellite measurements usually requires a computation initialized either directly from Radiosonde statistics or from the numerical weather forecast itself. In the latter case, the Radiosonde measurements ensure that the vertical structure in these forecasts remains accurate and stable with time. In addition, the Radiosonde measurements are used to calibrate satellite observations by a variety of techniques. Radiosonde observations are thus seen to remain absolutely necessary for meteorological operations for the foreseeable future. Other applications, independent of the main civilian meteorological organizations include environmental pollution, hydrology, radioactivity in the free atmosphere, significant weather phenomena (e.g. winter storms, thunderstorms, etc.) and investigation of a range of physical and chemical properties of the atmosphere.
The Radiosondes are operated on two frequency bands: 403 MHz band covers primary and co-primary allocations from 400,15 MHz to 406 MHz and 1 680 MHz band from 1668,4 MHz to 1690 MHz. The 403 MHz Radiosonde technology applies RNSS (Radio Navigation Satellite Systems) for wind measurement, whereas the 1 680 MHz systems base the wind measurement on balloon tracking with a RDF (Radio Direction Finding) antenna. Because the 403 MHz wind measurement depends on the availability of the RNSS signals, many operators do not consider this technology secure enough for critical applications (e.g. defence and national security), and consequently prefer 1 680 MHz systems.
About 150 000 Radiosondes are annually used in Europe, about 10 % of them are in 1 680 MHz band. This use is not decreasing with time, since with modern automation it is now much easier to successfully operate systems without highly skilled operators and a large amount of supporting equipment. SIST EN 302 454-1 V1.1.1:2007
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1 Scope The present document applies to digitally modulated Radiosonde transmitters and whole units in the range from 1 668,4 MHz to 1 690 MHz. Because the World Radio Conference WRC-2003, allocated the Mobile Satellite Service (MSS) in the band from 1 670 MHz to 1 675 MHz, and the sub band from 1 683 MHz to 1 690 MHz is used for meteorological satellite, it is encouraged to consolidate the Radiosondes in the sub band from 1 675 MHz to 1 683 MHz. The present document shall not be applied to the widely used analogue FM Radiosonde transmitter. The present document does not necessarily include all the characteristics, which may be required by a user, nor does it necessarily represent the optimum performance achievable. It is a product family standard, which may be completely or partially superseded by specific standards covering specific applications. For non-harmonized parameters, national regulatory conditions can apply regarding the type of modulation, channel/frequency separations, and the inclusion of an automatic transmitter shut-off facility as a condition of the issue of an individual or general license, or, as a condition of use under license exemption. The automatic transmitter shut-off facility may be based on elapsed time from the beginning of the sounding or atmospheric pressure measured by the Radiosonde. 2 References The following documents contain provisions which, through reference in this text, constitute provisions of the present document. • References are either specific (identified by date of publication and/or edition number or version number) or non-specific. • For a specific reference, subsequent revisions do not apply. • For a non-specific reference, the latest version applies. Referenced documents which are not found to be publicly available in the expected location might be found at http://docbox.etsi.org/Reference. NOTE: While any hyperlinks included in this clause were valid at the time of publication ETSI cannot guarantee their long term validity. [1] Directive 1999/5/EC of the European Parliament and of the Council of 9 March 1999 on radio equipment and telecommunications terminal equipment and the mutual recognition of their conformity (R&TTE Directive). [2] ETSI TR 100 028 (V1.4.1): "Radio Equipment and Systems (RES); Uncertainties in the measurement of mobile radio equipment characteristics". [3] CISPR 16-1: "Specification for radio disturbance and immunity measuring apparatus and methods; Part 1: Radio disturbance and immunity measuring apparatus". [4] ANSI C63.5 (2004): "American National Standard for Electromagnetic Compatibility-Radiated Emission Measurements in Electromagnetic Interference (EMI) Control-Calibration of Antennas (9 kHz to 40 GHz)". [5] IEC 60489-3: "Methods of measurement for radio equipment used in the mobile services. Part 3: Receivers for A3E or F3E emissions". SIST EN 302 454-1 V1.1.1:2007
