|
(b) If the receiver is a superheterodyne receiver---
(i) the image discrimination shall not be less than 35 decibels at frequencies above 3 MHz and not be less than 40 decibels at frequencies below 3 MHz; and
(ii) the intermediate frequency response ratio shall be less than the following :---
(7) The signal noise ratio of the output of the receiver shall be at least 20 decibels when the receiver is adjusted to give the standard output with an input signal of type A2 at a level of 30 decibels above one microvolt.
(8) The automatic gain control shall be such that when the receiver is adjusted to give, the standard output with an input signal of type A2 at a level of 30 decibels above one microvolt---
(a) an increase in input of 20 decibels will result in an improvement in the signal noise ration of at least 15 decibels; and
(b) an increase in input of 50 decibels will not increase the output by more than 10 decibels.
(9) The change in output of the receiver shall not exceed 3 decibels when the receiver is adjusted to give the standard output with an input wanted signal of type A2 at a level of 60 decibels above one microvolt and a type A1 input signal is simultaneously applied at a level of 100 decibels above one microvolt and at a frequency of 20 KHz above or below the wanted frequency.
(10) An output of level higher than 30 decibels below the standard output shall not be produced when the receiver is adjusted to give the standard output with an input wanted signal of type A2 at a level of 60 decibels above one microvolt, the modulation of the signal generator has been switched off, and a type A2 input signal is simultaneously applied at a level of 90 decibels above one microvolt and at a frequency of 20 KHz above or below the wanted frequency.
(11) An output exceeding the standard output shall not be produced when the receiver is adjusted to give the standard output with an input signal of type A2 at a level of 30 decibels above one microvolt, the wanted signal has been removed, and two interfering signals are simultaneously applied one of type A1 and one of type A2 each of level 10 decibels above one microvolt of which the frequency sum of difference is the same as the frequency of the wanted signal but neither of which will give an appreciable output when modulated and applied alone.
(12) The maximum change in level of the audio-frequency output shall be less than 8 decibels when the modulation frequency of the input signal is varied continuously from 250 Hz to 3,000 Hz, the input signal remaining constant in level and depth of modulation. When the modulation frequency is increased above 3,000 Hz the output shall fall rapidly. The input signal may have any level and depth of modulation provided the output of the receiver does not exceed the standard output.
(13) The total harmonic content of the audio frequency output voltage of the receiver at any output not exceeding the standard output shall not exceed---
(a) 5 per cent with an input signal at any level between 40 and 80 decibels above one microvolt and sinusoidally modulated to a depth of 30 per cent at 1000 Hz; or
(b) 15 per cent with an input signal as prescribed in (a) but modulated to a depth of 80 per cent at 1000 Hz.
(14) Each frequency of tune referred to in paragraph 3 shall be maintained within one Hz per second of its nominal value notwithstanding variation in the supply voltage of plus or minus 10 per cent and notwithstanding ambient temperature changes from minus 100C to plus 400C.
(15) (a) The receiver shall not in normal service produce a field exceeding 0.1 microvolt per metre when measured at a distance of one mile from the receiver.
(b) The receiver shall be deemed to comply with the requirement of sub-paragraph (a) of this paragraph, when---
(i) the receiver is placed centrally in a screened earthed enclosure of dimensions 1.83 metres cube;
(ii) the earth terminal of the receiver is connected to the inside of the screen;
(iii) the aerial terminal is connected through an unscreened four-turn rectangular search coil situated within the said enclosure of dimensions 30.5 centimetres square and an unscreened lead to a resistive measuring instrument mounted outside the enclosure and having its other terminal earthed; and
(iv) the receiver is then energized and unscreened headphones are contended thereto, the power measured by the measuring instrument does not exceed 4 x 10 – watts whatever the resistance of the measuring instrument or the adjustment of the receiver, and notwithstanding that the search coil is short-circuited or moved in any way without approaching within 152 millimetres of the receiver case.
7. Facilities for two-way communication---
(1) The equipment shall be capable of changing instaneously from transmitted to receiving and vice versa by means of a pressel or other single switch, aerial change-over relays, and such other devices as are necessary for that purpose. If, in addition, a voice operated device is provided for that purpose the operating lag shall not be less 10 milli-seconds, and the release lag shall not be less than 150 milli-seconds and not more than milli-seconds.
(2) Means shall be provided for protecting the receiver from damage when the equipment is transmitting.
(3) Means shall be provided to assure automatically that at all times when the microphone is in use the loud-speaker is disconnected.
8. Size of Controls.--- All controls on the receivr shall be of such size as to permit normal adjustment being performed by a person wearing thick gloves.
PART –II
RADIO TELEHPONE ALARM SIGNAL GENERATING DEVICE
1. General.---(1) The Radio telephone Alarm signal Generating Device (hereafter in this Part referred to as "the device") shall be capable of generating the radio telephone alarm signal specified in paragraph 3 and of being suitable connected to a Radio telephone transmitted referred to in Par I of this Schedule.
(2) The device, if designed for operation from the ship's mains shall meet the requirements for a range of supply voltage variations of plus and minus 10 per cent relative to the nominal mains voltage.
(3) The device, if designed for operation from batteries shall meet the requirements of this Part for a range of supply voltage variations of plus 5 and minus 10 per cent relative to the nominal battery voltage.
(4) The device shall not cause the ship's mains to be earthed.
2. Performance.---(1) The device shall be ready generate the radio-telephone alarm signal within a period of 30 seconds from the time the device is energized and shall be capable of generating for a period of not less than 30 and not more than 60 seconds.
(2) After generating the signal the device shall be ready to repeat the signal after an interval of not more than two minutes.
(3) Means shall be provided so that the device can be taken out of service at any time.
(4) It shall be possible to test the device without the generation of radio-frequency energy and shall include a sound reproducer to give an audible reproduction of the generated signal.
(5) The device shall be capable of modulating the ships radio telephone transmitter by each referred to the paragraph 3 to 9 depth in the range 80 to 95 per cent.
3. Radio Telephone Alarm Signal. The radio telephone alarm signal referred to in sub-paragraphs (1) of paragraph 1 shall consist of two substantially sinusoidal tones, one having a frequency of 2200 Hz plus or minus 1.5 per cent and the other of 1300 Hz plus or minus 1.5 per cent produced alternatively, the duration of each tone shall be 250 mills-seconds plus or minus 50 mills-second; the interval between successive tones shall not exceed 50 milliseconds. The ratio of the amplitude of the stronger tone to that of the weaker shall be within the range 1 to 1.2.
4. Modulation standard.---The device shall be capable shall of modulating the ship's radio telephone transmitter by each tone referred to in paragraph 3 to 9 depth in the range 80 to 95 per cent.
5. Controls.---(a) Not more than two operating controls shall be available at the exterior of the device. Each control shall be clearly labeled to show its purpose and shall be such as to permit normal operations to be by person wearing thick gloves.
(b) Controls, where provided, for the adjustment of frequency, duration or level of the signal elements shall be present controls not available at the exterior of the device.
PART – III
RADIO TELEPHONE LOUD-SPEAKER WATCH KEEPING RECEIVER
1. General.---(1) The radio telephone Loud-speaker watch keeping Receiver (hereinafter in this Part referred to as "the receiver") shall be fixed in tune on a frequency of 2182 KHz and shall be suitable for the reception of class A3, A3H, A3A and A3J emissions except when the ship's own radio telephone transmitter is radiating on 2182 KHz.
(2) Means shall be provided to prevent damage to the receiver when the ship's transmitter is radiating on 2182 KHz.
(3) The receiver, if designed for operation from the ship's mains, shall meet the requirements of this Part for a range of supply voltage variations of plus and minus 10 per cent relative to the nominal mains voltage.
(4) The receiver, if designed for operation from accumulator batteries, shall meet the requirements of this Part for a range of supply voltage variation of plus 5 and minus 10 percent relative to the nominal battery voltage.
(5) The receiver shall include a loudspeaker.
