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RSS-287 — Emergency Position Indicating Radio Beacons (EPIRB), Emergency Locator Transmitters (ELT), Personal Locator Beacons (PLB), and Maritime Survivor Locator Devices (MSLD)

5. Transmitter and Receiver Standard Specifications

5.1 406 MHz Transmitter Applicable Standards

The testing officer should be familiar with the standards and test procedures as follows:

  • COSPAS/SARSAT documents C/S T.001 and C/S T.007;
  • Section 5 of this RSS;
  • Battery reliability and registration card tests described in the TC (Marine Safety) or NSS document.

Caution: Some electrical tests (e.g. output power and frequency stability) are to be performed at the end-of-life battery test.

It is the responsibility of the equipment certification applicant to arrange for the tests specified in this section to be carried out, and to forward the test report (in duplicate) to:

  • Transport Canada (Marine Safety) in the case of EPIRBs; and
  • NSS in the case of PLBs.

The test report shall contain the following:

  • the signature of the testing and supervising officers;
  • the name of the signing persons;
  • phone and facsimile numbers;
  • full name and address of the testing facility; and
  • proof that the facility is an approved test facility.

The battery reliability and registration card test results as well as the electrical/electronic measurements on the 406 MHz transmitter will be evaluated by TC (Marine Safety) or NSS, as appropriate, who will forward a copy of the test report with a recommendation to Industry Canada (Manager, Certification and Market Surveillance) or to the appropriate Recognized Certification Body (CB).

Industry Canada or the appropriate Certification Body will evaluate the 406 MHz transmitter output power, field strength, and frequency stability measurement results. The test results for the homing transmitter will also be evaluated if applicable.

5.2 121.5/243 MHz Applicable Standards

Section 5.1 which applies to the 406 MHz transmitter, also generally apply to the 121.5 MHz and 243 MHz transmitters (except for the reference to the COSPAS/SARSAT documents).

The frequency 121.5 MHz is used as the homing frequency for EPIRBs and MSLDs. This homing frequency is optional for PLBs. PLBs can also be equipped to use both 121.5 MHz and 243 MHz as homing frequencies.

ELTs use either 121.5 MHz or both 121.5 and 243 MHz (with or without the 406 MHz).

5.3 Modulation Characteristics (121.5 MHz or 243 MHz Transmitter)

The modulation technique for each carrier is described as follows:

  1. The type of emission shall be A3X (described below), with periods of voice modulation or no modulation (CW) permitted as described below.

    During A3X transmissions, the emissions shall have the distinctive characteristic achieved by amplitude modulating the carrier with an audio frequency sweeping downwards for ELTs, and upwards or downwards for EPIRBs and upwards for PLBs, over a range of not less than 700 Hz within the band 300 Hz to 1600 Hz, at a sweep repetition rate between 2 and 4 Hz.

  2. The modulation factor for A3X modulation shall be at least 85% and not more than 100%, i.e. over-modulation is not permitted.

  3. The transmission shall be continuous except in the case of a homing transmitter when it may be interrupted for up to 2 seconds during the transmission of the 406 MHz burst.

  4. The A3X modulation must have a clearly defined carrier frequency distinct from the modulation sideband components. For this, at least 30%of the totalpower emitted during any transmission shall be contained within ±30 Hz of the carrier frequency in the case of the 121.5 MHz beacon, and ±60 Hz of the carrier frequency in the case of the 243.0 MHz beacon.

    Additionally, if the type of modulation is changed during transmission (e.g. to voice in the case of ELTs), the carrier frequency shall not shift by more than ±30 Hz and ±60 Hz for the 121.5 MHz and 243.0 MHz transmitters respectively.

  5. Voice (A3E) and/or carrier wave (N0N) emissions are permitted but only for ELTs and provided that they are consistent with the device's primary function. However, in the case of synthesized or recorded voice, each message must be accompanied by the words "this is a recording". Furthermore, the transmission of A3E and/or N0N shall not exceed 90 seconds in total without at least 3 minutes of A3X emission. These periods of alternate modulation shall not consume more power than the normal A3X modulation.

    The manufacturer shall provide the following or equivalent marking on the external surface of the ELT:

    Keep voice transmissions short. Les périodes d'émission en phonie doivent être réduites au minimum.