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3 Definitions, symbols and abbreviations 3.1 Definitions For the purposes of the present document, the following terms and definitions apply: allocated frequency band: as defined by ITU in the Radio Regulations carrier power: average power delivered to the artificial antenna during one radio frequency cycle in the absence of modulation NOTE: See clause 8.2.1. conducted measurements: measurements, which are made using a direct 50 Ω connection to the EUT dedicated antenna: removable antenna supplied and tested with the radio equipment, designed as an indispensable part of the equipment effective radiated power: power radiated in the direction of the maximum level under specified conditions of measurements in the absence of modulation NOTE: See clause 8.3.1. frequency error of the transmitter: difference between the measured unmodulated carrier frequency and the nominal frequency as stated by the manufacturer under normal and extreme conditions NOTE: See clause 8.1.1. frequency stability under low voltage conditions: ability of the equipment to remain on the assigned operating frequency band, when the battery voltage falls below the lower extreme voltage level NOTE: See clause 8.6.1. integral antenna: permanent fixed antenna, which may be built-in, designed as an indispensable part of the equipment manufacturer: means the manufacturer, or his authorized representative or the person responsible for placing the equipment on the market operating frequency range: total range of frequencies covered, either by one type, in which case the tuning range equals operating frequency range, or by a family of equipment, in which case there are different design transmitters involved NOTE: See clause 4.1.2.2. radiated measurements: measurements, which involve the absolute measurement of a radiated field spurious emissions: emission on a frequency or frequencies which are outside the necessary bandwidth and the level of which may be reduced without affecting the corresponding transmission of information. Spurious emissions include harmonic emissions, parasitic emissions, intermodulation products and frequency conversion products, but exclude out-of-band emissions NOTE 1: As defined by ITU. NOTE 2: See clause 8.5.1. telemetry: use of radio communication for recording measurement or other data at a distance transmission power spectral density: spectrum of a transmitter under defined conditions of modulation and output power NOTE: See clause 8.4.1. trimming: act by, which the value (in this case relating to frequency) of a component is changed within the circuit NOTE: This act may include the physical alteration, substitution (by components of similar size and type) or activation/de-activation (via the setting of soldered bridges) of components. See clause 4.1.2.1. SIST EN 302 454-1 V1.1.1:2007
ETSI ETSI EN 302 454-1 V1.1.1 (2007-07) 10 tuning range: maximum frequency range, as specified by the manufacturer, over which the transmitter can be operated without any changes to the circuit, other than the substitution or programming of read only memories or crystals and the trimming of discrete components NOTE: See clause 4.1.2.1. 3.2 Symbols For the purposes of the present document, the following symbols apply: dB decibel E field strength FRL Lower end of Frequency Range FRC Centre of Frequency Range FRH Higher end of Frequency Range SND/ND Signal + Noise + Distortion / Noise + Distortion °C Temperature in degrees Celsius hPa Atmospheric pressure in hecto Pascal %RH Air Relative Humidity in percentage λ Wavelength 3.3 Abbreviations
For the purposes of the present document, the following abbreviations apply: EUT Equipment Under Test GTS Global Telecommunications System ICAO International Civil Aviation Organization MSS Mobile Satellite Service OATS Open Area Test Site
OFR Operating Frequency Range R&TTE Radio and Telecommunications Terminal Equipment RDF
Radio Direction Finding RF Radio Frequency RH Relative Humidity RNSS
Radio Navigation Satellite Systems TR Tuning Range VSWR Voltage Standing Wave Ratio WMO
