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Planet Earth/5b. Properties of Earth’s Water (Density, Salinity, Oxygen, and Carbonic Acid)

Properties of Earth’s Water
As one of the most abundant molecules on Earth’s surface, and one vital to life, water plays an important role in the very dynamic nature of Earth, particularly how water interacts with the rocks, the soil, and the atmosphere, and how it changes depending on its depth in the Earth’s oceans.

Water Density
Density is the mass per unit volume of a substance, which means that an equal volume of a substance with high density will weigh more than an equal volume of a substance with low density. Liquid water has a density of 1 gram per milliliter (1 g/ml) or 1 gram per cubic centimeter (1 g/cm3). This makes comparing the density of water to other substances, both liquids and solids easy. Specific density is the density of water compared to other substances. For example, a solid cube that floats in a glass of water, will have a specific density less than 1, while a solid cube that sinks will have a specific density of more than 1. A hydrometer is a special tool used to measure the specific density of water or other liquids in a solution by floating a standardized weight in the water to be measured. Liquids with different specific densities will organize in layers, with the least dense liquid at the top and most dense at the bottom. A mixture of liquids with different densities may take time to form layers as they reach equilibrium, and as long as the individual liquids do not go into solution with each other. In large bodies of water on Earth, differences in densities can stratify the water in lakes and oceans into different layers with depth. Water’s density varies with temperature, such that pure water will have a density of 1 at 4°C, but water heated to the boiling point will have a density of 0.959 at 100°C. This means warm water will float on top of cold water. If the water is heated from the bottom, convection will cause the warm water to rise and more evenly distribute heat, however if water is heated at the surface, the warmer water will remain near the surface because it will be less dense than water at deeper colder layers. Water found in hot climates heated by the sun at the surface, will be more stratified (layered) than water heated by hydrothermal magma from below, which will cause the warm water to circulate convectively with surface waters and become mixed.

One strange aspect of water is that when it approaches the freezing temperature, the ultra-cold water near freezing and frozen water will be less dense, and float. It may seem like an obvious observation, that ice floats, especially if you have ever had a glass of ice water. But most substances when they freeze into a solid, will sink, as solids are typically denser then the liquid phase. Water is strange in that at about 4°C water is slightly denser than water at 0°C. In oceans and lakes and other large bodies of water as the water gets close to freezing it becomes slightly less dense and will rise from the bottom. Before it can freeze into a solid, the water will rise up to the surface and float. Frozen water, in the form of ice is only found near the surface as the top layer of bodies of water on Earth. This results in the floating ice on water to act as insulation to the warmer water below, due to the high heat capacity of the liquid water and high latent heat of the ice above. If frozen water sank, the bottom of oceans would be covered in thick layers of ice, and prevent life from living on the ocean floor. Hydrogen bonding can explain why ice is less dense than liquid water. As water molecules become linked together in a crystal lattice structure as they freeze, they are packed less densely together with hydrogen atoms linked to oxygen atoms. The individual molecules become arranged in a hexagonal crystalline structure, with each angle of the hexagon represented by an oxygen atom. This crystalline structure is approximately 8.3% less dense than liquid water, and when frozen will expand in volume about 9% more than liquid water. This is why leaving a soda can in a freezer will result in an exploded open can, because the water when it freezes takes up more volume. The effect of the expansion of the freeze-thaw cycle of water is important in rock weathering on Earth’s surface especially in temperate climatic zones. There are 18 known solid crystalline phases of ice, which can also form amorphous solid states, with inclusions of air and various gasses during its formation. Most ice on Earth’s surface is classified as ice-phase-1, or Ice Ih, at extremely cold temperatures and high pressures other types of crystalized ice will form. Most liquids under increasing pressures will freeze at higher temperatures because the pressure pushes the individual molecules tightly together. However, the hydrogen bonds in water resist this increased pressure, and results in a slight melting of ice at high pressure, below 0 °C. This peculiarity of ice will contribute to the motion of glaciers and ice sheets on Earth’s surface, by imposing a thin layer of liquid melt water which forms at the base of thick ice sheets.

Salinity
Salinity is a measurement of the amount of salt dissolved in a body of water. Water with salt dissolved within it is called saline water. This is typically measured by the number of grams of salt that are found in 1,000 grams of water. Typical sea water has a salinity around 35 g/kg (sometimes written as parts per thousand, or 35 ppt). Drinking water has very low salinity of just 0 to 0.5 g/kg. The saltiest portions of the ocean include the Red Sea, where ocean salinity can get up to 40 g/kg, as well as in the Mediterranean Sea at 38 g/kg, which is due to the hot climates and enhanced evaporation over these portions of the ocean. The Great Salt Lake in Utah has salinity levels that range from 50 to 270 g/kg, making it significantly saltier than sea water. The saltiest body of water on Earth is Don Juan Pond, a small lake found in a dry glacial valley near the McMurdo Station in Antarctica. Salinity in the lake is 400 g/kg (or 40% by weight). The extremely high salinity of Don Juan Pond allows the lake to be liquid, even in the freezing cold of Antarctica. The water is so enriched with salt that it has a viscosity of syrup. Viscosity is a measure of how well a liquid flows. The addition of salt to water lowers the freezing point of water by a process called freezing point depression. The freezing point depression occurs because the more random the nature in a solution of water with various dissolved salts, the more opposed it will be to freezing, so that lower temperatures must be reached before the liquid will form a solid. The freezing point of water is lowered when the salt is added, as the salt makes it more difficult for water to freeze. This is why salt is often sprayed on roads and sidewalks to prevent ice in the winter.

Water with a salinity of 100 g/kg will freeze at -6°C, rather than 0°C. It is important to note that a solution containing water with salt as it freezes will not incorporate any of the salt within the crystal lattice, and instead the remaining water will become saltier over time. Just like boiling water where dissolved salts become enriched in the remaining water through distillation, freezing water can also be used to remove much of the salt content of the water, as the frozen water will contain no salts. Dissolved salts in ocean water is not limited to sodium chloride (NaCl), table salt, but also includes sulfate (SO24-), magnesium (Mg2+), calcium (Ca2+), and potassium (K+) ions. If you were to boil ocean water through distillation, the salts that would be left behind would be a mixture of table salt (NaCl), anhydrite (CaSO2), gypsum (CaSO4·2H2O), magnesium sulfate MgSO4·7H2O also known as Epsom salt, and potassium sulfate (K2SO4) which is also called potash. Many of these salts are mined from regions on Earth where oceans or large bodies of water evaporated leaving behind these salts deposited in rock layers now buried underground.

The higher the salinity of water, the greater its density. In the ocean, water at depth tends to be saltier than water found near the surface of the ocean, this is due, in part to the continuous flow of freshwater that enters the ocean from land and will float on its surface. The density of surface ocean water can increase underneath the formation of sea ice. As the ice forms on the surface of the ocean, the remaining cold ocean water just below the icy surface will become saltier, and will tend to sink due to the combined increase in salinity and cold temperature making the ocean water denser below sea ice.

Salinity of the Earth’s Oceans Over Time
The ocean is salty because of the gradual concentration of dissolved ions that erode from the land and are washed into the sea. As such, scientists such as Edmond Halley in the early 1700s proposed that the oceans act as a net reservoir for the world’s salt, and that throughout Earth’s long history the oceans have increased in salinity over time. Little was known of variation in ocean salinity, but in 1872 the Royal Society converted a naval warship, the HMS Challenger to voyage around the world and study the ocean, collecting water samples, and dredging the ocean floor for deep sea life. The ship was equipped with oceanographic laboratories, state-of-art microscopes, and scientific tools to better understand the world’s oceans. From 1872 to 1876, the ship traveled around the world gathering samples of ocean water and recording its temperature. The samples were sent to a professor of chemistry, a German named William Dittmar for analysis. The results of the study demonstrate that the constitutes of the salts dissolved in the oceans do not vary greatly from region to region. Each sample had nearly equal amounts of Chloride (Cl) 19.350 ppt, Sodium (Na) 10.710 ppt, Sulfate (SO4) 2.690 ppt, Magnesium (Mg) 1.304 ppt, Calcium (Ca) 0.419 ppt, Potassium (K) 0.390 ppt, Bicarbonate (HCO3) 0.146 ppt, and Bromide (Br) 0.070 ppt, for a total of 35.079 ppt, or a salinity near 35 g/kg or ppt. One of the surprising discoveries was when these values were compared to freshwater from rivers entering the ocean, Dittmar found significantly more Calcium (Ca) and Bicarbonate (HCO3), compared to Sodium (Na) and Chloride (Cl). So why does ocean water contain less of these two salts? The reason is that both Calcium and Bicarbonate are used by organisms to build their aragonite and calcite shells, using calcium carbonate (CaCO3). Over time these organisms die, the empty shells fall to the ocean floor and are buried, forming limestones. There is a cycle over long periods of time, in which limestones are uplifted onto the land, erode into Calcium (Ca) and Bicarbonate (HCO3), wash into the ocean, and are again used by organisms to build their shells, and then redeposited. This cycle likely has resulted in the oceans salinity over time to reach an equilibrium. Sodium (Na) and Chloride (Cl) are also removed from the oceans during burial, when inlets and shallow seas evaporate, leaving a salty crust that becomes buried. Although it is difficult to estimate salinity over all of Earth’s history, it is likely that salinity of the oceans during the Phanerozoic Eon (last 541 million years) has not changed much because of these processes.

Oxygen
Oxygen is necessary for aerobic animals, which require a source of oxygen for respiration, even underwater. Oxygen makes up 20.95% of the atmosphere. Oxygen, as a gas gets mixed into the ocean near its surface, where this dissolved oxygen gas is greater than about 7 parts per million (ppm). Ocean water with 10 ppm or greater is considered well-oxygenated water able to support a healthy population of fish. The amount of oxygen however decreases with depth, with deep ocean water becoming depleted in oxygen, from hypoxic (low oxygen) to anoxic (no oxygen) bottom waters. This results in fewer aerobic animals living in these deep ocean waters, which are dominated by anaerobic organisms, those are organisms that do not require the presence of oxygen to live.

