I, THE GOVERNOR-GENERAL in and over the Commonwealth of Australia, acting with the advice of the Federal Executive Council, hereby make the following Regulations under the Navigation Act 1912-1967.
Dated this twentieth day of March, 1968.
CASEY
Governor-General.
By His Excellency’s Command,
(Sgd.) Ian Sinclair
Minister of State for Shipping and Transport.
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NAVIGATION (DIRECTION-FINDERS) REGULATIONS.
Citation.
These Regulations may be cited as the Navigation (Direction-Finders) Regulations.
Repeal.
The Navigation (Direction-Finders) Regulations (being Statutory Rules 1959, No. 48) are repealed.
Interpretation.
3.—(1.) In these Regulations, unless the contrary intention appears—
“mile” means nautical mile;
“radio surveyor” means a person, being a person skilled with regard to radio navigational aids, appointed under section 190 of the Navigation Act 1912-1967 to be a surveyor;
“ship” means a ship of not less than one thousand six hundred tons which is—
(a) registered in Australia;
(b) engaged in the coasting trade; or
(c) engaged in the carriage of passengers from a port in Australia to a port outside Australia,
but does not include—
(d) a Safety Convention ship in respect of which there is in force a valid Safety Convention certificate showing that the ship—
(i) complies with such of the requirements of the Safety Convention as relate to radio installations and radio navigational aids; or
(ii) is wholly exempt from those requirements or is partly exempt and complies with those requirements to the extent to which she is not exempt;
(e) a passenger ship of less than four thousand tons not engaged on international voyages;
(f) a cargo ship of less than six thousand tons not engaged on international voyages;
(g) a river and bay ship;
(h) a sailing ship; or
(i) a fishing boat.
(2.) In these Regulations—
(a) a reference to the tonnage of a ship shall be read as a reference to the gross registered tonnage of that ship;
(b) a reference to a Schedule shall be read as a reference to a Schedule to these Regulations;
(c) a reference to a wave or signal of type A1 shall be read as a reference to radiotelegraphy by the keying of a continuous wave on and off; and
(d) a reference to a wave or signal of type A2 shall be read as a reference to amplitude modulated radiotelegraphy by the keying of a modulating audio-frequency or of an emission continuously modulated by an audio-frequency.
Exemptions.
The Minister may exempt a ship from all or any of the requirements of these Regulations, either unconditionally or subject to such conditions as the Minister thinks fit.
Ships to be provided with direction-finders.
Subject to these Regulations, a ship shall be provided with a direction-finder in accordance with these Regulations.
Requirements for direction-finders.
6.—(1.) A direction-finder shall—
(a) comply with the requirements specified in the First Schedule; and
(b) be such that—
(i) when undergoing the vibration, dry heat and low temperature tests in accordance with the Second Schedule;
(ii) when subjected to the damp heat test in accordance with that Schedule; and
(iii) immediately after undergoing, in accordance with that Schedule, such other tests specified in that Schedule as are applicable,
it complies with the requirements of items 4 and 5 and 8 to 24 (inclusive) of the First Schedule and is free from mechanical defects.
(2.) The loop aerial system forming part of a direction-finder shall be such that, after undergoing the mould growth test in accordance with the Second Schedule, mould growth is not present on it.
(3.) A direction-finder shall be capable of efficiently determining radio bearings at all times while the ship in which it is installed is at sea notwithstanding such interference or mechanical noise as is produced by the direction-finder.
Installation of direction-finders.
7.—(1.) A direction-finder shall be installed in a ship in such a position and manner that efficient determination of radio bearings by means of the direction-finder is not hindered by extraneous noises or interference at any time while the ship is at sea.
(2.) The loop aerial system forming part of a direction-finder shall be so mounted that the efficient determination of radio bearings by means of the direction-finder is hindered as little as possible by the proximity of aerials, derricks, wire halyards and other large metal objects.
(3.) The feeder cables connecting the loop aerial system with the receiver forming part of a direction-finder shall, unless they consist of solid-dielectric screened cable, be protected by metal tubes that are bonded to earth.
(4.) The joints of the feeder cables shall be watertight.
Broadcast receiver aerials.
8.—(1.) Where the aerial of a broadcast receiver on a ship in which a direction-finder is installed after the commencement of these Regulations rises above the base of the aerial of the direction-finder, the aerial of the broadcast receiver shall—
(a) form part of a communal aerial system;
(b) be more than fifty feet from the aerial of the direction-finder; or
(c) be capable of being lowered quickly and stowed easily when the direction-finder is in use.
(2.) In this regulation, “broadcast receiver” means an appliance capable of being used for the reception, by means of wireless telegraphy, of broadcasting or television programmes.
Supply of electrical energy.
9.—(1.) Batteries or some other source of electrical energy sufficient for the operation of the direction-finder shall be available on the ship for that purpose.
(2.) Where batteries are provided as a source of electrical energy for the operation of a direction-finder, equipment shall be provided on board the ship for charging those batteries and the ship’s main source of electrical energy shall be available for that purpose.
Protection of high voltage parts.
Parts and wiring of a direction-finder that at any time are at an instantaneous voltage (excluding radio-frequency voltage) exceeding fifty volts—
(a) shall be protected from accidental access; and
(b) in the case of parts or wiring (other than a generator or a converter) that at any time are at an instantaneous voltage exceeding two hundred and fifty volts—shall be isolated automatically from all sources of electrical energy when the means of protection are removed.
Means of communication.
11.—(1.) An efficient two way means of calling and voice communication shall be provided in every ship between the receiver forming part of the direction-finder and the bridge from which the ship is normally navigated.
(2.) An efficient means of signalling shall be provided between the receiver forming part of the direction-finder and the ship’s standard compass or gyro compass repeater, if any.
Wiring diagram and instructions.
A schematic wiring diagram of the direction-finder on a ship, and a book containing adequate instructions as to the use of the direction-finder, shall be provided on board the ship and shall be available at all times for use by a person operating or testing the direction-finder.
Maintenance of direction-finders.
A direction-finder installed in a ship shall be maintained so that it is, at all times while the ship is at sea, capable of efficiently determining radio bearings.
Calibration.
