COMDTINST M2400.1F 8 MAY 1991

Transcription

1 Commandant United States Coast Guard 2100 Second Street, S.W. Washington, DC (202) COMDTINST M2400.1F 8 MAY 1991 COMMANDANT INSTRUCTION M2400.1F Subj: USCG Radio Frequency Plan 1. PURPOSE. This manual establishes policy for Coast Guard radio spectrum management. It prescribes procedures for obtaining and using radio frequencies, and resolving cases of interference and rodio misuse. It is also a plan of Coast Guard radio frequencies. 2. CANCELLATIONS. COMDTINST M2400.1E and COMDTINST are cancelled effective 30 JUN DISCUSSION. a. Uses. This publication may be carried and used in Coast Guard aircraft. b. Frequency Changes. All current HF radio frequency assignments in the exclusive maritime mobile bands, except for certain portions of the coast wideband telegraphy bands, will be changed to new replacement frequency assignments at 0001 UTC on 1 July These changes will require a comprehensive transfer of HF ship and coast station frequency assignments in the exclusive maritime mobile bands. Frequency assignments in other HF bands and in most of the coast wideband telegraphy bands will not be affected by this change. c. New Frequencies. This publication has been revised to incorporate the new HF replacement frequencies for existing circuits which were previously provided for advance planning in COMDTINST Expanded frequency resources made available by ITU conference action will not be assignable for use until international coordination has been effected. Upon completion of satisfactory coordination, additional frequency asignments will be included in existing circuits or new circuits as required.

2 COMDTINST M2400.1F 8 MAY d. GMDSS. An updated description and policy for implementation for the Global Maritime Distress and Safety System is provided in Chapter 6. e. Frequency Assignments and Spectrum Authorization. Every mobile or shore station installed at a fixed location which transmits a radio signal of any kind must have a frequency assignment before it can be operated. See paragraph 4.E. Every major new radiocommuication or radionavigation system must be certified for availability of spectrum before funds can be obligated. See paragraph 4.G. f. Errors or Omissions. Comments, suggestions and information as to errors or omissions noted to be in this directive shall be addressed to Commandant (G-TTM). 4. ACTION. This publication will become effective at 0001 UTC 1 July Area and District Commanders, Commanders of Maintenance and Logistics Commands, unit commanding officers and Commander, CG Activities Europe shall assure compliance with the contents of this manual. /s/ R. M. POLANT Chief, Office of Command, Control & Communications 2

3 Table of Contents CHAPTER 1 General Information 1-1 A. Purpose 1-1 B. General 1-1 C. Classification 1-1 D. Changes to COMDTINST M (series) 1-2 E. Presentation 1-2 F. Local Arrangements 1-3 G. Vacant 1-3 H. Compatibility of Equipment 1-3 I. Frequency Band Designators 1-3 J. Radio Frequency Emission Designators 1-3 CHAPTER 2 Search and Rescue 2-1 A. General 2-1 B. Distress Frequencies 2-1 C. Emergency and Safety Frequencies 2-3 D. Search and Rescue Control Frequencies 2-4 E. On-Scene Search and Rescue Frequencies 2-4 F. Maritime SAR Operations by CG Vehicles 2-4 G. Homing Frequencies 2-5 H. Disaster Communications Service 2-5 I. VHF-FM Maritime Mobile Frequency Plans 2-5 CHAPTER 3 Aids to Navigation 3-1 A. Maritime Radiobeacons 3-1 B. Aeronautical Radiobeacons 3-1 C. Loran-C 3-1 D. Loran-D 3-1 E. Radar 3-1 F. Radio Direction Finding 3-1 G. Radar Beacons (RACONS) 3-2 H. Airborne Transponders 3-2 I. Omega 3-2 CHAPTER 4 Radio Frequency Management Authority 4-1 and Procedures A. General 4-1 B. Frequency Management Authority 4-2 C. National Frequency Management Procedures 4-2 D. International Frequency Management Procedures 4-3 E. Requests for Frequency Assignments 4-3 F. Requests for Frequency Assignments Outside 4-5 the United States and Possessions (US&P) 1