(6) The receiver shall not cause the ship's mains to be earthed.
2. Controls. The receiver shall be provided with :-
(1) a manual gain control for the adjustment of audio-frequency gain.
(2) a manual gain control for the adjustment of RF and/or IF gain; and
(3) one or two present controls not available at the exterior of the receiver for the adjustment of RF, IF and/or AF gain.
3. Selectivity.---The selectivity preceding the detector shall satisfy the following requirements :-
________________________________________________________________________________________
Frequency Discrimination (relative
(KHz) to maximum response
_______________________________________________________________________________________
2178.5 to 2185. 5 Not more than 6 dB
Below 2182 and above 2192 At least 30 dB
Below 2162 and above 2202 At least 60 dB
Below 2142 and above 2222 At least 80 dB
________________________________________________________________________________________
4. Sensitivity.---The receiver shall have sufficient sensitivity to produce signals by means of a loudspeaker when the receiver input is as low as 50 microvolts either when used along or when fitted with any of the filtering units specified in paragraph 5 of this Part.
5. Filtered Loudspeakers.--- (1) The filtering unit used with the loudspeaker shall :-
(a) maintain the output level of the two alarm signal tone frequencies, 1300 Hz and 200 Hz at approximately the speech level normally used for listening and capable of reducing the strength of other audio frequencies.
(b) be such that its effect can be removed when the radio telephone alarm or distress signal is received so as to facilitated listening to the distress message.
(2) The frequencies of maximum response of the filters shall be subject to a tolerance of plus or minus 1.5 per cent.
(3) Any additional device when used in conjunction with the filtering units specified in subparagraphs (1) and (2) shall :-
(a) silence the loudspeaker in the absence of a radio telephone alarm signal specified in paragraph 3 of Part II, and
(b) when switched on, in the absence of noise or interference, and, if a radio telephone alarm signal is received, be capable of setting the loudspeaker in operation as quickly as possible and at most six seconds after receipt of the alarm signal.
6. Radiation.---(1) The receiver when in use shall not produce a field exceeding 0.1 microvolt per metre when measured at a distance of one mile from the receiver.
(2) The receiver shall be deemed to comply with the requirements of sub-paragraph (1) if,---
(a) the receiver is placed centrally in a screened earthed enclosure of dimensions at least 1.83 metres cube;
(b) the earth terminal of the receiver is connected to the inside of the screen;
(c) the aerial terminal is connected through an unscreened four turn rectangular search coil situated within the said enclosure and of dimensions 305 centimetres square and an unscreened lead to a resistive measuring instrument mounted outside the enclosure and having its other terminal earthed; and
(d) the receiver is then energized and unscreened headphones are connected thereto, the power measured by the measuring instrument does not exceed 4 X 10 – 10 watts whatever the resistance of the measuring instrument or the adjustment of the receiver, and notwithstanding that the search coil is short circuited or moved in anyway without approaching within 152 millimetres of the receiver case.
( See rule 5 )
CLIMATIC AND DURABIULITY TESTS
1. In this Schedule --
(1) references of Class B equipment shall be construed as references to equipment appropriated for use only below deck or in deckhouse or other similar compartment; and
(2) references to Class X equipment shall be construed as references to equipment appropriated for use or storage in the open or in an open boat.
2. (1) Class B equipment shall be subjected to the tests named opposite the letter B in the Table given in sub-paragraph (4) and Class X equipment shall be subjected to the tests named opposite the letter X in that Table.
(2) All such tests shall be conducted in order in which they appear in the aforesaid Table.
(3) At any time when the equipment is required by the provisions of paragraph 3 to be kept working for the purpose of such tests, power shall be supplied thereto at the voltage at which such equipment is designed to be operated.
(4) TABLE
________________________________________________________________________________________
Nature of Test Class of equipment
to which the test
shall be applied
_______________________________________________________________________________________
(1) Vibration test B and X
(2) Bump test B and X
(3) Dry heat test B and X
(4) Damp heat test B and X
(5) Low temperature test B and X
(6) Rain test X
(7) Immersion test X
(8) Corrosion test-salt water B and X
(9) Corrosion test-acid fumes B and X
(if a battery is included in
the equipment)
(10) Mould growth test X
_______________________________________________________________________________________
3. The tests referred to in paragraph 2 shall be conducted respectively as follows :-
(1) Vibration Test.--- The equipment, complete with its chasis covers and shock absorbers (if any) shall, in its normal operating position be clamped to a vibration table. The table shall be vibrated at all frequencies between 0 and 12 ½ Hz per second at an amplitude of plus or minus 0.1 cm. during which period the equipment shall be kept working continuously. The table shall be so vibrated for three periods each of which shall be of eight minutes duration. Throughout each such period the direction of the vibration shall be perpendicular to the direction of the vibrations during the other two periods.
(2) Bump Test.--- The equipment shall be subjected to not less than 500 bumps at a constant rate between one and four bumps per second with a free drop of lat least 2.5 cm.
(3) Dry Head Test.--- (a) Class B equipment shall be placed in a chamber which is maintained for a period of two hours at constant temperature of 550C within a tolerance of plus or minus 10C during which period the equipment shall be kept working continuously.
(b) Class X equipment shall be placed in a chamber which is maintained for a period of ten hours at a constant temperature of 700C, within a tolerance of plus or minus 10C during which period the equipment shall not be worked or tested. The said chamber shall then be cooled to a constant temperature of 550C within a tolerance of plus or minus 10C, and the equipment shall be kept working continuously at that temperature for a period of two hours.
(4) Dampt Heat Test.---The equipment shall be prepared for the damp heat test in the following manners :
(a) The equipment shall be placed in a chamber which within a period not exceeding two hours shall be heated from room temperature to 400C within a tolerance of plus or minus 10C and shall be brought to a relative humidity of not less than 95 per cent.
(b) The chamber shall be kept at a temperature of 400C within a tolerance of plus or minus 10C for a period of 2 hours, and at a relative humidity of not les than 95 per cent.
(c) At the beginning of the last 69 minutes of such period all accessible surfaces and components shall be wiped dry on any fans or drying lamps provided in the equipment shall be switched on.
(5) Low Temperature Test.---(a) Class B equipment shall exposed to a temperature of minus 150C within a tolerance of plus or minus 20C at normal atmospheric pressure for a period of not less than twelve hours.
(b) Class X equipment shall be exposed to a temperature of 250C within a tolerance of plus or minus 20C at normal atmospheric pressure for a period of not less than twelve hours.
(6) Rain Test.---The equipment shall be placed in a chamber fitted with either shower heads, the discharge and of which shall consist of flat, non-rustable metal plate, 0.16 cm, thick, having thirty-six holes each of 0.1 cm. diameter evenly spaced in concentric circles in the following manner :--
8 holes on the periphery of a circle of 3.8 cm. diameter.
8 holes on the periphery of a circle of 2.5 cm. diameter.
4 holes on the periphery of a circle of 1.3 cm. diameter.
The said shower heads shall be arranged at a distance of not less than 50 cm. and not more than 80 cm. from the equipment in such a manner that spray from four of such shower heads is directed downwards at an angle of 450C at each of the four uppermost corner of the equipment, and the spray from the other four shower heads is directed horizontally at the center of such area of the four sides of the equipment. Fresh water at room temperature and at a static pressure of not less than 15 or more than 25 pounds per square inch shall be sprayed on to the equipment from the aforesaid shower heads for a period of one hour with the equipment in the position in which it is normally operated. Throughout the test the equipment shall be rotated at between 12 and 20 revolutions per minute about a vertical axis passing through the center of equipment.
(7) Immersion Test.---The equipment in the condition in which it will normally be kept on board ship shall be immersed in water the surface of which is at least 10 cm. above the highest point of the equipment and shall remain for a period of one hour. Union its removal from the water the equipment shall be drained of water.
(8) Corrosion Test (Salt Water).---The equipment shall be placed in a chamber fitted with apparatus capable of spraying in the form of a fine mist either natural sea water or tap water containing the following salts in solution :-
Sodium Chloride 2.7 per cent.
