Circular No. 21/2018/TT-BTTTT Issuing "National Technical Regulations on Radio Beacon for Maritime Emergency Position Indicating Radio Beacons (EPIRB) Operating in the 406.0 MHz to 406.1 MHz Band"

CIRCULAR

Issuing the "National Technical Regulation on Emergency Position Indicating Radio Beacons (EOIRB) Operating in the 406.0 MHz to 406.1 MHz Frequency Band"

Camendpursuant to the Law on Standards and Technical Regulations dated June 29, 2006;

Pursuant to the Law on Telecommunications dated January 23,ng20181 ARTICLE 4. Finished traditional medicine is a form of traditional medicine that has undergone production processes, including packaging and labeling, using traditional or modern methods, belonging to one of the following forms: pills, liquids, tea, powder, extract, and other forms.

Pursuant to the Law on Radio Frequency Wavelengths dated November 23, 2009;No. and the Law on Radio Communications dated January 23, 11 ARTICLE 4. Finished traditional medicine is a form of traditional medicine that has undergone production processes, including packaging and labeling, using traditional or modern methods, belonging to one of the following forms: pills, liquids, tea, powder, extract, and other forms.

WHEREAS, Decree No. 127/2007/NĐ-CP dated August 1, 2007 of the Government detailing and guiding the implementation of certain provisions of the Law on Technical Standards and Regulations;

Pursuant to Decree No. 78/2018/NĐ-CP dated May 16, 2018 of the Government amending and supplementing certain articles of Decree No. 127/2007/NĐ-CP dated August 1, 2007 of the Government detailing the implementation of some provisions of the Law on Standards and Technical Regulationsrime Minister cn technical;

Pursuant to Decree No. 17/2017/NĐ-CP dated February 17, 2017, issued by the Government, on the functions, tasks, powers, and organizational structure of the Ministry of Information and Communications;

Pursuant to the proposal of the Director of the Science and Technology Department,

The Minister of Information and Communications issues this Circular stipulating the National Technical Regulation on Emergency Position Indicating Radio Beacons (EPIRB) Operating in the 406.0 MHz to 406.1 MHz Frequency Bandrime Minister curgent maritime (EPIRB) operating in the 406.0 MHz to 406,1 1 MHz frequency band

Article 1. This Circular promulgates the National Technical Regulation on Emergency Position Indicating Radio Beacons (EPIRB) Operating in the 406.0 MHz to 406.1 MHz Frequency Band (QCVN 57:2018/BTTTT) attached hereto.

Article 2.

1. This Circular shall take effect from July 1, 2019.

2. The National Technical Regulation on Emergency Position Indicating Radio Beacons (EPIRB) Operating in the 406.0 MHz to 406.1 MHz Frequency Band, designated as QCVN 57:2011/BTTTT, stipulated in Clause 17, Article 1 of Circular No. 29/2011/TT-BTTTT dated October 26, 2011 of the Minister of Information and Communications on National Technical Regulations on Telecommunications shall cease to be effective from July 1, 2019.

Article 3. The Director of the Office, Heads of Departments under the Ministry of Information and Communications, Heads of units under the Ministry of Information and Communications, Directors of Provincial Departments of Information and Communications, and organizations and individuals concerned are responsible for implementing this Circular./.

 

QCVN 57:2018/BTTTT

NATIONAL TECHNICAL REGULATION ON EMERGENCY POSITION INDICATING RADIO BEACONS (EPIRB) OPERATING IN THE 406.0 MHz TO 406.1 MHz FREQUENCY BAND

National technical regulation on Emergency Position Indicating Radio Beacons (EPIRBs) operating in the 406.0 MHz to 406.1 MHz frequency band

Section lục

Chapter 1. GENERAL PROVISIONS

1.1. Scope of Application

1.2. Applicability

1.3. Referenced Documents

1.4. Terms and Definitions

1.5. Abbreviations

Chapter 2. TECHNICAL PROVISIONS

2.1. General Requirements

2.1.1. Navigation aid equipment

2.1.2. Power source

2.2. Testing conditions

2.2.1. General Requirements

2.2.2. Quality inspection

2.2.3. Preparation of EPIRB for testing

2.2.4. Testing sequence

2.2.5. Test power supply

2.2.6. Test location

2.2.7. Test setup

2.2.8. Receiver test

2.2.9. Antenna test

2.2.10. Normal test conditions

2.2.11. Limit test conditions

2.2.12. Limit temperature test procedure

2.2.13. Measurement uncertainty

2.3. Environmental testing

2.3.1. General Requirements

2.3.2. Temperature testing

2.3.3. Vibration testing

2.3.4. Impact testing

2.3.5. Corrosion testing

2.3.6. Water immersion testing

2.3.7. Thermal shock testing

2.3.8. Water submersion testing

2.3.9. Water jet impact testing

2.3.10. Buoyancy testing

2.3.11. Solar radiation testing

2.3.12. Oil effect testing

2.4. Transmitter

2.4.1. Output power

2.4.2. Characteristic frequency

2.4.3. Short-term frequency stability

2.4.4. Medium-term frequency stability

2.4.5. RF spectrum mask

2.5. Signal format

2.5.1. General requirements

2.5.2. Repeat cycle

2.5.3. Total transmission time (T_{organize credit institutions, foreign bank branches are responsible for organizing the implementation of this Circular.})

2.5.4. Continuous wave (CW) preamble

2.5.5. Bit rate

2.6. Other technical requirements

2.6.1. Battery capacity

2.6.2. Navigation aid equipment

2.7. Radiated power measurement

2.7.1. General requirements

2.7.2. Radiated power

2.7.3. Antenna characteristics

3. MANAGEMENT PROVISIONS

4. RESPONSIBILITIES OF ORGANIZATIONS AND INDIVIDUALS

Chapter 5. ORGANIZATION OF IMPLEMENTATION

LIST OF REFERENCES

 

Foreword

QCVN 57:2018/BTTTT replaces QCVN 57:2011/BTTTT.

QCVN 57:2018/BTTTT complies with standard ETSI EN 300 066 V1.3.1 (2001-01) of the European Telecommunications Standards Institute (ETSI) and Recommendation C/S T.012 (2-2018) of the Cospas-Sarsat organization.

QCVN 57:2018/BTTTT was compiled by the Institute of Post and Telecommunications Science and Technology, reviewed and submitted for approval by the Department of Science and Technology, and issued together with Circular No. 21/2018/TT-BTTTT dated 2018.