4 CHAPTER 5 Radio Interference and Radio Violation Reports 5-1 A. Radio Interference Reports 5-1 B. Radio Violation Reports 5-2 EXHIBIT 1 Agreement Between FCC and USCG Relating to 5-4 Marine Radio Problems CHAPTER 6 Global Maritime Distress and Safety Systems 6-1 A. System Principles and Objectives 6-1 B. GMDSS System and Operational Details 6-1 C. Functions of the System 6-3 D. Satellite Ship-to-Shore Distress Alerting 6-3 E. SAR Coordinating Communications 6-4 F. On-Scene Communications 6-4 G. Locating Signals 6-4 H. Navigational and Meteorological Warnings and 6-4 Urgent Information I. General Radio Communication Channels 6-5 J. Intership Navigation Safety Communications 6-5 K. Preventive Action 6-5 L. Shore Based Communications Network 6-5 M. Coast Guard Ship and Coast Equipment Requirements 6-5 N. Implementation of the GMDSS 6-6 O. Frequency Plan in Effect for the GMDSS 6-6 P. GMDSS Implementation Dates 6-6 Enclosure (1) ANNEX A Ship/Shore (2) ANNEX B Broadcast Circuits (3) ANNEX E Aeronautical Circuits (4) ANNEX J Search and Rescue Circuits (5) ANNEX L Special Circuits (6) ANNEX M Maritime Defense Zone (7) ANNEX N Aids to Navigation Circuits (8) ANNEX P Point-to-Point Circuits (9) ANNEX Q Local Districts Circuits (10) ANNEX Z VHF, UHF, and SHF Fixed Circuits (11) INDEX Frequency Index 2

5 COMDTINST M2400.1F CHAPTER 1. GENERAL INFORMATION A. Purpose. COMDTINST M (series) is the basic U.S. Coast Guard Radio Frequency Plan and contains radio frequencies for U.S. Coast Guard use. It is issued for the use and guidance of responsible commanders in formulating supplementary plans and is furnished to lower echelons for information and planning purposes. COMDTINST M (series) is a radio frequency plan and does not constitute a radio frequency authorization to operate unless specifically indicated. Authorization for federal government stations to use radio frequencies is granted by the National Telecommunications and Information Administration (NTIA) and specific assignments are listed in the Government Master File (GMF). B. General. 1. Information. This publication provides explanatory information concerning application procedures for use of radio frequencies, a frequency index and lists of circuits. a. Frequency Index. The frequency index is a listing of all radio frequencies assigned by the Commandant for Coast Guard, and indicates the circuit designator for each of these assigned radio frequencies. b. Annexes. The list of circuits is divided into annexes denoting its function, and each circuit in a particular annex is arranged in circuit designator order. The circuit details normally include a descriptive title, a list of assigned radio frequencies and any special instructions governing the use of these frequencies. c. Circuit Designator. The circuit designators within the "B", "P", "Q", and "Z" annexes are arranged by Coast Guard District whenever the circuit is confined to an individual district (e.g., a "P05.01" circuit would indicate a fixed circuit in the Fifth Coast Guard District). Whenever the circuit is not restricted to a particular district, it is assigned a circuit designator "18" or higher. (e.g., "P18", "Q20", etc.). d. Circuits. The circuits within the remaining annexes are arranged by type in circuit designator order; e.g. "A01" is the Primary Ship-Shore Circuit, and "A01.01" and "A01.02" are sub-divisions of the Primary Ship-Shore Circuit indicating HF Ship-Shore Circuits for the Atlantic and Pacific Areas respectively. 2. Designating Symbol. The designating symbol will normally be used to identify circuits and radio frequencies in messages, letters, instructions or other documents; e.g. "A13.02" is the circuit designator for the High Seas Radiotelephone Service, " khz" is one of the several radio frequencies assigned to this circuit. 1-1

