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Planet Earth/6i. Earth’s Surface Processes: Sedimentary Rocks and Depositional Environments

James Hutton the Father of Geology
What makes Earth so dynamic compared to other planets can be found in the complex ways eroded sediment is transported across its surface. Earth is continually changing its surface, with the motion of sediments that erode from topographically high rocky terrain on the continents and carried to be deposited into the low basins and shallow ocean margins, as carried by rivers and wind. It is like blood, a circulatory system of sediment pumped from one place to another across the Earth.

James Hutton’s hands were covered in human blood, as he dissected cadavers at the University of Paris in 1749, his dissertation research delved into the human circulatory system, how blood pumped from the heart in arteries and into the lung, and then drained back through the veins through the heart to be oxygenated again. He was training to become a physician, a doctor, and had traveled to France to learn the trade from his native Scotland. Hutton was curious about everything he observed, often describing it in long almost stream-of-conscious writing that was as detailed as it was verbose. He planned to return to London, and continue his work as a physician, but utilized his scientific interests into making and processing dye. His knowledge and partnerships with friends back in England allowed him some money in the sale of dyes and chemicals that he had learned to extract from soot and plants, and after less than a year in London had decided to return to Scotland. He had never known his father, who sadly died when he was 3 years old, but his father had left him some farm land out in the country southeast of the city of Edinburgh where he had grown up. The farm land had laid fallow, and in 1751 he visited the farm land of his home, which sparked his interesting in farming and agriculture. With ambitious insight, James Hutton began the process of clearing the land, and like a scientist writing his observations in a book he intended to write entitled The Elements of Agriculture. Life on the farm was idyllic, and he recorded his fondness in studying the surface of the earth in his letters and with his friends. Curiosity held his thoughts as to what lay within each pit or layer of earth exposed in each ditch they dug, and how the rivers and streams carved sediment as they moved across the landscape like blood in arteries and veins in a human body that he studied back in Paris. Over the long period of twenty-five years, James Hutton wrote of these processes, the uplift of rocky terrains, the erosion by wind and rain, the vital sediments carried across the surface into the low lands and ocean coasts, of the endless continued cycle of sediment transport. Most notably he noted that “There is no vestige of a beginning, no prospect of an end.” His book was finally published in 1788, entitled the Theory of the Earth; or an investigation of the laws observable in the composition, dissolution and restoration of land upon the globe. James Hutton’s book was a lengthy discussion of the geological processes that operate on the Earth’s surface, and how over long periods of time, these processes lead to the deposition and lithification of sediments into rock. James Hutton’s ideas were radical for the time, a time in history when scientists viewed Earth’s history as short and cataclysmic, dominated by global disasters. To James Hutton, time is endless, so lengthy was the history of the Earth. Earth was shaped by the continued erosion, motion, and deposition of sediments, which would be uplifted into mountains to start the process over again. Hutton’s ideas gave rise to an interest in surface processes of the Earth, opening the door into new fields of geology, like geomorphology (the study of Earth’s landscapes), soil sciences, and sedimentary geology. In the United States, the National Academy of Science branded the newly coined term critical zone science in 2001, to describe the science of studying surface processes on Earth and how they affect agriculture and urban and industrial development on the landscape. One aspect of this science is the identification and study of depositional environments. A depositional environment is a region where transported sediments are deposited and accumulate on the Earth’s surface. These sediments can be later be buried, and through lithification turned into sedimentary rocks with compaction and heat.

Alluvial Fans
Alluvial fans form in areas of high relief, commonly at the base of a mountain range, where there is an abundant supply of sediment from the close proximity of the uplifted terrain. These sediments are transported through mountain valleys by streams and rivers, but also debris flows, mudslides, and landslides (or other types of mass wasting, like rock falls). This sediment accumulates at the intersection of the high topography and low topography due to reduced gravitational energy in carrying these sediments further. Alluvial fans are highly dependent on infrequent seasonal events, such as periodic flooding during the spring months due to snow melt, and debris flows following heavy rains. As a result of these regions being close to the mountains, they are very susceptible to erosion, and are more rarely preserved in the ancient rock record, compared to other depositional environments. Alluvial fans are characterized by a lack of fossils, a lobate geography, texturally immature sedimentary rocks, very poorly sorted and angular grains, cross bedding, and radial patterns of incised fluvial channels. Deposits are typically oxidized red in color as the sediment is rarely below the ground water table.

Braided River Systems
Braided rivers form in regions of high relief and typically have limited extent, as they wash out from glacial valleys or across uplifted plains. Braided rivers are characterized by their entangled channels and braided appearance when view from above. This braided pattern is due to the high load of transported sediments, and sporadic flow of water down the river. During periods of high discharge from the river, sediment is carried and becomes choked around sand bars and channels, which are repeatedly breached and become transitory. Braided river systems are likely the primordial pattern of river flow early in Earth’s history, when the surface of Earth lacked plants. The lack of roots and vegetation results in sediment filled river systems, which exhibit a braided appearance with many point bars and sand bars entangling the most direct route for the flowing water to follow. Braided river systems are highly seasonal, often located in temperate or cold regions of the Earth with little vegetation. Braided river systems are common in deserts and high plateaus, and often can be found in proximity to mountains and alluvial fans. Braided river systems are characterized by a dominance in gravel and sand size clasts, trough, planar or cross-bedding in sandstones, with little vertical succession of grain-size or shifts in the rock, with minor fining-upward trends in each bed. Fossils are rarely preserved in these environments. Flume studies, where tilted tanks filled with sand are washed by a spigot, which serves as a single source of water and allowed to flow across the sand, will mimic a braided river system in nature due to the physics of the water flow and its interaction with the sand. If the sand is unconsolidated and loose, the pattern will always result in a braided pattern of flow. However, if the sand is consolidated, cemented together or bound by vegetation and roots; a different pattern results.

Meandering River Systems
Rivers that become confined within a single major channel, characterized by cohesive banks which are difficult to erode, will result in a meandering pattern of flow. Meandering river systems are the dominate river system since the advent of terrestrial plants. They are also found in deep canyons, where the sides of the canyon are resistant to erosion. The flow of water across a resistant substrate will lead to the channelization of that material over time. Meanders become pronounced due to the cross-sectional differences in the velocity of the flowing water. Water flowing on one side will tend to flow slightly faster, pressing into the river bank, and erode the edge forming a cut-bank along the river channel, while on the opposite side the flow is slightly slower, resulting in deposition of sediment out of the river’s load of sediment, forming a point-bar. Over time, the river will curve into a meandering pattern, as it oscillates downstream into cut-banks and point-bars on opposite sides. Such meandering pattern results in the continued deposition of lag deposits that are added along the point bars, with coarse sand-size sediment. Meandering rivers will form natural-levee deposits, which will parallel either side of the river. These natural-levee deposits are formed by the deposition of sediments during periodic floods, however they can be overtopped by larger floods along the river, resulting in the deposition of fine-grained sediments that over-ride these river channels and deposit thick deposits in large regions near the river called a flood basin or floodplain deposits. Even greater floods will result in crevasse-splay deposits when the meandering river will be flooded with water to such an extent the water flows out across very large distances beyond the flood plain, bringing thick mud and clay sediments with this flowing floodwater. Meandering river systems will nearly always demonstrate a fining upward, with the coarsest and largest sediments forming the base in a series of layers, where the river lag deposits are the first to be deposited, while the upper layers will represent floodplain deposits and be dominated by mudstone and siltstone. Meandering river systems formed by the recycled sediment moving from cut-banks to point-bars, resulting in cross-bedding and cross-lamination that drifts horizontally across the flood plain. Channels can incise, and leave a winding pattern. Once filled with sand, these channel sands can be slowly lithified into sandstone, and the flow is preserved in rocks layers in the deserts and badlands of eastern Utah, as these sandstones are resistant to weathering. The direction and flow of ancient river channels can be studied from these petrified rivers, that erode like fossilized rivers in the desert, although others maybe hidden beneath vegetation. Meandering river systems, and floodplain deposits are excellent depositional environments to look for fossils, particularly animals and plants that live on land, including dinosaurs.

Eolian Desert Systems
Eolian deposits can be found in regions with little vegetation due to low precipitation (rain and snow), and exposure to high winds which can carry sand. In these regions, sand and smaller grains of sediment can be transported by the blowing wind. This windblown sand can travel great distances across the surface of the Earth and even across oceans, but most often accumulate in topographical traps, where mountains or ridges rise in elevation. These topographic ridges prohibit the sand to be carried over them, and sand-size particles drop out of the air and get deposited along the edges of these ridges. Along these topographical traps, great sand dunes can form, which can be very thick. In desert regions, like in North Africa, windblown sand can cover vast regions of the continental interiors, especially in regions with little rainfall and hot temperatures. Transverse dunes are extremely long dunes of sand perpendicular to the blowing wind, and these can further lead to sand migration, as sand is continually deposited on the back side (lee side) of the dune. These thin deposits of wind-blown sand can form wide broad striations of cross beds that are much larger and sweeping than those found in fluvial depositional environments. Transverse dunes can be blown out, to form barchan sand dunes, which form a broad crescent shaped, with a steep lee side, and broad face. Sand dunes can migrate over the desert landscape, but are heavily influenced by the climate and the amount of vegetation coverage. A source of sand particles is also important, which can often come from eroding exposed sandstone. Ancient records of eolian depositional environments are found across eastern and southern Utah. The classic sandstones of the Wingate and Navajo Sandstones in Zion National Park are remains of a vast eolian desert that existed during the late Triassic and early Jurassic Periods in Utah about 200 million years ago. The artistic broadly formed cross beds of red and yellow are remains of the wind-swept sand dunes of this prehistoric desert, and these sandstones are characterized by being well sorted with orange rounded clasts of quartz dominated grains.