 

NATIONAL TECHNICAL REGULATION ONMOBILE SATELLITE EARTH STATIONOPERATING IN THE KU BANDỀ EMERGENCY POSITION INDICATING RADIO BEACON (EPIRB) OPERATINGMOBILE SATELLITE EARTH STATIONIN THEA406.0 MHz TO 406.1 MHz O FREQUENCY BANDAThis regulation specifies the minimum quality and technical characteristics requirements for various types of Emergency Position Indicating Radio Beacons (EPIRBs) operating in the COSPAS-SARSAT satellite system to ensure radio information in the Global Maritime Distress and Safety System (GMDSS).

National technical regulation on Emergency Position Indicating Radio Beacons (EPIRBs) operating in the 406.0 MHz to 406.1 MHz frequency band

Chapter 1. GENERAL PROVISIONS

1.1. Scope of Application

This regulation applies to EPIRBs operating in the 406.0 MHz to 406.1 MHz frequency band, along with low-power navigation aids operating at 121.5 MHz.

This regulation applies to EPIRBs installed on marine vessels.

This regulation applies to EPIRBs operating through the satellite communication system within the following temperature range:

• -40 °C to +55 °C (Type 1); or

• -20 °C to +55 °C (Type 2);

with an automatic release mechanism.

This regulation applies to organizations and individuals, both domestic and foreign, engaged in the production and business of equipment within the scope regulated in Section 1.1 throughout the territory of Vietnam.

1.2. Applicability

ETSI EN 300 066 V1.3.1 (2001-01): Electromagnetic Compatibility and Radio Spectrum Matters (ERM); Float-free maritime satellite Emergency Position Indicating Radio Beacons (EPIRBs) operating in the 406.0 MHz to 406.1 MHz frequency band; Technical characteristics and methods of measurement.

1.3. Referenced Documents

C/S T.012 Issue 1 - Revision 13 February 2018: COSPAS-SARSAT 406 MHz frequency management plan.

Satellite EPIRB (satellite EPIRB)

1.4. Terms and Definitions

A ground station in the mobile satellite communications service, its emissions serve search and rescue operations.

Automatic release mechanism

A mechanism allowing the EPIRB to automatically release and float freely. Navigation aid equipment

A 121.5 MHz radio signal primarily for aircraft homing.

Remote control unit

A unit that allows remote activation of the EPIRB when it is installed in an automatic release mechanism.

EquipmentNo.EPIRB equipment includes the 121.5 MHz navigation aid, the automatic release mechanism, and the remote control unit.

Type 1:

Satellite EPIRB operating in the temperature range from -40°C to +55°C.

Type 2:

Satellite EPIRB operating in the temperature range from -20°C to +55°C. Antenna factor

Antenna Factor Carrier wave

1.5. Abbreviations

Chapter 2. TECHNICAL PROVISIONS

2.1. General Requirements

2.1.1. Navigation aid equipment

The EPIRB must be equipped with a navigation aid device operating at a frequency of 121.5 MHz, and this device must meet the requirements set out in Section 2.6.2.

2.1.2. Power source

2.1.2.1. Battery Requirements

The battery life, determined by the expiration date, must be ≥ 3 years.

The expiration date of the battery is calculated from the production date of the battery plus up to half of the useful operational time of the battery. The expiration date must be clearly marked.

The useful operational time of the battery is defined as the period following the production date during which the battery still meets the power supply requirements for the EPIRB float.

To determine the useful operational time of the battery, the following losses under conditions of temperature +20 °C ± 5 °C must be taken into account:

- Self-test once a month;

- Battery self-discharge;

- Losses in standby mode (if applicable).

2.1.2.2. Safety Requirements

Reverse polarity of the battery must not occur.

The battery must not leak harmful or corrosive substances inside or outside the EPIRB float under the following conditions:

- During or after storage at temperatures between -55 °C and +75 °C;

- While discharging the battery completely or partially at any rate, including short-circuiting externally;

- After complete or partial discharge of the battery.

The battery must not pose a danger to personnel handling, using, or manufacturing it when transported, stored, and installed according to specified conditions.

2.2. Testing conditions

2.2.1. General Requirements

The requirements of this Standard must be met after a 15-minute start-up period.

The manufacturer must provide sufficient information to establish, test, and operate the equipment during testing.

2.2.2. Quality inspection

In this Standard, "quality check" means:

- Determining the characteristic frequency from four measurements of the carrier frequency of the unmodulated signal fc⁽¹⁾under test conditions (Sections 2.2.11 and 2.2.12) over time S₁ (Figure 5) of four consecutive transmissions as follows:

- For the beacon with the nominal frequency of 406.025 MHz, the characteristic frequency must lie between 406.023 MHz and 406.027 MHz;

- For the beacon with the nominal frequency of 406.028 MHz, the characteristic frequency must lie between 406.027 MHz and 406.029 MHz;

- Measuring the output power of the EPIRB under normal test conditions. The output power must be: 37 dBm ± 2 dB;

- Measuring the output power of the 121.5 MHz navigation aid under normal test conditions. The output power must be: 17 dBm ± 3 dB;

- Measuring the carrier frequency of the 121.5 MHz navigation aid under normal test conditions. The carrier frequency must be: 121.5 MHz ± 3.5 kHz.

- Testing the operation of the low-power indicator light.

2.2.3. Standard bcouncillORS EPIRB for testing

During testing, the EPIRB must be programmed to transmit encoded data clusters according to the appropriate protocol and format as specified in the ETSI EN 300 066 standard. The navigation aid must be prepared to transmit during testing. Avoid transmitting distress signals on distress and safety frequencies by frequency offset or test coding.

The manufacturer must provide an EPIRB with an antenna port that can be connected to the test equipment via a coaxial cable with a 50 Ω load termination. This connection must be waterproof and withstand all environmental conditions, and the antenna port may be prepared by the manufacturer before testing.

2.2.4. Testing sequence

All measurements must be carried out in the sequence specified in this Standard.

All measurements must be performed on a single unit and prepared according to Section 2.2.3.

2.2.5. Test power supply

The equipment must use internal battery power when performing tests and quality checks.

2.2.6. Test location

The test location must be free of reflective objects such as trees and metallic objects. Reflective objects must not be within the range of an ellipse with dimensions as shown in Figure 1.