The amount of oxygen dissolved in the ocean is also related to the water’s salinity and temperature. As salinity increases, the amount of gas dissolved decreases because more water molecules are linked up with calcium and sodium ions. As water temperature increases, the heat increases the mobility of oxygen dissolved gas molecules allowing them to more easily escape from the water, reducing the amount of oxygen. This is why healthy fish populations are never found in salty and extremely warm waters. The colder and fresher the ocean water, the more availability there is for oxygen gas to be present. This is why estuaries, where cold freshwater flows into the oceans are such healthy regions for large schools of fish and other aerobic life forms in the oceans. Oxygen solubility is a function of pressure and temperature, and at sea level (with 1 atmosphere of pressure), the amount of oxygen found within the ocean surface water is directly related to the temperature of the ocean water at its surface. Pure water near freezing temperatures (0° C) can hold upwards of 14 ppm oxygen, at 25° C (77° F), water holds about 8 ppm oxygen, however, when warm water is heated to 45° C (113° F) it only holds 6 ppm oxygen. As water approaches the boiling point 100° C (212° F) little to no oxygen can be dissolved in the water. If you have ever boiled water, you may have noticed that as the water is heated, tiny air bubbles start to form, because the warmed water cannot hold the dissolved oxygen gas. At 100° C (212° F) the water itself starts to boil, and the large bubbles are formed by evaporation of water. However, if the water is cooled back down and then again reheated, bubbles will not appear until the water starts to boil, because the oxygen and other gasses have already escaped from the water during the first time the water was heated.

Since ocean water has a higher salinity than pure water, it is more susceptible to the loss of oxygen. With a salinity of 35 g/kg or ppt, most ocean water will fall below 10 ppm oxygen, and in areas of high salinity where there is increased evaporation and little wave action to contribute oxygen, ocean water near the surface can become deoxygenated. Deoxygenated surface waters are referred to as “dead zones,” because fish lack the necessary oxygen for respiration and die on mass. Dead zones can manifest when lakes or seas become too hot and salty, and lack mixing from crashing waves. In 2017, a dead zone in the Gulf of Mexico was observed when oxygen levels fell below 2 ppm and extended over 8,776 square miles of the coast of Texas, killing fish and shrimp that need more oxygen dissolved in the water. Fear exists that with rising global temperatures, dead zones, such as this one will become more common, and could destroy the fishing industry.

Another important factor in the amount of oxygen available in water is eutrophication. Eutrophication is when a body of water becomes enriched in fertilizers (nitrogen, phosphorus, and sulfate) which results in excess growth of algae on a water’s surface. Algae, which photosynthesizes and produces oxygen. Knowing this fact, it would seem that a healthy coat of algae on the surface of water would increase the amount of oxygen in the water. However, the excessive algae growth on the surface blocks light from reaching deeper depths in the water, resulting in a zone just below the algae covered surface where photosynthesizing lifeforms cannot grow. This dark zone becomes depleted in oxygen over time, and accumulates layers of dead algae that sinks into these dark waters. This graveyard of decaying algae supports scavenging microbial bacteria that feed on this decaying organic matter and thrive in the anoxic deep waters. Eutrophication is a major problem for bodies of water that receive run off from agricultural land where fertilizers have been used heavily.

Carbon dioxide
Carbon dioxide is necessary for photosynthesizing lifeforms, such as cyanobacteria, algae, and phytoplankton, which require both sunlight and a source of carbon dioxide for respiration and growth. However, carbon dioxide is much rarer in the atmosphere (250 to 410 ppm), but quickly rising over the last century. Just like oxygen, carbon dioxide as a gas enters the ocean by agitations of the surface by wind and crashing waves. However, one important aspect of carbon dioxide, that differs from oxygen gas is that it also reacts with water to form carbonic acid, by the chemical equation CO2 + H2O → H2CO3 (carbonic acid). This reaction can go both ways, and release carbon dioxide. Although the amount of carbon dioxide that undergoes this reaction is rather small. In water with carbon dioxide at 25° C (77° F), the ratio of carbonic acid to carbon dioxide, is just 0.0017, and in ocean water 0.0012, which means that most of the carbon dioxide is dissolved as a gas. In the upper parts of the ocean, carbon dioxide ranges greatly between 150 to 700 μatm partial pressure (pCO2), with typical numbers between 280 to 320 pCO2, but has been increasing by about 1.3 ± 0.5 μatm per year on average [Takahashi et al. 1997], in line with increases in atmospheric carbon dioxide over the last century. Just like oxygen gas, carbon dioxide solubility is a function of pressure and temperature, and at sea level (with 1 atmosphere of pressure), the amount of carbon dioxide found within the ocean surface water is directly related to the temperature of the ocean water at its surface. The warmer the ocean water becomes the less carbon dioxide gas the water will be able to hold. There is a fear that with increasing carbon dioxide in the atmosphere and warming global temperatures, the ocean will no longer act like a sink or reservoir for carbon dioxide gas, and the oceans will reach a saturation point with respect to carbon dioxide. If this were to happen, the amount of carbon dioxide in the atmosphere would rise more dramatically, since less carbon dioxide would able to be dissolved in the oceans. However, carbon dioxide reacts with water to form H2CO3 (carbonic acid), which would result in the continued capacity for the absorption of carbon dioxide. The product of this reaction, carbonic acid, will release more hydrogen H+ ions (H2CO3 -> H+ + HCO3- ), resulting in the ocean water becoming more acidic over time. Ocean water is slightly basic, with a pH of 8.12, which has been dropping in recent years to a pH of 8.06 since the 1990s. The slightly basic nature of ocean water is largely due to the excess bicarbonate (HCO3- ) ions that erode from land and are washed into the oceans by rivers. Normally with pH greater than 8, the excess bicarbonate (HCO3- ) ions further contribute a hydrogen ion (H+) resulting in carbonate ions (CO3-2), when this occurs the carbonate ions react to any Ca+2 forming CaCO3 which precipitates out as a solid. You may have noticed this type of reaction if you have used a household cleaner to clean a bathtub. Most cleaners contain calcium carbonate and calcium hydroxide, the calcium hydroxide keeps the pH very high, resulting in any excess of calcium Ca+2 ions in the water to precipitate out as a solid, as white flakes of calcium carbonate CaCO3 you might observe in the rinse water after cleaning. However, if the pH becomes less than 8, the bicarbonate (HCO3- ) ions no longer contribute an extra hydrogen ion (H+), and carbonate ions (CO3-2) no longer form. This results in a lack of deposition of calcium carbonate, and most of the bicarbonate (HCO3- ) ions would remain in solution in ocean water with pH lower than 8.

Oceanographers worry that as the Earth’s oceans become more enriched in H2CO3 (carbonic acid) and become increasingly acidic, that its carbonate chemistry is going to fundamentally change. With ocean depth, water increases in pressure and decreases in temperature, resulting in the dissolution of CaCO3. The carbonate compensation depth (CCD) is defined as the water depth at which the rate of supply of CaCO3 from the surface is equal to the rate of dissolution into Ca+ and CO3-2 ions. Below this depth, CaCO3 dissolves in the water. Organisms that live below the CCD depth in the ocean are unable to compose their shells with calcite or aragonite the two minerals that are made of CaCO3, some deep-water sponges use silica instead, but most reef building organisms cannot live in water that is below the CCD depth.

The geological record contains several examples of deep-sea calcium carbonate (CaCO3) dissolution events that were driving by acidification of the oceans, for example, the Paleocene–Eocene Thermal Maximum (55.5 million years ago), and the Permian-Triassic boundary (252 million years ago). During these global warming events, where the atmosphere was enriched in carbon dioxide, calcium carbonate deposition was dramatically reduced. This can be observed in ancient ocean sediments bracketing these events, where calcium carbon rich limestones are replaced by silica and clay rich mudstone and claystone. Tropical coral reefs are heavily impacted by such events, as these communities require ocean water that can support healthy amounts of calcium carbonate used to make calcite and aragonite skeletons for coral reef communities. When carbon dioxide increases in the world’s oceans, the coral reefs in tropical environments vanish, and most colonial organisms that live in these marine environments become extinct.


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History of wireless telegraphy and broadcasting in Australia/Topical/Publications/Australasian Radio World/Issues/1941 07

P.03 - Editorial Notes
'''Editorial Notes. . .'''

Nil

P.03 - Contents Banner
The Australasian Radio World

Incorporating the

All-Wave All-World DX News

Vol. 6 - JULY, 1941 - No. 2

P.03 - Contents
CONTENTS:

CONSTRUCTIONAL —

"Vibra 4" for Countryman. . . . 5

5-Band Modulated Oscillator. . . . 11

Thirteen-watt Amplifier. . . . 15

Power Oscillator. . . . 29

TECHNICAL —

How to Use an Oscillator. . . . 32

Modern Sound for Modern Hotels. . . . 33

Speedy Query Service. . . . 34

SHORT-WAVE SECTIONS —

Conditions Affecting Reception. . . . 20

Short-wave Review. . . . 23

Loggings of the Month. . . . 24

P.03 - Publication Notes
The "Australasian Radio World" is published monthly by A. G. Hull. Editorial offices, 117 Reservoir Street, Sydney, N.S.W. Telephone MA2455.

Subscription rates: 1/- per copy, 10/6 per year (12 issues) post free to Australia and New Zealand.

Printed by Bridge Printery Pty. Ltd., 117 Reservoir Street, Sydney, N.S.W., for the proprietor of the "Australasian Radio World," 117 Reservoir St., Sydney (Footnote P.36)

P.20 - Shortwave Sections - Conditions Affecting Reception
Conditions Afecting Short-Wave Reception AN AUTHORITATIVE ARTICLE FRO M THE ENGINEERS OF THE B.B.C. W HETHER or not a listener in any part of the world gets good reception of the B.B.C. short-wave programme is dependent upon conditions prevailing in the ionosphere and upon the solar cycle. An explanation of this, in language, which can be understood by the ordinary listener, is given in this article, specially prepared by the B.B.C.'s Engineering Division. The frequencies used for short-wave broadcasting have to be chosen with strict regard to the conditions prevailing in the inosphere over the particular route on which they are to be used. It is in the ionosphere — mainly in that part of it which lies about 180 miles above the earth and which is known as the F layer — that the waves are refracted or "bent round," so that they return to earth again at a distant point. And the behaviour of the wave in the ionosphere will depend upon the conditions existing there at the time, as well as upon the frequency used. • Briefly, it may be said that if the frequency is too high to suit the prevailing ionosphere conditions, the wave will pass clean through the ionised layers, and will not be bent back to earth at all. On the other hand, if the frequency used is too low, the loss of energy in the layers will be so high that a good signal will reach the receiving end of the circuit only if enormous power is used at the transmitting end. Hence it is most important that the frequency used be such that the wave will be properly dealt with by the ionised layers, i.e., that it will be well refracted and returned to earth with the minimum loss of energy in the layers. The frequency which is best suited to the prevailing ionosphere conditions is called the "optimum" frequency. Conditions in the ionosphere are, however, in a constantly changing state. At any one moment they are diferent for diferent latitudes, while at any one point above the world's surface they are subject to three changes of a periodic nature. These are, firstly, a change in conditions from day to night; secondly, a change from season to season; and, thirdly, a change which takes place over a relatively long period of time. The reason for that the condition electrification — of these changes is of ionisation — or the air in the