    The modulation technique employed shall be described in the test report/certification application, complete with a diagram showing the duration of each emission type.

  6. Modulation Duty Cycle: Modulation duty cycle is the ratio of the positive modulation duration, measured at the half-amplitude points on the modulation signal envelope, to the period of the audio modulating frequency. This duty cycle shall be between 33% and 55%.

    The modulation duty cycle (or ratio) is not to be confused with the transmission duty cycle described in Section 5.3(e).

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5.4 Frequency and Output Power Stability

The RF carrier frequency shall not depart by more than 0.005% (±50 ppm) from that measured at 20°C and rated supply voltage. If the 121.5 MHz and 243 MHz frequencies are derived from the same oscillator circuitry, it is not necessary to repeat the frequency stability test for the other frequency.

The RF output power shall not fall below the minimum 25 mW for any homer transmitter, or below 50 mW for an ELT primary frequency. Furthermore, in the latter case the antenna conducted power, if measured, should agree (within measurement error) with the power measurement made with the open area test method.

5.5 Output Power (Radiated)

The output power of EPIRBs, ELTs, and PLBs shall not be less than 50 mW when the transmitter is used as a primary beacon and not less than 25 mW when used as a homing transmitter. The output power of MSLDs shallbe less than 25 mW.

5.6 Unwanted Emissions

The power of unwanted emissions measured by an averaging meter of 300 Hz resolution bandwidth shall be attenuated below the level of the mean transmitter power (TP) by:

  1. at least 25 dB on any frequency removed from the centre of the authorized bandwidth by more than 50% up to and including 100% of the authorized bandwidth;
  2. at least 30 dB on any frequency removed from the centre of the authorized bandwidth by more than 100%.

The authorized bandwidth is 25 kHz.

5.7 Modulation Factor and Audio Sweep

The required standards are found in Sections 5.3(a) to (c), (e) and (f).

5.8 Spectrum Characteristics

The narrow band power shall not drop by more than 5 dB below the transmitter mean output power that is measured by a wide band meter (for the latter, see Section 3.2 or 3.1), indicating that at least 30% of the power resides within the band fc ±30 Hz (at 121.5 MHz) and within the band fc ±60 Hz (at 243 MHz).

5.9 Authorization to Perform Radiation Tests

Before carrying out any tests (at offset or at distress frequencies) that involve radiation of signal into the air (including any tests not performed in a proper shielded room, whether the antenna is attached to the beacon or not), the testing officer shall obtain prior authorization from the offices/agencies (addresses in Annex 1) nearest to where radiation testing is to be conducted, as follows:

  • NAV CANADA Area Control Centre (ACC)
  • NAV CANADA Air Traffic Control Agencies
  • Canadian Mission Control Centre (CMCC) at CFB Trenton, Ontario
  • Joint Rescue Coordination Centre (JRCC)

Note: The local NAV CANADA office should be contacted for up-to-date telephone numbers of the above mentioned personnel/agencies. In informing each party, the testing officer shall provide the following information several days in advance: name, telephone number, date and duration of the test (test time shall be as short as possible), and location of the test site.

The agencies' written consent to the test should be submitted to the local Industry Canada office for the purpose of issuing the authorization to use the radio frequency.

Unless there are valid reasons to use distress frequencies (other than 406.025 MHz), only offset frequencies may be authorized as follows:

  • 121.100 to 121.450 MHz; 121.550 to 121.900 MHz;
  • 242.200 to 242.900 MHz; 243.100 to 243.800 MHz;
  • 406.025 MHz (i.e. no offset provided that the beacon test bit pattern is set to "test protocol", see C/S T.007).

Great care shall be taken not to accidentally radiate in the forbidden bands (121.5 MHz ±50 kHz and 243 MHz ±100 kHz).

5.10 Transport Canada and National Search and Rescue Secretariat Requirements

Section 5.1 specifies the test report evaluation requirements of Transport Canada (Marine Safety) for EPIRBs and of the National Search and Rescue Secretariat for PLBs.

For ELTs, compliance with the ELT standard of Section 551.104 of the Airworthiness Manual must be demonstrated by a letter from Transport Canada Civil Aviation.