Lacustrine Systems
Lacustrine systems are sedimentary depositional environments of lake systems, which act as important sources of sediment deposition. Lakes can be either be open, with the outflow of water and stable shoreline dominated by clastic sediment transport into the system, or closed with little to no outflow of water, which results in chemical sedimentation, such as carbonate sediments or if the water is subjected to evaporation and drying up – evaporitic sediments. Lakes tend to exhibit layers of laminated mud, due to the low energy to transport sediments compared to fast moving rivers. This results in thick muddy sediments that can accumulate thick deposits of clay, mud and silt on the lake floor. This mud can be cyclical, with increased sediments during periods of spring flooding, as there can be yearly increases of inflow of water and sediments. This yearly cycle can be seen within the thin layers of mud, and are called varves. Varves are thin layers of clay, mud and silt of differing color and texture which represent the deposit of a single year in a lake bottom. They can be used as a chronological history in the study of sediments laid down on a lake bottom for thousands of years. Lacustrine systems can be identified by their homogeneous layers of laminated muds that lithify into shale. The Green River Shale exposed across northeastern Utah, southwestern Wyoming and western Colorado is an example of an ancient lacustrine system representing lakes that existed at one time in the intermountain basins of this region of the United States during the Eocene Epoch, about 50 million years ago.

Deltaic Systems
Deltas are discrete coastline protuberances formed where major rivers enter oceans, semi-enclosed seas, lakes or lagoons and supply sediment more rapidly than can be redistributed by the subsidence of the basin. Deltaic depositional environments carry sediments into basins, and these fluvially carried sand, silt, mud and clay grains accumulate along the coastline, shifting the shoreline into the ocean or sea basin, resulting in a regression of the coastline outward into the ocean. A delta is named for the triangular shape they produce as the river flows across this region in its attempt to find the most direct downslope path to the ocean, blocked by sediment deposited at this transition between land and sea. The first recognized delta is the Nile Delta near Alexander, Egypt, but other deltas include the Mississippi Delta in Louisiana, and the Ganges Delta in Bengal and Bangladesh in India. The path of the maze of tributaries of rivers across a delta are consistently changing due to sediment accumulation, and water flowing downslope through these sediments into complex channels. The result of these surface processes is a complex triangular shaped region at the intersection of a major river and the sea. They exhibit a coarsing upward in grain sizes, cross-bedding, ripple marks caused by tides, and clay and mud that flares upward through coarser overlaying grains. There is also a fair amount of bioturbation in deltas. Bioturbation is traces of organisms (like clams and crustaceans) that burrow or bore into the sediments, leaving traces of these burrows and a mix of sediments due to biological activity in the ground.

Beach and Barrier Islands
Beaches are long, narrow accumulations of sand which are aligned parallel to a coastline near the shore, while barrier islands are accumulations of sand that are cut off from the mainland by shallow lagoons, estuaries or marshes. Beach and barrier islands are dominated by wave action along the coastline, resulting in well-polished sand grains that are continually being agitated in this high energy system. Ocean tides and wind also play a role in sediment transport along these coastal environments. Beach depositional environments can be divided into zones based on their distance and location from the shoreline which is consistently shifting with tides and crashing waves. The backshore is the region of a beach or barrier island that is above the high tide. The backshore is only inundated by the ocean during high storms, and is protected from more cyclical monthly and daily tides by a berm. A berm is a slight rise along the beach formed from the highest level of daily to weekly tides along a shore line. Berms protect the beach within the backshore, but can be eroded during storm surges, when the ocean inundates these areas of the beach. Sediment deposition in the backshore of a beach or barrier island is dominated by windblown sands, that can form sand dunes and eolian sedimentary structures. They can also be overgrown with plants and vegetation over time, and also subjected to beach erosion. Within the zone of crashing waves, where your feet would get wet walking along the beach is the foreshore. The foreshore can be divided into the swash zone and surf zone, with the portion of the beach overrun by water called the swash zone, while the surf zone is where waves crash further out from the shore. Further out into the ocean is the nearshore (also called the shoreface). This region is where the ocean water is shallow enough that it interacts with the ocean floor, resulting in breaking waves, that over extend their crest, and produce surf. This zone is defined by the region that is shallower than localized wave base. Wave base is the maximum depth at which a surface wave’s passage across the top of the ocean’s surface can cause motion deeper in the water column. When this depth interacts with sediments on the ocean floor, this results in the wave to begin to crest and break, resulting in the surf zone observed in the nearshore. The surf is a result of the dynamic interaction of ocean waves with the ocean floor, and it is within this zone that surfers can be transported into the shore riding these crashing waves. The wave base is calculated by finding half the length of the distance between wave crests. For example, as waves spaced 3 meters apart approach a beach, they will be moving the water below up to depths of 1.5 meters. When the waves reach that portion of the shoreline with depths shallower than 1.5 meters, the waves will begin to crest as they also interact with the sediments on the ocean floor, resulting in the transportation of sand size particles. Longshore currents are generated when the waves approach the shoreline at an angle, which causes sediment transport along the length of the beach or barrier island. Longshore currents can significantly move sediment up and down a shoreline, as they are carried by the motion generated by the approaching waves. Beaches and barrier islands are susceptible to erosion due to changes in sea level, tides, wind and especially storm waves, which will scour sediments and redeposit them farther seaward. Beach and barrier island sediments are characterized by being dominated by sand grain sizes, as well as those grains being very mature, well rounded and well sorted. Bivalve (clams) and brachiopod shelled organisms are common in these deposits. Ripple marks with bidirectional symmetric profiles are common, as well as planar and trough crossbedding, and bioturbation.

Estuarine and Lagoonal Systems
Estuaries are the seaward portion of a drowned river valley system which receives sediment input from both downstream fluvial flow and upstream marine tidal sources, and are influenced by tides, waves, and fluvial processes. While lagoons are shallow stretches of water near or communicating with the sea, but separated by a low narrow strip of land. These depositional environments are especially important for marine life, as they often host brackish waters (water that is a mix of fresh and salt water). Estuary and lagoonal systems are formed during transgression events, when sea levels are high. Sediment input can be a result of fluvial and marine motion into these systems, resulting in a mix of sediment sources. This is influenced by episodic storms. Both types of regions are susceptible to evaporation, resulting in the accumulation or stratification of evaporitic deposits of salts.

Tidal Flat Systems
Tidal flats are marshy and muddy to sandy areas that are partially uncovered by the rise and fall of tides, often protected by the action of waves by a geographic barrier. Sediment transport in tidal flats is driven by tides, rather than rivers. As the tides flow in and out of these regions, they deposit sediment into narrow tidal channels that are continually reworked by the daily to monthly flooding of these areas. Barriers to wave action are required which most often is due to salt-marsh vegetation or mangrove trees that help dampen wave action, which would result in the erosion of these tidal flats. Tidal flats are characterized by mud as the predominate sediment, with plant debris, bioturbation, and strange herringbone cross-stratification due to the in and out motion of the flowing water. Tidal flats deposits will often produce shales with burial and lithification, which can be stratified or sandwiched between evaporitic salt deposits.

Oceanic Deepwater Depositional Systems
There exists vast regions on Earth that are beyond the shallow marine environment occupied by the continental rise, the deeper continental slope, down to the deep-sea trenches and dark abyssal ocean floor. All of these regions can accumulate sediment that is transported off of the eroding continents. The continental rise is the shallower region of the ocean that is proximal to the coastline of continents, which is surrounded by the much deeper ocean waters of the open ocean by a continental slope. As sediment is transported away from the continents and into deeper ocean waters, these sediments can over steepen the continental slope, resulting in underwater debris flows called turbidity flows. These fine-grained plumes of sediment can transport fine grain material deep and far distances along the ocean floor. These plumes of fine grain sediment can empty large amounts of tiny particles of sediment great distances on the ocean floor. The ocean floor also receives input of sediments from volcanic ash, and windblown sediment, as well as larger clasts carried out to sea by icebergs and floating ice. The largest input of sediment might be from pelagic rains of organic particles that are produced by marine organisms that live within the ocean’s water column, and sink to the ocean floor. Changes in the thermohaline circulation, acidic ocean waters and subduction can slow or stop the sediment input into these systems, which often is fairly continuous and rarely erode given their location on the ocean floor. These sediments often preserve an extraordinary complete record, with few if any gaps in deposition. As such many scientists, such as those abroad the JOIDES research vessel study sediment cores from these depositional systems to understand Earth’s past climate and oceanography.