layers is brought about by the action of the sun. The layers are, in fact, produced mainly by the sun's radiation of ultra violet light. Hence, conditions prevailing at any particular point in the ionosphere will depend, in the main, upon the position of that point relative to the sun, and also upon the state of activity of the sun. It is because of these changes that the frequencies used by a short-wave broadcasting station have to be changed from time to time. Over a long transmission path, where the wave must pass from earth to ionosphere and back again several times, as it were in a series of "hops," the "optimum" frequency will really be the frequency which best suits ionosphere conditions at a number of widely separated points. This must necessarily be something of a compromise, as it is rare that conditions at any two consecutive "hops" are the same. Daily and Seasonal Changes As far as the daily changes in ionosphere conditions are concerned, they are such as to render necessary the use of low frequencies during the night and relatively high frequencies during the day. In summer the degree of change as between day and night is much less than in winter, the consequently the difference between daylight and darkness frequencies is least during the summer. Nevertheless, it is still necessary to use lower frequencies during the night than during the day. The highest frequencies which are usable during the summer become most suitable just before sunset. During last summer the highest frequency suitable for long distance working — by normal methods —in Lat. 50 degrees N. was about 22 Mc/s just before sunset, and about 12 Mc/s, just before sunrise — when the ionisation of the layers is at its lowest. It is in winter that the change of conditions as between day and night is greatest, and, as a result, the working frequencies for winter nights are lower than at any other time of the year, while the winter daytime frequencies are higher. The highest usable frequencies in winter become most suitable about noon. During November the highest frequency suitable for long distance working in Lat. 50 degrees N. was about 32 Mc/s at noon, and about 9 Mc/s just before sunrise. In December the night-time

working frequencies were even lower than in November — about 6 Mc/s. Summarising the daily and seasonal change in working frequencies, we have a change from high to low frequencies from day to night, a change from low to still lower frequencies from summer night to winter night, and a change from high to still higher frequencies from summer day to winter day. The Solar Cycle In addition to the above changes — which are brought about by the varying position of the sun with regard to any particular point in the ionosphere — there is a further change in conditions brought about by a variation of activity within the sun itself. This is such that periods of maximum activity are reached about every eleven years, with periods of minimum activity about half-way between the maxima. The rise and fall in activity is not quite regular, though it is possible to estimate the degree of activity which will exist some time ahead with a fair amount of accuracy. The degree of solar activity is evidenced by the number of sunspots which appear on the sun's surface, and also by the size of the areas of flocculi, or clouds of gases, which can be observed around the sun. The point is that the amount of ionising radiation emitted by the sun varies according to its general degree of activity, and therefore it decreases considerably from the maximum to the minimum period of activity in the eleven year cycle. It is this radiation which produces the layers of the ionosphere, and so the amount of ionisation existing in the layers rises and falls in sympathy with the elevenyear solar cycle. During the year 1937 a period of maximum activity was reached and since then the general level of ionisation in the layers has been falling. The next period of minimum activity is expected to occur about 1945, so that ionisation is expected to occur about 1945, so that ionisation is expected to continue to fall towards that year. When ionisation in the layers is low we are obliged to use lower frequencies for short-wave communication, so it appears that we shall have to make more use of the lower broadcasting frequencies as year succeeds year until 1945. We must remember, however, that the decrease in work-

ing frequency is not a steady one and that, superimposed upon the gradual fall of ionisation, we have the seasonal changes already mentioned. Actually, there is a far bigger decrease in working frequency as between maximum and minimum periods of activity during the winter day than at any other time, a smaller one during the summer day and summer night, and a still smaller decrease during the winter night. During last summer the highest daytime frequency suitable for longdistance working in Lat. 50 degrees N. was about 12 per cent. lower than it was in the summer of 1937, while the highest night-time frequency was about 14 per cent. lower. How the Changes Afect the Frequencies Used So we have now passed the midwinter of the third year after the solar maximum, and the use of lower frequencies will have been noted by listeners. What has been said about the changes in ionisation and the consequent change in working frequency applies mainly to one particular point in the ionosphere. It must be remembered, however, that long transmission routes often pass from day into night or from night into day, and sometimes from midwinter into midsummer; so that ionosphere conditions will vary widely over the route, and the frequency used must be one that will suit the worst conditions encountered over the whole transmission route. In the case of very long routes conditions vary so widely at certain times of day and year that it sometimes becomes impossible to communicate over the route, for any frequency which will escape severe loss at one end of the route will penetrate the ionosphere of th other. Fortunately, this does not apply to many routes, nor at all times and seasons to the others. In fact, such a variety of conditions are encountered over a number of transmission routes that each one has to be separately examined for all seasons and times of day. Conditions of the Empire Routes We may now consider a few of the routes over which the B.B.C. regularly ,transmits, and see how the frequencies are likely to be afected during the coming summer in the northern hemisphere. Let us first take the route to India. The period during which it is most desired to serve India is during the evening hours in that country, and this will be from about 1.00 a.m. to 6.15 p.m. G.M.T. The transmission route will lie entirely within the summer hemisphere, and, as darkness falls in India several hours before it does in England, we shall be transmitting, for some part of the time, from day into night. We can therefore begin the transmission on summer day frequencies — 17 Mc/s au 15 Mc, s — and, in this connection, we may mention that the frequency of 21 lvic/s, which was used with success during former summers, has now become too high to provicL a reliable service, although it may again become serviceable during the autumn. Soon after darkness falls in India there will be a gradual fall in ionisation, and lower frequencies will become necessary. It is expected that between about 3 p.m. and about '7 p.m. ; G.M.T., the optimum frequency will fall from 17 Mc/s to 12 Mc/s, so that we shall probably finish the period on frequencies of 12 Mc/s and 1 Mc/s. Compare this with the recent midwinter period, when, between about noon and 7.0 p.m. G.M.T., the optimum frequency fell from 21 Mc/s to about 6 Mc/s. This was met by the successive introduction of lower frequencies during the English afternoon. Similar considerations apply to the routes to the Far East and to Malaya. In the case of the route to South Africa diferent conditions exist. In the first place we shall have summer conditions at the English end of the circuit and winter conditions at the South African end. A few months ago this position was reversed. Secondly, there is very little time difference over the route, so that, generally speaking, we transmit from day into day or night into night. Both these facts help to account for the fact that there is relatively little change in the optimum frequency from winter to summer. The working frequency usually has to be a compromise that will suit both summer and winter conditions, and its choice is rendered easier by the fact that the time difference over the route is small. Up to the present, the higher frequencies have been found to suit the summer and winter conditions during the day, and this applies also to the equinoctial periods. This year, however, owing to the fall in ionisation caused by the efect of the solar cycle, it is possible that conditions at the English end of the circuit may be such as to render 21 Mc/s too high a frequency. A good dayti me service in Africa, however, should continue to be given by 17 Mc/s. At night conditions are likely to be somewhat dificult, for then, during the northern summer, the extreme south of South Africa requires a lower frequency than is suited to more northerly areas. It is expected, therefore, that, in the case of the extreme south, the optimum frequency will fall from 17 Mc/s to 9 Mc/s — possibly even lower — between 4 p.m. and 10 p.m. G.M.T. In the case of the more northerly parts of Africa 1 Mc/s should still be a serviceable frequency at 10 p.m. G.M.T.

"American-style Communications" Receiver
To obtain best short-wave results it is deÉrable to be able to switch from cne wave-band to another quickly, os with the "American-style Com munications" receiver which was described in our August, 1940, issue. It had bond-switching for five bands.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


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Magic word templates that use undefined cannot call each other, as it would cause undefined to call itself; however, the client subtemplates  can call each other.

The main template is mostly concerned with figuring out what page name is to be parsed; the page name is then passed to subtemplate /parse, along with additional information gathered through subtemplate /find.

With no unnamed parameters, uses the name of the current page. With one unnamed parameter, if it has multiple fields or an  prefix, it's taken to be the page name, otherwise it's the global assistant name and is used to derive a suitable page name. With two unnamed parameters, the second must be suitable as a local assistant name, and both parameters are used to derive a suitable page name.

The alternative parameter arrangements —where an assistant name is specified instead of a page name— are provided because without them, the magic word templates would not relieve the user of having to continually recreate the assistant-page-naming conventions.

title: Template:ASST/doc


text: Template:ASST/parse

title: Template:ASST/parse


text:
Template:ASST/parse/doc

This subtemplate of ASST completes the parse after the page name has been identified and its assistant field located.

Usage
Provide as first unnamed parameter the page name, and as second unnamed parameter the result of applying ASST/find to the page name.

This subtemplate is designed so it can be substituted (via ) as well as transcluded.

title: Template:ASST/parse/doc


text: Template:ASST/find

title: Template:ASST/find


text:
Template:ASST/find/doc

This subtemplate of ASST determines which field of a page name has prefix. Meant to be used at option by other templates, not only by ASST and its subtemplates.

Usage
Specify the page name as unnamed parameter. If the parameter isn't a valid page name, returns blank. If no field of the page name starts with, returns. Otherwise, returns the index of the first field that starts with, starting with   for the first field.

This subtemplate is designed so it can be substituted (via ) as well as transcluded.

title: Template:ASST/find/doc


text: Template:ASST/prefix?

title: Template:ASST/prefix?


text:
Template:ASST/prefix?/doc

This subtemplate of ASST tests a string for prefix. Meant to be used at option by other templates, not only by ASST and its subtemplates.

Usage
Specify the string as unnamed parameter.

Internals
Returns non-blank (specifically, ) iff the parameter starts with. Designed so it can be substituted as well as transcluded.

title: Template:ASST/prefix?/doc


text:
Template:ASST/t

name: space: subpage: full:   parent:

title: Template:ASST/t


text:
Template:ASST/t/doc

This subtemplate of ASST reports parse information.

Usage
Pass (the name of) this subtemplate as parameter  to ASST.

Internals
Used by ASST/example. Designed so it can be substituted as well as transcluded.

title: Template:ASST/t/doc


text: Template:ASST/example

title: Template:ASST/example


text:
Template:ASST/example/doc

This subtemplate of ASST generates a single line of the template documentation's table of examples.

Usage
Specify the one or two unnamed parameters to be passed.

This template is designed so it can be substituted (via ) as well as transcluded.

Internals
Calls ASST with.

title: Template:ASST/example/doc


text: Template:ASST/trim

title: Template:ASST/trim


text:
Template:ASST/trim/doc

This subtemplate of ASST strips optional prefix  from a string. Meant to be used at option by other templates, not just by ASST and its subtemplates.

Usage
Specify the string as unnamed parameter.

This template is designed so it can be substituted (via ) as well as transcluded.

Internals
If the parameter doesn't start with, it's returned unchanged, otherwise the prefix is removed.