14.—(1.) A direction-finder in a ship shall, as soon as practicable and not later than thirty days after the ship first puts to sea after—
(a) the direction-finder has been installed in the ship;
(b) any change is made in the position of the loop aerial system forming part of the direction-finder;
(c) any change is made in any structure or fitting on or above the upper deck within fifty feet of the loop aerial system forming part of the direction-finder, not being a change that a radio surveyor has certified, in writing, to be a change that is not likely to affect the accuracy of the calibration tables or curves; or
(d) any change is made in the electrical characteristics of the loop aerial system forming part of the direction-finder, not being a change that a radio surveyor has certified, in writing, to be a change that is not likely to affect the accuracy of the calibration tables or curves,
be calibrated in accordance with this regulation and adjusted so that readings taken by it, when corrected with the calibration tables, differ from the corrected bearings by not more than plus or minus two degrees.
(2.) A direction-finder shall be calibrated by two persons, one being experienced in taking radio bearings and the other in taking visual bearings, in the following manner:—
(a) the calibration shall be carried out by taking simultaneously visual bearings upon a calibrating transmitter and radio bearings upon that transmitter by means of the direction-finder—
(i) the ship being either swung through a complete circle or circled by another ship carrying the calibrating transmitter; and
(ii) the bearings being taken throughout three hundred and sixty degrees at intervals of five degrees or as close to those intervals as is practicable;
(b) the calibrating transmitter upon which the bearings are taken, whether it is situated on shore or on board another ship, shall be a transmitter operating on a frequency of not less than two hundred and eighty-five kilocycles per second and not more than three hundred and twenty-five kilocycles per second; and
(c) calibration tables and curves shall be prepared on the basis of the bearings taken.
Verification of calibration tables and curves.
15.—(1.) Calibration tables and curves prepared in accordance with the last preceding regulation shall be verified by means of check bearings taken—
(a) at intervals not exceeding twelve months; and
(b) when a change is made in any structure or fitting on or above the upper deck of the ship, not being a change that a radio surveyor has certified, in writing, to be a change that is not likely to affect the accuracy of the calibration tables or curves—as soon as practicable and not later than thirty days after the ship first puts to sea after the change has been made.
(2.) The check bearings referred to in the last preceding sub-regulation shall be—
(a) simultaneous radio and visual bearings of the calibrated transmitter, being, in the case of the radio bearings, bearings made on a frequency not lower than two hundred and fifty-five kilocycles per second and not higher than five hundred and twenty-five kilocycles per second; or
(b) simultaneous radio and calculated bearings of a transmitter in a known position, being—
(i) in the case of the radio bearings, bearings made on a frequency not lower than two hundred and fifty-five kilocycles per second and not higher than five hundred and twenty-five kilocycles per second; and
(ii) in the case of the calculated bearings, bearings calculated by the master or a mate of the ship who, for the purposes of the calculation, has determined the position of the ship by visual bearings of known points.
(3.) If the verification made in accordance with this regulation shows that the calibration tables or curves are materially inaccurate, the direction-finder shall, as soon as practicable, be recalibrated in the manner specified in the last preceding regulation.
Records of calibration and verification.
There shall be kept on board a ship, in a place accessible to a person operating the direction-finder on the ship—
(a) a list or diagram indicating the condition and position, on the most recent occasion on which the direction-finder was calibrated, of the aerials, and all movable structures, on board the ship that might affect the accuracy of the direction-finder;
(b) the calibration tables and curves which were prepared on the most recent occasion on which the direction-finder was calibrated;
(c) a certificate of calibration, in accordance with the form specified in the Third Schedule, relating to the most recent occasion on which the direction-finder was calibrated, and signed by the persons making the calibration; and
(d) a record, in accordance with the form specified in the Fourth Schedule, of check bearings taken for the verification of calibration, the bearings being numbered in the order in which they were taken.
Master to make calibration records available to radio surveyor.
The master of a, ship shall make the list or diagram, calibration tables and curves, certificate of calibration and record required by the last preceding regulation to be kept on the ship available, at all reasonable times, to a radio surveyor for inspection.
Penalty: Two hundred dollars.
Charging of batteries.
The master of a ship shall cause batteries provided as a source of electrical energy for the direction-finder on the ship to be tested once each day by voltmeter and once each month by hydrometer, and shall cause a battery which is found not to be fully charged to be fully charged as soon as practicable.
Penalty: Two hundred dollars.
Supply of electrical energy for testing.
The master of a ship shall cause a sufficient supply of electrical energy for testing the direction-finder on the ship to be available at all reasonable times while the ship is in port.
Penalty: Two hundred dollars.
Use of direction-finders.
A direction-finder on a ship shall not be used—
(a) for a purpose other than the business of the ship; or
(b) for keeping the radio watch required to be kept by the Navigation (Radio) Regulations.
Interference, &c.
The master of a ship shall not, while the ship is at sea, permit the occurrence of noise or interference on the ship likely to hinder the efficient determination of radio bearings by the direction-finder on the ship.
Penalty: Two hundred dollars.
Direction-finders installed before 26 June, 1959.
22.—(1.) Sub-regulations (1.) and (2.) of regulation 6 of these Regulations do not apply to or in relation to a direction-finder that—
(a) has been installed before the twenty-sixth day of June, 1959;
(b) complies with the requirements of Article 47 and paragraph 17 of Article 31 of the International Convention for the Safety of Life at Sea signed in London on the thirty-first day of May, 1929; and
(c) is capable of—
(i) receiving waves of type A1 and type A2 on all frequencies from and including two hundred and fifty-five kilocycles per second to and including five hundred and twenty-five kilocycles per second; and
(ii) taking radio bearings when the field strength at the loop aerial system is as low as fifty microvolts per metre.
(2.) This regulation ceases to have effect on and after the first day of January, 1969.
Direction-finders installed before the commencement of these Regulations.
Sub-regulations (1.) and (2.) of regulation 6 of these Regulations do not apply to or in relation to a direction-finder that has been installed before the commencement of these Regulations if—
(a) the direction-finder complies with the requirements of the Fifth Schedule; or
(b) the direction-finder—
(i) has been installed on or after the twenty-sixth day of June, 1959;
(ii) complies with the requirements of regulation 11 of Chapter IV. of the International Convention for the Safety of Life at Sea, 1960; and
(iii) is capable of receiving waves of type A1 and type A2 on all frequencies from and including two hundred and fifty-five kilocycles per second to and including five hundred and twenty-five kilocycles per second.