Figure 1 - Sample Test Location

The terrain outside the test location must be flat. Any conductors within the ellipse must have a size smaller than 7 cm. Prepare a metal floor or wire mesh to cover at least the major and minor axes of the ellipse as shown in Figure 1. All wires and cables must be run under the floor. The antenna cable must be extended 1.5 meters beyond both axes along the major axis before going down to the floor.

During testing, no person must stand within a 6-meter radius of the EPIRB. The test report must detail the test environment.

The test location may be surrounded by materials such as fiberglass, plastic, wood, or fabric.

2.2.7. Test setup

Set up the test as shown in Figure 2.

The EPIRB must be placed in its operational position as designed and positioned within a circular surface capable of rotating 360° in the azimuth plane. As shown in Figure 2, the rotating surface B must have a minimum radius of 1.7λ (125 cm) and be made of high-conductivity material (copper or aluminum). It must be placed on surface A at a standard height X = 0.75 m ± 0.10 m. The EPIRB's horizon mark must be level with the rotating surface B, and the EPIRB's antenna must be centered.

Figure 2 - Test Setup

2.2.8. Receiver test

The receiving test instrument (which may be a field strength meter or spectrum analyzer) must be calibrated as follows:

a) Connect the equipment as shown in Figure 2. Install the EPIRB as described in Section 2.2.7.

b) Turn on the EPIRB to transmit normally. Set the receiver bandwidth to measure the transmission power. This bandwidth is used during the antenna measurement process. Adjust the receiver to obtain the maximum received signal. Position the test antenna in the plane (vertical or horizontal) where the received signal is strongest. Rotate the EPIRB antenna and determine the direction with the highest average radiation field intensity. Record the reception level;

c) Disconnect the test antenna and supply a standard RF signal to the receiver through the test antenna cable. Adjust the signal source to achieve the same reception level as in b);

d) Disconnect the standard RF signal from the test antenna cable and measure the RF output using a power meter;

e) Reconnect the standard RF signal to the test antenna cable and adjust the receiver gain.

2.2.9. ĂTest antenna

The EPIRB antenna's radiation pattern is searched for and measured using a dual-polarized antenna. The dual-polarized antenna is placed 3 meters away from the EPIRB antenna and mounted on a vertical support column that can change the height of the test antenna from 1.3 m to 4.3 m (i.e., from 10 to 15 degrees relative to the rotating surface B at the standard height X = 0.75 m, Figure 2). The test antenna must be raised to an elevation angle calculated using the following formula:

h = 3 tanθ and H = h + X

Where:

X is the standard height (0.75 m);

h is the height of the test antenna above the standard height X;

θ is the elevation angle relative to the rotating surface B (at the standard height X);

H is the height of the test antenna above the surface A.

NOTE: The midpoint of the dual-polarized antenna is used to determine its height.

When the measuring antenna is raised vertically, the distance (R) between the EPIRB antenna and the measuring antenna increases. The distance (R) is a function of the elevation angle (θ) and is calculated using the following formula:

It is necessary to know the antenna factor (AF) of the measuring antenna at 406 MHz.

This factor is usually provided by the manufacturer of the dual-polarized antenna. It is used to convert the measured voltage reading into electromagnetic field strength.

Since the value of AF depends on the direction of the wave propagation relative to the orientation of the receiving antenna, the dual-polarized antenna must always be perpendicular to the direction of wave propagation. To reduce measurement errors, use the directional correction factor of the measuring antenna (Figure 3) if the measuring antenna is not perpendicular to the direction of wave propagation. For dual-polarized antennas, the antenna correction factor is calculated as follows:

and

Where:

AF is the antenna factor of the antenna at 406.0 MHz;

θ is the elevation angle;

P is the correction factor for the dual-polarized antenna.

NOTE: The correction factor (P) equals 1 when the measuring antenna is perpendicular to the direction of wave propagation. Therefore, P equals 1 at any elevation angle when the measuring antenna is horizontally polarized. The correction factor only applies to measurements with vertical polarization.

Figure 3 - ĂMeasuring antenna perpendicular to the direction of wave propagation

Figure 4 - Measuring antenna not perpendicular to the direction of wave propagation

2.2.10. Normal test conditions

Temperature and humidity conditions:

- Temperature: +15 °C to 35 °C;

- Relative humidity: 20 % to 75 %.

2.2.11. Limit test conditions

Measurements are performed according to the procedure in Section 2.2.12 at extreme temperatures below and above as follows:

- For Class 1 EPIRB: -40 °C and +55 °C;

- For Class 2 EPIRB: -20 °C and +55 °C.

When testing the automatic release mechanism at extreme temperatures, the lower and upper extreme temperatures are -30 °C and +65 °C.

2.2.12. Procedure organize credit institutions, foreign bank branches are responsible for organizing the implementation of this Circular.for temperature testing in The equipment must be turned off during temperature stabilization.

Before performing measurements, the equipment must reach thermal equilibrium in the test chamber and be powered on for 15 minutes.

Table 1 - Maximum values of measurement uncertainty

2.2.13. Measurement uncertainty

Maximum errorNo.i

environmental conditionsđổ This test may not be required if the manufacturer can provide sufficient evidence that the components, materials, etc., maintain electrical and mechanical specifications for the EPIRB under the specified environmental conditions in Section 2.3.

2.3.1. General Requirements

Environmental tests in this section must be conducted before other tests and must be carried out under normal test conditions unless otherwise specified. The EPIRB must be installed in its automatic release mechanism in normal operating condition but not transmitting (Section 2.1.2), unless otherwise specified.

2.3.2. Temperature test

2.3.2.1. Definition

The ability of the equipment to maintain unchanged electrical and mechanical specifications after temperature testing.

The maximum rate of temperature increase and decrease in the test chamber is 1 °C/min.

2.3.2.2. Dry heat test

2.3.2.2.1. Test method

The equipment must be placed in a test chamber at room temperature. Then, the temperature must be increased and maintained at 70 °C (± 3 °C) for a period of 10 to 16 hours.

After this period, the temperature control unit within the equipment must be activated and the chamber temperature reduced to +55 °C (± 3 °C). The cooling process must be completed within 30 minutes.

Subsequently, the EPIRB must be turned on and operate normally for 2 hours. The chamber temperature must be maintained at +55 °C (± 3 °C) during this time. The equipment must be quality checked during the last 30 minutes.