At this writing, this template is not used by ASST or any of its (other) subtemplates. However, it seemed naturally to group  and   under the same template; and of the likely choices, ASST is both the shortest-named and most generic.

title: Template:ASST/trim/doc


text: Template:ASST/weight

title: Template:ASST/weight


text:
Template:ASST/weight/doc

This subtemplate of ASST uses an option to decide whether to put given text in boldface. Meant to be used at option by other templates, not just by ASST and its subtemplates.

Usage
Specify the string as unnamed parameter. Specify non-blank parameter  to put the string in boldface.

This template can be substituted (via ) as well as transcluded.

Internals
This is a convenient way to use a parameter to determine whether or not to bold something, without writing the whole markup twice,.

At this writing, this template is not used by ASST or any of its (other) subtemplates; though it is used by some templates that also use ASST.

title: Template:ASST/weight/doc


text:
Template:ASSTCATEGORY/t

Category:

title: Template:ASSTCATEGORY/t


text:
Template:ASSTCATEGORY/t/doc

This subtemplate of ASSTCATEGORY derives the result from parse information.

Usage
Pass (the name of) this subtemplate as parameter  to ASST.

Internals
For local assistants, this subtemplate consults ASSTCATEGORY/parent cat. Can be substituted as well as transcluded.

title: Template:ASSTCATEGORY/t/doc


text: Template:ASSTCATEGORY/parent cat

title: Template:ASSTCATEGORY/parent cat


text:
Template:ASSTCATEGORY/parent cat/doc

This subtemplate of ASSTCATEGORY names the general category, if any, associated with the parent of a local assistant. Meant to be used at option by other templates, not just by ASSTCATEGORY and its subtemplates.

Usage
Pass the name of the parent page as unnamed parameter. The result is blank if the parent page has no associated general category. If provided, the result omits the  prefix.

Internals
This subtemplate is meant to be customized for different projects.

If this subtemplate returns non-blank, it has, at this writing, two effects on the local assistant category: renaming it (per ASSTCATEGORY), and making it a subcategory of the parent category (per AssistantCat).

For example, as of this writing, on English Wikibooks all the pages associated with a book would be arranged under. So an assistant would have associated  (rather than the same without the   prefix), and the assistant category would itself belong to the book category (as well as to Category:Interactive assistants).

Customizations should prefix any template calls or magic words with, so the subtemplate can be substituted as well as transcluded.

title: Template:ASSTCATEGORY/parent cat/doc


text: Template:ASSTCATEGORY

title: Template:ASSTCATEGORY


text:
Template:ASSTCATEGORY/doc

This template returns the full name of the collective category for the interactive assistant to which the page it's used on belongs, assuming certain naming conventions.

Usage
Simply place  on a page to get the output.

Optionally specify a page as a parameter to see the output for a different page than the current one; or the name of a global assistant, or parent and name of a local assistant (see parameter examples at ASST).

This template can be substituted (via ) as well as transcluded.

Internals
Calls ASST with /t.

title: Template:ASSTCATEGORY/doc


text:
Category:Templates for project-specific customization

These templates provide information that may vary from project to project, so that other templates can be written independent of this information.


text: Template:AssistantCat/t

title: Template:AssistantCat/t


text:
Template:AssistantCat/t/doc

This subtemplate of AssistantCat derives the result from parse information.

Usage
Pass (the name of) this subtemplate as parameter  to ASST.

Internals
Uses ASSTCATEGORY/t, ASST/trim, and ASSTCATEGORY/parent cat. Can be substituted as well as transcluded.

title: Template:AssistantCat/t/doc


text: Template:AssistantCat/case

title: Template:AssistantCat/case


text:
Template:AssistantCat/case/doc

This subtemplate of AssistantCat generates a row in a table of examples. Meant to be used at option for documentation of other related templates, not only for documentation of AssistantCat.

Usage
Simply call this subtemplate to generate a row in a table of examples, calling the current base template (i.e., current page name truncating from the first slash). The first unnamed parameter and any named parameters are passed through to the template being tested, via Module:TScope.

title: Template:AssistantCat/case/doc


text: Template:AssistantCat/examples

title: Template:AssistantCat/examples


text:
Template:AssistantCat/examples/doc

This subtemplate of AssistantCat contains a table of examples. Meant to be used at option for documentation of other related templates, not only for documentation of AssistantCat.

Usage
Simply call this subtemplate to generate a table of examples, calling the template named by OBJECTPAGENAME. Additional rows may be specified through optional parameter.

Internals
Uses AssistantCat/case to generate each row.

title: Template:AssistantCat/examples/doc


text: Template:AssistantCat

title: Template:AssistantCat


text:
Template:AssistantCat/doc

This template categorizes a page belonging to an interactive assistant, assuming certain naming conventions.

Usage
Simply place  on a page to categorize it.

Optionally specify a page as a parameter to base categorization on a different page than the current one; or the name of a global assistant, or parent and name of a local assistant (see parameter examples at ASST).

This template can be substituted (via ) as well as transcluded.

Internals
Calls ASST with AssistantCat/t.

title: Template:AssistantCat/doc


text:
History of wireless telegraphy and broadcasting in Australia/Topical/Publications/Australasian Radio World/Issues/1941 08

P.03 - Contents Banner
The Australasian Radio World

Incorporating the

All-Wave All-World DX News

Vol. 6 - AUGUST, 1941 - No. 3

P.03 - Contents
CONTENTS:

CONSTRUCTIONAL —

"Trade Builder Five" Mantel Model. . . . 5

All-wave One-valve Receiver. . . . 19

The Crystal Circuit to End All Crystal Circuits. . . . 32

Amplifier for Fidelity at Low Volumes. . . . 19

Pre-amplifier Circuit for Microphones. . . . 31

TECHNICAL —

Curing Instability in Modern Superheterodynes. . . . 15

Attaining High Speed at the Morse Code. . . . 13

What Is "Radio Location"? . . . . 30

Free Technical Data Chart Offer. . . . 38

Analysing Push-pull Output Circuits. . . . 33

SHORT-WAVE SECTION —

Loggings of the Month. . . . 24

Short-wave Review. . . . 22

New Members of the DX Club. . . . 34

TRADE SECTION —

New "Westex" Cabinets. . . . 35

Philips' 50 Years of Progress. . . . 35

Mullard Mantel Models Reviewed. . . . 29

Ultimate Catalogue Issued. . . . 37

P.03 - Publication Notes
The "Australasian Radio World" is published monthly by A. G. Hull. Editorial offices, 117 Reservoir Street, Sydney, N.S.W. Telephone MA2455.

Subscription rates: 1/- per copy, 10/6 per year (12 issues) post free to Australia and New Zealand.

Printed by Bridge Printery Pty. Ltd., 117 Reservoir Street, Sydney, N.S.W., for the proprietor of the "Australasian Radio World," 117 Reservoir St., Sydney (Footnote P.40)

P.03 - Editorial Notes
Dit d' d' dah!

It is significant that the morse code sign for "V" is figuring so prominently in the Victory Campaign. When the full history of this war is written, it will be revealed that the assistance of radio and aviation has been vital. It is fairly obvious that the Victory Campaign has been nicely timed, as we are undoubtedly around the corner now, and victorious peace may be with us again at any day now. Let us hope that the two sciences will never again have the restrictions of officialdom which have hampered their progress in the past. Let us hope that the rising generation will be afforded every assistance to enjoy both radio and aviation as scientific hobbies. Never let us forget that "The Price of Peace Is Eternal Vigilance."

P.34 - Short-wave Section - New Members of the DX Club
ALL-WAVE ALL-WORLD DX CLUB

NEW MEMBERS

AW678DX - L. T. Woods, Larras Lake North, Larras Lee, N.S.W.

679 - W. Smith, "The Nook," Honor Avenue, Chelmer, Qld.

680 - H. T. Collier, "Idavill," Wentworth Street, Blackheath, N.S.W.

681 - R. Taylor, 45 Myahgah Road, Mosman, N.S.W.

682 - G. D. Gilbert, 52 Nicholson Street, Burwood, N.S.W.

683 - J. S. Beatty, Department of Public Health, Kavieng, T.N.G.

684 - S. A. Grocott, Kallara Station, Louth, N.S.W.

685 - K. E. Odell, C/- Box 52, P.O., Armidale, N.S.W.

686 - I. D. Broadfoot. 73 Fisher Street, Fullarton Estate, S.A.

687 - W. A. Easterling. . 35 First Street, Ashbury, N.S.W.

688 - N. C. Wolens, Mount Crosby, via Ipswich, Qld.

689 - R. C. Harvey, 10 Linley Avenue, Prospect, S.A.

690 - A. Gauter 251 Botany Street, Kingsford, N.S.W.

691 - M. B. Darby, Box 23, Lake Grace, W.A.

692 - D. M. Geeves, Military Post Office, Redbank, Qld.

693 - R. R. Collins, 116 Carlisle Street, Glanville, S.A.

694 - L. Richards, Logan Downs, Nine-mile, Clermont, Qld.

695 - R. E. Gallasch, Pine Avenue, Hahndorf, S.A.

696 - J. R. Dunmall, Russell Street, Dalley, Qld.

697 - J. Page, 206 Aro Street, Wellington, N.Z.

698 - Rev. N. Patrinacos, 56 Stanley Street, South Brisbane, Qld.

699 - L. W. Adams, 22 Crimeo Street, Parramatta, N.S.W.

700 - J. Houlahan 34 Howe Street, Lambton, Newcastle, N.S.W.

701 - J. V. Davis. Castle Road, Wootton, nr. Woodstock, Oxon, Eng.

702 - O. Ablett, Church Street, Balranald, N.S.W.

703 - R. Price, Empire Hotel, Scone, N.S.W.

704 - K. Goard, 2 Southerland Road, Chatswood, N.S.W.

705 - D. Battvall, 31 Forest Avenue East, Clarence Gardens, S.A.