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THE SCHEDULES
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FIRST SCHEDULE
Direction-finder
General
For the purposes of this Schedule—
(a) “locally generated signals” means signals obtained from a signal generator or signal generators;
(b) a goniometer forming part of a direction-finder shall, except for the purposes of item 17 of this Schedule, be deemed to be part of the direction-finding aerial system; and
(c) “signal to noise ratio” means the ratio of the signal plus noise to the noise alone.
The direction-finder shall include a receiver, a direction-finding aerial system and any other equipment required to enable the radio bearing and sense of the signal to be determined.
The mechanical parts of the direction-finding aerial system, other than ball bearings, hose clips, set screws and other similar small parts, shall consist of non-magnetic material.
First Schedule—continued
Capability
4.—(1.) The direction-finder shall be capable of headphone reception of waves of type A1 and type A2 of any frequency within the range, 255 kilocycles per second to 525 kilocycles per second so as to enable the radio bearing and sense of the signal to be determined by aural-null or other means.
(2.) The direction-finder shall be capable of operation within one minute of its being connected to a source of energy.
Controls
The direction-finder shall be provided with—
(a) a manual control for the adjustment of radio frequency gain or intermediate frequency gain or both;
(b) a manual control for the adjustment of audio frequency gain;
(c) means of audio monitoring for any method that may be used for direction finding;
(d) a tuning control;
(e) a tuning scale that is calibrated directly in frequency and in which, at no point in the tuning range, an interval of ⅛ inch corresponds to a frequency change of more than 8 kilocycles per second; and
(f) where the direction-finder incorporates a loud speaker—means to make the loud speaker inoperative.
Power Supply
6.—(1.) The direction-finder shall, unless otherwise specified, be capable of complying with the requirements of this Schedule for a range of voltage variation of plus or minus 10 per centum relative to the nominal supply voltage.
(2.) Where the direction-finder is capable of operation from more than one source of energy, means shall be provided for changing the direction-finder quickly from one source of energy to another.
(3.) Neither vibrators nor dry cells shall be incorporated in the direction-finder or in any source of electrical energy for the direction-finder.
General Method of Testing
The receiver shall, unless otherwise specified, comply with the requirements of items 8 to 21 (inclusive) of this Schedule when tested in the following manner on any frequency within the range 255 kilocycles per second to 525 kilocycles per second:—
(a) locally generated signals shall be injected through a network in such a manner that the signal generator or generators, as the case may be, and the network are together equivalent to a constant voltage zero impedance generator in series with an impedance substantially equal to the impedance of the direction-finding aerial system at the test frequency when—
(i) the direction-finding aerial system is adjusted for the determination of radio bearings;
(ii) the sense-finder is not in operation; and
(iii) the impedance is measured between the two terminals to which the receiver is normally connected;
(b) the effective height (he) in metres of the direction-finding aerial system shall be the ratio E/e, where “E” is the voltage produced by a vertically polarized field of strength “e” volts per metre when—
(i) the direction-finding aerial system is adjusted for the determination of bearings and for maximum pick-up;
(ii) the sense-finder is not in operation;
(iii) the receiver is not connected to the direction-finding aerial system; and
(iv) the voltage is measured between the terminals of the direction-finding aerial system to which the receiver is normally connected;
(c) the standard input level shall be the input level obtained when the electromotive force of the equivalent signal generator referred to in paragraph (a) of this item is 50he microvolts root mean square;
(d) the standard output level shall be—
(i) for headphone reception, an audio-frequency output of 1 milliwatt into a resistance substantially equal to the modulus of the impedance of the telephone receivers at 400 cycles per second; and
(ii) for loud-speaker reception, an audio-frequency output of 50 milliwatts into a resistance substantially equal to the modulus of the impedance of the loudspeaker at 400 cycles per second;
First Schedule—continued
(e) a type A2 test signal shall, unless otherwise specified, be modulated to a depth of 30 per centum by a signal of 400 cycles per second; and
(f) the automatic gain control, if any, shall, unless otherwise specified, be inoperative.
Signal and Intermediate Frequency Selectivity
8.—(1.) The signal frequency selectivity of the receiver or, in the case of a superheterodyne receiver, the signal and intermediate frequency selectivity shall satisfy the following requirements:—
(a) the minimum bandwidth for 6 decibels discrimination shall be 2 kilocycles per second;
(b) the maximum bandwidth in relation to discrimination shall be in accordance with the following table:—
Where the maximum bandwidth is—
The discrimination shall be not less than—
8 kilocycles per second........................
30 decibels
16 kilocycles per second........................
60 decibels
35 kilocycles per second........................
90 decibels
(c) at a frequency outside the bandwidth of plus and minus twenty kilocycles per second the discrimination—
(i) shall be not less than ninety decibels except at the image frequency in superheterodyne receivers; and
(ii) shall be not less than eighty decibels at the image frequency in superheterodyne receivers.
(2.) In testing non-aural null type equipment for the purposes of this item, the automatic gain control shall be inoperative.
Gain
9. The gain of the receiver shall be such that, when—
(a) the input terminals of the receiver are closed solely through an external impedance substantially equal to that of the direction-finding aerial system at the test frequency;
(b) the receiver is in the condition for reception of signals of type A1;
(c) the sense-finder is not in operation; and
(d) impedance is measured between the two terminals of the direction-finding aerial system to which the receiver is normally connected,
receiver noise can produce an output level of minus 10 decibels relative to the standard output level at any frequency within the, range of frequencies specified in item 4 of this Schedule.
Signal to Noise Ratio
10.—(1.) When—
(a) the note filter, if any, is switched out of circuit;
(b) a signal of type A1 or type A2 of standard input level is injected into the receiver; and
(c) the receiver gain is adjusted manually to give standard output,
the signal to noise ratio shall be not less than the value determined in accordance with the following table:—
Type of signal
Ratio—Aural-null type equipment
Ratio—other equipment
A1...................
20 decibels
15 decibels
A2...................
10 decibels
6 decibels
(2.) For the purposes of this item, spurious whistles shall be regarded as noise.