6 1.C. Classification. 1. Unclassified. All circuits in this publication are unclassified, so that the radio frequency, circuit designators, and/or circuit titles may be coupled without affecting their classification. 2. Classified. U.S. Navy circuits and/or frequencies that may be contained in OPLANS, may be classified and care should be taken in referring to them. D. Changes to COMDTINST M (series). 1. Discrepancies. Certain information contained in the annexes to COMDTINST M (series) is subject to frequent change. It is the responsibility of any command concerned to report to the Commandant (G-TTM) errors or discrepancies found in this publication. 2. Corrections. Corrections to COMDTINST M (series) are made by formal changes. Interim changes will be promulgated by letter, message or electronic mail to those concerned and subsequently included in the next formal change or reprint of COMDTINST M (series). E. Presentation. Unless otherwise indicated, information contained in this publication is presented as follows: 1. khz-mhz. Radio frequencies at or below 30 megahertz are expressed in kilohertz although normally the khz symbol is not shown. Radio frequencies above 30.0 megahertz are shown with the MHz symbol. 2. Carrier-Dial Frequency. Each radio frequency shown reflects the assigned or authorized frequency, which is the center frequency of the band occupied regardless of the type of emission employed. In the case of single sideband operation, the radio frequency shown in parenthesis after the assignment indicates the carrier or dial frequency. 3. Emissions. The emissions shown indicate the authorized bandwidth for transmission on the radio frequency(ies) of the circuit. Where more than one emission is authorized, it is appropriately noted. 4. UTC. All times are Universal Goordinated Time (UTC). 1-2

7 1.E.5. Abbreviations. Abbreviations used in this publication. CW - Continuous Wave FM - Frequency Modulation MCW - Modulated Continuous Wave P - Primary Frequency(ies) RATT - Radio Teletype S - Secondary Frequency(ies) SSB - Single Sideband V - Voice NIB - Not-to-Interfere Basis ISB - Independent Sideband NBDP - Narrow-band direct printing, also called SITOR or radiotelex F. Local Arrangements. Nothing in this manual is intended to abrogate any local arrangements made by district commanders for establishing liaison circuits with other agencies needed to accomplish assigned missions. However, the details of such arrangements must be forwarded to the Commandant (G-TTM) for approval by the appropriate radio frequency assignment authority and inclusion in this manual. G. Vacant. H. Compatibility of Equipment. Tuning Capability. Certain single sideband radio equipments within the Coast Guard are limited to integral, 1 kilohertz tuning increments in the operating band (example: 2670, 2671, 2672 khz as shown on the equipment tuning dial). These equipments cannot tune to other frequencies within the 1 khz integrals (e.g., khz). Accordingly, those Coast Guard SSB equipments that do not possess 100 hertz incremental tuning capability, shall follow the interim procedures listed below when the carrier frequency does not fall on a whole khz step (noting that the carrier frequency for H3E/J3E and F1B emissions are normally located 1.4 khz and 2.0 khz respectively below the assigned frequency unless otherwise indicated: 1. Emission. Subtract 1.4 khz (2K8H3E/J3E emission) or 2.0 khz (280HF1B/1K24F1B emission) from the assigned frequency. 2. Remainder. Round out the remainder to the nearest whole khz step (0.1 through 0.5 to the lower step, 0.6 through 0.9 to the higher step). 3. Carrier or Dial Frequency. Place the carrier or dial frequency on the resulting whole khz step and use upper sideband emission. 4. NBDP Offset. Frequency offset for NBDP (SITOR) using exclusive maritime narrowband channels (500 Hz) should be 1700 Hz to preclude the residual carrier energy falling within the pass band of the lower adjacent channel. 1-3