706 - B. W. Battis, Surry Street, Coraki, N.S.W.


text:
History of wireless telegraphy and broadcasting in Australia/Topical/Publications/Australasian Radio World/Issues/1942 01

P.03 - Contents Banner
The Australasian Radio World

Devoted entirely to Technical Radio

and incorporating the

All-Wave All-World DX News

Vol. 6 - JANUARY, 1942 - No. 8

P.03 - Publication Notes
Proprietor, Publisher, Editor - A. G. HULL

Editorial Offices - 117 Reservoir Street, Sydney, Phone MA2455

Office Hours - Week-days: 9 a.m. - 5 p.m. Not open Saturday morning

Subscription Rates - 6 issues 5/3, 12 issues 10/6, 24 issues £1, Post free to any address

Service Departments - Back Numbers, 6d. ea., post free; Reply-by-mail Queries, 1/- each; Laboratory Service, 2/6 per set

Printed by Bridge Printery Pty. Ltd., 117 Reservoir Street, Sydney, N.S.W., for the proprietor of the "Australasian Radio World," 117 Reservoir St., Sydney (Footnote P.36)

P.03 - Contents
CONTENTS:

CONSTRUCTIONAL -

Signal Tracer for Battery Operation. . . . 13

Countryman's Seven-valve Dual-waver. . . . 23

A Portable Battery Circuit. . . . 9

Renovating Radio Cabinets. . . . 10

TECHNICAL -

Direct-coupled Phase-changers. . . . 5

Five-way Tone Control. . . . 12

Fundamentals of the C.R.O. .. . . 15

Some Battery Set Considerations. . . . 20

SHORT-WAVE SECTION -

Notes from My Diary. . . . 24

Loggings of the Month. . . . 26

New Stations Heard. . . . 25

THE SERVICE PAGE -

Answers to Queries. . . . 34

Battery Circuit Contest Results. . . . 11

P.03 - Editorial Notes
Editorial

The arrival of a recent mail has again emphasised the amazing way in which the English "can take it." Notwithstanding the difficult conditions which must prevail on account of the incessant bombings, the radio press is still performing its work of national importance by disseminating technical information. In London the good old "Wireless World" carries on in grand style, strongly supported by the leading advertisers. In their latest issue we notice nearly all the famous brand names amongst the twenty-two pages of advertising. Fortunately, our position in Australia is infinitely safer than in Britain, although our radio business has its trading difficulties. It is encouraging to notice that these difficulties are being faced in true Digger spirit and with a long-range outlook to the wide span of years which lies beyond our immediate task of dealing with the present disturbers of the peace. In the meantime, we radio men will need to show the keenest initiative to keep our million and a half radio receivers in good operating condition.


text:
History of wireless telegraphy and broadcasting in Australia/Topical/Publications/Australasian Radio World/Issues/1942 02

P.03 - Contents Banner
The Australasian Radio World

Devoted entirely to Technical Radio

and incorporating the

All-Wave All-World DX News

Vol. 6 - FEBRUARY, 1942 - No. 9

P.03 - Publication Notes
Proprietor, Publisher, Editor - A. G. HULL

Editorial Offices - 117 Reservoir Street, Sydney, Phone MA2455

Office Hours - Week-days: 9 a.m. - 5 p.m. Not open Saturday morning

Subscription Rates - 6 issues 5/3, 12 issues 10/6, 24 issues £1, Post free to any address

Service Departments - Back Numbers, 6d. ea., post free; Reply-by-mail Queries, 1/- each; Laboratory Service, 2/6 per set

Printed by Bridge Printery Pty. Ltd., 117 Reservoir Street, Sydney, N.S.W., for the proprietor of the "Australasian Radio World," 117 Reservoir St., Sydney (Footnote P.32)

P.03 - Contents
CONTENTS:

CONSTRUCTIONAL -

Tried and Tested One-valver. . . . 5

Detector Unit for Amplifiers. . . . 17

Re-building Radio Batteries. . . . 19

Alternative Bias Amplifier. . . . 21

TECHNICAL -

Victorian Champion Amplifier. . . . 9

Two Effective Battery Circuits. . . . 11

Baffling the Loud-speaker. . . . 14

Crystals for Frequency Control. . . . 16

The Reduction of Harmonic Distortion. . . . 22

SHORT-WAVE SECTION -

Short-wave Review. . . . 24

Tokyo's Broadcast Propaganda. . . . 25

The Month's Loggings. . . . 26

New Stations. . . . 26

Latest Loggings. . . . 28

THE SERVICE PAGE -

Wanted - Old Transmitting Valves. . . . 18

Answers to Queries. . . . 30

P.03 - Editorial Notes
Editorial

Owing to difficult trading conditions - most radio lines being easier to sell than to buy - there is a falling off in advertising, thus allowing more space to be devoted to reading matter. Scarcity of paper, however, tends to offset this gain, and so we find ourselves this month with an issue which contains only a small number of pages, a few scattered advertisements, but a full complement of technical matter which will give some idea of the way in which "Australasian Radio World" will face up to changed conditions. Space being so much at a premium, we are unable to go over the fundamentals thoroughly in each issue, but we do keep a stock of back numbers so that these may be referred to for such matters. We find that these back numbers are in keen demand, and the success of our recent special offer of a set of a dozen for 5/- prompts us to make another special offer. This time we are prepared to supply, post free, a complete set of the 1941 issues to every reader taking out a subscription for 1942. Only a limited number of sets are available and so an early application is essential.


text:
Linux Basics/Basic commands

Root vs user permission

 * - root permission
 * - user permission

User can execute things with root permission that the user wouldn't do with base permission like, but using sudo does the same job as if you were in root. Linux Basics/User management (System administrator) chapter dives deeply into this topic.

Commands

 * : it will display all the switches for the command
 * : change directory (→ cd .. = it will go back by one folder/directory)
 * : print working directory – it'll display which folder you're in right now
 * : it shows who are logged in and what they are doing (w displays the particular user's activity)
 * : it displays only the tty interface, the date and ip address with the username
 * : listing files in a directory
 * : it lists all the hidden files aside the non-hidden ones
 * : same as previous, but it lacks . and .. (. means the current folder, .. means previous folder)
 * : detailed directory list
 * : based on the commands above: detailed directory list + hidden files with . and ..
 * : it'll quit the user from the shell and close the shell
 * : you can do commands as superuser
 * : move, moving from A to B: syntax: mv : midnight commander's command (you have to install it, because most distros don't contain mc by default)
 * : creating "file" named file
 * : "something" will be directed to the echo's standard output.
 * : editing "file" named file with nano (by default on some distros it's not installed, so you have to install it)
 * : outputting "file" named file to the terminal, but you can move in the word viewer, and you can quit from it by pressing q
 * : remove, delete
 * : recursive, so the rm command will delete everything that is given
 * : force, so without any arguments the folder will be deleted
 * : folder deletion, but rm -rf is simpler to delete a folder with files.
 * : connecting devices
 * : disconnecting devices
 * : creating link (hard-link)
 * : creating soft-link/symlink the differences between and softlink is written in Linux Basics/The structure of Linux chapter)
 * = disk free = it says how many free spaces are on each partition
 * = disk usage; you have to give parameters, else it's gonna list all the directories
 * : it's gonna list the content of /home and the usage of the folders
 * it says which folder and file how many kB, MB, GB does it take, if we won't put this, it's gonna list everything in bytes
 * summarizes (it takes every folder as one, and it'll write the sum of their size)
 * = free memory and swap space
 * (black and white) /  (color) = it displays the currently running apps (like Task Manager in Windows)
 * = displays info about the system, -a switch tells everything about the kernel

Output in Manjaro:

 * = it's gonna update your system's time based on the time server address you gave (like time.nist.gov => ntpdate time.nist.gov)
 * = how long have your system been running, and how much it's loaded
 * = network statistics
 * = It opens the manual pages of the command, short and straightforward description
 * = same as man, just it's more common in Red Hat systems

Network managemenent

 * = ip address, network settings, amount of sent and received packages
 * = same as ifconfig, just this is for wireless settings
 * (pinging an IP address) : ping www.google.com ; ping -c 3 www.google.com (we can give after the -c switch how much packets do we want to send to a page)
 * = interface up – it runs a script when it's enabled (e.g. ifup eth0 -> it enables eth0 interface)
 * = interface down – same as ifup, just here we disable the interface e.g. ifdown eth0
 * - interface status
 * – it monitors the upload/download speed of the interfaces

User management

 * / – user creation
 * – user deletion
 * - change mode - we can set the permissions for the files and directories(Linux Basics/Filesystem, permissions has more information on this)
 * – change owner
 * – modifying user

package management commands: dpkg, rpm, apt, yum, dnf, pacman, zypper stb.

Other commands

 * – clears terminal
 * – changing root folder
 * – killing/terminating process based on PID (ps -A displays that)
 * – kills every subthread
 * - kills the list's all elements but kill -9 @(...) is easier
 * - computer shuts down, but its PSU still goes(in case of ATX v2 PSUs)
 * /  – computer shuts down completely
 * – computer reboots –
 * – bash command prompt
 * – we can start/restart services running on the computer
 * – same as service
 * : computer does things without your input (in intervals, startups, shutdowns), cron daemon runs these (hourly, daily, weekly..)
 * : user's own cron setting
 * : editing crontab

/etc/skel folder: the content of this folder goes to the new user's home folder (skel = skeleton)

/etc/sudoers file: those users who can use sudo. (Linux Basics/Filesystem, permissions explains it in depth)

title: Linux Basics/Basic commands


text:
Cookbook:Chestnut Puree

This recipe is a translation of a recipe in Ma cuisine 2 500 recettes by August Escoffier, written in French and published in 1934 (Purée de Marrons, page 522). The recipe has been reformatted in line with modern recipe writing conventions.

Ingredients

 * Whole chestnuts
 * 1 pinch white granulated sugar
 * 1 pinch salt, if needed
 * Butter
 * 1 quart (950 ml) chicken, veal, or beef stock

Procedure

 * 1) Carefully split the skin at the thin (protruding) side of the chestnuts, and place them on a baking tray that contains a little water.
 * 2) Bake chestnuts in the oven for around 7–8 minutes. This will make it easier to peel them.
 * 3) Peel the chestnuts.
 * 4) Cook the chestnuts in just enough consommé for them to be damp. The chestnuts should not be hard but not be too well cooked either.
 * 5) Pass the cooked chestnuts through a fine sieve.
 * 6) Put the puree into a saucepan, then add a pinch of sugar and a pinch of salt if necessary.
 * 7) Add fine butter and turn off the heat once thick.

title: Cookbook:Chestnut Puree


text: Template:ASSTDOC/t

title: Template:ASSTDOC/t


text:
Template:ASSTDOC/t/doc

This subtemplate of ASSTDOC derives the result from parse information.

Usage
Pass (the name of) this subtemplate as parameter  to ASST.

Internals
Can be substituted as well as transcluded.

title: Template:ASSTDOC/t/doc


text: Template:ASSTDOC

title: Template:ASSTDOC


text:
Template:ASSTDOC/doc

This template returns the name of the main documentation page for the interactive assistant to which the page it's used on belongs, assuming certain naming conventions.

Usage
Simply place  on a page to get the output.

Optionally specify an anchor within documentation page, as parameter.

Optionally specify a page as unnamed parameter to see the output for a different page than the current one; or the name of a global assistant, or parent and name of a local assistant (see parameter examples at ASST).

This template can be substituted (via ) as well as transcluded.

Internals
Calls ASST with /t. Given an,  s it.

title: Template:ASSTDOC/doc


text:
Template:ASSTDOCHEADING/t

|

title: Template:ASSTDOCHEADING/t


text:
Template:ASSTDOCHEADING/t/doc

This subtemplate of ASSTDOCHEADING derives the result from parse information.