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Annex 1 - Addresses

The following are addresses relevant to this document. The addresses, especially telephone and fax numbers, are subject to change without notice:

Canadian Mission Control Centre (CMCC)
P.O. Box 1000, Canadian Forces Base Trenton, 8 Wing
Astra, Ontario
K0K 3W0
Duty Officer Telephone: 613-965-2026/fax: 613-965-7045
Telephone: 613-965-3660
Fax: 613-965-7190
700 de la Gauchetière West
Suite 2450
Montréal, Quebec
H3B 5M2
Telephone: 514-954-6761
International Civil Aviation Organization
Document Sales Unit
999 University Street
Montréal, Quebec
H3C 5H7
Telephone: 514-954-8022
Fax: 514-954-6769
International Maritime Organization
4 Albert Embankment
London, England, SE1 7SR
Telephone: (44) 71-735-7611
Fax: (44) 71-587-3210
International Telecommunication Union
General Secretariat - Sales Service
Place Des Nations
CH -1211 Geneva 20, Switzerland
Fax: (41) 22 730 5194
Telex: 421000 UITCH
National Search and Rescue Secretariat
275 Slater Street, 4th Floor
Ottawa, Ontario
K1A 0K2
Telephone: 613-992-6667
Fax: 613-996-3746
Joint Rescue Coordination Centres (JRCCs), East to West:
Joint Rescue Co-ordination Centre Halifax
Canadian Forces Base, Halifax
P.O. Box 99000 Stn Forces
Halifax, Nova Scotia
B3K 2X0
Telephone: 902-427-2104
Fax: 902-424-2114
Joint Rescue Co-ordination Centre Trenton
Canadian Forces Base, Trenton
P.O. Box 810
Trenton, Ontario
K8V 5W6
Telephone: 613-392-2811 ext. 3875
Fax: 613-965-7190
Joint Rescue Co-ordination Centre Victoria
Canadian Forces Base, Esquimalt
P.O. Box 17000 Stn Forces
Victoria, British Columbia
V0F 1B0
Telephone: 604-363-2988
Fax: 604-363-2944
Transport Canada Civil Aviation
Attention: Manager, Avionics and
Electrical Systems Engineering (AARDD/A)
Place de Ville, Tower "C"
330 Sparks Street
Ottawa, Ontario
K1A 0N8
Telephone: 613-952-4328
Fax: 613-996-9178
Transport Canada (Marine Safety)
Place de Ville, 10th Floor
330 Sparks Street
Ottawa, Ontario
K1A 0N5
Telephone: 613-991-3134
Fax: 613-993-8196
NAV CANADA Air Traffic Control Agencies, East to West:
Eastern Regional Director
1601 Tom Roberts Avenue, U53
Gloucester, Ontario
K1V 1E5
Telephone: 613-248-4070
Fax: 613-248-4061
Western Regional Director
300-9925 109 Street, Suite 300
Edmonton, Alberta
T5K 2J8
Telephone: 780-413-5303
Fax: 780-413-5304
NAV CANADA Area Control Centre (ACC), East to West:
Gander Area Control Centre
ANS Building
2C Memorial Drive
P.O. Box 328
Gander, Newfoundland
A1V 1W7
Telephone: 709-651-5230
Fax: 709-651-5235
Ottawa Terminal Control Unit
1601 Tom Roberts Avenue
P.O. Box 9824 Stn. T
Gloucester, Ontario
K1G 6R2
Telephone: 613-248-3818
Fax: 613-248-3823
Moncton Area Control Centre
222 Old Coach Road
Riverview, New Brunswick
E1B 4G2
Telephone: 506-851-7150
Fax: 506-851-7170
Winnipeg Area Control
777 Moray Street
Winnipeg, Manitoba
R3J 3W8
Telephone: 204-983-8566
Fax: 204-983-8347
Montréal Area Control Centre
1750 Chemin St-François
Dorval, Quebec
H9P 2P6
Telephone: 514-633-2870
Fax: 514-633-2881
Edmonton Area Control Centre
P.O. Box 9867
Edmonton, Alberta
T5J 2T2
Telephone: 403-890-8322
Fax: 403-890-8451
Toronto Area Control Centre
6055 Midfield Rd.
Mississauga, Ontario
L4W 2P7
Telephone: 905-676-4561
Fax: 905-676-4654
Vancouver Area Control Centre
4611 Cowley Crescent
Richmond, British Columbia
V7B 1B9
Telephone: 604-775-9613
Fax: 604-775-9657

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