8 1.I. Frequency Band Designators. The Institute of Electrical and Electronic Engineers (IEEE) letter designators are often used, as a matter of convenience, to define certain bands of frequencies. These letter designators are repeated below for reference purposes. DesignatorBand (MHz)DesignatorBand (MHz) "A" "C" "G" "X" "P" "K" "L" "Q" "S" "V" J. Radio Frequency Emission Designators. 1. Type of Signal. Radio frequency emissions are designated by the necessary bandwidth and classification symbols that describe the type of signal transmitted. 2. Bandwidth. Necessary bandwidth is calculated using formulas recommended by the CCIR for a frequency band just sufficient to transmit information at the rate and with the quality required under specified conditions. 3. Classification Symbols. Emission classification symbols are determined by the basic characteristics of an emission as follows: (a) First Symbol - Indicates the type of modulation of the main carrier. (b) Second Symbol - Indicates the nature of signals(s) modulating the main carrier. (c) Third Symbol - Indicates the type of information to be transmitted. (d) Fourth Symbol - Indicates the details of the signal (Optional, recommend use when applicable). (e) Fifth Symbol - Indicates the nature of multiplexing (Optional, recommend use when applicable). 1-4

9 1.J.4. Emissions Abbreviations. Necessary bandwidths are expressed using a letter in lieu of a decimal to indicate the bandwidth of an emission as follows: (a) Hertz..01 to Hz in hertz using the letter H; 6H1 = 6.1 Hz (b) Kilohertz to khz in kilohertz using the letter K; 1K1 = 1.1 khz (c) Megahertz to MHz in megahertz using the letter M; 2M1 = 2.1 MHz (d) Gigahertz to GHz in gigahertz using the letter G; 6G5 = 6.5 GHz 5. Emission Classification Symbol. Emission classification symbols are derived from the tables below. A basic emission designator consists of three symbols, and if desired, two optional additional symbols. (a) First symbol - designates the type of modulation of the main carrier: (figure 1-1) (b) Second symbol - designates the nature of signal(s) modulating the main carrier: (figure 1-2) (c) Third symbol - designates the type of information to be transmitted. (In this context the word "information" does not include information of a constant, unvarying nature such as provided by standard frequency emissions, continuous wave and pulse radars, etc.) (figure 1-3) (d) Fourth symbol - designates the details of signal(s): (figure 1-4) (e) Fifth symbol - designates the nature of multiplexing: (figure 1-5) 1-5

10 Symbol Type of Emission UNMODULATED N Emission of an unmodulated carrier. AMPLITUDE-MODULATED - Emission in which the main carrier is amplitude-modulated (including cases where sub-carriers are angle-modulated.): A B C H J R Double-sideband Independent sidebands Vestigial sideband Single-sideband, full carrier Single-sideband, suppressed carrier Single-sideband, reduced or variable level carrier ANGLE-MODULATED - Emission in which the main carrier is angle-modulated: F G Frequency modulation Phase modulation AMPLITUDE-MODULATED AND ANGLE-MODULATED D Emission in which the main carrier is amplitude-modulated and angle-modulated either simultaneously or in a preestablished sequence. PULSE - Emission of pulses: (Emissions, where the main carrier is directly modulated by a signal which has been coded into quantized form (e.g., pulse code modulation), shall be designated as either an emission in which the main carrier is amplitude-modulated, or an emission in which the main carrier is angle-modulated). P K L M Q V Sequence of unmodulated pulses. A sequence of pulses: Modulated in amplitude Modulated in width or duration Modulated in position or phase Carrier is angle-mounted during the period of the pulse A combination of the foregoing or produced by other means COMBINATION W X Cases not covered above, in which an emission consists of the main carrier modulated, either simultaneously or in a combination of two or more of the following modes: amplitude, angle, pulse. Cases not otherwise covered. figure 1-1

11 Symbol Type of Emission 0 No modulating signal. 1 A single channel containing quantized or digital signals without the use of a modulating subcarrier. (This excludes time-division Multiplex.) 2 A single channel containing a quantized or a digital signal with the use of modulating subcarrier. 3 A single channel containing an analogue signal. 7 Two or more channels containing quantized or digital signals. 8 Two or more channels containing analogue signals. 9 A composite system with one or more channels containing quantized or digital signals, together with one or more channels containing analogue signals. X Cases not otherwise covered. figure 1-2