Magnesium Chloride 0.6 per cent.
Calcium Chloride 0.1 per cent.
Potassium Chloride 0.07 per cent.
The quantity of each salt shall be subject to a tolerance of plus or minus 10 per cent.
The spraying apparatus shall be such that the products of corrosion cannot mix with the sea water or solution contained in the spray reservoir. The equipment shall be sprayed simultaneously on all its external surfaces with the sea water or solution for a period of one hour and shall be kept working continuously for the last thirty minutes thereof. The equipment shall immediately thereafter be stored for a period of seven days at a temperature of 400C within a tolerance of plus or minus 10C at a relative humidity of not less than 60 per cent, and not more than 80 per cent. The equipment shall be sprayed and stored as aforesaid on four separate occasion.
(9) Corrosion Test (Acid Fumes)—Any battery included in the equipment shall be fully charged and shall be fitted into the equipment. If the arrangements are such that the battery can be charged without being removed from the equipment the battery shall continue to be charged at a maximum rate appropriate to it for a period of twenty four hours. The equipment shall immediately thereafter be stored for a period of four weeks at a temperature of 400C within a tolerance of plus or minus 10C at a relative humidity of not less than 60 per cent and not more than 80 per cent.
(10) Mould Growth Test.--- The equipment shall be inoculated by spraying with an aqueous suspension of mould spores containing all the cultures named in column A or all the cultures named in column B of the following Table :-
TABLE
________________________________________________________________________________________
A B
________________________________________________________________________________________
Aspergillus niger; Aspergillus niger;
Aspergillus amstelodami; Aspergillus amstclodami;
Pacecilomyccs varioti; Aspergillus versicolor;
Satchybotrys atra; Stachybotrys atra;
Pencillium brevi-compactum; Pencillium brevi-compactum;
Peneillium cyclopium; Caldosporum heaoasum
Chetomium globosum
Immediately after it has been so sprayed the equipment shall be placed in a chamber, the temperature of which shall be maintained at any fixed value within the range 300C to 330C inclusive and controlled to within a tolerance of plus or minus 10C at a relative humidity of not less than 95 per cent. The equipment shall remain in the said chamber for a period of twenty-eight days.
( See rules 7(2), 29 and 30 )
RADIO EQUIPMENT FOR LIFEBOATS AND SURVIVAL CRAFTS
Motor Lifeboat Fixed Radio Equipment
1. General.---(1) The fixed radio equipment for lifeboats (hereinafter in this Part referred to as "the equipment") shall include a radiotelegraph and a radiotelephone transmitter and receiver, an aerial and earth system, a source of energy, and all other equipment necessary for the operation of the installation.
(2) The equipment shall be so designed that an unskilled person can readily cause it do transmit the signals referred to in paragraph 5.
(3) The purpose of all controls not required for transmitting the said singles shall be clearly and permanently indicated.
(4) Simple instructions for the operation of the equipment on the frequencies specified in subparagraphs (1) of paragraph 4 and subparagraph (1) of paragraph 6 shall be affixed in clear and permanent form to or near the equipment.
(5) All controls shall be of such size as will permit normal adjustments to be made by a person wearing thick cloves, and in particular all tuning knobs shall not be less than 5 centimetres in diameter.
(6) For manual radiotelegraph transmission a morsekey of approved design shall be fitted in an approved position.
(7) The change-over from transmitting to receiving and vice-versa, including automatic change of aerial connections, shall be made by means of one switch.
(8) The equipment shall be readily removeable from the life boat.
(9) An electric lamp of power between 3 watts and 15 watts with water-proof casing, shall be provided to illuminate the control panels and the aforesaid instructions.
(10) An electrical heater, connected to the ship's mains shall be provided and shall be capable of maintaining the interior of the case in which the equipment is installed at a temperature at least 100C above the ambient temperature. The heater shall be so mounted that it will reduce the risk of the controls or cover of the equipment becoming frozen into position but will not cause any part of the installation to become overheated.
(11) All parts other than the aerial and its terminal which are not at earth potential shall be enclosed. The aerial terminal shall be guarded against accidental contact.
(12) The equipment shall be capable of complying with the performance requirements specified in this Part while the lifeboat engine is running and whether or not the battery is being charged.
2. Aerial and earth System.---(1) The equipment shall include.---
(a) a single---wire aerial of high conductivity standard or braided wire capable of being supported by the lifeboat mast without the use of top-masts at a maximum height of not less than 6.7 metres above the waterline; and
(b) in addition to the aerial referred to in clause (a), an aerial supported by a kite or bottom may be provided; and
(c) an earth systems which shall be of the same material throughout and shall consist of at least three independent bolted connection.
(i) to the hull in the case of metal lifeboat; or
(ii) to a bare copper plate of area at least 0.55 square metres fixed to the hull below the waterline in the case of a wooden lifeboat.
(2) The aerial system shall be mechanically robust.
(3) All practicable steps shall be taken to reduce aerial losses to a minimum.
(4) All parts of the aerial which may come in contact with the occupants of the lifeboat when the equipment is in use shall be insulated.
3. Source of Energy.---(1) The equipment shall include one 24 volt battery composed of accumulators and of a capacity sufficient to operate the receiver for two hours and the transmitter under full power marking conditions for four hours.
(2) If it is intended to operate a searchlight from the battery, the capacity thereof shall be at least 30 ampere hours in excess of that referred to in sub-paragraph (1)
(3) The battery shall be capable of being completely recharged :-
(a) in not more than 20 hours from a dynamo working in conjunction with and throughout the normal range of speeds of the lifeboat engine if the battery is not in use at the same time; and
(b) from the ship's main source of electrical energy without its being removed from the lifeboat.
(4) The battery shall not spill when tiled to an angle of 600C form its normal position in any direction.
(5) The battery shall be electrically isolated from the rest of the equipment when the transmitter and receiver are switched off.
(6) If a vibrator power unit is employed, a reserve vibrator shall be provided and so controlled by a changeover switch that can be put into circuit immediately.
4. Transmitter.---(1) The equipment shall include a transmitter capable of :---
(a) sending continuously but not simultaneously Class A2 and A2H emissions on the frequencies of 500 KHz and 8.364 KHz and Class A3 and A3H emissions on the frequency of 2182 KHz:
(i) by manual operation when using radiotelegraphy at all speeds upto at least 25 bands without critical relay adjustment; and
(ii) by means of an automatic keying device complying with the requirements 5 ; and
(b) maintaining without adjustment of any control, a frequency tolerance throughout every transmission :---
(i) plus or minus 0.5 per cent on a frequency of 500 KHz; and
(ii) plus or minus 0.02 per cent on a frequency of 8.364 KHz; and
(iii) plus or minus 0.02 per cent on a frequency of 2182 KHz.
notwithstanding variations of the impedance of the aerial or of any other load to which it is connected or of supply voltage within plus or minus 10 per cent; and
(2) When class A2 and A2H emissions are being transmitted the carrier wave shall be modulated to a depth of 100 per cent by an approximately rectangular wave of frequency between 450 and 1350 KHz so that the carrier is switched on for 30 to 50 per cent of modulation cycle.
(3) When class A3 and A3H emissions are being transmitted, it shall be possible to fully modulate the carrier by speech.
(4) The facility for transmission on the frequency of 2182 KHz shall include a device for the generation of radio telephone alarm signal specified in Part II of the Second Schedule except that the duration of the radio telephone alarm signal may be determined by manual control.
(5) The power of the transmitter :-
(a) shall not be less than 15 metre-amperes on a frequency when determined in the manner specified in paragraphs 2 and 3 of the Fifth Schedule.
(b) shall not be less than 50 watts on a frequency of 500 KHz when measured into an artificial aerial consisting of a 30 ohm non-inductive resistor in series with a capacitor of every value between 200 and 300 picofards ; and
(c) shall not be less than 15 watts on a frequency of 8.364 KHz when measured into an artificial aerial simulating the impedance of the aerial specified in paragraph 2.