Blocking
The Change in output of the receiver shall not exceed 3 decibels when—
(a) the receiver is adjusted to give standard output with an input wanted signal of type A2 at a level of 50 decibels above the standard input level and of any frequency in the range specified in item 4 of this Schedule; and
First Schedule—continued
(b) a signal of type A1 is applied simultaneously, the signal being at a level of 85 decibels above the standard input level and at a frequency 10 kilocycles per second above or below that of the wanted signal.
Linearity
12.—(1.) With the receiver adjusted to give standard output with an input signal of type A1 at a level 20 decibels above standard input level, the input-output characteristic shall be such that any increase of input level to a level not more than 60 decibels above the standard input level shall not cause a diminution of output level below that required for a straight characteristic exceeding 1 decibel relative to maximum output level.
(2.) With the receiver adjusted to give standard output with an input signal of type A1 at a level 40 decibels above standard input level, the input-output characteristic shall be such that any increase of input level to a level not more than 60 decibels above the standard input level shall not cause a diminution of output level below that required for a straight characteristic exceeding 1 decibel relative to maximum output level.
Intermodulation
The output level of the receiver shall not exceed the standard output when—
(a) the receiver is adjusted to give standard output level with an input wanted signal of type A2 at standard input level and at any frequency specified in item 4 of this Schedule;
(b) the input wanted signal has been removed; and
(c) any two unwanted locally generated signals—
(i) each of which is at a level 70 decibels above standard input level and of a frequency not less than 50 kilocycles per second from the frequency of the wanted signal; and
(ii) one of which is of type A1 and the other of type A2, are applied simultaneously.
Harmonic Production
The output level of the receiver shall not exceed the standard output when—
(a) the receiver is adjusted to give standard output level with an input wanted signal of type A2 at standard input level and at the frequency of 500 kilocycles per second;
(b) the input wanted signal has been removed; and
(c) a type A2 signal that is—
(i) of a frequency that is any sub-harmonic of 500 kilocycles per second; and
(ii) at a level of 80 decibels above the standard input level, is applied to the receiver.
Fidelity
15.—(1.) The maximum change in level of the output of the receiver shall be less than 8 decibels when the modulating frequency of an input signal that is—
(a) of any frequency in the range specified in item 4 of this Schedule; and
(b) of constant level and modulation depth, not being a level or depth that causes the output of the receiver to exceed the standard output level,
is varied continuously from 300 cycles per second to 1,350 cycles per second.
(2.) For the test referred to in the last preceding sub-item in relation to equipment that is not aural-null type equipment the receiver shall be set for the reception of waves of type A2.
Radiation
The direction-finder shall not in normal service produce a field exceeding 0.1 microvolt per metre when measured at a distance of 1 nautical mile from the receiver.
The direction-finder shall be deemed to comply with the last preceding item, if, when—
(a) the receiver, with the goniometer (if any) but without the aerial system, is placed centrally in a screened earthed enclosure at least 6 feet cube;
(b) the earth terminal is connected to the inside of the screen;
(c) each aerial terminal in turn is connected through an unscreened 4-turn rectangular search coil, 1 foot square, situated within the enclosure and an unscreened lead to a resistive measuring instrument mounted outside the enclosure and having its other terminal earthed;
First Schedule—continued
(d) the aerial terminal or terminals of the receiver, other than the terminal connected to the measuring instrument, are earthed one at a time or in any combination or remain unearthed or are interconnected in any combination; and
(e) the receiver is energized and unscreened headphones are connected to it,
the power measured by the measuring instrument, connected in the manner specified in paragraph (c) of this item, does not exceed 4 x 10-10 watt whatever the resistance of the measuring instrument or the adjustment of the receiver and whether or not the search coil is short-circuited or moved in any way other than a way that causes it to approach within six inches of the receiver case.
Tuning Drift and Stability
After the receiver has been switched on for 5 minutes and tuned to any frequency within the frequency range specified in item 4 of this Schedule, the tune frequency shall not change by more than 5 parts in 10,000 in any period of 5 minutes.
A change of 5 per centum in any one of the supply voltages to the receiver, or to a power unit associated with the supply voltages, shall not cause the tune frequency to change by more than 3 parts in 10,000.
A change of ambient temperature of 5 degrees Centigrade within the range 0 degrees Centigrade to 50 degrees Centigrade applied after the receiver has been switched on for one hour shall not cause the tune frequency to change by more than 1 part in 1,000.
Heterodyne Note Stability
The heterodyne note stability of the receiver shall be such that—
(a) the frequency of a heterodyne note that is initially 1 kilocycle per second shall not vary by more than 100 cycles per second when an input signal is increased over a range of levels from 0 to 60 decibels above the standard input; and
(b) at all levels within the range specified in the last preceding paragraph, a beat note of 200 cycles per second can be obtained by tuning either towards or away from zero beat.
Bearing Indicator Scales
22.—(1.) If the direction-finder includes a circular bearing indicator scale—
(a) the scale shall be marked at intervals of one degree with a mark of one of three different kinds, one kind being used for each tenth mark, another kind for each fifth mark, not being a tenth mark, and the third kind for all other marks;
(b) each tenth mark on the scale shall be numbered to indicate the number of the degrees that it is intended to denote;
(c) the interval between marks on the scale shall be big enough to make it possible to read a bearing to at least 0.25 degree; and
(d) the bearing indicator shall not obscure more than 0.5 of a degree of the scale.
(2.) If the equipment includes a digital display for the bearing indicator—
(a) the display shall be easily readable; and
(b) it shall be possible to read bearings to at least 0.25 degree.
Aural-Null Type Direction-Finders
23.—(1.) This item applies in relation to direction-finders suitable for determining bearings by aural-null means.
(2.) The bearings indicated by the scale of the direction-finder, due allowance being made for site errors and the previous setting of the indicator being disregarded, shall, at all frequencies in the range of frequencies specified in item 4 of this Schedule, throughout the whole 360 degrees of azimuth, be correct within plus or minus one degree of the correct bearing when the direction-finder is tested using—
(a) waves of type A2 modulated to a depth of from 80 per centum to 100 per centum; and
(b) waves of type A1,
with a substantially vertically polarized field having a field strength of 40 decibels above 1 microvolt per metre.