At the end of the test, the chamber temperature must be reduced to room temperature within at least 1 hour. The equipment must be placed in normal room temperature and humidity conditions for at least 3 hours before the next measurement is performed.

2.3.2.2.2. Requirements

Quality check requirements must be met.

2.3.2.3. Humid heat test

2.3.2.3.1. Test method

The equipment must be placed in a test chamber at room temperature. The humidity level in the chamber must be kept constant for 3 hours (± 0.5 hours). The equipment must be heated from room temperature to 40 °C (± 3 °C) while maintaining a relative humidity of 93% (± 2%) throughout this period.

These conditions must be maintained for a period of 10 to 16 hours. Thirty minutes later, the EPIRB must be turned on and operated for 2 hours.

The chamber temperature and relative humidity must be maintained at 40 °C (± 3 °C) and 93% (± 2%) for 2 hours and 30 minutes. The equipment must be quality checked during the last 30 minutes.

At the end of the test, the chamber temperature must be reduced to room temperature within at least 1 hour. The equipment must be placed in normal room temperature and humidity conditions for at least 3 hours or until the humidity is evenly distributed before the next quality check.

2.3.2.3.2. Requirements

2.3.2.4. Low temperature test

2.3.2.3. Humid heat test

2.3.2.4.1. Test method

The equipment must be placed in a test chamber at room temperature. Then, the temperature must be decreased and maintained at -40 °C (± 3 °C) for Class 1 EPIRB and -30 °C (± 3 °C) for Class 2 EPIRB for a period of 10 to 16 hours.đổ

The temperature control unit of the equipment must be activated and the chamber transferred to -20 °C (± 3 °C) (for Class 2 equipment). This process must be completed within 25 minutes (± 5 minutes).

The chamber temperature must be maintained at -20 °C (± 3 °C) for 2 hours.

The equipment must be quality checked during the last 30 minutes of the test.

At the end of the test, the chamber temperature must be reduced to room temperature within at least 1 hour. The equipment must be placed in normal room temperature and humidity conditions for at least 3 hours or until the humidity is evenly distributed before the next measurement is performed.

During the test, the equipment must operate normally.

2.3.3.1. Definition

2.3.2.4The ability of the equipment to maintain unchanged electrical and mechanical specifications after vibration testing.

2.3.2.3. Humid heat test

2.3.3. Vibration testing

2.3.3.2. Test method

The equipment must be mounted on a vibration table using its mounting means. The equipment may be suspended to compensate for weight that the vibration table cannot support.

Avoid affecting the equipment's specifications due to the electromagnetic field of the vibration mass.

The equipment is mounted on a vibration table with the support means provided. The equipment may be suspended to offset the weight that the vibration table cannot bear.

Avoid effects on the equipment criteria due to the electromagnetic field of the vibration mass.

The device must withstand sinusoidal vibration along the vertical axis at all frequencies between:

- 2 Hz (-0/+3 Hz) and 13.2 Hz with a vibration amplitude of ±1 mm ± 10% (maximum acceleration 7 m/s² at 13.2 Hz); and² - 13.2 Hz and 100 Hz with a constant maximum acceleration of 7 m/s²;

The frequency sweep rate must be sufficiently slow to allow resonance detection in all parts of the device.².

Resonance detection must be performed during the vibration test. If resonance is found in any part, the device must undergo vibration testing at that resonant frequency for a duration of not less than 2 hours. Testing must be repeated at the same vibration level in the horizontal plane perpendicular to the initial direction.

Quality checks of the EPIRB and remote control unit (if equipped) must be conducted both before and after the vibration test. At the end of the test, mechanical failures of the device must be examined.

2.3.3.3. Requirements

The EPIRB must not be ejected from its mounting position and must not automatically activate during the vibration test.

The quality check requirements must be met. There should be no visible mechanical failures.

2.3.4.1. Definition

2.3.4. Impact testing

The ability of the device to maintain electrical and mechanical performance criteria unchanged after impact testing.

2.3.4.2. Test Method

The EPIRB must be installed in its release mechanism. Testing is conducted with:

- Peak acceleration: 98 m/s²;

- Pulse width: 18 ms ± 20%;² ± 10 %:

- Waveform: Half-sine wave;

- Axis: Vertical;

- Number of impacts: 4,000.

At the end of the test, the device must be inspected for mechanical failures. Self-test of the EPIRB (section 2.1.8) must be performed.

2.3.4.3. Requirements

The EPIRB must not be ejected from its position and must not automatically activate during the test.

Completion of the self-test must be indicated.

There should be no visible mechanical failures.

2.3.5. Corrosion

Testing may not be required if the manufacturer can provide sufficient information about components, materials, and the ability to maintain electrical and mechanical performance criteria unchanged under corrosion effects.đổ 2.3.5.1. Definition

The ability of the device to maintain electrical and mechanical performance criteria unchanged after corrosion testing.

2.3.5.2. Test Method

Use a salt spray solution with composition as shown in Table 2.

Table 2 - Composition of Salt Solution

NaCl

MgCl₂

The pH of the solution must be between 6.5 and 7.2 at 20°C (±2°C). Maintain the pH within this range by adding HCl or NaOH to adjust the pH.

The salt spray equipment must ensure that there are no corrosive components in the salt solution.

Spray the salt solution over the entire outer surface of the device for 1 hour. After each spraying, store the device for 7 days at 40°C (±2°C). Relative humidity during storage must be maintained between 90% and 95%. This process is repeated four times.

At the end of the test period, the device must be visually inspected. The EPIRB self-test (section 2.1.8) must be performed.

3. Requirements

The quality check requirements must be met and metal parts must not show signs of corrosion.

2.3.5.In the case of sealed installation, the device must not show signs of moisture ingress.

2.3.6.1. Definition

The ability of the EPIRB to maintain electrical and mechanical performance criteria unchanged after immersion in water.

There should be no visible mechanical failures.

2.3.6. Water immersion testing

2.3.6.2. Test Method

The EPIRB is removed from its release mechanism and dropped into water. The EPIRB is dropped three times from a height of 20 m ± 1 m in normal operating position, inverted position, and position perpendicular to the normal operating position.

At the end of the test, perform the self-test procedure (section 2.1.8).

2.3.6.3. Requirements

There should be no visible mechanical failures.

2.3.7. Thermal Shock

There should be no visible mechanical failures.