Usage
Pass (the name of) this subtemplate as parameter  to ASST.

This subtemplate can be substituted (via ) as well as transcluded.

title: Template:ASSTDOCHEADING/t/doc


text: Template:ASSTDOCHEADING

title: Template:ASSTDOCHEADING


text:
Template:ASSTDOCHEADING/doc

This template returns the content for a section heading for the current page, suitable for use on the main documentation page for the interactive assistant to which the page belongs, assuming certain naming conventions.

Usage
Simply place  on a page to get the output. Intended primarily for use on the main documentation page of an assistant, between double-equals:

Optionally specify a page as unnamed parameter to see the output for a different page than the current one; or the name of a global assistant, or parent and name of a local assistant (see parameter examples at ASST).

The generated section header includes an anchor to the full name of the linked page.

This template can be substituted (via ) as well as transcluded.

Internals
Calls ASST with /t.

title: Template:ASSTDOCHEADING/doc


text:
Linux Basics/Terminals, command prompt, alias, history

What's a terminal?

 * Terminal = command prompt → shell = command-line interpreter
 * Text-mode, DOS-like
 * There are several terminals
 * Gnome-terminal, Xfce4-terminal, xterm, etc.
 * There are many shells (e.g. bash, fish, ksh, zsh etc.)
 * you can also customize the shells, for example this video on YouTube shows it: [GNOME 3.28 PowerLevel9k -  The Most Cool Linux Shell EVER! ]
 * commands can be executed
 * command list: https://ss64.com/bash/ (and also the Linux Basics/Basic commands chapter)
 * alias: we can shorten a complex command with an alias or we can create our own one.
 * Location of definition (in case of bash shell): ~/.bashrc
 * Global aliases: /etc/bashrc

History

 * It can be recalled by pressing up and down arrows on keyboard
 * you can switch tabs on terminal by pressing ctrl+page up or ctrl+page down
 * ~/.bash_history shows the commands before login

Environment variables
Environment variables: it stores information of the operating system or programs. Environment variables get set automatically after startup. For example, PATH environment variable tells the shell where to search the executable files.

 * Printing them to terminal: ,
 * but particular environment variables can be displayed too:
 * to set up an environment variable:
 * to delete an environment variable:
 * displaying a particular one(same as printenv basically):
 * to have the setting in the system permanently:
 * we can create an own command under  folder, but it works only if we added the folder to PATH environment variable:
 * , and to make it permanent in .bashrc:

Thottee explained it on his website in more detail that what we do exactly (his website is in hungarian so you may need to translate it with a translator program: http://linuxkezdoknek.hu/articles.php?article_id=33 (the article's second half)

Help

 * help for using a command:
 * command for the manual (detailed help): ,
 * usage:


text: Template:ASSTDOCLINK/t

title: Template:ASSTDOCLINK/t


text:
Template:ASSTDOCLINK/t/doc

This subtemplate of ASSTDOCLINK derives the result from parse information.

Usage
Pass (the name of) this subtemplate as parameter  to ASST.

Internals
Can be substituted as well as transcluded.

title: Template:ASSTDOCLINK/t/doc


text:
Template:ASSTDOCLINK/doc

This template returns a link to the main documentation page of the interactive assistant to which the page it's used on belongs, assuming certain naming conventions.

Usage
Simply place  on a page to get the output. By default, when called from any subsidiary page of the assistant, the link is to the section about that subsidiary page on the main documentation page, while when called from the main page of the assistant the link is to the main documentation page as a whole.

Optional parameters:
 * unnamed — page name to use instead of the name of the transcluding page. Alternatively, name of a global assistant, or parent and name of a local assistant (cf. ASST).
 * — if non-blank, puts the assistant name (but not the parent) in boldface.
 * — anchor when linking to the main documentation page for the assistant, overriding the default behavior. See ASSTDOCHEADING.
 * — label for the link instead of the name of the assistant (name being the field after ).
 * — used for page-creation list if the main documentation page for the assistant does not exist.
 * — used for page-creation list if the main documentation page for the assistant does not exist.
 * — if non-blank, and no  is specified, the part of the page name after the assistant name is used for the label; see ASSTSUB.

If  is non-blank, the   (as provided by ASST) is omitted.

If  or   is non-blank, and the target doesn't exist, the label has   pefixed to it.

This template can be substituted (via ) as well as transcluded.

Internals
Calls ASST with /t.

title: Template:ASSTDOCLINK/doc


text: Template:ASSTDOCLINK

title: Template:ASSTDOCLINK


text: Template:ASSTROOT

title: Template:ASSTROOT


text:
Template:ASSTROOT/doc

This template returns the name of the main page of the interactive assistant to which the page it's used on belongs, assuming certain naming conventions.

Usage
Simply place  on a page to get the output.

Optionally specify a page as a parameter to see the output for a different page than the current one; or the name of a global assistant, or parent and name of a local assistant (see parameter examples at ASST).

This template can be substituted (via ) as well as transcluded.

Internals
Calls ASST with /t.

title: Template:ASSTROOT/doc


text:
Template:ASSTROOT/t/doc

This subtemplate of ASSTROOT derives the result from parse information.

Usage
Pass (the name of) this subtemplate as parameter  to ASST.

Internals
Can be substituted as well as transcluded.

title: Template:ASSTROOT/t/doc


text: Template:ASSTROOT/t

title: Template:ASSTROOT/t


text: Template:ASSTROOTLINK

title: Template:ASSTROOTLINK


text:
Template:ASSTROOTLINK/doc

This template returns a link to the main page of the interactive assistant to which the page it's used on belongs, assuming certain naming conventions.

Usage
Simply place  on a page to get the output.

Optional parameters:
 * unnamed — page name to use instead of the name of the transcluding page. Alternatively, name of a global assistant, or parent and name of a local assistant (cf. ASST).
 * — anchor when linking to the main page for the assistant.
 * — used for page-creation link if the main page for the assistant does not exist.
 * — used for page-creation link if the main page for the assistant does not exist.
 * — label for the link instead of the name of the assistant (name being the field after ).

If  is non-blank, the   (as provided by ASST) is omitted.

If  or   is non-blank, and the target doesn't exist, the label has   pefixed to it.

This template can be substituted (via ) as well as transcluded.

Internals
Calls ASST with /t.

title: Template:ASSTROOTLINK/doc


text:
Template:ASSTROOTLINK/t/doc

This subtemplate of ASSTROOTLINK derives the result from parse information.

Usage
Pass (the name of) this subtemplate as parameter  to ASST.

Internals
Can be substituted as well as transcluded.

title: Template:ASSTROOTLINK/t/doc


text: Template:ASSTROOTLINK/t

title: Template:ASSTROOTLINK/t


text: Template:ASSTTEXT

title: Template:ASSTTEXT


text:
Template:ASSTTEXT/doc

This template identifies the interactive assistant to which the page it's used on belongs, assuming certain naming conventions.

Usage
Simply place  on a page to get the output.

Optional parameters:
 * unnamed — page name to use instead of the name of the transcluding page. Alternatively, name of a global assistant, or parent and name of a local assistant (cf. ASST).
 * — if non-blank, puts the assistant name (but not the parent) in boldface.
 * — if non-blank, don't link the assistant name to the main documentation page for the assistant.
 * — anchor when linking to the main documentation page for the assistant.
 * — used for page-creation list if the main documentation page for the assistant does not exist.
 * — used for page-creation list if the main documentation page for the assistant does not exist.

This template can be substituted (via ) as well as transcluded.

Internals
Calls ASST with /t.

title: Template:ASSTTEXT/doc


text: Template:ASSTTEXT/t

title: Template:ASSTTEXT/t


text:
Template:ASSTTEXT/t/doc

This subtemplate of ASSTTEXT derives the result from parse information.

Usage
Pass (the name of) this subtemplate as parameter  to ASST.

Internals
Can be substituted as well as transcluded.

title: Template:ASSTTEXT/t/doc


text: Template:ASSTTEMPLATE

title: Template:ASSTTEMPLATE


text:
Template:ASSTTEMPLATE/doc

This template returns the basic name for templates of the interactive assistant to which the page it's used on belongs, assuming certain naming conventions.

Usage
Simply place  on a page to get the output.

Optionally specify a page as a parameter to see the output for a different page than the current one; or the name of a global assistant, or parent and name of a local assistant (see parameter examples at ASST).

This template can be substituted (via ) as well as transcluded.

Internals
Calls ASST with /t.

title: Template:ASSTTEMPLATE/doc


text:
Template:ASSTTEMPLATE/t

Template:

title: Template:ASSTTEMPLATE/t


text:
Template:ASSTTEMPLATE/t/doc

This subtemplate of ASSTTEMPLATE derives the result from parse information.

Usage
Pass (the name of) this subtemplate as parameter  to ASST.

Internals
Can be substituted as well as transcluded.

title: Template:ASSTTEMPLATE/t/doc


text:
Template:ASSTSUB/t/doc

This subtemplate of ASSTSUB derives the result from parse information.

Usage
Pass (the name of) this subtemplate as parameter  to ASST.

Internals
Can be substituted as well as transcluded.

title: Template:ASSTSUB/t/doc


text:
Template:ASSTSUB/doc

This template returns the part of the page name that comes after the name of the interactive assistant to which it belongs, assuming certain naming conventions.

Usage
Simply place  on a page to get the output.

Optionally specify a page as a parameter to see the output for a different page than the current one; or the name of a global assistant, or parent and name of a local assistant (see parameter examples at ASST).

This template can be substituted (via ) as well as transcluded.

Internals
Calls ASST with /t.