(d) On a frequency of 2182 KHz :-
(i) shall not be less than 5 watt when measured with an artificial aerial consisting of 15 ohm non-inductive resistor in series with a capacitor having every value from 125 to 200 picofarado, and
(ii) ten watts when measured with an artificial aerial consisting of 30 ohm non-inductive resistor in series with a capacitor having every value from 300 to 400 picofarado.
(6) The transmitter shall be so designed and constructed that when it is adjusted for maximum power and the transmitting key is depressed the aerial may be disconnected or the output short circuited without damage being caused to any part of the installation.
(7) There shall be provided:-
(a) an artificial aerial for testing the transmitter on full power, which shall include an indicator or lamp to indicate the passage of radio-frequency currents; and
(b) an aerial ammeter, and a visual indicator to indicate the passage of radio frequency current, the failure of either of which shall not disconnect the aerial circuit.
5. Automatic Transmission.---(1) A device automatic keying shall be provided as part of the radio telegraph installation for lifeboats which when switched into circuit with the transmitter, shall be capable of automatically :-
(a) sending the alarm signal specified in sub-paragraph (2) and immediately thereafter stopping and opening the keying circuit unless reset or re-wound; and
(b)(i) sending the distress call specified in sub-paragraph (3) in such manner that if the device is used without attention the transmission will be repeated once every twelve minutes; and
(ii) switching off the electrical energy to the transmitter in the silent interval between such transmission and, so far as is necessary for the protection of the transmitter automatically delaying the application of electrical energy after the device has been switched on.
(2) The alarm signal shall consist of twelve four second dashes separated by one second spaces, the length of the dashes and spaces being maintained within a tolerance of plus or minus 0.2 second.
(3) The distress call shall consist of the following signals in the following order namely :-
(a) the radio telegram distress signal SOS (3 times) ;
(b) the more characters for the word DE;
(c) the more characters for the lifeboat's call sign (3 times); and
(d) two long dashes each of 10 to 15 seconds duration separated by a space of between 0.5 and 1.5 seconds. The total duration of the distress call shall not be more than 90 seconds.
(4) Means shall be provided to ensure that, when the distress signal is sent, the transmission being at the commencement of the signal within 40 seconds after the device for automatic keying has been switched into circuit.
(5) The characters of the distress call specified in sub-paragraph (3) shall be keyed at 10 to 16 words per minute.
(6) Receiver.—(1) The equipment shall include a receiver capable of receiving A1, A2 and A2H emission. The receiver shall also be capable of receiving on a spot frequency of 2182 KHz for reception of A3, and A3H emissions.
(2) The receiver shall be tunable over the frequency ranges 488 to 513 and 8320 to 8745 KHz.
(3) The receiver shall be fitted with a manual gain control.
(4) Headphones which are whether tight shall be provided and shall be shrouded to exclude noise.
(5) The receiver shall comply with the requirements of sub-paragraphs (6) to (9) inclusive when tested in the following manner :-
(a) An artificial aerial shall be used and shall consist of 40 ohm resistance in series with a 2 microhnry inductance and 100 picofarad capacitance;
(b) A type A2 signal shall, unless otherwise specified, be modulated to a depth of 30 per cent at 100 Hz.
(c) The standard audio-frequency output shall be one milli-watt into a resistance substantially equal to the modulus of the impedance of the telephone receivers at 100 Hz.
(6) The selectivity preceding the final detector of the receiver shall comply with the following requirements, namely :-
(a) when tuned to a frequency to 500 KHz and 8364 KHz :-
(i) not more than 6 decibels discrimination shall be obtained at frequencies removed from tune by 1 KHz;
(ii) at least 6 decibels discrimination shall be obtained at frequencies removed from tune by 4 KHz;
(iii) at least 30 decibels discrimination shall be obtained at frequencies removed from tune by 15 KHz;
(iv) at least 60 decibels discrimination shall be obtained at frequencies removed from tune by 40 KHz;
(b) when tuned to a frequency of 2182 KHz.--
(i) not more than 60 decibels discrimination shall be obtained at frequencies removed from tune by 3 KHz;
(ii) at least 30 decibels discrimination shall be obtained at frequencies removed from tune by 15 KHz;
(c) in the case of superheterodyne receiver, the image response ration shall be at least 20 decibels.
(7) The sensitivity of the receiver shall be such that the standard audio-frequency output is obtained with an input not exceeding the following level :-
TABLE
_________________________________________________________________________________________
Frequencies Maximum Maximum
input for A1 input for
emissions A2 emissions
_________________________________________________________________________________________
488 to 513 KHz 30 decibels above 40 decibels
1 micro-volt above 1 microvolt
_________________________________________________________________________________________
8320 to 8745 KHz 30 decibels above 40 decibels above
1micro-volt 1micorvolt
_________________________________________________________________________________________
2182 KHz ---- 30 decibels above
above 1 microvolt
_________________________________________________________________________________________
(8)(a) The signal noise ratio shall, with the inputs and emissions respectively specified in sub-paragraph (7) and with the rotary converter or vibrator running, be not less than :--
(i) 15 decibels on a frequency of 500 KHz;
(ii) 25 decibels on a frequency of 8364 KHz; or
(iii) 20 decibels on a frequency of 2182 KHz.
(8)(b) The fidelity of the receiver shall be such that the change in level of the audio-frequency output shall when the level and modulation depth in the input signal is kept constant, be less than 8 decibels as the modulation of input signal is varied continuously :--
(i) from 300 KHz to 1500 Hz for A2 and A2H emission; and
(ii) from 250 Hz to 3000 Hz for A3 and A3H emission. For this purpose, the input signal m have any level and depth of modulation, provided that the output of the receiver does not exceed the standard audio-frequency output.
9. Connection with the Ships Mains.--- Any connections of the equipment with ship's main source of energy shall be so provided as not to interfere with the launching of the lifeboat.
PART – II
PORTABLE RADIO EQUIPMENT FOR SURVIVAL CRAFT
1. General.---(1) The portable radio equipment for survival crafts (hereinafter in this Part referred to as "the equipment") shall include a hand generator, a transmitter, a receiver and all other apparatus necessary for the operation of the equipment.
(2) Simple instructions for the operation of the equipment on the frequencies specified in sub-paragraph (1) of paragraph 5 shall be affixed in clear and permanent form, to the equipment.
(3) The equipment shall bear a removable plate on which shall be indicated in clear and permanent form the call sign of the lifeboats in letters and numbers and in more characters.
(4) For the purposes of the Third Schedule the equipment shall be deemed to be class X equipment. The immersion test specified in sub-paragraph (7) of paragraph 3 of the said Schedule shall be applied to the equipment when packed in the manner in which it will be stored on board ship.
2. Design and Construction.--- The equipment shall be so designed and constructed that---
(1) the entire equipment is contained in a single unit : provided that the mast referred to in sub-paragraph (2) of paragraph 3 may be attached to the single unit ; and
(2) an unskilled person can erect the aerial system without difficulty and by simple operation and automatic means, transmit the radiotelegraph signals specified in sub-paragraph (4)(a) of paragraph 5.
(3) the equipment is provided with handless and is readily portable by one person;
(4) it is watertight and capable of floating in water;
(5) it can be lowered into the sea or lifeboat from the boat deck ;
(6) it can be lowered into the sea or lifeboat from the boat deck ;
(7) it can be clamped to a lifeboat ;
(8) the number of manual controls are kept to the minimum required to meet the requirements of this Part of this Schedule, but include---
(a) send-receive switching;
(b) a switch for changing transmission from 500 KHz to 2182 KHz and from 2182 KHz to 8364 KHz and vice-versa;
(c) a switch position so that the transmitter valve filaments can be energized continuously whilst the receiver is energized;
(d) a single control of receiver gain;
(e) a more key of approved design fitted to the equipment in an approved position;
(9) all manual controls are of such size as to permit normal adjustments to be made by a person wearing thick gloves; and
(10) the operation of manual controls is not impeded by, and does not impede, the hand generation of electrical energy.