2.3.7.1. Definition

The ability of the device to maintain electrical and mechanical performance criteria unchanged after thermal shock testing.ệorganize credit institutions, foreign bank branches are responsible for organizing the implementation of this Circular.

2.3.7.2. Test Method

The device is placed in an air environment at +65°C (±3°C) for 1 hour. It is then immersed in water at +20°C (±3°C) to a depth of 10 cm (measured from the highest point of the EPIRB to the water surface) for 1 hour.

2.3.7.3. Requirements

2.3.8. Immersion

There should be no visible mechanical failures.

2.3.8.1. Definition

There should be no visible mechanical failures.

2.3.7.1. Definition

The ability of the EPIRB to maintain electrical and mechanical performance criteria unchanged after immersion testing.đổ 2.3.8.2. Test Method

The device must withstand a hydrostatic pressure of 100 kPa (equivalent to a depth of 10 meters) for 5 minutes.

2.3.8.3. Requirements

2.3.9. Water Jet Impact

2.3.9.1. Definition

There should be no visible mechanical failures.

The ability of the EPIRB to remain in its release mechanism and not trigger a distress alert during water jet impact testing.

There should be no visible mechanical failures.

2.3.7.1. Definition

2.3.9.2. Test Method

The EPIRB is installed in its release mechanism. A direct water jet is sprayed onto the EPIRB for 5 minutes. The nozzle diameter must be 63.5 mm and the water flow rate must be 2,300 liters per minute. The nozzle tip must be 3.5 m away from the EPIRB and 1.5 m higher than the base of the antenna. During the test, the water jet nozzle must be moved to spray water onto the EPIRB from all directions within a 180° arc perpendicular to the normal installation position of the EPIRB.

2.3.9.3. Requirements

The EPIRB must not be ejected from its position and must not automatically activate during the test.

2.3.10.1. Definition

Buoyancy is calculated as the percentage ratio of buoyant force to gravity.

2.3.10.2. Test Method

2.3.10. Buoyancy testing

The EPIRB is submerged in water.

One of the following two methods may be used:

- Measure the buoyant force while the entire EPIRB is submerged in water. Then divide the buoyant force by the measured weight. Record the result; or

- Calculate buoyancy by dividing the volume above water by the volume below water. Record the result.

2.3.10.3. Requirements

Buoyancy ≥ 5%.

This test may not be required if the manufacturer can provide sufficient evidence that components, materials... maintain specified electrical and mechanical performance under continuous solar radiation exposure.

2.3.11.1. Definition

The ability of the device to maintain electrical and mechanical performance criteria unchanged after solar radiation testing.

2.3.11. Solar radiation testing

2.3.11.2. Test Method

2.3.11.1. Definition

The ability of the equipment to maintain its electrical and mechanical specifications unchanged after exposure to solar radiation testing.

2.3.11.2. Test Method

The device must be placed under artificial solar radiation sources (see Table 3) for 80 hours.

At the end of the testing process, the self-test procedure (section 2.1.8) must be carried out.

The illuminance at the test point (including reflected radiation from surroundings) must be 1,120 W/m²² ± 10% with spectral distribution as in Table 3.

Table 3 - Solar spectrum distribution, amended and supplemented by Decree No. 109/2025/NĐ-CP and Decree No. 193/2025/NĐ-CP sunlight

2.3.11.3. Requirements

There should be no visible mechanical failures.

2.3.7.1. Definition

2.3.12. Oil effect testing

This test may be omitted if the manufacturer can provide sufficient evidence that the components, materials... maintain electrical and mechanical specifications due to the effect of oil.

2.3.12.1. Definition

The ability of the equipment to maintain unchanged electrical and mechanical specifications after immersion testing in oil.

2.3.12.2. Test Method

The EPIRB must be immersed in oil for 6 hours at a temperature of 19 °C (± 1 °C) with the following requirements:

- Marking point: 120 °C ± 5 °C;

- Brightness point: Minimum 240 °C;

- Viscosity: 10 - 25 sST at 99 °C.

The following oils may be used:

- ASTM Oil Number 1;

- ASTM Oil Number 2;

- ISO Oil Number 1.

At the end of the testing process, the self-test procedure (section 2.1.8) must be carried out. After testing, the EPIRB must be cleaned according to the manufacturer's instructions.

2.3.12.3. Requirements

There should be no visible mechanical failures.

The EPIRB must not show signs of damage such as shrinking, cracking, swelling, melting, or changes in mechanical characteristics.

2.4. Transmitter

2.4.1. Output power

2.4.1.1. Definition

The output power of the EPIRB is the average power supplied to the 50 Ω RF terminal over a radio frequency cycle.

2.4.1.2. Measurement Method

Power at the EPIRB output is measured under normal test conditions and recorded. This power is used as the standard output power of the EPIRB (PR).

The measurement is repeated under limit test conditions. These values are recorded.

2.4.1.3. Requirements

The output power is: 37 dBm ± 2 dB.

2.4.2. Characteristic Frequency

2.4.2.1. Definition

The characteristic frequency (f₀) is the frequency of the unmodulated signal transmitted by the EPIRB.

2.4.2.2. Measurement Method

The characteristic frequency (f₀) is determined from 18 measurements of the carrier frequency of the unmodulated signal f_{specialized agency under the People's Committee of the province/city.}⁽¹⁾, conducted under limit conditions (sections 2.2.11 and 2.2.12) during time S₁ (Figure 5) of 18 consecutive transmissions as follows:

Figure 5 - Measurement time for characteristic frequencyNo. - Pulse S

starts 12 ms after the start of the unmodulated carrier wave.₁ starts at bit 23.

starts 12 ms after the start of the unmodulated carrier wave.₂ starts 15 ms after the end of S

starts 12 ms after the start of the unmodulated carrier wave.₃ 2.4.2.3. Requirements₂.

The EPIRB's characteristic frequency channels must fall within the 406.0 MHz to 406.1 MHz band designated by Cospas-Sarsat, specifically defined in document (C/S T.012 - Issue 1 - Rev.13 February 2018), while the frequency deviation shall not exceed the following value:

Table 4 - Frequency Channels

Frequency deviation upon manufacture

2.4.3.1. Definition

Short-term frequency stability is determined for a predetermined number of transmissions. , amended and supplemented by Decree No. 109/2025/NĐ-CP and Decree No. 193/2025/NĐ-CP2.4.3.2. Measurement Method

Short-term frequency stability is obtained from measurements of f

and f

, conducted under limit test conditions (sections 2.2.11 and 2.2.12) during times S

and S_i⁽²⁾ Short-term frequency stability must be < 2 x 10_i⁽³⁾2.4.4. Medium-term frequency stability₂ 2.4.4.1. Definition₃ (Figure 5) of 18 consecutive transmissions as follows:

2.4.3.3. Specific requirements

Medium-term frequency stability is evaluated based on two parameters: the average slope of the frequency-time curve over a predetermined period and the residual frequency variation relative to that slope.^-9.