The part of the page name omitted by this template is provided by either ASSTROOT, ASSTTEMPLATE, or ASSTCATEGORY, depending on whether the page is in the assistant's native space, template space, or category space. Thus, if this template returns non-blank, the full page name should be either ASSTROOT/ASSTSUB, ASSTTEMPLATE/ASSTSUB, or ASSTCATEGORY/ASSTSUB.

title: Template:ASSTSUB/doc


text: Template:ASSTSUB/t

title: Template:ASSTSUB/t


text: Template:ASSTSUB

title: Template:ASSTSUB


text:
Linux Basics/User management (System administrator)

The system administrator (superuser) and its functions

 * The most important user in Linux is: root
 * UID: 0, GID: 0
 * Root can access everything in the system!
 * The „su” command:
 * Changing user and executing command:
 * For example, we can become user mary:
 * If we use dash, then we get the whole environment of mary:
 * We can add a group with the sg command. For example, we can add info:
 * Sudo command
 * With sudo command we can execute superuser commands. It asks the user's password, this is important because we don't want anybody to modify our system.
 * Ubuntu-based systems get root permissions only by sudo, root user doesn't get password.
 * We don't edit sudo's settings from directly the file. We use the following command instead:
 * Settings → in /etc/sudoers file
 * Syntax:  Example:
 * Without NOPASSWD it asks the given user's password.
 * Setting superuser permission:
 * Syntax:  Example:
 * Without NOPASSWD it asks the given user's password.
 * Setting superuser permission:


text:
History of wireless telegraphy and broadcasting in Australia/Topical/Publications/Australasian Radio World/Issues/1942 03

P.03 - Contents Banner
The Australasian Radio World

Devoted entirely to Technical Radio

and incorporating the

All-Wave All-World DX News

Vol. 6 - MARCH, 1942 - No. 10

P.03 - Publication Notes
Proprietor, Publisher, Editor - A. G. HULL

Editorial Offices - 117 Reservoir Street, Sydney, Phone MA2455

Office Hours - Week-days: 9 a.m. - 5 p.m. Not open Saturday morning

Subscription Rates - 6 issues 5/3, 12 issues 10/6, 24 issues £1, Post free to any address

Service Departments - Back Numbers, 6d. ea., post free; Reply-by-mail Queries, 1/- each; Laboratory Service, 2/6 per set

Printed by Bridge Printery Pty. Ltd., 117 Reservoir Street, Sydney, N.S.W., for the proprietor of the "Australasian Radio World," 117 Reservoir St., Sydney (Footnote P.32)

P.03 - Contents
CONTENTS:

CONSTRUCTIONAL -

"Little Companion". . . . 5

TECHNICAL -

Economy in Amplifier Design. . . . 13

Copper Wire Production. . . . 14

Harmonics in Reproduction. . . . 15

SHORT-WAVE SECTION -

Breaking into DX. . . . 22

Short-wave Review. . . . 24

New Stations. . . . 25

Loggings of the Month. . . . 26

THE SERVICE PAGES -

Guide to Back Numbers. . . . 18

Answers. . . . 30

P.03 - Editorial Notes
Editorial

At the moment of writing, the future, to put it mildly, is obscure. Nobody can possibly imagine that the prospects are rosy, and so I have been doubly pleased to find that my readers have expressed their confidence in me so positively by renewing subscriptions. At the moment our list of direct subscribers is the highest it has ever been in the history of the publication. New subscriptions have come along steadily during the past month and quite a considerable proportion of these have taken advantage of the special offer of £1 for two years! Such expressions of confidence have spurred me to make every effort to safeguard the future. Precautions have been taken, and even a direct hit on the office by a 500-lb. bomb will not stop the old "Radio World" from coming out on time every month. But I feel that it is up to me to do my bit for the national effort, and so I am at present engaged on a matter directly connected with the war effort. This means the temporary suspension of the laboratory service, and may mean delays in the queries service, but I am sure that readers will appreciate the difficulties of the moment. V for Victory! A. G. HULL.


text:
History of wireless telegraphy and broadcasting in Australia/Topical/Publications/Australasian Radio World/Issues/1942 05

P.03 - Contents Banner
The Australasian Radio World

Devoted entirely to Technical Radio

and incorporating the

All-Wave All-World DX News

Vol. 6 - MAY, 1942 - No. 12

P.03 - Publication Notes
Proprietor, Publisher, Editor - A. G. HULL

Editorial Offices - 117 Reservoir Street, Sydney, Phone M4078 - M4079

Office Hours - Week-days: 9 a.m. - 5 p.m. Not open Saturday morning

Subscription Rates - 6 issues 5/3, 12 issues 10/6, 24 issues £1, Post free to any address

Service Departments - Back Numbers, 6d. ea., post free; Reply-by-mail Queries, 1/- each; Laboratory Service, 2/6 per set

Printed by Bridge Printery Pty. Ltd., 117 Reservoir Street, Sydney, N.S.W., for the proprietor of the "Australasian Radio World," 117 Reservoir St., Sydney (Footnote P.28)

P.03 - Contents
CONTENTS:

CONSTRUCTIONAL -

Adding A.V.C. to "Little Companion". . . . 5

TECHNICAL -

Strange Theories and Facts. . . . 6

The Alignment of Modern Receivers. . . . 10

Radio Step By Step (Part 2). . . . 15

The Triplex Single. . . . 18

SHORT-WAVE SECTION -

Short-Wave Review. . . . 20

New Stations. . . . 21

Loggings of the Month. . . . 22

THE SERVICE PAGES -

Answers. . . . 26

P.03 - Editorial Notes
Editorial

The recent increases in sales tax on radio parts appear to place most unfortunate load on an industry which is already carrying more than a fair share of the war's unavoidable burdens. The possibility of a long war makes it desirable to think of the rising lads who will be swelling the ranks of the air crews and the signals section in a year or two. Steps are being taken to train them for service in the R.A.A.F. by that most worthy effort, the Air Training Service. Yet, so far as we know, there is nothing being done to encourage youngsters to study the practice of radio communication, in fact they are being discouraged. The heavier sales tax makes it difficult for them to afford to buy the necessary parts with which to experiment. Even so, we can readily imagine what a rush there would be from modern lads if they were given the opportunity to enlist in a radio training corps with permission to build, erect and operate their own transmitting and receiving centres. Even whilst training they could be put to good use for N.E.S. and other emergency work. Yet we hesitate to push the suggestion for already there seems to be enough talking and wrangling; enough man-power spent at the income tax office to put up a good war effort if only directed at some better purpose than struggling for a tupenny-ha'penny refund. And so we appeal to the radio enthusiasts and the radio trade to bear the burden of increased sales tax as best they can, accepting it as part of their war effort.


text:
History of wireless telegraphy and broadcasting in Australia/Topical/Publications/Australasian Radio World/Issues/1942 04

P.03 - Contents Banner
The Australasian Radio World

Devoted entirely to Technical Radio

and incorporating the

All-Wave All-World DX News

Vol. 6 - APRIL, 1942 - No. 11

P.03 - Publication Notes
Proprietor, Publisher, Editor - A. G. HULL

Editorial Offices - 117 Reservoir Street, Sydney, Phone MA2455

Office Hours - Week-days: 9 a.m. - 5 p.m. Not open Saturday morning

Subscription Rates - 6 issues 5/3, 12 issues 10/6, 24 issues £1, Post free to any address

Service Departments - Back Numbers, 6d. ea., post free; Reply-by-mail Queries, 1/- each; Laboratory Service, 2/6 per set

Printed by Bridge Printery Pty. Ltd., 117 Reservoir Street, Sydney, N.S.W., for the proprietor of the "Australasian Radio World," 117 Reservoir St., Sydney (Footnote P.28)

P.03 - Our Front Cover
OUR FRONT COVER

Our photograph shows Mr. Ron Bell, managing director of R.C.S. Radio Pty. Ltd., at the mouth of a large concrete air-raid shelter which has been built at the R.C.S. factory. Mr. Bell has the interests of his employees at heart, and is also keen to make certain that there will be no interruption in the supply of R.C.S. components, which are used so extensively for both civil and defence requirements.

P.03 - Contents
CONTENTS:

CONSTRUCTIONAL -

The Latest Signal Tracer. . . . 5

High Fidelity Amplifier. . . . 11

TECHNICAL -

Test Bench Arrangement. . . . 16

"Radio Step by Step"- Part 1. . . . 18

SHORT-WAVE SECTION -

Contempt for Tokyo Propaganda. . . . 17

Short-wave Review. . . . 20

New Stations. . . . 21

Loggings of the Month. . . . 22

THE SERVICE PAGES -

Answers. . . . 26

P.03 - Editorial Notes
Editorial

Pioneers often hove a tough time of it before their work receives proper recognition. John Bristoe, author of our series of articles on signal tracers, might be considered a pioneer, and accordingly his articles hove not been accepted by all our readers. Quite a few hove their doubts about the value and efficiency of the signal tracer, and the subject is a fertile one for arguments. Frankly, we hove not hod much experience with them in our own laboratory, but there are two factors which influence us to put our backing behind Mr. Bristoe. Firstly, we know that Mr. Bristoe is a practical man, in charge of a radio deportment, handling hundreds of sets, and, secondly, we note that those who doubt the value of the signal tracer are mostly those who have not actually tried them in practice. They base their opinions on theoretical considerations, which ore not, to our way of thinking, sufficient in themselves in a case like this. To those in doubt we can only suggest that a little practical work with one or another of the signal tracer outfits will soon convince them that they are well worthwhile for those who hove a volume of servicing work to handle.


text:
Template:Assistant category header

These s are part of the assistant. Use  to categorize s here. You can view a list of all s in the assistant here.

title: Template:Assistant category header


text:
Template:Assistant category header/doc

Usage
Use this template on either an assistant category, containing the non-template pages of an assistant, or on a subcategory thereof.

Specialized subcategories should generally use customized text rather than this template (see, for example, /Request pages).

title: Template:Assistant category header/doc


text:
Writing Adolescent Fiction/Depression and suicide

Teenage Depression and suicide

Many teens are not educated about depression which can also lead to suicide. They think when you are depressed you are crazy and you're not, you're actually have a lot in your plate that you feel like just taking a time off from everyone and everything.

When you're depressed you have body pains, you often feel sad and cry a lot, you actually distance yourself from your loved ones, at some point you feel like the situation you're in is not gonna get better and you end up being vulnerable and not paying attention to yourself and you think about ways to end the mixed emotions you are getting.

You may end up wanting to drink to actually cope and you may actually think about committing suicide. Everyone gets suicidal thoughts and its normal. Those thoughts just trigger your mind and make you think you're gonna be at peace. When this happens you should always think about the people who love you.