(3.) A change in the setting of the bearing indicator of the direction-finder of 5 degrees or 90 degrees in either direction from the position or any of the positions of minimum output shall, at all frequencies in the range of frequencies specified in item 4 of this Schedule, cause
First Schedule—continued
the audio-frequency output to increase by not less than 18 decibels or 35 decibels, as the case may be, when the direction-finder is arranged for the taking of bearings and is tested under the conditions specified in the last preceding sub-item but with—
(a) a field strength sufficient to give a signal to noise ratio of not less than 50 decibels with the direction-finding aerial system adjusted for maximum output; and
(b) any minimum clearing control in the same position as it was when the direction-finder was tested under the last preceding sub-item.
(4.) The audio-frequency output level of the receiver due to the wanted signal shall,
when—
(a) the direction-finder is adjusted for the determination of sense, and is tested under the conditions specified in sub-item (2.) but with a field strength sufficient to give a signal to noise ratio of not less than 50 decibels with the direction-finding aerial system adjusted for maximum output; and
(b) the sense indicator is adjusted to indicate any bearing within plus or minus 10 degrees of the correct bearing,
be not less than 20 decibels below the output level that is obtained when the sense indicator is adjusted to indicate a bearing within 180 degrees, plus or minus 10 degrees, of the correct bearing.
Other Types of Direction-Finders
24.—(1.) This item applies in relation to direction-finders suitable for determining bearings by other than aural-null means.
(2.) The direction-finder shall include a device to indicate that the receiver gain and signal strength are sufficient to enable a correct bearing to be taken.
(3.) When the direction-finder is tested throughout the whole 360 degrees of azimuth at all frequencies in the range of frequencies specified in item 4 of this Schedule with a substantially vertically polarized field using a signal of a type set out in column 1 of the following table and of a field strength set out in column 2 of that table opposite to that type—
(a) the bearings indicated by the scale or display of the direction-finder shall not, due allowance being made for site errors and the previous indicated bearing being disregarded, differ from the correct bearing by more than the number of degrees shown in column 3 of that table; and
(b) the fluctuations in the indicated bearing shall not, due allowance being made for site errors and the previous indicated bearing being disregarded, exceed the values shown in column 4 of that table,
opposite to the type and field strength of the signal set out in columns 1 and 2 of that table.
Column 1
Column 2
Column 3
Column 4
Type of signal
Field strength
Maximum error
Maximum fluctuation from mean bearing
A2 modulated to a depth of 80 to 100 per centum
40 decibels above 1 microvolt per metre
Plus or minus 1 degree
Plus or minus 0.5 degree
A1...............
40 decibels above 1 microvolt per metre
Plus or minus 1 degree
Plus or minus 0.5 degree
A2 modulated to a depth of 80 to 100 per centum
100 decibels above 1 microvolt per metre
Plus or minus 1 degree
Plus or minus 0.5 degree
A1...............
100 decibels above 1 microvolt per metre
Plus or minus 1 degree
Plus or minus 0.5 degree
A2 modulated to a depth of 80 to 100 per centum
30 decibels above 1 microvolt per metre
Plus or minus 2 degrees
Plus or minus 1degree
A1...............
30 decibels above 1 microvolt per metre
Plus or minus 2 degrees
Plus or minus 1degree
(4.) When—
(a) the direction-finder is adjusted for the reception of a wanted signal of any frequency in the range specified in item 4 of this Schedule, and of field strength 40 decibels above one microvolt per metre or of 6 decibels above standard input level; and
(b) there is applied simultaneously a second signal—
(i) that is an unwanted signal of the same type as, and from a source 90 degrees from that of, the wanted signal;
First Schedule—continued
(ii) in respect of which the frequency separation in relation to the wanted signal is equal to a frequency separation specified in column 1 of the following table; and
(iii) in respect of which the field strength or equivalent input level is the strength or level, as the case may be, specified in column 2 or column 3, as the case may be, of that table opposite to the frequency separation in column 1 referred to in the last preceding sub-paragraph,
the change in indicated bearing shall not exceed one degree.
Column 1
Column 2
Column 3
Frequency separation in kilocycles per second
Field strength
Equivalent input level
Plus or minus 1...............
30 decibels above 1 microvolt per metre
4 decibels below standard input
Plus or minus 4...............
60 decibels above 1 microvolt per metre
26 decibels above standard input
Plus or minus 20...............
100 decibels above 1 microvolt per metre
66 decibels above standard input
(5.) The equipment shall comply with the provisions of the last preceding sub-item notwithstanding that both signals are of type A1 or both are of type A2.
(6.) The indicated bearing shall not change by more than 1 degree when, with an input signal with a field strength of 60 decibels above 1 microvolt per metre or a signal 26 decibels above standard input level and the automatic gain control, if fitted, operative, the receiver is mistuned until either—
(a) the audio frequency output falls by 6 decibels; or
(b) the device referred to in sub-item (2.) of this item shows that the signal has fallen to the minimum at which a bearing can be taken,
whichever first occurs.
(7.) With the equipment adjusted for taking bearings and with the ratio of signals as specified by the manufacturer applied to the direction-finding and sense paths, an increase or decrease of 10 decibels in sense level shall not—
(a) where sense finding is not a separate operation—change the indicated bearing by more than 1 degree; or
(b) where sense finding is a separate operation—leave any ambiguity of sense.
(8.) When, with the bearing indicator in any rest position, a signal simulating one from a bearing of 175 degrees from that indicated by the rest position is applied at any and every level in the range between 6 and 60 decibels above standard input level—
(a) a new indicated bearing within 1 degree of the correct bearing shall be obtained within two seconds at room temperature and within four seconds at minus 15 degrees Centigrade; and
(b) without further adjustment of the equipment or signal source, the indicated bearing shall remain within 1 degree of the correct bearing during a further twenty seconds.
(9.) There shall be no observable change of indicated bearing when the beat frequency oscillator is switched on, whether or not the signal is of a strength sufficient to give a bearing indication.
(10.) It shall be possible to make, in not more than 10 seconds after identifying a station the bearing of which is required, any check or adjustment of any control that is necessary as part of the process of direction-finding.