3. Aerial and Earth System---The equipment shall include---
(1) a single-wire aerial consisting of not less than 9.2 metres of high conductivity stranded or braided wire so fitted as to be capable of being supported from the lifeboat most without the use of top-mast at the maximum practicable height;
(2) a collapsible stayed mast capable of being easily and quickly installed in a lifeboat and of supporting the aerial at a height of at least 4.9 metres above the sea when the base of the mast is resting on the bottom of any lifeboat in which it is intended to be used; and
(3) an earth wire of high conductivity firmly connected to the equipment and loaded in such manner that the wire will sink when placed overboard.
4. Hand Generator.—(1) The hand generator shall be of such design and construction that when the handle of the generator is rotated at any speed within the normal range of handle speeds sufficient electrical energy shall be generated ---
(a) to enable the transmitter to comply with the requirements of sub-paragraph (4)(a) of paragraph 5; and
(b) the transmitter shall comply with the requirements of sub-paragraph (4)(a) of paragraph 5 with a torque speed at the handle of not more than 550 expressed in grammes/centimeters multiplied by revolutions per minute; and
(c) an indicator lamp will be lit.
Explanation.---In this Part the expression "normal range of handle speeds" in relation to a generator means the range of speeds extending from the minimum speed at which the generator enables the transmitter forming part of the same equipment to comply with the requirements of sub-paragraph (4)(c) of paragraph 5 to a speed at least 40 per cent greater than that speed.
(2) The hand generator shall be of such design and construction that ---
(a) it can be operated by :---
(i) one person; or
(ii) two persons simultaneously ;
(b) the handles cannot be rotated in the wrong direction.
5. Transmitter.---(1) The transmitter shall be capable of ---
(a) sending continuously, but not simultaneously, class A2 and A2H emissions on the frequencies of 500 KHz and 8364 KHz and class A3 and A#H emissions on 2182 KHs---
(i) by manual operation at all speeds upto 16 bauds ; and
(ii) by automatic means at the speeds specified in sub-paragraph (4) (a).
(b) maintaining over the normal range of handle speeds throughout every transmission a frequency tolerance---
(i) of plus or minus 0.5 per cent on a frequency of 500 KHz;
(ii) of plus or minus 0.02 per cent on a frequency of 8364 KHz; without adjustment of any control, and notwithstanding any variations of the impedance of the aerial or artificial aerial to which it is connected; and
(c) operating on full power, when the aerial system or artificial aerial has been connected and the necessary controls have been adjusted, within 30 seconds after the generation of electrical energy has commenced.
(2)(a) when A2 and A2H emissions are being transmitted, the carrier wave shall be modulated to a depth of 100m per cent by wave of rectangular character so that the carrier wave is switched on for not less than 30 per cent, and not more than 50 per cent of a modulation cycle.
(b) when A3 and A3H emissions are being transmitted, full modulation of the carrier wave by speech shall be possible with out being over modulated.
(3) The note frequency shall not be less than 450 Hz or more than 1350 Hz.
(4)(a) the signal to be sent by the automatic means referred to in sub-paragraph (1)(a)(ii)---
(i) when the transmission is on a frequency of 500 KHz shall consist of the alarm signal of twelve four second dashes separated by one-second spaces, followed by the distress signal repeated three times, and two long dashes each of 10 to 15 seconds duration separated by a space of between 0.5 and 1.5 seconds; and
(ii) when the transmission is on a frequency of 8.364 KHz shall include the distress signal repeated three times, and two long dashes each of 10 to 15 seconds duration separated by a space of between 0.5 and 1.5 seconds.
(b) Over the normal range of handle speeds ---
(i) the speed of the automatic transmission of the distress signal shall not be less than 8 and not more than 15 words a minute
(ii) the tolerance in the timing of the dashes of the alarm signal shall not be more than plus or minus 0.2 seconds.
(c) The automatic transmission shall cease and open the keying circuit after one complete transmission unless the mechanism is re-set or re-wound.
(d) Means shall be provided---
(i) to ensure that the transmission begins at the commencement of the signal;
(ii) to indicate to the operator that the mechanism should be re-set or re-wound.
(e) The mean power developed by the transmitter in the load during a marking period, shall---
(i) on frequency of 500 KHz be not less than [(3.81 log 10C0 – 5.5] watts, C being the capacitance of the artificial aerial in picofarads, when measured, with an artificial aerial consisting of a 15 ohm non-inductive resistor in series with a capacitor having any value between a minimum of 10 picofarads less than that of the aerial referred to in sub-paragraph (1) of paragraph 3 and 150 picofamds, and not less than 3.5 watts when measured with an artificial aerial consisting of a 30 ohm non-inductive resistor in series with a capacitor having any value between 200 and 300 picofarads
(ii) on a frequency of 8364 KHz be not less than 1.5 watts when measured with an artificial aerial consisting of 20 ohm non-inductive resistor in series with a capacitor having an value between 70 and 100 picofarads.
(ii) On a frequency of 2182 KHz be not less than 1.5 watts when measure with an artificial aerial consisting of a 15 ohm non-inductive resistor in series with a capacitor having any value between a minimum of 10 picofarads less than that of the aerial referred to in sub-paragraph (i) of paragraph 3 and a maximum of 110 picofarads and not less than 3.5 watts when measured with an artificial aerial consisting of 30 ohm non-inductive resistor in series with a capacitor having any and every value between 300 and 400 picofarads.
(f) The aerial circuit shall include ---
(i) a tuning control suitable for use with all types of aerial provided; and
(ii) a tuning indicator, the failure of which shall not disconnect the aerial circuit..
(g) There shall be provided ---
(i) an artificial aerial within the equipment suitable for testing the transmitter on full power;
(ii) means for testing the facilities for automatic transmission without the generation of radio-frequency energy.
(5) The facility or transmission on the frequency of 2182 KHz shall include a device for the generation of radio-telephone alarm signal specified in Part II of the Second Scheduleexcept that the duration of the radio-telephone alarm signal may be determined by manual control.
(6) The transmitter shall be so designed and constructed that when it is transmitting and adjusted for maximum power the aerial may be disconnected or the output short-circuit in either case without damage being caused to any part of the equipment.
6. Receiver.---(1) The receiver shall be a fixed tune receiver which shall be capable of receiving A2 emissions over the frequency band 490 to 510 KHz when used with headphones. The receiver shall also be capable of receiving A3 and A3 H missions on the radio-telephone distress frequency of 2182 KHz.
(2) Headphones which are shrouded to exclude external noises shall be provided and shall be permanently attached to the receiver.
(3) The receiver shall comply with the requirements of sub-paragraph (4) when tested in the following manner :-
(a) artificial aerials shall be used and shall consist of either ---
(i) a 15 ohm non-conductive resistor in series with a capacitor having any value between a minimum of 10 picofarads; less than that of the aerial referred to in sub-paragraph (1) of paragraph 3 and a maximum of 110 picofarads; or
(ii) a 30 ohm-conductive resistor in series with a capacitor of any value within the range 200 to 400 picofarads;
(b) the signals used shall be type A2 signals modulated to a depth of 30 per cent at 1000 Hz.
(4) Over the normal range of handle speeds---
(a) the standard audio-frequency output of the receiver into a resistance substantially equal to the modulus of the impedance of the telephone receivers at 1,000 Hz shall be one milliwatt.
(b) the selectivity preceding the final detector of the receiver shall comply with the following Table :-
TABLE
________________________________________________________________________________________
When operating on frequency 500 KHz 2182 KHz
________________________________________________________________________________________
response to the uniform 490-510 KHz 2177-2187 KHz
within 6 decibels over the range of
_______________________________________________________________________________________
at least 40 decibels discrimi- below 470 KHz below 2147 KHz
nation relative to the and above 530 and above 2217
response of mid band to be KHz. KHz.
obtained at all frequencies.