World Meteorological Organization 4 Technical requirement specifications 4.1 Presentation of equipment for testing purposes Each equipment submitted for testing shall fulfil the requirements of the present document on all frequencies over which it is intended to operate. Where appropriate the nominal frequency 1 680 MHz should be used for testing. If equipment is designed to operate with different carrier powers, measurement of each transmitter parameter shall be performed at the highest power level at which the transmitter is intended to operate. To simplify and harmonize the testing procedures between the different testing laboratories, measurements shall be performed, according to the present document, on samples of equipment defined in clauses 4.1.1 to 4.1.4. SIST EN 302 454-1 V1.1.1:2007
ETSI ETSI EN 302 454-1 V1.1.1 (2007-07) 11 4.1.1 Choice of model for testing The manufacturer shall provide one or more samples of the equipment, as appropriate, for testing. If equipment has several optional features, considered not to affect the RF parameters then tests need only be performed on the equipment configured with that combination of features considered being the most complex, as proposed by the manufacturer and agreed by the test laboratory. 4.1.2 Definitions of Switching Range, Alignment Range and Operational Frequency Range 4.1.2.1 Definition of Tuning Range (TR) The manufacturer shall state the tuning range of the transmitter. The TR is the maximum frequency range, as specified by the manufacturer, over which the transmitter can be operated without any changes to the circuit, other than the substitution or programming of read only memories or crystals and the trimming of discrete components, see clause 3.1. Trimming is an act by, which the value (in this case relating to frequency) of a component is changed within the circuit, see clause 3.1. This act may include the physical alteration, substitution (by components of similar size and type) or activation/de-activation (via the setting of soldered bridges) of components. Usually Radiosondes are tuned to the used frequency prior to immediate use. 4.1.2.2 Definition of Operating Frequency Range (OFR) The Operating Frequency Range is the total range of frequencies covered, either by one type, in which case the TR equals OFR, or by a family of equipment, in which case there are different design transmitters involved, see clause 3.1. 4.1.2.3 Allocated Frequency Range The allocated frequency range for Radiosondes is 21,6 MHz, but the band sharing constraints suggest that only 8 MHz, that is from 1 675 MHz to 1 683 MHz, should be used for Radiosondes. The OFR may be equal to the allocated range. 4.1.2.4 Number of samples for testing If the TR equals the OFR the tests shall be carried out on 1 680 MHz or on the center frequency of the OFR if better applicable. In this case, only one sample shall be tested.
If a family of equipment covers the OFR, each family member shall be submitted to tests, which shall be carried out on the center frequency of the TR.
4.1.3 Testing of equipment with alternative power levels If a family of equipment has alternative output power levels provided by the use of separate power modules or add on stages, then each module or add on stage shall be tested in combination with the equipment. The necessary samples and tests can be proposed by the manufacturer and/or test laboratory, based on the requirements of clause 4.1. SIST EN 302 454-1 V1.1.1:2007
ETSI ETSI EN 302 454-1 V1.1.1 (2007-07) 12 4.1.4 Testing of equipment that does not have an external 50 Ω RF connector (integral antenna equipment) 4.1.4.1 Equipment with an internal permanent or temporary antenna connector The means to access and/or implement the internal permanent or temporary antenna connector shall be stated by the manufacturer with the aid of a diagram. The method shall be recorded in the test report. No connection shall be made to any internal permanent or temporary antenna connector during the performance of radiated emissions measurements, unless such action forms an essential part of the normal intended operation of the equipment, as declared by the manufacturer. 4.2 Mechanical and electrical design
4.2.1 Controls Those controls, which, if maladjusted, may increase the interfering potential of the equipment, shall not be easily accessible to the user. 4.2.2 Transmitter shut-off facility If the transmitter is equipped with an automatic transmitter shut-off facility, it should be made inoperative for the duration of the test. 4.2.3 Marking
The equipment shall be marked in a visible place. This marking shall be legible and durable. 4.2.3.1 Regulatory marking The equipment shall be marked in accordance with the R&TTE Directive [1].