We as young people we should be the one teaching people about it and the most important thing is to talk. You shouldn't bottle things up because they gonna drain your soul


text:
History of wireless telegraphy and broadcasting in Australia/Topical/Publications/Australasian Radio World/Issues/1942 06

P.03 - Contents Banner
The Australasian Radio World

Devoted entirely to Technical Radio

and incorporating the

All-Wave All-World DX News

Vol. 7 - JUNE, 1942 - No. 1

P.03 - Publication Notes
Proprietor, Publisher, Editor - A. G. HULL

Editorial Offices - 117 Reservoir Street, Sydney, Phone M4078 - M4079

Office Hours - Week-days: 9 a.m. - 5 p.m. Not open Saturday morning

Subscription Rates - 6 issues 5/3, 12 issues 10/6, 24 issues £1, Post free to any address

Service Departments - Back Numbers, 6d. ea., post free; Reply-by-mail Queries, 1/- each; Laboratory Service, 2/6 per set

Printed by Bridge Printery Pty. Ltd., 117 Reservoir Street, Sydney, N.S.W., for the proprietor of the "Australasian Radio World," 117 Reservoir St., Sydney (Footnote P.28)

P.03 - Contents
CONTENTS:

CONSTRUCTIONAL -

Circuit for a Two-valve Portable Set. . . . 15

Simple Set Testing without Meters. . . . 18

TECHNICAL -

Tone Compensation for Scale Distortion. . . . 5

The Construction and Operation of Meters. . . . 7

A Battery Quiz. . . . 9

Technical Press does a Vital Job. . . . 11

Dealing with the Problem of Instability. . . . 12

A Radio Crossword Puzzle. . . . 14

Radio Step by Step (Part 3). . . . 16

SHORT-WAVE SECTION -

Short-wave Review. . . . 20

New Stations. . . . 21

Loggings of the Month. . . . 22

THE SERVICE PAGES -

Answers. . . . 26

P.03 - Editorial Notes
Editorial

There is plenty of important work for every man in Australia who hos any knowledge of technical radio. The spheres of war are now so close that the big bombers come home to roost, often with their radio equipment riddled with bullets. Repairs must be made immediately, as we cannot afford to have any bombers idle. What splendid work for the radio repair man. Not so spectacular, yet mighty important, however, is the maintenance of the modest home receiver. Through it comes the news and the propaganda which forges the national spirit, the will to win and right angle from which to view the set-backs and disasters which a're inevitable, even when winning. If there were no radio broadcasting or newspapers there would be only rumour to spread such news. Yes, every radio receiver in Australia, and there are over a million and a half of them, must be kept in perfect condition, especially since the manufacture of new receivers is restricted. The job of keeping the sets in good operating condition calls for plenty of replacement ports and also o lot of work by those with technical knowledge. Anyone who has this knowledge should not hove a spare moment of time. Every set he con keep in operating condition means that another man is available for reconditioning the transceivers of the big bombers. So we appeal to all our readers; use your technical knowledge now, as it is certain to be either of direct or indirect assistance to the war effort!


text:
History of wireless telegraphy and broadcasting in Australia/Topical/Publications/Australasian Radio World/Issues/1942 07

P.03 - Contents Banner
The Australasian Radio World

Devoted entirely to Technical Radio

and incorporating the

All-Wave All-World DX News

Vol. 7 - JULY, 1942 - No. 2

P.03 - Publication Notes
Proprietor, Publisher, Editor - A. G. HULL

Editorial Offices - 117 Reservoir Street, Sydney, Phone M4078 - M4079

Office Hours - Week-days: 9 a.m. - 5 p.m. Not open Saturday morning

Subscription Rates - 6 issues 5/3, 12 issues 10/6, 24 issues £1, Post free to any address

Service Departments - Back Numbers, 6d. ea., post free; Reply-by-mail Queries, 1/- each; Laboratory Service, 2/6 per set

Printed by Bridge Printery Pty. Ltd., 117 Reservoir Street, Sydney, N.S.W., for the proprietor of the "Australasian Radio World," 117 Reservoir St., Sydney (Footnote P.28)

P.03 - Contents
CONTENTS:

CONSTRUCTIONAL -

Interesting Circuit Suggestions. . . . 15

Wave Trap to Improve Sensitivity. . . . 18

TECHNICAL -

About Screws and Screw-Threads. . . . 5

Radio Step by Step - Part 4. . . . . 7

Modern Set Building Methods. . . . 9

SHORT-WAVE SECTION -

Short-wave Review. . . . 19

Loggings of the Month. . . . 19

New Stations. . . . 22

THE SERVICE PAGES -

Answers. . . . 26

P.03 - Editorial Notes
Editorial

In times like these we are prepared to bear our extra burdens with a smile. But we feel sure our readers will join with us in raising a bit of a squeal about the new law which insists on extra licence fee if more than one radio set is installed in the home. If the money were to be used for a good purpose, we might feel better about it, but all of us know only too well of the way in which the A.B.C. has insisted on maintaining their worthless "A.B.C. Weekly", which drags nearly £1,000 a week from the licence revenue, is not read by three per cent of the listeners, and cannot even be considered as good publicity for the A.B.C. or its programmes. We feel sure that the A.B.C. would be making a far wiser move if they abandoned the "A.B.C. Weekly", even if they have to square off with Editor Deamer by paying out his contracted salary (and what a salary, too!) The money saved would be ample to allow the Commission to carry on with its efforts to provide programmes without this extraordinary licence fee, which con only have a negative effect on the popularity of broadcasting.


text:
History of wireless telegraphy and broadcasting in Australia/Topical/Publications/Australasian Radio World/Issues/1942 08

P.03 - Contents Banner
The Australasian Radio World

Devoted entirely to Technical Radio

and incorporating the

All-Wave All-World DX News

Vol. 7 - AUGUST, 1942 - No. 3

P.03 - Publication Notes
Proprietor, Publisher, Editor - A. G. HULL

Editorial Offices - 117 Reservoir Street, Sydney, Phone M4078 - M4079

Office Hours - Week-days: 9 a.m. - 5 p.m. Not open Saturday morning

Subscription Rates - 6 issues 5/3, 12 issues 10/6, 24 issues £1, Post free to any address

Service Departments - Back Numbers, 6d. ea., post free; Reply-by-mail Queries, 1/- each; Laboratory Service, 2/6 per set

Printed by Bridge Printery Pty. Ltd., 117 Reservoir Street, Sydney, N.S.W., for the proprietor of the "Australasian Radio World," 117 Reservoir St., Sydney (Footnote P.28)

P.03 - Contents
CONTENTS:

CONSTRUCTIONAL -

A New Version of "Little Companion". . . . 5

Making Most of the Milliammeter. . . . 9

TECHNICAL -

Why no Technical Radio in Programmes? . . . . 6

A New Light Source. . . . 14

Some Notes on Servicing Vibrator Sets. . . . 15

Radio Step by Step - Part 5. . . . 18

Parts of Maintenance of Receivers. . . . 24

SHORT-WAVE SECTION -

Short-Wave Review. . . . 20

Loggings of the Month. . . . 22

New Stations. . . . 23

THE SERVICE PAGES -

Answers. . . . 26

P.03 - Editorial Notes
Editorial

There are several clauses in the new Broadcasting Act which vitally affect the radio serviceman and dealer. It seems that quite a number of our readers are not yet acquainted with them, but ignorance of the law is not likely to hold good if any trouble ensues. Probably the most important regulation is the one which states that any person who sells a radio set must notify the Radio Inspector of the sale. Anyone who deals in radio, whether conducting a shop or not, should make immediate application to the Senior Radio Inspector, at the G.P.O., for registration as a dealer. No fee is required. Another point to be watched is in connection with the multiple licences required when more than one set is operated in any house. If there are two sets, the second requires an extra fee of 10/-. If there are three sets in the house capable of receiving programmes, then the licence fee for the three will be £2. Those who repair and service sets are entitled to special consideration and require only the one licence. The position of the extension speaker is interesting, being allowed without extra fee in the case of a private, house, but fees must be paid for each and every extension in the case of a hotel or lodging house. In a boarding house, any lodgers who operate receivers must have their own licences. In all cases of doubt about the new regulations it is safer to be sure than sorry. We suggest you make enquiries at the local post office, and if you cannot get a definite ruling be sure to contact the Radio Inspector.


text: Template:Assistant/template

title: Template:Assistant/template


text:
Template:Assistant/template/doc

Usage
If a template is part of an assistant, call this template at top of the Usage section of its documentation, thus:

For dialog edit forms in an assistant, see assistant/form. For non-template pages in a multi-page assistant, see assistant/viewable. For single-page assistants, see assistant/single. For non-template pages documenting an assistant, see assistant/documentation.

title: Template:Assistant/template/doc


text: Template:Assistant/form

title: Template:Assistant/form


text:
Template:Assistant/form/doc

Usage
If a dialog edit form is part of an assistant, call this template at top of the Usage section of its documentation, thus:

otherwise, for templates in an assistant, see assistant/template; for non-template pages in a multi-page assistant, see assistant/viewable; for single-page assistants, see assistant/single; and for non-template pages documenting an assistant, see assistant/documentation.

title: Template:Assistant/form/doc


text:
History of wireless telegraphy and broadcasting in Australia/Topical/Publications/Australasian Radio World/Issues/1942 09

P.03 - Contents Banner
The Australasian Radio World

Devoted entirely to Technical Radio

and incorporating the

All-Wave All-World DX News

Vol. 7 - SEPTEMBER, 1942 - No. 4

P.03 - Publication Notes
Proprietor, Publisher, Editor - A. G. HULL

Editorial Offices - 117 Reservoir Street, Sydney, Phone M4078 - M4079

Office Hours - Week-days: 9 a.m. - 5 p.m. Not open Saturday morning

Subscription Rates - 6 issues 5/3, 12 issues 10/6, 24 issues £1, Post free to any address

Service Departments - Back Numbers, 6d. ea., post free; Reply-by-mail Queries, 1/- each; Laboratory Service, 2/6 per set

Printed by Bridge Printery Pty. Ltd., 117 Reservoir Street, Sydney, N.S.W., for the proprietor of the "Australasian Radio World," 117 Reservoir St., Sydney (Footnote P.28)

P.03 - Contents
CONTENTS:

CONSTRUCTIONAL -

The "Victory Set". . . . 5

How to Make a Metal Chassis. . . . 16

TECHNICAL -

Great News for Enthusiasts. . . . 11

Fresh Ideas in Circuits - No. 3. . . . 12

Radio Step by Step - Part 6. . . . 15

Points About Aerial Efficiency. . . . 24

SHORT-WAVE SECTION -

Short-Wave Review. . . . 18

Loggings of the Month. . . . 20

Stop Press. . . . 22

THE SERVICE PAGES -

Answers. . . . 26

P.03 - Editorial Notes
Editorial

We hear plenty about the problems which experimenters and radio mechanics have to face on account of the difficulty in obtaining component parts. Yet when we go into the matter fully we find that the position is not nearly as bad as it might be. We proved beyond a shadow of doubt that it is still possible to walk into almost any good radio warehouse and purchase a complete kit of parts for the construction of a. serviceable receiver, as mentioned elsewhere in the description of this particular set. Things are bad, but after all, not nearly as bad as in New Zealand, for example, where the construction of radio receivers is totally prohibited. At the moment of writing there is talk of the new austerity campaign and we wouldn't be greatly surprised if this austerity plan embraced similar legislation to that already in force in New Zealand. Even if this does come about, the position is not hopeless, as the authorities fully appreciate the value of the broadcast receiver and, doubtless, arrangements will be made which will ensure adequate component parts being made available for the maintenance of the million and a half receivers at present in use. So long as these components are available it would appear that the wide-awake experimenter will find plenty of scope for employing his energies most usefully. Even if the manufacture of sets is totally prohibited he will be able to make a dandy job of taking an old-time chassis to bits and rebuilding it with a modern coil kit and other components to make it into a really effective set.