Carbonate Depositional Systems
Carbonate sediments are deposited primarily in shallow-marine shelf platforms, but are also present in marginal-marine environments and more rarely lacustrine systems. They form what is called a carbonate platform, such as coral reefs and atolls. Unlike the other depositional systems, carbonate deposition is a chemical and biochemical process, where organisms form their skeletons from calcium carbonate, and this is laid down as a framework of biological activity in these shallow ocean and lake waters. There can be physical processes in the rework and transport of these carbonate materials, but they are sourced from chemical and biochemical processes rather than erosion from the continents. Carbonate systems are active when there are numerous organisms that form their skeletons from calcium carbonate, but carbonate can also be deposited when ocean water becomes more basic in pH (increase in carbonate anions), and with an increase of dissolved calcium cations from continental weathering. Carbonate systems are limited to shallow waters, above the carbonate composition depth (CCD), and often most active in warm tropical ocean waters within the photic zone. This makes carbonate deposition highly affected by sea level changes, as drops in sea level can result in the chemical erosion or karstification of carbonate once exposed to more acidic rainwater. Carbonate systems are also influenced by the pH of the ocean water, as they require more basic ocean pH (8 or higher). If the ocean water becomes more acidic, carbonate will not precipitate as a solid and will dissolve. This can also cause risk to shelled marine organisms to dissolve their protective skeletons and shells. Carbonate depositional systems lead to the thick deposits of limestone that are common across much of Earth’s surface, particularly abundant in rocks that are younger than 545 million years old, when shelled multicellular organisms first appeared on Earth.

Unconformities
Within these depositional environments you can see the daily evidence of the continued process of sediment transport and deposition across the Earth’s surface. James Hutton was profoundly interested in the nature of these processes and how they could occur for long periods of time, unyielding and ever flowing in the continued uninterrupted transport of sediment that accumulates into the observed rock layers found in Earth’s subsurface. But he was also interested in their gaps (called an unconformity), when these lithified sediments would rise up to be worn away again, continuing the cycle.

Siccar Point and the Abyss of Time
In 1788, he took a boat trip with his friends John Playfair and James Hall along the coast of Scotland searching for these gaps in the craggy rocky shores in the county of Berwickshire, when they discovered a point of rock called Siccar Point. The lower layers of rock project vertically, overlaid by horizontal rocks. The age of the rocks were unknown at the time to the early scientists, but the vast length of time for such configuration of sedimentation to occur, the uplift, the folding and re-deposition was astonishing to them. It was a window into the antiquity of the Earth. John Playfair wrote that “their minds grew giddy at looking so far back into the abyss of time.” This rock point along the Scottish coastline was the first evidence of the great length of time Earth has existed. These observations grew into the theory of uniformitarianism; that the changes on Earth’s surface and the deposition of sediments are a result the actions of a continuous and uniform process that operates even today. Later they would be summarized by the geologist Charles Lyell, as the present is the key to the past. The observed transport of sediment and deposition of these sediments has been continuous throughout Earth’s long history, and its record is preserved within the layers of lithified sediments that cover much of Earth’s continents.


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User:TripleShortOfACycle

My user page on English Wikipedia. Leave a talk message there!

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User:Leowebbhk

I am a secondary school student graduating from the IB Diploma Programme in 2021. My subjects are HL Mathematics Analysis and Approaches, HL Physics, HL Chemistry, SL Economics, SL English Literature A, and SL Chinese (Mandarin) B.

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Eric 6 User's Guide/Getting Started/Installation

Install from PyPI or Use a Packaging System?
Eric can be installed via the Python Packages Index (PyPI) using  (see below). That is the recommended and simplest way to get Eric working on your computer.

Your Linux distributions may have an installation package for Eric. Whether to use it instead of  may come down to a question of trade-offs. Packaging systems like anaconda, apt, yum and pacman are great at quick, reliable installation of software, avoiding “dependency hell.” On the other hand, the package system almost surely will not install the most recent Eric release and may be a major version behind. Also, recognize that you are adopting the installation choices made by the distribution packager.

The details are distribution-specific and the choice also depends on your comfort and experience level (although installing with  could hardly be simpler). Regardless, it is inadvisable to mix-and-match. For example, using a packaging system to install PyQt5 and QScintilla and then trying to install Eric using its install.py script may not work. Eric requires particular version numbers of those products – if the installed ones don’t match, Eric may abort its installation.

Similarly, if you get a partial copy of Qt5 from somewhere other than The Qt Company, you may find that certain features in Eric mysteriously don’t work.

Prerequisites
Eric requires Qt5, PyQt5 and QScintilla be installed first. PyQt5 and QScintilla will be installed automatically if you use.

Download the online installer for Qt5 from The Qt Company. You should end up with a file called something like: To use it, make it executable first. In a terminal: then run it:

Eric has a number of hooks into Qt, so it’s better to select broadly from the installation choices in the Qt version you’re installing. You may be able to deselect sections that definitely don’t apply to you (perhaps Wayland?).

Installation in a Virtual Environment Using pip
Installing Eric into a Python virtual environment will keep Eric and its associated packages isolated from other Python applications/packages/projects. This helps to minimize conflicts between them.

You may need to install the Python module  first.

Then, in a terminal: If pip is not installed, the Python documentation has comprehensive advice.
 * confirm that you have pip installed:
 * make a folder to contain Eric:
 * create a Python virtual environment in the folder:
 * activate it:
 * (for bash. Other shells have their own scripts in Eric/bin.)

 * confirm that pip, setuptools and wheel are up to date:
 * install Eric:

Using pip for installation has the added advantage of installing the prerequisites from PyQt5 and QScintilla as well.

Alternative Installation Method
You can download the .zip archive from SourceForge via the link on Eric's [https://eric-ide.python-projects.org/eric-download.html Installation\ page. Unpack it into an appropriate folder. There will be an  script in its /scripts folder. Install Qt, PyQt5 and QScintilla as outlined above.

Next, install PyQt5 using pip:

Then install QScintilla:

(It is also possible to build these packages from source – see the Riverbank site for details.)

Finally create and activate the virtual environment for Eric, as above, then run:

Upgrading
Using pip to upgrade Eric is as simple as:

Windows
Install and verify that Python is working, then enter the following at a Command Prompt (elevation may be required):


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History of wireless telegraphy and broadcasting in Australia/Topical/Publications/Australasian Radio World/Issues/1948 03

P.01 - Front Cover
The Australasian Radio World

Registered at the G.P.O., Sydney, for transmission by post as a periodical.

1/-

Vol. 12 - No. 10; MARCH 15, 1948

P.03 - Contents Banner
THE AUSTRALASIAN RADIO WORLD

Devoted entirely to Technical Radio

and incorporating

ALL-WAVE ALL-WORLD DX NEWS

VOL. 12 - MARCH, 1948. - No. 10

P.03 - Publication Notes
Editor, Publisher, Proprietor — A. G. HULL, Balcombe St., Mornington, Vic.

Short-wave Editor — L. J. KEAST, 6 Fitzgerald Road, Ermington, N.S.W. 'Phone: WL1101

Ham Notes By — D. B. KNOCK (VK2NO), 43 Yanko Av., Waverley, N.S.W.

Advertising Representative for N.S.W. - Amalgamated Publications Pty. Ltd., 83 Pitt St., Sydney, Phone: B1077

Representative in Queensland - John Bristoe, Box 82, Maryborough, Q.

Representative in England - Anglo Overseas Press Ltd., 168 Regent St., London, W1.

Subscription Rates: 12 issues - 10/6; 24 issues - £1; Post free; To N.Z. and Overseas - 12 issues, 12/-

Address for all correspondence - Australasian Radio World, Balcombe St., Mornington, Victoria

Printed by Bridge Printery Pty. Ltd., 117 Reservoir Street, Sydney, N.S.W., for the proprietor of the "Australasian Radio World," Balcombe St., Mornington, Vic. (Footnote P.44)

P.03 - Contents
CONTENTS

TECHNICAL —

In Search of Fidelity. . . . 5

A Modern Battery Receiver. . . . 9

Radio World Review. . . . 11

Among Our Readers. . . . 15

A Personal Portable. . . . 19

3-Valve Triple-Wave Receiver. . . . 27

Calling CQ. . . . 34

SHORTWAVE REVIEW —

Notes From My Diary. . . . 38

THE SERVICE PAGES —

Speedy Query Service. . . . 42

P.03 - Editorial
EDITORIAL

Ever since the earliest days of radio, most of us have been battling to get a wider and flatter frequency response from our amplifiers. Now things have advanced to such a stage that it is fairly easy to get a set-up of the flattest and widest response, such as a Lexington pick-up, Williamson amplifier circuit, and Goodmans speaker. I have such an outfit in operation and I can tell you that it is useless with the ordinary records as sold in the shops to-day. Using the amplifier and speaker with, a wide-band tuner it is possible to get some brilliant results on radio from certain "live" broadcasts, but to enjoy the reproduction of gramophone recordings it is essential to lop off the highs. Lest you imagine that all is lost, I hasten to say that the latest wide-range pick-ups have more than mere wide range, their wave form on the normal frequencies is better than that of the old magnetic pick-ups; the amplifiers with triodes and inverse feedback have low distortion as well as wide range; the high-fidelity speakers can handle the middle register well. It seems strange that we should have to strive so hard for wide-range reproduction and then turn around and lop off the highs, but that is the position at the moment with ordinary records. Later when full frequency range records become available things may be different. In the meantime I can only recommend true wide-range equipment for radio work, and it has its draw backs there, too. Static and noise are both reproduced with added brilliance in a manner which you won’t appreciate. — A. G. Hull.


text:
History of wireless telegraphy and broadcasting in Australia/Topical/Publications/Australasian Radio World/Issues/1948 04

P.01 - Front Cover
The Australasian Radio World

Registered at the G.P.O., Sydney, for transmission by post as a periodical.