12 Symbol N A B C D E F W X Type of Emission No information transmitted. Telegraphy-for aural reception. Telegraphy-for automatic reception. Facsimile. Data transmission, telemetry, telecommand; (the symbol D indicates that data, telemetry, or telecommand information is being transmitted individually or, that any combination of the three are being transmitted simultaneously. If any combination is being transmitted simultaneously, one of the multi-channel symbols, 7, 8, or 9, must be used for the second symbol.) Telephony (including sound broadcasting). Television (video) Combination of the above. (Use only for multi-channel systems having the capability of transmitting all information simultaneously). Cases not otherwise covered. figure 1-3

13 Symbol A B C D E F G H J K L M N W X Type of Emission Two-condition code with elements of differing numbers and/or durations. Two-condition code with elements of the same number and duration without error-correction. Two-condition code with elements of the same number and duration with error-correction. Four-conditon code in which each condition represents a signal element (of one or more bits). Multi-condition code in which each condition represents a signal element (of one or more bits). Multi-condition code in which each condition or combination of conditions represents a character. Sound of broadcasting quality (monophonic). Sound of broadcasting quality (stereophonic or quadraphonic). Sound of commercial quality (excluding categories defined for symbols K and L below). Sound of commercial quality with the use of frequency inversion or band-splitting. Sound of commercial quality with separate frequency-modulated signals to control the level of demodulated signal. Monochrome. Color. Combination of the above. Cases not otherwise covered. figure 1-4

14 Symbol N C F T W X Type of Emission None. Code-division multiplex (This includes bandwidth expansion techniques.) Frequency-division multiplex. Time-division multiplex. Combination of frequency-division multiplex and time-division multiplex. Other types of multiplexing. EXAMPLES: Designator 100HA1A 2K10A2A 280HF1B 300HF1B 1K24F1B 2K8H3E 2K8J3E 4KF3C 2K8J3C 16KF3E or 16KG3E 16KF1E 16KF2D 6KA3E 6KB9W 20K00PXX 1K03H2A 35M00PON 10M00PON Type of Emission Continuous Wave Morse Telegraphy (CW) Modulated Morse Telegraphy (MCW) Single Channel RATT (170 Hz Shift) Single Channel RATT with error correction (HF Telex or SITOR) Single Channel RATT (850 Hz shift) SSB Single Channel Telephony (Re-inserted Full Carrier) SSB Single Channel Telephony (Suppressed Carrier) Facsimile (800 Hz Shift) Facsimile (Narrow Band) FM Single Channel Telephony FM Single Channel Telephony (Digital) FM Single Channel Data with modulated sub-carrier AM Telephony (Double Sideband) ISB LORAN C Radiobeacon Radar RACON figure 1-5

15 CHAPTER 2. SEARCH AND RESCUE A. General. 1. Initial Communication. Initial communications between vessels or aircraft in distress and the mobile units proceeding to their assistance is normally made on the frequency used by the vessel or aircraft making the distress call. In the case of merchant vessels equipped for radiotelegraphy, the initial contact frequency would normally be 500 khz. In the case of small vessels voluntarily equipped with radiotelephone, such as fishing vessels and pleasure craft, the inter-ship frequencies (see Circuit L2.2) should be tried after attempts to call these vessels on (2182) khz and MHz have been unsuccessful. 2. Initial Contact. The initial contact frequencies allow the mobile search and rescue units to establish communications with aircraft or vessels in distress. After communications have been established, the selection of a frequency for handling traffic between the vessel or aircraft in distress and the rescue units proceeding to assist is the responsibility of the unit in distress or the station which has transmitted the distress message for the unit in distress, except when the control of distress traffic has been delegated to another station. Communications should be shifted to available working frequencies as soon as practicable, except when it is not possible to do so because of a lack of common frequencies. For communications involving only Coast Guard units regular Coast Guard frequencies should normally be used. In any event, due regard must be given to the guard requirements on the calling, distress and emergency frequencies. 3. Aircraft. The first transmission of an aeronautical distress message is on the frequency in use for normal communications with the aeronautical stations at the time of the incident. For that reason, search and rescue craft proceeding to the assistance of the aircraft must establish communications on that frequency. It is necessary that search and rescue craft obtain pertinent frequency information from the controlling surface radio station, whether it be an International Civil Aviation Organization air-ground control radio station or a controlling military radio station. That frequency normally will be used for establishing initial communication as well as for handling ensuing communications between the distressed aircraft, assisting mobile craft, and the controlling surface radio station. When a mobile search and rescue unit is within line of sight range of a distressed aircraft the initial contact frequency would normally be either MHz for civil aircraft or 243 MHz for military aircraft. 2-1