________________________________________________________________________________________
(c) the audio-frequency response of the receiver shall be inform to within 8 decibels over the range of modulation frequencies 400 to 3000 Hz and shall substantially fall for frequencies outside the ranges ;
(d) the standard output specified in sub-paragraph (a) shall be obtained with a test signal input not exceeding 40 decibels above one microvolt on a frequency of 500 KHz and not exceeding 30 decibels above one microvolt on a frequency of 2182 KHz.
(e) with the test signal specified in sub-paragraph (d) the signal/noise radio shall be at least 15 decibels.
[ See rules 11(3) and 15(3)]
RANGE OF RADIO TELEGRAPH TRANSMITTERS
1. For the purposes of this Schedule the normal range of a radio telegraph transmitter when determined by calculation on a frequency of 500 KHz shall be calculated in the manner specified in paragraph 2 or, as the case may be paragraph 3.
2. In the case of transmitting aerials of the 'L' and "t" types the product of the root mean square current in amperes at the base of the main aerial and the maximum height in metres of the aerial measured from the load link mark indicating the greatest depth to which the ship may at any time or place be submerged in accordance with the Merchant shipping (Load Line) Rules, 1979, or if there is no such mark on the ship from the mean level of the surface of the water in which the ship is afloat, shall be converted to miles in accordance with the following Table :-
TABLE
_________________________________________________________________________________________
Product in metro-amperes Equivalent in miles
_________________________________________________________________________________________
128 . . . . . . . . 200
102 . . . . . . . . 175
76 . . . . . . . . 150
58 . . . . . . . . 125
45 . . . . . . . . 100
34 . . . . . . . . 75
10 . . . . . . . . 25
_________________________________________________________________________________________
3.(1) In the case of all types of transmitting aerials except 'L' and 'T' types, the product of … (Ie) the effective radiation current in amperes and (He) the effective height in metres of the aerial shall be calculated and converted to miles in accordance with the following Table :-
TABLE
_________________________________________________________________________________________
Product in metro-amperes Equivalent in miles
_________________________________________________________________________________________
54 . . . . . . . . 175
44 . . . . . . . . 150
21 . . . . . . . . 100
15 . . . . . . . . 75
5 . . 25 _________________________________________________________________________________________
(2)(a) The effective radiation current (Le) shall be obtained by multiplying the root mean square current in amperes fed into the aerial system by a factor which shall be determined by the ratio of the radiation capacitance (Cr) to the total measured capacitance (Ct).
(b) The radiation capacitance (Cr) shall be obtained from the product of the radiation length (Lr) and the capacitance per unit length as given in the following Table :-
_________________________________________________________________________________________
Radiation length (Lr) PF per metre
Diameter of aerial
________________________________________________________________________________________
25 . . . . . . 15.4
35 . . . . . . 14.0
50 . . . . . . 12.9
70 . . . . . . 11.9
100 . . . . . . 11.1
200 . . . . . . 9.8
400 . . . . . . 8.7
600 . . . . . . 8.2
800 . . . . . . 7.2
1500 . . . . . . 7.2
3000 . . . . . . 6.6
6000 . . . . . . 6.0
10000 . . . . . . 5.7
_________________________________________________________________________________________
(c) The radiation length shall be as follows :-
(i) Single vertical aerial without capacitive loading Radiation Length (Lr) = Measured length of aerial metres.
(ii) Single vertical aerial with top capacitive loading Radiation Length (Lr) = Measured length on aerial = twice the diameter of loading structure in metres.
(iii) Other types of aerial---
Radiation length (Lr) = Total length of conductor (Vertical and horizontal)
(d) The radiation capacitance of "n" number of similar vertical aerials jointed in parallel shall be taken to be "N" times the radiation capacitance of one, provided the spacing between them is greater than Lr
4
(e) The total capacitance (Ct) of the aerial shall be obtained by measurement.
(3) The effective height of the aerial (He) shall be obtained by measurement of the vertical distance from the load line mark indicating the greatest depth to which the ship may at any time or place be submerged in accordance with the Merchant Shipping (Load Lines) Rules, 1979 or if there is such mark on the ship, from the mean level of the surface of the water in which the ship is afloat, to the base of the aerial, plus half the radiation length (Lr) of the aerial or its physical height whichever is the smaller.
( See rules 14 and 24 )
Tools, Measuring Instruments, Spares parts etc.
PART - I
RADIO TELEGRAPH SHIPS
Tools
1 Contact burnisher;
1 6, in smooth file;
1 joining knife;
1 pair 7 in. wireman's insulated pliers;
1 pair 6 in. long nose pliers with side cutters;
1 insulated screwdriver. not less than 8 in. in length with ¼ in blade.
1 insulated grab screwdriver with 1/8 in., blade ;
1 watch screwdriver with 1/16 in blade;
1 set of spanners, sizes 0.2, 4 and 6 B.A.;
1 spanner adjustable to 1 in nuts.
*1 ¼ in. hand drill;
* 1 set of high speed twist drills, sizes 3/16 in., 26.34 and 44;
1 clamp vice;
2 electric soldering irons to suit the ship's voltage, one with a power consumption of about 60 watts and the other with a power consumption of not more than 25 watts;
1 dusting bruch;
1 ½ 1b. ball-pane hammer :
1 hacksaw and blades
1 tool box or compartment for containing the foregoing tools and capable of being locked.
*1 Jointing Knife;
*1 pair 6 in. long nose pliers with side cutters;
*1 insulated screw driver, not less than 8 in.
in length, with ¼ in. blade.
*Note 1 --- These items need not in ship other than those engaged on International voyages.
*Note 2 –These items are to be provided with spares for the Fixed Radio equipment in a Motor Lifeboat and located in the Radio cabine of the lifeboat.
2 Hydrometers;
1 dipping fahreheit thermometers;
An ammeter capable of measuring direct current from 1 milliampere to 500 milliamperes; and voltmeter capable of measuring alternating and direct current voltage from 1 volt to 1000 volts: and an ohm-meter capable of measuring resistance from 10 ohms and 20,000 ohms; provided that a measuring instrument in which the requirements for an ammeter, a voltmeter, and an ohm-meter specified above are combined may be substituted for the said instruments.
SPARE PARTS AND SPARE EQUIPMENT
1 set of brushes for each machine installed;
2 cartridges for each cartridge fuse in use;
1 main aerial made up (wire only);
50 per cent of the number of insulators in use (excluding lead-in insulators)
100 per cent of the number of shackles and thimbles in use;
12 bull dog grips to suit the aerial wire;
1 set of telephone and leads (with plugs if used) for each type of telephones and lead in use;
1 valve for each two of the first six of each type of valve in use and them 1 valve for each additional 3 valves part of 3 valves of that type in use;
3 vibrators for each type of vibrator in use;
1 indicator lamp for each indictor lamp in use;
1 emergency lamp;
1 charging mat if a mat type charging unit is in use
2 charging lamps for each type of charging lamp in use
1 rectifier if a rectifier-type charging unit is in use.
MISCELLANEOUS ITEMS
4 Ozs petroleum jelly;
3 sheets glass paper;
8 Ozs resin-cored solder;
4 Ozs insulating tape;
½ pint lubricating oil (where a machine lubricated with oil forms part of the installation) otherwise, 2 ozs lubricating oil for general purposes;
½ 1b grease suitable for machine in use;
10 yards of each rating of fuse wire, 1 ampere, 5 ampere and 15 ampere;
1 length of aerial wire equal to the length of the emergency aerial plus 10 feet (uncut);
4 Ozs copper binding wire;
6 yards flexible wire (5 amperes) for adjustable connections;
4 Ozs trichlorethylene for contact cleaning.
PART - II
RADIO TELEPHONE SHIPS
[See rule 24(f)]
Tools :-
1 6 in. smooth file;
1 jointing knife;
1 Insulated screwdriver, not less than 8 in.
in length with ¼ in. blade;
1 Spanner adjustable to 1 in. gap;
1 Hacksaw and 6 blades;
1 Watch Screwdriver with 1/16 in. blade;
1 Dusting brush.
MEASURING INSTRUMENTS
2. Hydrometers.
Spare parts and spare equipments :
50 per cent of the number of insulators
3 Vibrators for each type of vibrator in use.
1 Indicator lamp for each indicator lamp in use.
1 Charging mat if a mat-type charging unit is in use.
Miscellaneous items :
10 yards of each rating of fuse wire, 1 amp, 5 amps and 15 amps.