1/-

Vol. 12 - No. 11; APRIL 15, 1948

P.03 - Contents Banner
THE AUSTRALASIAN RADIO WORLD

Devoted entirely to Technical Radio

and incorporating

ALL-WAVE ALL-WORLD DX NEWS

VOL. 12 - APRIL, 1948. - No. 11

P.03 - Publication Notes
Editor, Publisher, Proprietor — A. G. HULL, Balcombe St., Mornington, Vic.

Short-wave Editor — L. J. KEAST, 6 Fitzgerald Road, Ermington, N.S.W. 'Phone: WL1101

Ham Notes By — D. B. KNOCK (VK2NO), 43 Yanko Av., Waverley, N.S.W.

Advertising Representative for N.S.W. - Amalgamated Publications Pty. Ltd., 83 Pitt St., Sydney, Phone: B1077

Representative in Queensland - John Bristoe, Box 82, Maryborough, Q.

Representative in England - Anglo Overseas Press Ltd., 168 Regent St., London, W1.

Subscription Rates: 12 issues - 10/6; 24 issues - £1; Post free; To N.Z. and Overseas - 12 issues, 12/-

Address for all correspondence - Australasian Radio World, Balcombe St., Mornington, Victoria

Printed by Bridge Printery Pty. Ltd., 117 Reservoir Street, Sydney, N.S.W., for the proprietor of the "Australasian Radio World," Balcombe St., Mornington, Vic. (Footnote P.43)

P.03 - Contents
CONTENTS

TECHNICAL —

ZAAYER Crosses Atlantic on "Six". . . . 5

The L.s.d. of High Fidelity. . . . 7

Amateur Personalities. . . . 13

Narrow-Band F.M. Adaptor. . . . 15

A Direct Coupled Circuit. . . . 17

T.R.F. Mantel Four. . . . 18

Speaker Impedance Matching. . . . 20

Permags Here to Stay. . . . 28

Circuit for an F.M. Receiver. . . . 29

Among Our Readers. . . . 31

Calling C.Q. .. . . 35

SHORTWAVE REVIEW —

Notes From My Diary. . . . 39

THE SERVICE PAGES —

Speedy Query Service. . . . 42

P.03 - Editorial
EDITORIAL

Eighteen years ago there were a number of people engaged in floating television companies. They were annoyed when I denied that "television is just around the corner." Twelve years ago I ran into plenty of abuse when I returned from a world trip and reported adversely on television. Now again, to day, there is an element in the radio trade which is campaigning for television. I will again risk their displeasure by expressing my opinion that television in Australia is still well "around the corner," and that corner won’t be turned for a year or two yet. What is more to the point, I feel sure that when television does come it will not in any way displace the ordinary broadcasting as we know it now. It will not make present radio receivers obsolete or any less useful than they are today. The problems of television are not technical ones. Back in 1936 I saw several television demonstrations which left little to be desired. The big problems of television are practical ones, especially finance and the provision of sustained program es. It is easy enough to keep a radio station going all day when you have a big pile of records and a couple of big-mouthed announcers. It is much more difficult to arrange a full-time programme of television, not that it is required, as the looker-in gets a stiff neck after a few hours of intently watching a small screen in a semi-dark room. For the televising of the Melbourne Cup and that sort of thing a television service would be greatly appreciated, but is it worth millions? — A. G. HULL.


text:
History of wireless telegraphy and broadcasting in Australia/Topical/Publications/Australasian Radio World/Issues/1948 05

P.01 - Front Cover
The Australasian Radio World

Registered at the G.P.O., Sydney, for transmission by post as a periodical.

1/-

Vol. 12 - No. 12; MAY 15, 1948

P.03 - Contents Banner
THE AUSTRALASIAN RADIO WORLD

Devoted entirely to Technical Radio

and incorporating

ALL-WAVE ALL-WORLD DX NEWS

VOL. 12 - MAY, 1948 - No. 12

P.03 - Publication Notes
Editor, Publisher, Proprietor — A. G. HULL, Balcombe St., Mornington, Vic.

Short-wave Editor — L. J. KEAST, 6 Fitzgerald Road, Ermington, N.S.W. 'Phone: WL1101

Ham Notes By — D. B. KNOCK (VK2NO), 43 Yanko Av., Waverley, N.S.W.

Advertising Representative for N.S.W. - Amalgamated Publications Pty. Ltd., 83 Pitt St., Sydney, Phone: B1077

Representative in Queensland - John Bristoe, Box 82, Maryborough, Q.

Representative in England - Anglo Overseas Press Ltd., 168 Regent St., London, W1.

Subscription Rates: 12 issues - 10/6; 24 issues - £1; Post free; To N.Z. and Overseas - 12 issues, 12/-

Address for all correspondence - Australasian Radio World, Balcombe St., Mornington, Victoria

Printed by Bridge Printery Pty. Ltd., 117 Reservoir Street, Sydney, N.S.W., for the proprietor of the "Australasian Radio World," Balcombe St., Mornington, Vic. (Footnote P.44)

P.03 - Contents
CONTENTS

TECHNICAL —

Limelight on Quality. . . . 5

A Home-made Hi-Fi Pick-up. . . . 9

Sad Lack of Technical Development. . . . 13

Protective Circuits. . . . 16

Deaf Aids From Health Clinics. . . . 19

An English Three-Element Beam. . . . 21

Germanium Crystals. . . . 23

Well-tested Battery Receiver. . . . 25

Among Our Readers. . . . 28

Effective Static Reduction. . . . 29

The "VK2NO" Ribbon Beam. . . . 32

Calling CQ. . . . 35

SHORTWAVE REVIEW —

Notes From My Diary. . . . 39

THE SERVICE PAGES —

Speedy Query Service. . . . 42

P.03 - Editorial
EDITORIAL

There are still quite a few of our supporters who deplore the passing of the "good old days." They cannot become reconciled to existing conditions. Some are giving up their hobby because they feel that the price of components is too high, taking as a basis for comparison the prices they paid in 1939. Others point out to me that the present issues of Radio World are not as attractive as those of the 1939 era; the quality of the actual paper not so good. Dealing with my own problems, I readily agree that in several ways the present issues are not as glamorous as in prewar days. There are two reasons. Paper is scarce and we have considerable difficulty in getting sufficient, irrespective of its quality. The second is purely economic. Not being backed by a big newspaper organisation with unlimited financial resources, it is necessary for each issue of Radio World to pay its own way. Paper cost is up about 400 per cent., printing costs about double, all wages and material prices have risen considerably. Yet the price of the publication has not been raised, and advertising rates are still the same as twelve years ago. Only the great increase in the number of subscribers makes it possible for the business to be carried on as a profitable proposition. Although the modern issues may lack glamour they still contain a lot of good technical reading matter, and this is not overlooked because of the absence of ballyhood, fancy headings and artistic layouts. — A. G. HULL.


text:
IB Physics/Measurements and Uncertainties (2016)

In taking IB Physics, you have made a two-year commitment to understand the fundamental rules of our universe, and, more importantly, understand the ways in which we investigate and refine our knowledge of them.

It must not be forgotten that Physics is an experimental science; it only moves forward through the infinite cycle of thinking that we, as humanity, know something, disproving it with experiments, creating a new theory to account for the inconsistency we see and establishing limitations on the old theory, and trying again.

Understanding perfectly the unique mathematical framework that is used to describe quantities that we can measure from real life, and uncertainty that arises from testing ideas against real life, is of critical importance to understanding the rest of the physics ideas we will encounter in the syllabus.

So begins the first topic in the IB Physics Course. It is broken into three sub-topics, regarding measurements in physics, uncertainties in physics, and the differences between and applications of vector and scalar quantities. 5 hours of teaching and learning time is recommended.


text:
History of wireless telegraphy and broadcasting in Australia/Topical/Publications/Australasian Radio World/Issues/1948 06

P.01 - Front Cover
The Australasian Radio World

Registered at the G.P.O., Sydney, for transmission by post as a periodical.

1/-

Vol. 13 - No. 1; JUNE 15, 1948

P.03 - Contents Banner
THE AUSTRALASIAN RADIO WORLD

Devoted entirely to Technical Radio

and incorporating

ALL-WAVE ALL-WORLD DX NEWS

VOL. 13 - JUNE, 1948 - No. 1

P.03 - Publication Notes
Editor, Publisher, Proprietor — A. G. HULL, Balcombe St., Mornington, Vic.