16 2.B. Distress Frequencies khz: The frequency 500 khz is an international distress and calling frequency, and is used by ships to request assistance from the maritime services using morse code. It is also used for the distress call and distress traffic, and for urgency and safety signals and urgency and safety messages. Additionally: a. 500 khz. 500 khz may only be used for call and reply, or by coast stations to announce their traffic lists under certain restrictions. b. Usage. With the exception of distress communications and urgency and safety signals, no transmissions will be made on 500 khz for three minutes twice each hour beginning at HX + 15 and HX + 45 UTC. c. Coast Guard Usage. Coast Guard units may (subject to limitations stated above) employ 500 khz as follows: (1) Transmit and receive distress calls and distress traffic (using either CW or MCW emission). (2) Transmit and receive urgency and safety signals and urgency and safety traffic. (Safety messages should be transmitted on an authorized working frequency wherever possible after preliminary announcement on 500 khz.) (3) Transmit the alarm signal when authorized (MCW must be used). (4) Establish communications with ships equipped with radiotelegraph. (5) Call Coast Guard units. (6) Announce Maritime Safety Information Broadcasts (2182) khz: The frequency (2182) khz is the distress and calling voice frequency for the maritime mobile service. The frequency may be used by ship or aircraft radiotelephone stations to request assistance from the maritime service. It may used for distress calls and distress traffic and for urgency, safety and Emergency Position Indicating Radio Beacon (EPIRB) signals and urgency and safety messages. In addition it may be used for call and reply, for signals preparatory to traffic, and by coast radiotelephone stations to announce transmissions, on other frequencies, which are of general interest to ship stations including ordinary weather and hydrographic information. Coast Guard units may use (2182) khz as follows: a. Distress. Transmit and receive distress calls and distress messages. b. Safety Messages. Transmit and receive urgency, safety and EPIRB signals and urgency and safety traffic. (Safety messages should be transmitted on an authorized working frequency wherever possible after preliminary announcement on (2182) khz). 2-2

17 2.B.2. c. Transmission. With the exception of distress communications and urgency and safety signals, no transmission will be made on (2182) khz for three minutes twice each hour beginning at HX00 and HX + 30 UTC. d. Calling. Call radio stations other than Coast Guard when other means of communications are not available or not desired. (After a preliminary call to establish communications, when practicable, units shall shift to an appropriate working frequency.) e. Working Frequencies. Call Coast Guard units for the purpose of establishing communications and then shift to an appropriate working frequency for the passing of traffic. In districts where a guard is maintained on a working frequency, units should call and work on those channels. f. Broadcasts. Announce Maritime Safety Information Broadcasts. 3. a. Carrier Frequencies 4125 and 6215 khz. The carrier frequencies 4125 and 6215 khz are used to supplement the carrier frequency 2182 khz for distress and safety purposes and for call and reply. These frequencies are also used for distress and safety traffic by radiotelephony. b. Carrier Frequency 4125 khz. The carrier frequency 4125 khz may be used by aircraft stations to communicate with stations of the maritime mobile service for distress and safety purposes MHz: This frequency is the VHF-AM aeronautical distress frequency, also used by aircraft Emergency Locator Transmitter (ELT's), ship Class A, B, S and Category I EPIRB's, and COSPAS-SARSAT Search and Rescue Satellite-Aided Tracking system distress alerting and locating. Coast Guard units may use MHz to transmit (from aircraft, or using an EPIRB), or receive distress calls and messages. Class A EPIRB's are automatically activated, float free devices, and Class B and S EPIRB's are manually activated devices. Class S EPRIB's, intended for survival craft, are designed to float MHz: The VHF-FM frequency MHz is the International distress, safety and calling voice frequency in the MHz band for the maritime mobile service. The frequency may be used by ship radiotelephone stations to request assistance from maritime services. It may be used for distress calls and distress traffic and for urgency And safety signals and urgency and safety messages. In addition it may be used for call and reply, for signals preparatory to traffic, and by coast radiotelephone stations to announce transmissions, on other frequencies, which are of general interest to ship stations including ordinary weather and hydrographic information. It is also used by Class C EPIRB's for distress alerting purpose MHz must not be used for the transmission of any traffic other than specified above. Coast Guard units may use MHz as follows: a. Distress Calls. Transmit and receive distress calls and distress messages. 2-3