( See rules 15, 17 and 18 )
RADIO TELEGRAPH AUTO-ALARM EQUIPMENT
1. General---(1) The auto-alarm shall---
(a) include a receiver, selector, a test signal generator and an audible alarm system ;
(b) in the absence of interference of any kind be capable without manual adjustment of give ing audible warning of the receipt of a radio-telegraph alarm signal transmitter on a frequency of 500 KHz and consisting of a series of 12 consecutive dashes, each with a duration of 4 seconds and separated by internals of one second in each case subject ot the tolerance specified in paragraph 3 :
Provided that the strength of the signal at the receiver input is greater than 100 micro volts and less than one volt.
(c) be capable of being rapidly connected with the main aerial referred to in rule 11 or to an efficient aerial;
(d) comply with the requirements of this Schedule notwithstanding variations of the supply voltage of---
(i) plus 5 per cent or minus 10 per cent if the equipment is operated from the emergency source of electrical energy required by sub-rule (2) of rule 13 or from batteries ; or
(ii) plus or minus 10 per cent of the equipment is operated from the main source of electrical energy required by sub-rule (1) of the said rule.
(2) The receiver, selector and test signal generator shall be installed in radio-telegraph room.
(3) The receiver shall have provision for head phone and loudspeaker reception. The loudspeaker shall be rendered inoperative when reception is being made by headphone.
(4) The auto-alarm shall include a manual resetting device to enable the selector to be re-set after the audible alarm system has been actuated.
2. Receiver.---(1) The receiver forming part of the auto-alarm shall be capable of reception of class A2, A2H and emissions having a note frequency between 400 and 1400 Hz, the carrier wave being in the frequency range 492 Khz to 508 KHz.
(2) All tuning controls and gain controls which affect the operation of the receiver as part of the auto-alarm shall be preset and shall not be capable of operation from the outside of the auto-alarm.
(3) The receiver shall comply with the requirements of sub-paragraphs (4) to (7) inclusive when tested in the following manner, except where another method of testing is specified in the said sub-paragraph---
(a) an artificial aerial shall be used for the test and shall consist of 10 ohm resister in series with a capacitor having any value between 300 and 750 picofards;
(b) type A2 signals used in the test shall be modulated to a depth of 70 per cent and shall have note frequency of 400 Hz.
(4) The selectivity of the receiver shall be such that.---
(a) the radio-frequency response is uniform to within 3 decibels in a frequency range 496 to 504 KHz;
(b) the total variation of audio-frequency response is not more than 3 decibels in the case of note frequencies in the range 400 to 1400 Hz;
(c) the audio-frequency response falls rapidly in the case of note frequencies below 400 Hz. and above 1400 Hz;
(d) the auto-alarm gives response to an alarm signal of a frequency of 500 KHz and input level of 42 decibels above one microvolt, in the presence of another signal having the following characteristics :-
_________________________________________________________________________________________
Type of Modulation Modulation Carrier Input
emission frequency depth frequency level
_________________________________________________________________________________________
A1 --- ---
A2 Any audio 70 per cent Below 475 120 dB
frequency KHz and above one
in the range above 525 microvolt
50 Hz to KHz
1400 Hz.
________________________________________________________________________________________
(5)(a) The sensitivity of the receiver shall for the purpose of this paragraph be taken to be the minimum input level of the test alarm signal injected at a frequency of 500 KHz which will operate the selector. The sensitivity of the receiver shall be such that the selector will operate by the injection of an alarm signal from the test signal forming part of the auto-alarm.
(b) The receiver shall be provided with an automatic gain control which shall--
(i) during periods when the selector is continuously in operation, steadily reduce the sensitivity of the receiver at a rate within the range 7.5 to 15 decibels per minute in the case of a range of sensitivity of 40 to 80 decibels above one microvolt notwithstanding that the input level of an injected signal is at any level above the minimum necessary to operate the selector.
(ii) during period when the selector is not continuously in operation, steadily increase the sensitivity of the receiver to a maximum level of between 35 and 40 decibels above one microvolt at a rate of increase within the range of 30 to 60 decibels per minute in the case of a range of sensitivity of 40 to 80 decibels above one microvolt, notwithstanding that the input level of an injected signal is at any level below the level corresponding to the threshold selector release.
(6) The automatic gain control when more interference in simulated by continuous keying of a test signal of a frequency of 500 KHz and an input level of 100 decibels above one microvolt with a mark-to-space ration of 19 to 1, and variation of frequency of interruption is obtained by varying the speed of transmission, shall be such that ---
(a) when such test signal produce three interruptions per second, the sensitivity of the receiver is not reduced below that necessary for the reception of a signal of an input level of 40 recibels above one microvolt ; and
(b) when the speed of such test signal is arranged so that there are three interruptions per period of 2 seconds the sensitivity of the receiver is so reduced after operating for a period of 15 minutes that a signal of at least 70 decibels above one microvolt is required to operate the selector.
(7) If, in addition to the automatic gain control, a preset manual control of receiver gain is provided the range of sensitivity variations provided by that control shall be not more than 10 decibels.
(8) The receiver shall be such that the auto-alarm will respond to a test alarm signal transmitted on any frequency in the range 496 KHz to 504 and at an input level of 50 decibels above one microvolt in the presence of an interfering signal with the following characteristics--_________________________________________________________________________________________
Type of Depth of Modulation Input Speed
Signal modulation frequency level transmission
________________________________________________________________________________________
Type A2 7 per cent 400 Hz 120 decibels 15-40
1400 Hz above one words per
microvolt minute
________________________________________________________________________________________
(9) The receiver shall be such that it will not operate the selector upon the simultaneous injection of any two continuous carrier waves, of which the frequency difference sum falls within the range 496 KHz to 504 KHz, being waves with the following characteristics :-
_________________________________________________________________________________________
Frequency Input Level Modulation
_________________________________________________________________________________________
Outside the range 120 decibels above One unmodulated the other modulated
475 KHz to one microvolt to a depth of 70 per cent at any audio
525 KHz frequency in the range 400 Hz Hz.
to 1400
_________________________________________________________________________________________
(10)(a)The receiver shall not in normal service produce a field exceeding 0.1 microvolt per metre when measured at a distance of one mile from the receiver, unless the test signal generator is in operation.
(b) the receiver shall be deemed to comply with the requirements of sub-paragraph (a) of this paragraph if, when---
(i) the receiver is placed centrally in a screened earthed enclosure of dimensions at least 1.83 metres cube;
(ii) the earth terminal of the receiver is connected to the inside of the screen;
(iii) the aerial terminal of the receiver is connected through an un-screened search coil situated within the said enclosure and of dimensions 30.5 centimetres square and an unscreened to a resistive measuring instrument mounted outside the enclosure and having its other terminal earthed; and
(iv) the receiver is energized, the power measured by the measuring instrument does not exceed 4 X 10 – 10 watts whatever the resistance of the measuring instrument or the adjustment of the receiver and notwithstanding that the search coil is short circuited or moved in any way without approaching within 15.2 centimetres of the receiver case.
3. Selector.--- (1) The selector in conjunction with the receiver shall be capable of :-
(a) accepting---
(i) dashes of a duration within the tolerance 3.5 to 6.0 seconds;
(ii) spaces between dashes, being spaces of a duration within the tolerance 0.01 to 1.5 seconds; and
(b) rejecting---
(i) dashes of a duration of less than 3.4 seconds;
(ii) dashes of a duration of more than 6.2 seconds; and
(iii) spaces between dashes, being spaces of a duration of more than 1.6 seconds.