4.3 Declarations by the manufacturer The manufacturer shall declare the necessary information of the equipment with respect to all technical requirements set by the present document. 4.4 Auxiliary test equipment
All necessary test signals sources and setting up information shall accompany the equipment, when it is submitted for testing. 5 Test conditions, power sources and ambient conditions 5.1 Normal and extreme test conditions
Testing shall be performed under normal test conditions, and also, where stated, under extreme test conditions. The test conditions and procedures shall be as specified in clauses 5.2 to 5.4. SIST EN 302 454-1 V1.1.1:2007
ETSI ETSI EN 302 454-1 V1.1.1 (2007-07) 13 5.2 Test power source The equipment shall be tested using the appropriate power source. Where equipment can be powered using either external or internal power sources, and then equipment shall be tested using the external test power source as specified in clause 5.2.1 then repeated using the internal power source as specified in clause 5.2.2. The test power source used shall be recorded and stated. 5.2.1 External test power source During tests, the power source of the equipment shall be replaced by an external test power source capable of producing normal and extreme test voltages as specified in clauses 5.3.2 and 5.4.6. The internal impedance of the external test power source shall be low enough for its effect on the test results to be negligible. For the purpose of the tests, the voltage of the external test power source shall be measured. The external test power source shall be suitably de-coupled and applied as close to the equipment battery as practicable. For radiated measurements any external power, leads should be so arranged so as not to affect the measurements. During tests, the external test power source voltages shall be within a tolerance < ±1 % relative to the voltage at the beginning of each test.
5.2.2 Internal test power source For radiated measurements fully charged internal batteries should be used. The batteries used should be as supplied or recommended by the manufacturer. At the end of each test manufacturer shall within the normal operating range specify the voltage. 5.3 Normal test conditions 5.3.1 Normal temperature and humidity The normal temperature and humidity conditions for tests shall be any convenient combination of temperature and humidity within the following ranges: - temperature: +15°C to +35°C; - Relative Humidity: 20 % RH to 75 % RH. 5.3.2 Normal test power source For operation from other power sources or types of battery, the normal test voltage shall be that declared by the manufacturer and where appropriate agreed by the accredited test laboratory. Values shall be recorded and stated. 5.4 Extreme test conditions 5.4.1 General Tests at extreme conditions simulate the extreme atmospheric conditions, which apply to the Radiosondes in normal operations. The atmospheric model, ICAO Standard Atmosphere, gives -56,5°C as minimum temperature in high atmosphere in low pressure, and it is selected as the first low extreme temperature. The other low temperature, -25°C, corresponds to low extremes conditions close to the earth surface in high pressure. The test conditions are combined air temperature and air pressure test. SIST EN 302 454-1 V1.1.1:2007
ETSI ETSI EN 302 454-1 V1.1.1 (2007-07) 14 5.4.2 Procedure for tests at extreme conditions Before measurements are made, the equipment shall have reached thermal balance in the test chamber. The equipment shall be switched off during the temperature stabilizing period. Usually Radiosondes are designed for continuous operations, however there may be applications where transmit bursts are applicable. 5.4.2.1 Procedure for equipment designed for continuous operation If the manufacturer states that the equipment is designed for continuous operation, the test procedure shall be as follows: - before tests at the upper extreme temperature, the equipment shall be placed in the test chamber and left until thermal balance is attained. The equipment shall then be switched on in the transmit condition for a period of 30 minutes, after which the equipment shall meet the specified requirements; - for tests at the lower extreme temperatures, the equipment shall be left in the test chamber until thermal balance is attained, then switched to the on condition for a period of one minute after which the equipment shall meet the specified requirements. 5.4.2.2 Procedure for equipment designed for intermittent operation If the manufacturer states that the equipment is designed for intermittent operation, the test procedure shall be as follows:
- before tests at the upper extreme temperature, the equipment shall be placed in the test chamber and left until thermal balance is attained. The equipment shall then either: - transmit for five minutes; or - if the duty cycle, one period of "on" and "off" exceeds one minute: - transmit five periods; or - if none of these are applicable, the test cycle shall be agreed upon with the accredited test laboratory.
5.4.3 High temperature test The equipment shall be tested in conditions corresponding to high temperature conditions in the low altitude given in the table 1. The transmitter shall be tested in the high temperature and pressure using a controlled external power source if applicable. 5.4.4 Low temperature tests The equipment shall be tested in conditions corresponding to low temperature conditions in the high altitude, and low temperature in the low altitude cold climate conditions given in table 1. A heat producing element (e.g. water activated battery) may be included in the normal use configuration
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