Additional Safeguards to be Incorporated where the Equipment includes Semi-conductor Devices
Where semi-conductor devices are incorporated in the equipment—
(a) the maker’s maximum ratings for each type of semi-conductor device shall not be disregarded and, in particular, the recommended junction temperature shall not be exceeded;
First Schedule—continued
(b) adequate screening and filtering shall be provided to protect the devices from damage due to radio frequency energy; and
(c) the devices shall be effectively protected from damage due to—
(i) transient changes in power supply voltage;
(ii) accidental reversal of power supply polarity; or
(iii) a sustained increase in power supply voltage of 25 per centum or more, relative to the nominal battery voltage when the equipment is operated from a battery of secondary cells.
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SECOND SCHEDULE Regulation 6.
Climatic and Durability Tests
General
In this Schedule—
(a) a reference to Class B equipment shall be read as a reference to parts of the direction-finder other than the loop aerial system; and
(b) a reference to Class X equipment shall be read as a reference to the loop aerial system of the direction-finder.
2.—(1.) Subject to this item—
(a) Class B equipment shall be subjected to the tests specified in column 1 of the table in this sub-item; and
(b) Class X equipment shall be subjected to the tests specified in column 2 of that table,
in the order indicated by the numbers preceding the references to those tests in those columns.
(2.) Class X equipment that has been subjected to the rain test at a static pressure of not less than 45 pounds per square inch or more than 55 pounds per square inch shall not be subjected to the immersion test.
(3.) Where the provisions of this Schedule require the equipment to be kept working for the purposes of any test, power shall be supplied to the equipment at the voltage at which the equipment is intended to be operated.
The tests referred to in the last preceding item shall be conducted in accordance with the succeeding provisions of this Schedule.
Vibration Test
The equipment, complete with its chassis covers and shock absorbers (if any), and in its normal operating position, shall be clamped to a vibration table.
The table shall be vibrated at all frequencies between 0 and 12.5 cycles per second at an amplitude of plus and minus 0.16 centimetre while the equipment is kept working continuously.
The table shall be so vibrated for 3 periods each of 8 minutes’ duration.
The direction of the vibration during each period referred to in the last preceding item shall be perpendicular to the direction of the vibrations during the other two periods,
Second Schedule—continued
Bump Test
The equipment shall be subjected to not less than 500 bumps at a constant rate, not being less than 1 bump or more than 4 bumps per second, with a free drop of at least 2.5 centimetres.
Dry Heat Test
Class X equipment shall be placed in a chamber which is maintained for a period of 10 hours at a constant temperature of 70 degrees Centigrade, within a tolerance of plus or minus 1 degree Centigrade.
The chamber shall then be cooled to a constant temperature of 55 degrees Centigrade, within a tolerance of plus or minus 1 degree Centigrade, and the direction-finder shall be kept working continuously at that temperature for a period of 2 hours.
Damp Heat Test
The equipment shall be placed in a chamber which shall, within a period not exceeding 2 hours, be heated from room temperature to 40 degrees Centigrade and brought to a relative humidity of not less than 95 per centum.
The chamber shall be kept at a temperature of 40 degrees Centigrade, within a tolerance of plus or minus 1 degree Centigrade, for a period of 12 hours, and at a relative humidity of not less than 95 per centum.
At the beginning of the last hour of the period of 12 hours, all accessible surfaces and components shall be wiped dry and any fans or drying lamps provided in the equipment shall be switched on.
After the fans or drying lamps have been in operation for 30 minutes and while the temperature of the chamber is still 40 degrees Centigrade, within a tolerance of plus or minus 1 degree Centigrade, the equipment shall be operated and checked.
The temperature of the chamber shall then, in preparation for the low temperature test, be allowed to fall below 25 degrees Centigrade, the equipment being retained in the chamber.
Low Temperature Test
Class B equipment shall be exposed to a temperature of minus 15 degrees Centigrade, within a tolerance of plus or minus 1 degree Centigrade, at normal atmospheric pressure, for a period of not less than 12 hours.
Class X equipment shall be exposed to a temperature of minus 25 degrees Centigrade, within a tolerance of plus or minus 1 degree Centigrade, at normal atmospheric pressure for a period of not less than 12 hours.
Rain Test
The equipment shall be placed in a chamber fitted with 8 shower heads, the discharge end of each of which consists of a flat, non-rustable metal plate, 0.16 centimetre thick, having 36 holes each of 0.1 centimetre diameter evenly spaced in concentric circles in the following manner:—
16 holes on the periphery of a circle of 5.1 centimetres diameter.
8 holes on the periphery of a circle of 3.8 centimetres diameter.
8 holes on the periphery of a circle of 2.5 centimetres diameter.
4 holes on the periphery of a circle of 1.3 centimetres diameter.
The shower heads shall be arranged at a distance of not less than 50 centimetres and not more than 80 centimetres from the equipment in such a manner that spray from 4 of the shower heads is directed downwards at an angle of 45 degrees at each of the four uppermost corners of the equipment, and the spray from the other 4 shower heads is directed horizontally at the centre of each area of the four sides of the equipment.
Fresh water at room temperature and at a static pressure—
(a) not being less than 15 pounds per square inch or more than 25 pounds per square inch, if the equipment is to be subjected to the immersion test; or
(b) not being less than 45 pounds per square inch or more than 55 pounds per square inch, in any other case,
shall be sprayed on the equipment from the shower heads for a period of 1 hour, the equipment being in the position in which it is normally operated.
Second Schedule—continued
The equipment shall, throughout the test, be rotated at not less than 12 and not more than 20 revolutions per minute about a vertical axis passing through the centre of the equipment.
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 centimetres above the highest point of the equipment, and shall remain so immersed for a period of 1 hour.
Upon its removal from the water the equipment shall be drained of water.
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 water which contains, within a tolerance of plus or minus 10 per centum, the following percentages of salts in solution:—
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 1 hour and shall be kept working continuously for the second 30 minutes of that hour.
The equipment shall, immediately after the expiration of the hour, be stored for a period of 7 days at a temperature of 40 degrees Centigrade, within a tolerance of plus or minus 1 degree Centigrade, and at a relative humidity of not less than 60 per centum and not more than 80 per centum.
The equipment shall be so sprayed and stored on four separate occasions.
Corrosion Test (Acid Fumes)
A battery included in the equipment shall be fully charged and then fitted into the equipment.
If the battery can be charged without being removed from the equipment, the battery shall continue to be charged at the maximum rate appropriate to it for a period of 24 hours.