(2) The selector, after accepting three or four consecutive dashes of the alarm signal, shall actuate the audible alarm system. The fourth consecutive dash may be of any duration greater than 3.5 seconds.
(3) Any timing controls provided as part of the selector shall be preset and shall not be capable of being operated from the outside of the equipment.
4. Test signal generator.---(1) The test signal generator shall be capable of :-
(a) generating for purposes, of test a signal with the following characteristics :
(i) frequency – within plus or minus 3 KHz of 500 Khz
(ii) type of wave – A2
(iii) Depth of modulation---within the range of 70 to 100 per cent
(iv) Modulation of frequency---within the range of 400 to 1400 Hz;
(v) Input level equivalent to a voltage modulated to a depth of 70 per cent within the range 37 to 43 decibels above one microvolt in series with the artificial aerial; and
(b) injecting into the receiver the alarm signal specified in paragraph 1(b) within the tolerance specified in sub-paragraph (1)(a) of paragraph 3 and the characteristics specified in the foregoing provisions of this paragraph both by means of :-
(i) a manual key of a non-locking type, and
(ii) the automatic keying device specified in Part V of the First Schedule to these rules.
(2) The methods of injection shall be such that the test alarm will not operate the audible alarm system when the aerial is disconnected.
(3) The test signal generator shall be so designed and constructed that the input level of the signal specified in sub-paragraph (1)(a) can be increased by approximately 20 decibels by means of a non-locking switch.
5. Audible alarm system.---(1) The audible alarm system shall consist of three alarm bells installed respectively in a radio-telegraph room on the bridge and in the sleeping room of a radio officer. the bells shall be operated from the source of electrical energy required by sub-rule (2) of rule 13 by means of a power circuit taken from an unfused circuit, and so fused that the efficiency of the audible alarm system will not be affected by the rupture of any fuse other than a fuse forming part of that system. the power circuit shall be controlled by a locking switch situated on or near to the receiving forming part of the auto alarm, and clearly and permanently marked to indicate its purpose.
(2) Subject to the provisions of sub-paragraph (3), the alarm bells shall, wherever the auto alarm is in operation as such, give an alarm.
(a) when actuated by the selector; and
(b) within 15 seconds after any failure for 9 seconds (subject to tolerance of plus or minus 6 seconds) of---
(i) the direct-current voltage feeding the anode of any valve of the receiver forming part of the auto-alarm, if the receiver is not provided with a vibrator;
(ii) any vibrator forming part of the receiver;
(iii) a circuit of a filament of any directly heated valve forming part of the receiver if it is operated from the main source of electrical energy required by sub-rule (1) of rule 13, and
(iv) any continuously rotating mechanism forming part of a selector operated from the said main source of electrical energy ;
(c) within 15 seconds after the failure of ---
(i) a circuit of a filament of a directly heated valve forming part of the receiver if it is operated from batteries;
(ii) any continuously rotating mechanism forming part of a selector operated from batteries.
(3) A device shall be provided which will enable the bells situated on the bridge to be disconnected from the aforesaid power circuit. The device may include means for so disconnecting the bell situated in the radio officers sleeping room. The device shall be non-locking and shall not be capable of disconnecting the bell in the radio telegraph room. The device shall be clearly and permanently marked to indicate its purpose.
6. Field test.---If the auto-alarm is in operation for 28 days in connection with an aerial having an effective height of not less than 10 metres and situated at any point within three miles from the coasts of India, the auto-alarm shall not be actuated during that period by signals other than---
(a) signals locally generated to test the auto-alarm ; and
(b) signals within the tolerance specified in sub-paragraph 1(a) of paragraph 3.
( See rule 17 )
TABLE OF WATCH HOURS
Ship of class I
(i) 000 hours to 0400 hours (Ship's time)
(ii) 0800 hours to 1200 hours (Ship's time)
(iii) 1600 hours to 1800 hours (Ship's time)
(iv) 2000 hours to 2200 hours (Ship's time)
(iv) four more hours which may be
decided by the shipmaster at his
discretion depending upon
propagation conditions, traffic
requirements and demand for
meeting essential communication
needs of the ship.
Ship of class II, III and IV
(i) 0300 hours to 1200 hours (Ship's time)
(ii) 1930 hours to 2130 hours (Ship's time)
(iii) two more hours which may be
decided by the shipmaster at his
discretion depending upon
propagation conditions, traffic
requirements and demand for
meeting essential communication
needs of the ship.
(See rule 20 )
FORM OF RADIO TELEGRAPH LOG
PART-I
________________________________________________________________________________________
Name of Ship Official Number and International Call Sig. Port of Registry Gross Tonnage ______________________________________________________________________________________
_________________________________________________________________________________________
Name of Company operating the Radio Service ………………………….
_________________________________________________________________________________________
Port at which Nature of the voyage Port at which and
which the date of employment date when voyage
when voyage terminated
commenced
________________________________________________________________________________________
Date ……………….
Port………………..
_________________________________________________________________________________________
Delivered to the Shipping Master of the Mercantile Marine Department at the port of ………………………………. on the …………………… day of ……………….. 19………………… together with Radio telegraph Log Part II, Serial Number ………….
……………………… Master
…………………………… Shipping Master……………………………… Address.
SECTION A- PARTICULARS OF RADIO STAFF
_________________________________________________________________________________________
Name Home Address Certificate Number and Class ________________________________________________________________________________________
SECTION B – PARTICULARS OF BATTERIES ON BOARD
_______________________________________________________________________________________
Battery Number Number of Cells Type Date Supplied Voltage and Purposes for which
ampere-hour used.
capacity
_______________________________________________________________________________________
_______________________________________________________________________________________
THE TENTH SCHEDULE
(See rule 28)
FORM OF RADIO TELEPHONE LOG
RADIO TELEPHONE LOG
________________________________________________________________________________________
Name of ship Official Number and call letters Port of Registry Gross Tonnage
_______________________________________________________________________________________
________________________________________________________________________________________
Name of Company operating the Radio Service……………………………….
period covered by Log-From……………………. to ……………………………..
Delivered to the Shipping Master of the Mercantile Marine Department at the Port of ………………………………. on the day of ……………. 19………….
Countersigned
………………….. Master
…………………………. Shipping Master……………………….. Address
_________________________________________________________________________________________
SECTION A – PARTICULARS OF RADIO TELEPHONE OPERATORS
_________________________________________________________________________________________
Name Home Address Certificate number and Class
________________________________________________________________________________________
S.S. …………………..
M.V……………………
SECTION B – DIARY OF THE RADIO TELEPHONE SERVICE
_________________________________________________________________________________________
Date and time (GMT) Station from Station to Frequency used Record of working as
prescribed by rule 30
_________________________________________________________________________________________
________________________________________________________________________________________
SECTION C – DAILY EXAMINATION OF BATTERIES
________________________________________________________________________________________
Date Battery Number Voltage off load Voltage on load Remarks
________________________________________________________________________________________
Date Battery Specific Gravity Remarks Battery Specific Gravity Remarks
number as measured number as measured
and Cell ______________ and Cell _________________
Number Before After Number Before After
Charge Charge Charge Charge
________________________________________________________________________________________
_______________________________________________________________________________________
RADIO TELEGRAPH LOG
PART II
______________________________________________________________________________________
Name of Ship Official number and International Call Sign. Port of Registry Gross Tonnage
______________________________________________________________________________________
______________________________________________________________________________________
Serial Number ……………………… from…………….. to………………………
Name of Company operating the Radio Service………………………………...
S.S………………………..
M.V……………………….
DIARY OF THE RADIO TELEGRAPH SERVICE
______________________________________________________________________________________
From Station to Full Details of Call Signals and Distress Working Frequency
as prescribed by rule 22
_____________________________________________________________________________________
_______________________________________________________________________________________
[ No. SW/5-MSR(9)/74-MA]
S.K. SHARMA
Under Secy.
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