18 b. Urgency Calls. Transmit urgency and safety signals and urgency messages. (Safety messages should be transmitted on an authorized working frequency wherever possible after preliminary announcement on MHz). 2.B.5. c. Radio Station. Call radio stations other than Coast Guard when other means of communication are not available or are not desired. d. Working Frequencies. Call Coast Guard units for the purpose of establishing communications and then shift to an appropriate working frequency for the passing of traffic. In districts where a guard is maintained on a working frequency, units should call and work on those channels. e. MSIB. Announce Maritime Safety Information Broadcast when required MHz MHz is used exclusively by satellite EPIRB's and ELT's for transmission of distress alerting, locating and identifying information to COSPAS-SARSAT satellites. Category I EPRIB's are automatically activated, float free devices. Category II EPIRB's are manually activated devices. Category III devices are similar to Category II, except they are designed to work in a warmer climate and for a shorter duration. All of these EPIRB's also transmit a low power MHz signal for homing purposes. C. Emergency and Safety Frequencies khz: The frequency 8364 khz, is designated for use by Survival Craft Stations and except as explained below its use shall be confined to this primary function. This frequency will not be used for this purpose upon full implementation of the GMDSS in a khz. Coast Guard units, other than aircraft, shall not transmit on 8364 khz except in cases involving distress. A unit in distress may call a Coast Guard station on 8364 khz and request a reply on 8364 khz. Since the unit in distress is in control of traffic on the frequency used for distress, the Coast Guard unit should comply with the request by answering on 8364 khz if possible to do so. After replying to the call on 8364 khz, and if it is within the capability of the unit in distress to receive on another appropriate Coast Guard working frequency, the Coast Guard station shall shift to this frequency as soon as practicable, care being taken that positive communications are not disrupted with the unit in distress. D. Search and Rescue Control Frequencies. Search and Rescue (SAR) control frequencies are for use between the Rescue Coordination Center ashore and the On-Scene-Commander. In addition to the frequencies listed in Annex J for this purpose, the appropriate Coast Guard common, District working, ship/shore and air/ground frequencies may be used for SAR control. 2-4

19 E. On-Scene Search and Rescue Frequenices. 1. On-Scene SAR. On-Scene SAR frequencies are for communications among aircraft and surface ships (including submarines) engaged in and at the scene of SAR. These frequencies are assigned as working frequencies and normally shall be used as the primary search and rescue frequencies in their particular frequency bands. In addition to the frequencies listed in Annex J for this purpose the appropriate Coast Guard common, District working and air/ground frequencies may be used at the scene of SAR. 2-5

20 2.E.2. VHF-AM Frequency MHz. The VHF-AM frequency MHz is a world-wide SAR on-scene action working freqeuncy. This frequency was assigned to provide government and non-government land, mobile and portable radiotelephone stations a compatible common channel for voice communications when participating jointly in SAR incidents. 3. VHF-FM Frequency MHz. The VHF-FM frequency MHz (channel 6) may be used for communications between ship stations and aircraft stations, using F3E emission, engaged in coordinated search and rescue operations. When control of the scene of a SAR incident is under a Coast Guard coast station, MHz may be used by ship stations to communicate with that coast station.