Short-wave Editor — L. J. KEAST, 6 Fitzgerald Road, Ermington, N.S.W. 'Phone: WL1101

Ham Notes By — D. B. KNOCK (VK2NO), 43 Yanko Av., Waverley, N.S.W.

Advertising Representative for N.S.W. - Amalgamated Publications Pty. Ltd., 83 Pitt St., Sydney, Phone: B1077

Representative in Queensland - John Bristoe, Box 82, Maryborough, Q.

Representative in England - Anglo Overseas Press Ltd., 168 Regent St., London, W1.

Subscription Rates: 12 issues - 10/6; 24 issues - £1; Post free; To N.Z. and Overseas - 12 issues, 12/-

Address for all correspondence - Australasian Radio World, Balcombe St., Mornington, Victoria

Printed by Bridge Printery Pty. Ltd., 117 Reservoir Street, Sydney, N.S.W., for the proprietor of the "Australasian Radio World," Balcombe St., Mornington, Vic. (Footnote P.44)

P.03 - Contents
CONTENTS

TECHNICAL —

Fidelity Tuner With A.V.C. .. . . 5

Interesting Pre-Amplifier. . . . 8

Well-Tested Inter-Com. System. . . . 11

Oscillator for Code Speed. . . . 13

Communications Coil Assembly. . . . 17

The "Economy Three". . . . 19

Service By Substitution. . . . 24

SHORTWAVE REVIEW —

Calling CQ. . . . 35

Notes From My Diary. . . . 39

THE SERVICE PAGES —

Speedy Query Service. . . . 42

P.03 - Editorial
EDITORIAL

Last month's editorial has had a strong reaction. A large number have written to say that they think the obvious solution to the problem is to increase the price of each issue, enlarging and improving it so that it will be worth the money. Several point out that the value of good technical advice on radio matters is worth more than pence, and may actually save the reader pounds of hard-earned cash. One reader suggested, apparently quite seriously, that the price should be advanced to 5/-. He said that if we did he still wouldn’t ever miss an issue. Since production costs have been so much increased the actual nett return from sales has been less than the production cost. The revenue from advertising has kept the business on a paying basis, but there has always been the thought in the back of my mind that the fewer copies I sell the more profit I make. Such a state of affairs does not provide an incentive to turn out attractive issues. So now it seems that in the near future the price will be raised to 1/6 or perhaps even 2/- per copy, which is the usual price of technical magazines overseas. Such a price increase, however, will not be made until I can get together the technical staff to provide additional editorial matter, nor until the printer is able to handle the extra load without delaying the publication date. Just in case anyone jumps to the conclusion that this story is an invitation to readers to express opinions as to what improvements should be made, I may as well add that I know just exactly what I want to do, and it is mainly a matter of getting the required organisation into gear. Then when it can be arranged you will have a better publication, but at a higher price. — A. G. HULL.


text:
IB Physics/Measurements and Uncertainties (2016)/Uncertainties and Errors (2016)

Errors
Physics is an experimental science, and not all measurements are made in an infinitely precise way. As such, physicists have developed mathematical methods to deal with the errors that crop up from doing experiments in the real world - a field of study called Error Analysis. In IB Physics, this is lightly tested but critical for your IA, where you do an experiment. In the most formal sense, think of an error as a deviation, or difference, of a measured value from an accepted (or real) value.

Random Errors
A random error is an error affecting a measured value that an experimenter has found which is unknown and unpredictable. It is usually caused by:

 * 1) Variations in the experimental situation, like random fluctuations in temperature. In these cases, the maximum random error, (or uncertainty), is of unpredictable and usually unknown size.
 * 2) Estimating when reading a measured value off of a measuring instrument, like taking the mass of a body from a digital scale. In these cases, you can usually know the size of the maximum random error, (or uncertainty), from the precision of the measuring instrument.

In doing practical experiments in Physics, it is important to reduce the random error of your measurements in order to get the most accurate possible result.

The easiest way to reduce random error in experiment is using equipment that is more precise. (Precision here refers to how closely measured values agree with each other. A measurement being precise might not imply it's close to the true value- just that it's very reliably consistent.) For instance, one could use an electronic balance that is precise to 0.01 g over a kitchen balance that is precise to 1 g.

Systematic Errors
Systematic errors are errors that cause the measured value of a quantity to be different from the real value by a reasonably consistent amount. They are usually associated with a particular measuring instrument or experimental technique.

For example, a 30 cm plastic ruler with margins of 0.3 cm on either side of the 0 cm and 30 cm markings would have a systematic error if you used it incorrectly, by assuming the end of the ruler was the real 0 marking, and lining that up against, say, the height of a block to measure it. This kind of systematic error is called a zero error, so named because measuring a 0 cm actual value would leave you with a systematic error of 0.3 cm.

You can reduce systematic errors in an experiment by identifying them from your equipment and method, followed by accounting for them in your calculations, usually by subtraction. You can also reduce systematic errors by using equipment that has been tuned to have none, and by using existing equipment in a way that will not lead to the creation of systematic errors, like measuring from the actual 0 cm mark of a ruler.

Uncertainties
Uncertainties are extra information added to the accepted value of a quantity that signify how precise our knowledge of a quantity is.

For example, one might measure a length of a copper cable as $$0.600\,\mathrm{m}$$, with a yardstick accurate to the nearest $$0.001\,\mathrm{m}$$. Measuring a length on an analogue ruler is taken to be the act of finding where two points are on the ruler, and finding the difference. Each point on the ruler is a millimetre apart, so the real start and end of the wire can be recorded by a point on the ruler that is at most half a millimetre away. Subtracting these two points creates a total uncertainty of two half-millimetres, or one millimetre.

We would therefore write the quantity signifying our knowledge of the length of copper wire as $$0.6\,\mathrm{m} \pm 0.001\,\mathrm{m}$$. The symbol in the centre is pronounced "plus or minus", and it shows that the value could be up to $$0.6 \,\mathrm{m} + 0.01 \,\mathrm{m} = 0.601 \,\mathrm{m}$$, or as low as $$0.6 \,\mathrm{m} - 0.001 \,\mathrm{m} = 0.599 \,\mathrm{m}$$. That is, from the accepted value minus the uncertainty up to the accepted value plus the uncertainty.

Note: this use of the plus-or-minus symbol means that uncertainties are always positive numbers and should be treated as such. This is why there are $$|\mathrm{absolute\, value\, signs}|$$ on all of the formulas about uncertainties. These signs mean that you must change whatever is within them, positive or negative, into a positive number of equal magnitude. The signs have other meanings in maths, but this is beyond the scope of this Wikibook.

Absolute Uncertainties
An absolute uncertainty is an uncertainty attached to a quantity, which is of a certain known value. It answers the question - how wrong exactly are we? It is not a proportion of the accepted value. The absolute uncertainty of a given quantity $$x$$ is written as $$\Delta x$$. For instance, if we knew that $$x = 300 \pm 6$$, we could say that $$\Delta x = 6$$.

You should write them to a maximum of 1 or 2 (based on your judgement) significant figures. The reasoning behind this is that the extra significant figures add no real meaning to our understanding of the main value.

Fractional Uncertainties
A fractional uncertainty is an uncertainty attached to a quantity which represents the magnitude of the absolute uncertainty involved, as a proportion of the accepted value for the quantity. Basically speaking, it answers the question - how much does our wrongness matter? For instance, in our example of the wire, we could calculate the uncertainty like this:

$$\frac{\Delta x}{x} = \frac{0.001\,\mathrm{m}}{0.600\,\mathrm{m}} = 0.001666\ldots$$

There is usually no need to round a fractional uncertainty because, very often, it is an intermediate step in calculating something more complex. The symbol $$\frac{\Delta x}{x}$$ represents a fractional uncertainty.

Percentage Uncertainties
Percentage Uncertainties of quantities are much like fractional uncertainties, except for the fact that they are expressed as a percentage rather than a fraction or decimal. The mathematical skill of converting a fraction or decimal into a percentage is below the scope of the IB Physics Syllabus, and so will not be detailed here.

For our example of the yardstick, the percentage uncertainty is easily found by converting the fractional uncertainty to a percentage. The symbol which represents a percentage uncertainty, $$\frac{\Delta x}{x}$$, is the same. See here:

$$\frac{\Delta x}{x} = \frac{0.001\,\mathrm{m}}{0.600\,\mathrm{m}} = 0.001666\ldots = 0.17\ldots\% \approx 0.2\%$$

Percentage Uncertainties are the usual way to express uncertainties by the proportion of a value. Exactly the same as absolute uncertainties, you should write them to a maximum of 1 or 2 (based on your judgement) significant figures.

Uncertainties from Averages
When you have taken multiple readings of a value to find an average and increase your accuracy, there are two ways to determine the uncertainty of your final average value.