2.4.4.2. Measurement MethodcouncillORSMedium-term frequency stability is derived from measurements of f

, conducted under limit test conditions (sections 2.2.11 and 2.2.12) during consecutive transmissions at times t

over a 15-minute period (Figure 6).

Figure 6 - Measurement of medium-term frequency stability

For a group (n) of measurements, medium-term frequency stability is determined by the average slope of the least squares straight line and the residual frequency variation relative to that slope._i⁽²⁾The average slope is calculated as follows:_i The y-intercept of the least squares straight line is calculated as follows:

The residual frequency variation is calculated as follows:

With a transmission repetition cycle of 50 seconds, there will be 18 measurements in 15 minutes (n = 18).

2.4.4.3. Requirements

Average slope ≤ 1 x 10

Residual frequency variation ≤ 3 x 10

2.4.5.1. Definition

The RF spectrum mask is defined by the output power relative to the maximum power in the 406.0 - 406.1 MHz band.

2.4.5.2. Measurement Method^-9

The device is connected to a spectrum analyzer.^-9

2.4.5. RF spectrum mask

The EPIRB transmits a modulated signal on frequency f

under limit test conditions (sections 2.2.11 and 2.2.12).

The input impedance of the spectrum analyzer is 50 Ω. The center frequency of the system display of the spectrum analyzer must be the carrier frequency of the EPIRB. The frequency resolution of the spectrum analyzer is 100 Hz.

The display on the screen must be recorded.

2.4.5.3. Requirements_{specialized agency under the People's Committee of the province/city.} Transmission must not exceed levels defined by the spectrum mask in Figure 7.

P

= Unmodulated carrier output power of the EPIRB

f

= Carrier frequency of the EPIRB

Where:

"5. The pre-tax weighted average cost of capital i (%) is determined according to the formula below:_F dBc = Transmitted signal power level of the EPIRB in dB relative to P

f_{specialized agency under the People's Committee of the province/city.} (spectrum analyzer bandwidth resolution is 100 Hz)

Figure 7 - Spectrum Mask_F 406.0 to 406.1 MHz band

The EPIRB transmission is modulated by a digital signal consisting of a header, message, and error-correcting code. The signal format is defined in this section. in NOTE: Measurements in section 2.5 are performed on 18 consecutive transmissions.

2.5. Signal format

2.5.1. General requirements

2.5.2.1. Definition

The interval between the 90% (0.9 PN) power points of two consecutive transmissions (T

2.5.2. Repeat cycle

) (Figure 8).

Figure 8 - Repetition Cycle_R2.5.2.2. Measurement Method

HThe repetition cycle (T

) is measured over 18 consecutive transmissions. The measurements are conducted under limit test conditions (sections 2.2.11 and 2.2.12) and the error between the maximum and minimum values of the repetition cycle must be less than 1 second. Record the maximum and minimum values of T

2.5.2.3. Requirements_Rmust be within the range: 47.5 s to 52.5 s._R.

If the EPIRB has a fixed repetition time, it will be within the range of 47.5 s to 52.5 s and the EPIRB manufacturer will provide technical documentation about how the repetition time will vary with at least eight different values.

T_R 2.5.3.1. Definition

If the EPIRB has a fixed repetition time, it will be within the range of 47.5 seconds to 52.5 seconds, and the EPIRB manufacturer shall provide technical documentation regarding how the repetition time will change using at least eight different values.

2.5.3. Total transmission time (T_{organize credit institutions, foreign bank branches are responsible for organizing the implementation of this Circular.})

2.5.3.1. Definition

The duration of power transmission at the characteristic frequency during one transmission.

2.5.3.2. Measurement Method

The total transmission time (T_{organize credit institutions, foreign bank branches are responsible for organizing the implementation of this Circular.}) is measured under limit testing conditions (Sections 2.2.11 and 2.2.12) between points where the carrier wave output power equals 90% of its limit value (Figure 12).

2.5.3.3. Requirements

The total transmission time (T_{organize credit institutions, foreign bank branches are responsible for organizing the implementation of this Circular.}T

must be within the following limits:

- Short message: 435.6 ms to 444.4 ms;

2.5.4. - Long message (optional): 514.8 ms to 525.2 ms.

Carrier Wave Preamble

2.5.4.1. Definition

The carrier wave preamble is an unmodulated carrier wave with a defined duration at the beginning of each digital message.

2.5.4.2. Measurement Method_{"5. The pre-tax weighted average cost of capital i (%) is determined according to the formula below:}The duration of the CW preamble (T

) is measured under limit testing conditions (Sections 2.2.11 and 2.2.12) between the point where the carrier wave output power reaches 90% of its limit value and the start of the digital message (Figure 12). This measurement is performed over 18 consecutive transmissions.

2.5.4.3. Requirements

2.5.5. Bit rate

The carrier wave preamble must be within the range: 158.4 ms to 161.6 ms.

2.5.5.1. Definition

) is measured over 18 consecutive transmissions. The measurements are conducted under limit test conditions (sections 2.2.11 and 2.2.12) and the error between the maximum and minimum values of the repetition cycle must be less than 1 second. Record the maximum and minimum values of T

Bit rate is bits per second._bThe bit rate (f

) is measured under limit testing conditions (Sections 2.2.11 and 2.2.12) on the first 15 bits of one transmission. This measurement is conducted over 18 transmissions and the bit rate is recorded.

2.5.5.3. Requirements

2.6. Other technical requirements

2.6.1. Battery capacity

The bit rate must be within the range: 396 bit/s to 404 bit/s.

2.6.1.1. Definition

Battery capacity is the ability of the internal power source to provide sufficient power for continuous operation of the device for a specified period of time.

2.6.1.2. Measurement Method

Using a new battery, the EPIRB is activated (at ambient temperature) for a time period provided by the manufacturer corresponding to the reduction in capacity due to self-testing and self-discharge during the useful operational life of the battery. The manufacturer must explain the method used to determine this time period.