The equipment shall immediately after the expiration of that period be stored for a period of 4 weeks at a temperature of 40 degrees Centigrade, within a tolerance of plus or minus 1 degree Centigrade, and at a relative humidity of not less than 60 per centum and not more than 80 per centum.
Mould Growth Test
The equipment shall be inoculated by spraying with an aqueous suspension of mould spores containing the cultures specified in column 1, or the cultures specified in column 2, of the following table:—
Column 1
Column 2
Aspergillus niger
Aspergillus niger
Aspergillus amstelodami
Aspergillus amstelodami
Paecilomyces varioti
Aspergillus versicolor
Stachybotrys atra
Stachybotrys atra
Penicillium brevi-compactum
Penicillium brevi-compactum
Penicillium cyclopium
Cladosporum herbasum
Chaetomium globosum
Immediately after it has been so sprayed, the equipment shall be placed in a chamber the temperature of which shall be maintained at a fixed value not less than 31 degrees Centigrade or more than 33 degrees Centigrade and controlled to within a tolerance of plus or minus 1 degree Centigrade at a relative humidity of not less than 95 per centum, and shall be kept in the chamber for a period of 28 days.
THIRD SCHEDULE Regulation 16 (c).
Navigation (Direction-Finders) Regulations
CERTIFICATE OF CALIBRATION OF DIRECTION-FINDER
We, the undersigned, hereby certify that we have this day—
(a) calibrated, in accordance with the Navigation (Direction-Finders) Regulations, the direction-finder installed in the ship ;
(b) handed to the Master of that ship tables of calibration corrections; and
(c) adjusted the direction-finder so that the readings taken by it, when corrected with the tables, differed from the correct bearings by no more than plus or minus 2 degrees.
We further certify that the Master of the above-mentioned ship has been furnished with a list or diagram indicating the condition and position, at the time of the calibration, of the aerials and of all movable structures on board the ship which might affect the accuracy of the direction-finder.
Dated this day of , 19 .
Radio Observer.
Visual Observer.
FOURTH SCHEDULE Regulation 16(d).
Image unavailable in extracted textRECORD OF CHECK-BEARINGS TAKEN BY MEANS OF THE DIRECTION-FINDER
Image unavailable in extracted textImage unavailable in extracted textFIFTH SCHEDULE Regulation 23.
Alternative Requirements for Direction-finders installed before the commencement of these Regulations
General
For the purposes of this Schedule—
(a) “locally generated signals” means signals obtained from a signal generator or signal generators; and
(b) a goniometer forming part of a direction-finder shall, except for the purposes of item 13 of this Schedule, be deemed to be part of the loop aerial system.
The direction-finder shall include a receiver and a loop aerial system.
The loop aerial system, other than ball bearings, hose clips, set screws and other similar small parts, shall consist of non-magnetic material.
Capability
The direction-finder shall be capable of headphone reception of waves of type A1 and type A2 of any frequency within the range 255 kilocycles per second to 525 kilocycles per second so as to enable the radio bearings and sense of the signal to be determined by reference to its minimum strength.
Controls
The receiver shall be provided with—
(a) a radio-frequency gain control;
(b) a tuning control; and
(c) a tuning scale in which, at no point in the tuning range, an interval of ⅛ inch corresponds to a frequency change of more than 8 kilocycles per second.
General Method of Testing
The receiver shall comply with the requirements of items 7 to 18 (inclusive) of this Schedule when tested in the following manner on any frequency within the range 255 kilocycles per second to 525 kilocycles per second:—
(a) Locally generated signals shall be injected through a network in such a manner that the signal generator or generators, as the case may be, and the network are together equivalent to a constant voltage generator in series with an impedance substantially equal to the impedance of the loop aerial system at the test frequency, when—
(i) the loop aerial system is adjusted for the determination of radio bearings;
(ii) the sense-finder is not in operation; and
(iii) the impedance is measured between the two terminals to which the receiver is normally connected.
(b) The effective height (he) in metres of the loop aerial system shall be the ratio E/e, where “E” is the voltage produced by a vertically polarized field of strength “e” volts per metre when—
(i) the loop aerial system is adjusted for the determination of bearings and for maximum pick-up;
(ii) the sense-finder is not in operation;
(iii) the receiver is not connected to the loop aerial system; and
(iv) the voltage is measured between the terminals of the loop aerial system to which the receiver is normally connected.
(c) The standard input level shall be the input level obtained when the electromotive force of the equivalent signal generator referred to in paragraph (a) of this item is 50e microvolts root mean square.
(d) The standard output level shall be an audio-frequency output of 1 milliwatt into a resistance substantially equal to the modulus of the impedance of the telephone receivers at 1,000 cycles per second.
(e) The signal-noise ratio of the direction-finder shall be determined either—
(i) by using vertically polarized waves for transmission of the input signal, and with the loop aerial system arranged for the determination of bearings and adjusted for maximum pick-up, but without the sense-finder in operation; or
(ii) by using locally generated signals applied to the receiver only in the manner specified in paragraph (a) of this item.
Signal and Intermediate Frequency Selectivity
The signal frequency selectivity of the receiver or, in the case of a superheterodyne receiver, the signal and intermediate frequency selectivity shall satisfy the following requirements:—
(a) The minimum bandwidth for 6 decibels discrimination shall be 2 kilocycles per second.
Fifth Schedule—continued
(b) The maximum band-width in relation to discrimination shall be in accordance with the following table:—
Where the maximum bandwidth is—
The discrimination shall be not less than—
8 kilocycles per second..................................
30 decibels
16 kilocycles per second..................................
60 decibels
35 kilocycles per second..................................
90 decibels
(c) At a frequency outside the bandwidth of 35 kilocycles per second the discrimination shall not be less than 90 decibels except in the case of superheterodyne receivers where, at the image frequency, the discrimination shall not be less than 80 decibels.
Gain
The gain of the receiver shall be such that, when—
(a) the input terminals of the receiver are closed solely through an external impedance substantially equal to that of the loop aerial system at the test frequency;
(b) the sense-finder is not in operation; and
(c) impedance is measured between the two terminals of the loop aerial system to which the receiver is normally connected,
receiver noise can produce an output level of minus 10 decibels relative to the standard output level at any frequency within the range of frequencies specified in item 4 of this Schedule.