 * 1) If the range of the data is more than the range of possible values of the mean when the same absolute uncertainty is kept, then you must account for this in expressing your final value. For instance, if your experimental data for a value are $$5.5 \pm 0.2, 6.5 \pm 0.2, 7.5 \pm 0.2$$, then you have underestimated the random error, because the ranges of possible values do not overlap on one single value. You need to correct this. The rule of thumb for doing so is for the absolute uncertainty of the mean to be half of the range of the data; the reasoning behind this is to include all of the data points as possible values. In our example, the range of the data is $$2.0$$, so we would express our mean as $$6.5 \pm 1$$.
 * 2) If the uncertainty of each value means that the possible range of real values from each reading is smaller than the range of the data, then you simply retain the same absolute uncertainty when expressing the data's mean. For instance, if your data were $$6.6 \pm 0.2, 6.5 \pm 0.2, 6.7 \pm 0.2$$, then, because every value is within the uncertainty of the mean ($$6.6 \pm 0.2$$), there is no need to increase the uncertainty to account for the spread of the data.

A note on the reasoning behind keeping the same absolute uncertainty for the mean even though taking an average is used to make a measurement more accurate is made a few sections below.

Graphical Analysis
The skills involved with graphing a relationship between two quantities based on experimental data are generally prerequisite to the IB Physics course. However, here's a quick refresher on how you should do your graphs.

 * 1) Linearise the axes to test for a straight-line graph if necessary for analysis: if $$A^3 = kB^2$$, then plot $$A^3$$ and $$B^2$$ on the axes rather than leaving the two quantities as they are.
 * 2) Include a descriptive title on the graph, and turn on all major and minor grid lines.
 * 3) Label the axes in the format "description symbol /unit"; for instance, a label like "distance $$s\,/\mathrm{m}$$" is appropriate.
 * 4) Ensure that the numbers on the axes are labelled and spaced out in a logical manner - without the unit, as you have already divided the quantity by the unit in your labelling scheme.
 * 5) Generally, a physicist would analyse an experiment by plotting the thing they are changing (the independent variable) on the horizontal x-axis, and plot the thing they are measuring (the dependent variable) on the vertical y-axis.
 * 6) Make sure you use "X" markers or "+" markers rather than circular blobs to indicate a plotted point, so that it is visually more precise.

That's pretty much the sum of physics graphing skills that you would be expected to have up to the point of the IB course. For the rest of this section of the article, assume I am talking about Microsoft Excel (2020) (and not Google Sheets - Sheets is incapable of proper error bars and uncertainty analysis).

Error Bars
Error bars are a physicist's most useful visual interpretation of uncertainty. They are extensions of the plotted marker that show how far up, down, left, or right, the real value indicated by the marker could possibly be plotted on the graph; that knowledge is based on the uncertainties of the value you are plotting. Search: "error bars physics" on Google Images for a visual idea of them.

Error bars for an experiment might all be of equal size, or different points may have different uncertainties - in this case, you should record, or generate, a column of uncertainty values (e.g. a column for $$\Delta x$$ and $$\Delta y$$ alongside the typical columns for $$x$$ and $$y$$) for the spreadsheet software to use as values for error bars.

Generally speaking, the error bars up and down in the y-axis and the error bars left and right in the x-axis will be the same size, unless you know for sure that the uncertainty in one direction is far less or far greater than the uncertainty in another direction.

Sometimes, error bars are not appropriate for a graph simply because they are so small. For instance, if you are working in lengths of a couple of metres, but your uncertainties in the length are just a millimetre - that being the precision of the ruler - then your error bars with respect to length are likely to be so small on the plotted graph that they can be ignored.

A useful exercise, after this section, would be to see if you can use drawing and intuition based on error bars to demonstrate the rules for adding uncertain quantities together, multiplying an uncertain quantity by a constant, and, as a challenge, multiplying or dividing two uncertain quantities together.

Uncertainty of Gradient and Intercepts
Finding the uncertainty of a gradient or an intercept in physics is very useful because it allows uncertainty values to be "calculated" for quantities that we are unable to directly measure.

For instance, most experiments involving the acceleration of free-fall, $$g$$, do not measure it directly - they derive it from another dependent and independent variable, perhaps as the gradient of the graph that links the two variables together. Another example is how experiments determine the value of absolute zero - physicists back in the 19th century absolutely would not have had access to any equipment that might let them bring the temperature of something down even close to absolute zero, and they determined it using the x-intercept of a graph linking two quantities about the behaviour of a gas together.

The technique to use here is called the use of "max-min lines". Essentially, you try to plot a "max line", which is as steep as possible but still passes through all the error bars, and then a "min line", which is as shallow as possible, but, again, passes through all the error bars. The logic behind this is that you are pushing the error bars to their limits, using your knowledge of how the real point may be anywhere inside the rectangle created by the error bars.

After you have created these max-min lines, you can take the steeper gradient to be the maximum possible gradient, and then you can take the shallower gradient to be the minimum possible gradient. As a rule of thumb, you can generally take the arithmetic mean (add then divide by 2) of the two gradients to get your "measured value" of the gradient. Naturally, it then follows that the gap between your measured gradient and each of the maximum and minimum possible gradients is the uncertainty in the gradient.

You can analyse the intercepts of the graph (intercepts with another line, with the axes, etc) with a similar technique. Note the extreme possible values of the intercept, taking them to be the maximum and minimum values as appropriate, and, again, take the arithmetic mean of the values to be your "measured value". The uncertainty in the intercept is calculated from the difference between the measured and the extreme values.

Uncertainties Expressed as Ranges
There are, of course, some exceptions. For instance, you might realise that the difference between a max line and a min line in some pattern that is close to vertical might end up massive - think a minimum of 10 and a maximum of 5,000. Here, taking the arithmetic mean is not appropriate, and so by necessity you would have to express the gradient as a range (i.e. $$10 \leq m \leq 5,000$$).

Expressing uncertainties in any form as a range is an easy skill. Although it is not always necessary, it can be helpful. Generally, given an uncertain quantity $$x \pm \Delta x$$, knowing that the extremes are such that $$m - \Delta m \leq m_{real} \leq m + \Delta m$$, for instance, $$300 \pm 6$$, we would express our knowledge of the quantity with the range statement "$$x$$ is between 294 and 306"; or, simply with the interval/inequality $$294 \leq x \leq 306$$.

Calculation: Propagating Uncertainties
When determining the uncertainty of a value which has been itself calculated from other uncertain values, the following rules apply.

Adding and Subtracting Values
When adding and subtracting values from each other, you will need to add the absolute uncertainties together.

For instance, $$6.0 \pm 0.2 + 4.2 \pm 0.1 = 10.2 \pm 0.3$$.

The reasoning behind this is that, when adding two uncertain values, $$a \pm \Delta a$$ and $$ b \pm \Delta b$$, the lowest possible value is $$(a+b) - \Delta a - \Delta b$$, and the highest possible value is $$(a+b) + \Delta a + \Delta b$$. The total range of possible values is equal to the sum of the ranges of possible values for the two quantities you added together. In other words,

 * If $$a + b = c$$,
 * then $$\Delta a + \Delta b = \Delta c$$
 * because $$a \pm \Delta a + b \pm \Delta b = (a+b)\pm (\Delta a + \Delta b)$$.

Multiplying or Dividing an Uncertain Value by an Exact Value
The rules regarding propagating an uncertainty through multiplication and division are perhaps some of the most important.

If you have some uncertain value $$a \pm \Delta a$$, then it can take a lowest value of $$a - \Delta a$$ and a highest value of $$a + \Delta a$$. If you multiply the lowest value and the highest value each by some exact factor $$k$$, then you'll get a lowest value of $$ka - k\Delta a$$ and a highest value of $$ka + k\Delta a$$.

The main value has been scaled up by a factor of $$k$$, becoming $$ka$$. At the same time, we can see that the minimum and maximum possible values have scaled up by the same factor - the amount by which they are lower or higher than $$ka$$, that amount being the uncertainty in $$ka$$, has correspondingly been increased by that factor of $$k$$. Mathematically speaking, we can write this in a really simple form - $$\Delta ka = k \Delta a$$. In the IB formula booklet, this isn't actually included - you may have noticed that this is in fact just an application of the rule regarding adding uncertain quantities together.

Dividing a quantity by a constant, which we'll call $$j$$, can be thought of as multiplying by $$\frac{1}{j}$$. So, likewise to the previous paragraph, $$\Delta \frac{a}{j} = \frac{1}{j}\Delta a$$.

As an example - say you have the uncertain quantity $$100 \pm 4$$. If you divided this quantity by 4, you'd get $$25 \pm 1$$; the absolute uncertainty is divided by 4, and the percentage uncertainty remains the same - a very important fact to bear in mind. If you multiplied this uncertainty by 4, you'd get $$400 \pm 16$$. Notice that I've kept the second significant figure; that's because rounding it to an absolute uncertainty of 20 would make it significantly more uncertain than it really was (the uncertainty increases in size by a whole 25%! That is a meaningful difference, and so I have concluded with my own judgement that 2 significant figures is appropriate here).

Multiplying or Dividing two Uncertain Values
The rules get a little more complicated when we move into the realm of multiplying and dividing uncertain values by one another. Let's try and find minimum and maximum values when we multiply two uncertain quantities together.

Suppose you have two quantities, $$a$$ and $$b$$, that multiply to the quantity $$c$$. Suppose that each of the data are uncertain by an amount $$\Delta a$$ and $$\Delta b$$ respectively. In other words, $$ab = c$$.