The EPIRB is placed in a room with normal temperature. Then, the temperature is reduced and maintained at -40 °C (± 3 °C) for EPIRB type 1 or -30 °C (± 3 °C) for EPIRB type 2 for 10 hours.

At the end of this period, the temperature control unit is turned on and the room is transferred to -20 °C (± 3 °C) (for type 2 equipment). This process must be completed within 20 minutes. Thirty minutes later, the device is activated and maintained in continuous operation for 48 hours. The temperature of the test chamber must be kept stable throughout the 48-hour period.

2.6.1.3. Requirements

2.6.2. Navigation aid equipment

The EPIRB must comply with the requirements of Sections 2.4.1 (output power), Section 2.4.2 (characteristic frequency), Section 2.4.3 (short-term frequency stability), and Section 2.4.4 (medium-term frequency stability) for 48 hours.

2.6.2.1. General Requirements

2.6.2.1.1. Type of Transmission

Dual-tone signal including the carrier wave (A3X).

2.6.2.1.2. Modulation Frequency

A sweeping audio signal from high to low between 1600 Hz and 300 Hz over a band not less than 700 Hz.

2.6.2.1.3. Transmitter Operation Cycle

While transmitting the 406.0 MHz signal, the transmitter must operate continuously and can only be interrupted for a maximum of 2 seconds.

2.6.2.1.4. Sweep Repetition Rate

The sweep repetition rate of the transmitter is: 2 Hz to 4 Hz.

2.6.2.2. Frequency Error

2.6.2.2.1. Definition

Frequency error is the difference between the measured frequency and its nominal value.

2.6.2.2.2. Measurement Method

The carrier wave frequency is measured using a frequency counter or spectrum analyzer under both normal and limit testing conditions.

2.6.2.2.3. Requirements

The carrier wave frequency is: 121.5 MHz ± 50 ppm.

2.6.2.3. Modulation Operation Cycle

2.6.2.3.1. Definition

Where:

- T₁ The modulation operation cycle =

- T₂ is the half positive cycle duration of the amplitude modulation measured at the mid-amplitude points of the envelope curve; and

2.6is the cycle of the basic modulation frequency.

2.6.2.3.2. Measurement Method₁ The transmitter output is connected to a memory oscilloscope. T₂ and T

are measured at the start, midpoint, and end of the modulation cycle. The modulation operation cycle must be calculated.

2.6.2.3.3. Requirements

The modulation operation cycle must be between: 33% and 55%.

2.6.2.4. Modulation Index

2.6.2.4.1. Definition

Where:

Modulation index =

- A is the maximum amplitude value of the envelope;

- B is the minimum amplitude value of the envelope.

2.6.2.4.2. Measurement Method

2.6.2.4The transmitter output is connected to a memory oscilloscope. A and B are measured at the start, midpoint, and end of the modulation cycle. The modulation index must be calculated.

2.6.2.4.3. Requirements

The modulation index must be within the range: 0.85 and 1.

2.6.2.5. Peak Effective Radiated Power

2.6.2.5.1. Definition

2.6.It is the average power in a radio frequency cycle at the peak of the envelope curve.

2.6.2.5.2. Measurement Method

The measurement is carried out under normal temperature conditions and uses an EPIRB whose battery has been on for at least 44 hours. If the measurement time exceeds 4 hours, the battery may be replaced with another that has been on for at least 44 hours.

When testing outside the test chamber, prevent the emission of distress signals on safety and rescue frequencies, for example, by frequency offsetting.

The receiver must detect the carrier wave frequency of the transmitter. The test antenna is vertically polarized. Adjust the height of the test antenna so that the receiver detects the maximum signal level. The transmitter must rotate 360° around the vertical axis to locate the direction of the maximum signal. Record the maximum signal level detected by the receiver. The transmitter must be replaced with a substitute antenna. The substitute antenna must be connected to a standard signal generator. The frequency of the standard signal generator must be adjusted from the carrier wave frequency of the transmitter. The input attenuation of the test receiver must be adjustable to increase the receiver sensitivity if necessary.

The test antenna must be adjustable within the specified height range to ensure that the maximum signal is received.

The input signal to the substitute antenna must be adjusted to a level that the test receiver detects, which is equal to the level detected from the device by adjusting the test receiver's input attenuation.

The maximum ERP is the transmitter signal power increased by the gain of the substitute antenna and adjusted by the change in attenuation.

2.6.2.5.3. Requirements

The peak effective radiated power must be within the range of 25 mW and 100 mW.

2.6.2.6. False Emission

Spurious emissions are emissions on one or more frequencies outside the necessary bandwidth and the emission level can be reduced without affecting the corresponding information transmission. Spurious emissions include harmonic emissions, parasitic emissions, modulation products, and frequency-shifted products but do not include out-of-band emissions.

2.6.2.6.2. Measurement method

Spurious emissions are measured in the frequency bands 108 MHz - 137 MHz; 156 MHz - 162 MHz; 406.0 MHz - 406.1 MHz and 450 MHz to 470 MHz,

2.6.2.6.3. Requirements

The power of spurious emissions at any frequency ≤ 25 µW.

2.7. Radiated power measurement

2.7.1. General requirements

The power emission measurement method provides data representing antenna characteristics by measuring vertical and horizontal polarization standing waves.

2.7.2. Radiated power

2.7.2.1. Definition

Radiated power is equivalent isotropically radiated power (e.i.r.p).

2.7.2.2. Measurement method

The EPIRB operates normally and uses a new battery. The signal from the antenna is fed to a spectrum analyzer or field strength meter. The EPIRB is rotated 360° with at least 12 equal steps of 30° (± 3°) and measurements are taken.

To measure total e.i.r.p., the measuring antenna must have linear polarization and be positioned in two orientations to align with the vertical and horizontal components of the emitted signal.

Then, the measuring antenna is placed at elevation angles of 10°, 20°, 30°, 40°, and 50° (± 3°) with azimuth angles from 0° to 360° in 30° increments and voltage readings are taken for each polarization at these 60 positions.

The values V_h and V_v at each measurement position are recorded.

The following steps are performed for each set of measured voltages and results are recorded.

Step 1: Calculate the total voltage reading V_rec in dBV using the formula:

Where:

- V (VND/year): is the total investment capital allocated annually for the usable area of social housing for rent, ensuring the preservation of capital, calculated according to the following formula:_v and V_h are the measured voltage readings (V) when the measuring antenna is oriented in the vertical and horizontal planes.