Signal-Noise Ratio
9.—(1.) The signal-noise ratio shall not be less than 20 decibels when—
(a) the note filter (if any) is switched out of circuit;
(b) a signal of type A1 is injected at the standard input level; and
(c) the receiver gain is manually adjusted to give the standard output level.
(2.) The signal-noise ratio shall not be less than 10 decibels when—
(a) the note filter (if any) is switched out of circuit;
(b) a signal of type A2 modulated to a depth of 30 per centum with a frequency of 400 cycles per second is injected at the standard input level; and
(c) the receiver gain is manually adjusted to give the standard output level.
(3.) For the purposes of this item, spurious whistles shall be regarded as noise.
Blocking
The change in output of the receiver shall not exceed 3 decibels—
(a) at any frequency within the range of frequencies specified in item 4 of this Schedule; and
(b) at all levels of a wanted signal up to 50 decibels above the standard input level, whether of type A1 or type A2, when locally generated signals of type A1 or type A2 at a level of 40 decibels above the level of the wanted signal and spaced 10 kilocycles per second from the carrier of the wanted signal are applied.
Intermodulation
The input level of each of two unwanted signals shall not be less than plus 75 decibels relative to the standard input level when—
(a) the receiver is adjusted to give standard output level with a locally generated wanted signal of standard input level modulated to a depth of 30 per centum with a note frequency of 400 cycles per second at any frequency within the range of frequencies specified in item 4 of this Schedule;
(b) the input wanted signal has been removed; and
(c) two unwanted locally generated signals—
(i) each of which is of a frequency not less than 50 kilocycles per second from the frequency of the wanted signal;
(ii) the frequency sum or frequency difference of which is equal to the frequency of the wanted signal; and
(iii) one of which is modulated to a depth of 30 per centum with a note frequency of 400 cycles per second and the other is unmodulated,
are applied simultaneously at equal input levels so as to give an output equal to that previously obtained with the wanted signal.
7139/67—3
Fifth Schedule—continued
Radiation
The direction-finder shall not in normal service produce a field exceeding 0.1 microvolt per metre when measured at a distance of 1 mile from the receiver.
The direction-finder shall be deemed to comply with the last preceding item if, when—
(a) the receiver, with the goniometer (if any) but without the aerial system, is placed centrally in a screened earthed enclosure at least 6 feet cube;
(b) the earth terminal is connected to the inside of the screen;
(c) each aerial terminal in turn is connected through an unscreened 4-turn rectangular search coil, 1 foot square, situated within the enclosure and an unscreened lead to a resistive measuring instrument mounted outside the enclosure and having its other terminal earthed;
(d) the aerial terminal or terminals of the receiver, other than the terminal connected to the measuring instrument, are earthed one at a time or in any combination or remain unearthed or are interconnected in any combination; and
(e) the receiver is energized and unscreened headphones are connected to it,
the power measured by the measuring instrument, when connected in the manner specified in paragraph (c) of this item, does not exceed 4 x 10–10 watt 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 other than a way that causes it to approach within 6 inches of the receiver case.
Tuning Drift and Stability
After the receiver has been switched on for 5 minutes and tuned to any frequency within the frequency range specified in item 4 of this Schedule the tune frequency shall not change by more than 1 part in 1,000 in any period of 5 minutes.
A change of 5 per centum in any one of the supply voltages to the receiver, or to a power unit associated with the supply voltages, shall not cause the tune frequency to change by more than 3 parts in 10,000.
A change of ambient temperature of 5 degrees Centigrade within the range 0 degrees Centigrade to 50 degrees Centigrade applied after the receiver has been switched on for 1 hour shall not cause the tune frequency to change by more than 1 part in 1,000.
Heterodyne Note Stability
The heterodyne note stability of the receiver shall be such that—
(a) the frequency of a heterodyne note which is initially 1 kilocycle per second shall not vary by more than 100 cycles per second when an input signal is increased over a range of levels from 0 to 60 decibels above the standard input; and
(b) at all input levels within the range specified in the last preceding paragraph, a beat note of 200 cycles per second can be obtained by tuning either towards or away from zero beat.
Fidelity
The maximum change in level of the output of the receiver shall be less than 8 decibels when—
(a) the modulation frequency of an input signal of constant level and modulation depth, applied at a level in the range from the standard input level to 50 decibels above the standard input level, is varied continuously from 300 cycles per second to 1,500 cycles per second; and
(b) the output of the receiver does not exceed the standard output level.
Accuracy of Bearings
The bearings indicated by the scale of the direction-finder shall, at all frequencies in the range of frequencies specified in item 4 of this Schedule, throughout the whole 360 degrees of azimuth and after due allowance has been made for site errors, be correct within plus or minus 1 degree of the true bearing when the direction-finder is tested using waves of type A2 modulated to a depth of from 80 per centum to 100 per centum and with a vertically polarized field having a level of 40 decibels relative to 1 microvolt per metre.
Quality of Minima
Changes in the setting of the bearing indicator of the direction-finder 5 degrees and 90 degrees in either direction from the position or positions of minimum output shall, at all frequencies in the range of frequencies specified in item 4 of this Schedule, cause the audio-frequency output to increase by not less than 18 decibels and not less than 35 decibels, respectively, when the direction-finder is arranged for the taking of bearings and is tested under the conditions specified in the last preceding item, but with a field strength sufficient to give a signal/noise ratio of not less than 50 decibels with the loop aerial system adjusted for maximum output.
Fifth Schedule—continued
Efficiency of Sense-Finder
The audio-frequency output level of the receiver due to the wanted signal shall, when—
(a) the direction-finder is adjusted for the determination of sense, and is tested under the conditions specified in item 19 of this Schedule, but with a field strength sufficient to give a signal/noise ratio of not less than 50 decibels with the loop aerial system adjusted for maximum output; and
(b) the sense indicator is adjusted to indicate any bearing within plus or minus 10 degrees of the true bearing,
be not less than 20 decibels below the output level that is obtained when the sense indicator is adjusted to indicate a bearing within 180 degrees plus or minus 10 degrees of the true bearing.
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By Authority: A. J. Arthur, Commonwealth Government Printer, Canberra