At a minimum, $$c = (a - \Delta a)(b - \Delta b) = ab - a \Delta b - b \Delta a + \Delta a \Delta b$$, taking the smallest values of the initial data possible. At a maximum, $$c = (a + \Delta a)(b + \Delta b) = ab + a \Delta b + b \Delta a + \Delta a \Delta b$$.

Try to do this with your own pencil and paper - if you subtract the minimum from the maximum, you find a range of values $$2(a \Delta b + b \Delta a)$$ wide; the uncertainty is $$a \Delta b + b \Delta a$$. You will also find that the measured value of the quantity $$c$$ is $$ab + \Delta a \Delta b$$, because that's the centre-point between the minimum and maximum values. Consider that, usually, $$\Delta a \Delta b$$ will be too small to affect the measured value. You can basically cancel it to 0. As such, our final value for $$c$$ is $$ab \pm (a \Delta b + b \Delta a)$$.

Generally, the rule for multiplying two uncertain values is that the percentage uncertainty of the result will be the sum of the percentage uncertainties that you are multiplying together. This is a property that can be seen in the calculation above. If we try to calculate the overall percentage uncertainty in $$ab$$, we get the below.

$$\frac{a \Delta b + b \Delta a}{ab} = |\frac{\Delta a}{a}| + |\frac{\Delta b}{b}|$$

This explains the rule for multiplying two uncertain quantities together. Now we ought to consider what happens if we divide one uncertain quantity by another. Say we have a quantity $$\frac{a}{b} = c$$. $$a$$ and $$b$$ are both uncertain by an amount $$\Delta a$$ and $$\Delta b$$ as before.

At a maximum, $$c = \frac{a + \Delta a}{b - \Delta b}$$. At a minimum, $$c = \frac{a - \Delta a}{b + \Delta b}$$. The difference between these two quantities is $$\frac{a + \Delta a}{b - \Delta b} - \frac{a - \Delta a}{b + \Delta b} = \frac{ab + \Delta a \Delta b + a \Delta b + b \Delta a - (ab - a \Delta b - b \Delta a + \Delta a \Delta b)}{b^2 - (\Delta b)^2} = 2\frac{a \Delta b + b \Delta a}{b^2 - (\Delta b)^2}$$. As before, $$(\Delta b) ^2$$ is a quantity that would generally be insignificant to the final result, so we cancel it to 0. Keep in mind that the algebra here is quite hard, and I wouldn't expect every reader of this textbook to follow it. The general rule for division is stated later.

We find that, dividing by two, the absolute uncertainty is $$\frac{a \Delta b + b \Delta a}{b^2} = \frac{a}{b}(\frac{\Delta b}{b} + \frac{\Delta a}{a})$$. You may realise that this absolute uncertainty is the new value multiplied by the sum of the percentage uncertainties - the percentage uncertainty in the new value is the initial percentage uncertainties added up. You may want to come back to this section later and attempt the algebra yourself. Until then, the rule to be remembered is quite simple, below.

To summarise - when multiplying or dividing two uncertain quantities by one another, the percentage uncertainty of the answer can be found by adding up the percentage uncertainties of the two inputs. When $$a = bc = \frac{d}{f}$$:

$$|\frac{\Delta a}{a}| = |\frac{\Delta b}{b}| + |\frac{\Delta c}{c}| = |\frac{\Delta d}{d}| + |\frac{\Delta f}{f}|$$

Raising Uncertain Values to a Power
When raising an uncertain value, which we'll call $$x$$, to a certain power, which we'll call $$n$$, the rule is actually quite simple. You take your original percentage uncertainty in $$x$$ and multiply it by the absolute value of the power. This is a pretty much direct logical conclusion that can be drawn from our knowledge of the rules for multiplying and dividing uncertain quantities.

For instance, if we want to calculate the percentage uncertainty in $$x^4$$, we just need to note that $$x^4 = x \times x \times x \times x$$. If we want to calculate the percentage uncertainty in $$\frac{1}{x^3}$$, we just need to note that $$x^{-3} = 1/x/x/x$$. In the first case, we are multiplying four $$x$$'es together, and so the percentage uncertainty must be $$\frac{\Delta x^4}{x^4} = |\frac{\Delta x}{x}| + |\frac{\Delta x}{x}| + |\frac{\Delta x}{x}| + |\frac{\Delta x}{x}| = 4|\frac{\Delta x}{x}|$$. In the second case, we are dividing an exact quantity by $$x$$ 3 times, and so the percentage uncertainty must be $$\frac{\Delta x^{-3}}{x^{-3}} = |\frac{\Delta x}{x}| + |\frac{\Delta x}{x}| + |\frac{\Delta x}{x}| = 3|\frac{\Delta x}{x}| = |-3\frac{\Delta x}{x}|$$.

This uncertainty principle needs a little more mathematical proving if we are to use it for fractional and decimal powers. However, I'm just going to leave it - the math is beyond the scope of this course. To summarise what is learned in this section:

$$\frac{\Delta x^n}{x^n} = |n\frac{\Delta x}{x}|$$

Special Functions
For IB SL and HL Physics, calculating the uncertainty of a value after it's been passed through a special function, like $$\mathrm{sin}$$ or $$\mathrm{ln}$$, is not necessary. In pursuing analytical work that needs this, the fractional uncertainty of the function's input is taken to be that of its output. For instance, if I am $$1\%$$ uncertain in a quantity $$A$$, then I would also say that I am $$1\%$$ uncertain in $$\sin A$$ or $$\ln A$$.

This paragraph is only relevant for some very difficult IA topics that may need it. For some functions $$f(x)$$ where a shift in $$x$$ of $$\Delta x$$ causes changes of wildly different size to $$f(x)$$, it is more appropriate to manually calculate the highest and lowest possible values of $$f(x)$$ across the domain of possible real values of the quantity from $$x + \Delta x$$ to $$x - \Delta x$$, which are often (but not necessarily) equal to $$f(x + \Delta x)$$ and $$f(x - \Delta x)$$.


text:
The Arab Identity

Table of Contents

 * /Introduction/
 * /The Orient/
 * /Religion/

title: The Arab Identity


text:
User:Dvcorpus

I've begun a book here instead of typing elsewhere and pasting. It's written page by page so I guess a collection or categorization is in order. I'm aware that individual pages get deleted here so I guess this page would have to do now for an introduction. Is that a fair way to go about it? I will eventually put an author (User) page up here. Discussions are welcome.

This was originally published under ... The Arab Identity

Introduction Saudi Arabia's buzz words for the year 2016 were "change and modernization ". Yet as the world grapples with the Coronavirus, and a looming Oil war, Saudi US relations seem to be stretched tight. The increasingly heartbreaking war in Syria and now Yemen puts Saudi Arabia and the Arab world by large in an increasingly desperate situation. With Israels' talk of Annexing forbidden lands in occupied Palestine, are we looking at a world about to be reshaped again with Arabs relegated to its fringes? The Western world was largely introduced to the Arab during the Age of Oil. The Islamic Clergy and the Saudi Establishment have long stood for what it means to be Arab. With the West increasingly at its border, it was only a matter of time before this Identity was questioned for what it really stood for. On the onset, Orientalism answered the West's increasing occupation with what they saw as the Decadent East. For Muslims, though this was not so. For them, it's not difficult to imagine the Arab identity. After all, Arabs have crossed the desserts of Najd to conquer large parts of the larger Arab and African lands and have crossed far into Asia by sea as well as to the borders of Europe by land. The Arabs are proud people. And their pride is justified by Muslims all over the world coming to Mecca in Saudi Arabia annually, to the birthplace of the Prophet Muhammad, in a pilgrimage that is the largest the world witnesses, congregating believers from the second-largest religious denomination in the world. Muslims all over the world, early in life are introduced to the 'Arab-ideal'. Old Najd, and its surrounding lands, in Mecca and Medina, Jerusalem, Palestine, and even Syria, Yemen and Iraq are seen as holy lands by all Muslims. The Arabs and their place in the world are central to how all Muslims see themselves with regards to their relationships, national identity, and politics, even in an increasingly global century. This book aims to explore 'Arab identity' and the 'Arab ideal' more than it seeks to answer global and political questions concerning the Arab world. But to do so we first have to see what it means to be an Arab, and how the rest of the world sees them.

Contents The Orient

title: User:Dvcorpus


text: User:Dvcorpus/sandbox

title: User:Dvcorpus/sandbox


text:
Selected Essays/Communal Harmony

“A house divided against itself cannot stand together” is an old saying and it holds true in the present context of increasing communal disharmony in the society. These dividing forces weaken and mutilate the society. The culture, civilization and tradition of India is approximately 12,000 years old. The spirit of tolerance and assimilation as made it possible for our civilisation to survive the test of time. But with the passage of time, the growing attachment with the passage of time, the growing attachment to one’s own ethnic, religious, racial or cultural group rather than being a part of wider circle of group rather than being a part of a wider circle of the entire social milieu, has posed one of the gravest problems of modern times. Somehow with the increase in science and technology, the man who should have opened up to assimilation and integration has instead receded into his own cells and has become more conservative and protective towards his culture and community.