Step 2: Calculate the field strength E in dBV/m at the measuring antenna using the formula:

E_(dBV/m) = V_rec + 20logAF_{specialized agency under the People's Committee of the province/city.} + L_{specialized agency under the People's Committee of the province/city.}

Where:

- V (VND/year): is the total investment capital allocated annually for the usable area of social housing for rent, ensuring the preservation of capital, calculated according to the following formula:_rec is the signal level calculated from step 1 (dBV);

- AF_{specialized agency under the People's Committee of the province/city.} is the measuring antenna correction factor;

-_{specialized agency under the People's Committee of the province/city.} is the system reception loss and cable attenuation (dB).

Step 3: Calculate e.i.r.p

Calculate e.i.r.p for each angular coordinate using the formula:

Where:

- R is the distance between the EPIRB and the dual-polarized measuring antenna;

- E is the field strength converted in step 2 to V/m.

Measurements are conducted under normal test conditions.

2.7.2.In the case of sealed installation, the device must not show signs of moisture ingress.

Radiated power must be within the range of -5 dB to +6 dB relative to the 5 W e.i.r.p level.

2.7.3. Antenna characteristics

2.7.3.1. Definition

Antenna characteristics are determined with elevation angles greater than 5° and less than 60°.

2.7.3.2. Measurement method

The antenna gain coefficient is calculated for each angular coordinate using the formula:

Where:

- e.i.r.p. is the radiated power (section 2.7.2);

- P_{organize credit institutions, foreign bank branches are responsible for organizing the implementation of this Circular.} is the power supplied to the EPIRB antenna;

: bid price after corrections and adjustments, minus any discount (if applicable) of the lowest bidder among those detailed financial evaluations;_i is the ratio of the EPIRB antenna gain coefficient to the isotropic antenna.

Analyze the data (V_vfor each specific service package in the service provision contract between the ISP and the customer._h) obtained during measurement, the antenna must be able to determine whether the EPIRB antenna polarization is linear or circular.

If the voltage readings (V_v ,V_h) for each angular coordinate (azimuth angle, elevation angle) differ by at least 10 dB, the polarization is linear. Polarization will be vertical or horizontal if V_v or V_h is larger.

If the voltage readings (V_vfor each specific service package in the service provision contract between the ISP and the customer._h) differ by less than 10 dB, the EPIRB antenna has circular polarization.

Compare the received signals using known right-hand circular polarized antennas and left-hand circular polarized antennas while the EPIRB is transmitting. The antenna with the higher received signal determines the direction of polarization.

2.7.3.3. Limits.

The antenna has the following characteristics:

- Type: Hemispherical;

- Polarization: Right-hand circular or linear;

- Gain (in the perpendicular direction): From -3 dBi to +4 dBi;

- Gain variation (by azimuth angle): <3 dB;

- Antenna vertical-to-horizontal voltage ratio ≤1.5:1.

3. MANAGEMENT PROVISIONS

3.1. Marine emergency position-indicating radio beacons (EPIRBs) operating in the 406.0 MHz to 406.1 MHz band within the scope regulated in section 1.1 must comply with the provisions of this standard.

3.2. Testing/measurement requirements for technical standards of this standard (except sections 2.3, 2.5, and 2.7.3) for declaration of conformity must be carried out according to current regulations. Organizations and individuals may use testing/measurement results from designated domestic laboratories or recognized foreign laboratories or manufacturer testing/measurement results for sections 2.3, 2.5, and 2.7.3 for declaration of conformity.

3.3. Measuring equipment: Comply with current regulations.

4. RESPONSIBILITIES OF ORGANIZATIONS AND INDIVIDUALS

Organizations and individuals related are responsible for declaring conformity of marine emergency position-indicating radio beacons (EPIRBs) operating in the 406.0 MHz to 406.1 MHz band and are subject to inspection by state management agencies according to current regulations.

Chapter 5. ORGANIZATION OF IMPLEMENTATION

5.1. The Telecommunications Administration Department, the Radio Frequency Management Department, and Provincial Departments of Information and Communications are responsible for organizing guidance and implementing management of marine emergency position-indicating radio beacons (EPIRBs) operating in the 406.0 MHz to 406.1 MHz band according to this standard.

5.2. This standard replaces QCVN 57:2011/BTTTT "National technical regulation on marine emergency position-indicating radio beacons (EPIRBs) operating in the 406.0 MHz to 406.1 MHz band."

5.3. In case there are changes, supplements, or replacements to the provisions set out in this Standard, they shall be implemented according to the new document.

5.4. During the implementation of this standard, if there are issues or difficulties arising, organizations and individuals concerned should report them in writing to the Ministry of Information and Communications (Science and Technology Department) for guidance and resolution./.

 

LIST OF REFERENCES

[1] Manufacturer-listed Cospas-Sarsat type-approved beacon models.

[2] FCC-02-271A1: Amendment to Part 95 of the Commission's Rules to authorize the use of 406.025 MHz for Personal Locator Beacons (PLB).

[3] Manufacturer-listed Cospas-Sarsat type-approved beacon models. (http://www.Cospas-Sarsat.org/beacons/type-approved-models).

[4] ETSI EN 300 066 V 1.3.1 (01-2001): Electromagnetic Compatibility and Radio Spectrum Matters (ERM); Float-free maritime satellite Emergency Position Indicating Radio Beacons (EPIRBs) operating in the 406.0 MHz to 406.1 MHz frequency band; Technical characteristics and methods of measurement. Part 1: Technical characteristics and methods of measurement.

[5] ETSI EN 302 152-1 V1.1.1 (2003-11): Electromagnetic compatibility and Radio spectrum Matters (ERM); Satellite Personal Locator Beacons (PLB) operating in the 406,0 MHz to 406,1 MHz frequency band; Part 1: Technical characteristics and methods of measurement.

[6] C/S T.001 2018: Specification for Cospas-Sarsat 406 MHz distress beacons.

[7] C/S T.007 2018: Cospas-Sarsat 406 MHz distress beacons type approval standard.

[8] C/S G.005 2018: Cospas-Sarsat guidelines on 406 MHz beacon coding, registration and type approval.

[9] C/S T.012 2018: Cospas-Sarsat 406 MHz frequency management plan.