Fear, suspicion and a sense of insecurity towards the other communities have given rise to hatred, which acts as fuel, feeding the flame of communities have given harmony can be achieved by making people realize the significance of oneness. People should be awakened to the fact that the differences of ethnic and religious origins have no foundations at all and these feelings should be discouraged if a nation has to survive, and on a larger scale if humanity has to survive. Roses alone cannot make a garden. It is the variety of different coloured and perfumed flowers that lends beauty to a garden.

Fostering the spirit of brotherhood and mutual trust is the most challenging task that our country needs to accomplish. We have to make every possible efforts to eradicate vestiges of communal hatred and prejudice. One way of accomplishing this huge task in India is by promoting scientific temperament and removing the cobwebs of caste and religious prejudices.

India has had a long and proud history of mutual cooperation and trust. People belonging to various ethnic groups, races, religions, creeds, cultures have come and settled on this land and since centuries have made it their home. But the divide and rule policy that took its roots deeper than what the colonial masters could have imagined, shows its predatory signs time and again. These seeds of communal divide, sown to meet short-germ selfish political ends, are now deep-rooted and threatening to uproot the century-old harmony and unity of the country.

This hatred was at its worst during the ill-fated partition of the country. The articulation of two-nation theory and creation of the state of Pakistan implied that the enmity between the two communities was so great that it was virtually impossible for them to live together in peace as one nation.

Even today India’s fragile peace is shattered by communal riots every now and then. During the British rule, riots were triggered to either distract the attention form the growing freedom movement or else to dilute and weaken the unity of Hindus and Muslim Unity has always been one of the essential pillars of any progressive national movement.

India’s valiant attempt to build a secular polity in a desperately impoverished nation was a step of profound importance and key to the rehabilitation of the Indian people. But the task of reconstruction has not been easy at all and from time to time the unity of the Indian people has been challenged by the anti-social and anti-secular elements of the society. They their purpose is defeated in the face of growing unity and understanding among people of different communities and cultures; hence they try to instigate the hatred of a common man to serve their own selfish and ulterior motives. The recent communal violence of Gujarat, the anti- Sikh campaigns during the mid-80s, the Mumbai riots, the Ayodhya episode, the evacuation of Kashmiri Pandits, the attacks on the pilgrims on their way to pilgrimage are all blots on the secular fabric of the country. Now-a-days, any controversy even if it happens in a remote village reaches all over the world due to the advanced communication technology and vibrant media. Social networking sites, mass messages etc. proves both a boon and a bane to the society in the times of riots, But the nation should take lessons from its past and pledge not to let the demon of communal violence ever rise again.

We, as responsible citizens, should continuously and ferociously guard our great secular heritage. Communal d should be nipped in the bud itself and not be allowed to rise and flourish. The children should be taught to appreciate the diversity of the country. They should be taught to learn divergent cultures and ways of living. Also, youths are the country’s power, whose participation is very important. They are the strong forces in the movements, who recognize problems and solve them. Religious snobbery, fanaticism and conservatism should be discouraged and scorned at.

One cannot and should not make a sweeping judgement about India’s secular nature just by browsing through a few shameful incidents of hatred, which are registered on the pages of history. One cannot ignore that in difficult times the secular minded citizens of the country have joined hands together to fight against the forces of dissension. Media, which is known as the fourth pillar of society, has always played a significant role for the betterment of society. Role of media in the coverage of Communal Riots in the past, riots of late 60’s, the violence of 1980-81, the separatist movement of mid 80’s and early 90’s, the incidents at Ayodhaya, Mumbai, Gujarat can’t be ignored by any means.

Media always moulds the public opinion on correct lines in regard to the need of friendly and harmonious relations between various communities and religious groups and thus has promoted national solidarity. Although, a handful of anti-social elements try to create an atmosphere of turmoil, turbulence and fear, yet time and again and entire nation has risen against those handful to guard and protect the peace and harmony of the country. Moreover, a few power hungry political parties, sects and communities, for their vested interests try to use diversity as a weapon to maintain their status-quo. The greed makes them so short-sighted that they fail to see that they are fin turn digging their own graves.

The road to peace and harmony can never be smooth. Every nation has had its share of violence in order to create a society where all can have equal rights and can live with respect and dignity. Who can forget the bloody Civil War of America, the division of Germany and Korea, the Bolshevik Revolution, the violence after the French Revolution, the prevailing disturbances in the Middle East, Israel- Palestine problem etc, the list is endless and the instances bloodier and more violent than the other.

India has emerged as a strong nation, every time these communal forces have tried to test their secular foundation. One cannot sit back and relax at such times rather one has to work persistently against such forces that pose danger to the idea of a United Nation. This cannot happen by waving a magical wand.

It is we, the people of the nation, who have to rise above these forces of dissent and division, so that India becomes a nation where religion of humanity is superior to every other religion.

title: Selected Essays/Communal Harmony


text:
User talk:Leowebbhk

The edits that you made to the main page of IB Physics have broken the table of contents so that none of the existing pages are accessible. This doesn't seem helpful on the face of it. Can you explain what you are doing? Thanks - QuiteUnusual (discuss • contribs) 15:18, 15 June 2020 (UTC)

Sure! I am sorry for not writing this out in the documentation earlier. Essentially, the IB course has updated significantly since the last time it seems like any changes of reasonable size were made. This renders the organisation and a lot of the content of the old edition of the book unuseable for students taking the current IB Physics Syllabus, a group of which I am a part. For instance, the development stages on the main table of contents had not been updated since 2011 at the latest, and 2007 for the majority of chapters. In addition, I noticed that a lot of pages were incomplete and written in a manner that was difficult to read. Physics is a subject that, even further, requires proper mathematical notation to explain fully in a way that is useful to students taking the exam at the end of the course.

In summary, because
 * 1) The content is 9 to 13 years out of date,
 * 2) poorly and unclearly explained,
 * 3) and therefore is not useful in any means to the IB Physics student population, especially when other Physics books exist on this site that are better at explaining more general concepts,

I am attempting a rewrite of the IB Physics Book for the 2016 (current) syllabus. — Preceding unsigned comment added by Leowebbhk (talk • contribs)

 * How about a new book based on the 2016 syllabus? You could leave the old one as it was, an create a new updated one. You could also import material from the old book, adapt it, and put it in your new one. I can help you with the process if needs be. -- Jules (Mrjulesd) 17:59, 18 June 2020 (UTC)

title: User talk:Leowebbhk


text: Template:Irish/VocabularyList

title: Template:Irish/VocabularyList


text:
User:Kimberly naidoo

RECIPES

title: User:Kimberly naidoo


text:
Geography of Race in the United States/Causes of housing segregation

[Image to come]

The systematic racial segregation observable on the maps in this site is the product of the interaction of federal, state/local government, and private sector causes. The chart to the left offers an overview of some of these interactions. Roll your mouse over individual items to get a more detailed view of some of them.

These causes of racial segregation form a vicious circle, via the ways segregation in turn causes concentrated urban poverty among African-Americans and Hispanics, which reinforces racial prejudice, further fueling white flight from neighborhoods inhabited by or proximate to blacks and Hispanics.

 * Next: Economic consequences of segregation


text:
History of wireless telegraphy and broadcasting in Australia/Topical/Publications/Australasian Radio World/Issues/1948 07

P.01 - Front Cover
The Australasian Radio World

Registered at the G.P.O., Sydney, for transmission by post as a periodical.

1/-

Vol. 13 - No. 2; JULY 18, 1948

P.03 - Contents Banner
THE AUSTRALASIAN RADIO WORLD

Devoted entirely to Technical Radio

and incorporating

ALL-WAVE ALL-WORLD DX NEWS

VOL. 13 - JULY, 1948 - No. 2

P.03 - Publication Notes
Published by the Proprietor — A. G. HULL, Balcombe St., Mornington, Vic. Phone: M'ton 344.

Technical Editor — Paul Stevens, 21 Fletcher's Av., Bondi, N.S.W. Phone: FW6157

Short-wave Editor — L. J. KEAST, 7 Fitzgerald Rd., Ermington, N.S.W. Phone: WL1101

Ham Notes By — Don B. KNOCK (VK2NO), 43 Yanko Av., Waverley, N.S.W.

Advertising Representatives —

In N.S.W.: Amalgamated Publications Pty. Ltd., 83 Pitt St., Sydney. Phone: B1077

In Victoria: R. L. McKillop, Regency Advertising Contractors, 60 Market St., Melbourne. Phone M1279

In Queensland: John Bristoe, Box 82, Maryborough, Q.

In New Zealand: H. Barnes & Co., 4 Boulcott Terrace, Wellington.

In England: Anglo Overseas Press Ltd., 168 Regent St., London, W1.

Distributed throughout the World by Gordon & Gotch (A/asia) Ltd.

Subscription Rates: 12 issues - 10/6; 24 issues - £1; To N.Z. and Overseas - 12 issues, 12/-; Post free

Address for all correspondence - Australasian Radio World, Box 13, Mornington, Vic.

Printed by Bridge Printery Pty. Ltd., 117 Reservoir Street, Sydney, N.S.W., for the proprietor of the "Australasian Radio World," Balcombe St., Mornington, Vic. (Footnote P.35)

P.03 - Contents
CONTENTS

TECHNICAL —

Building Box Baffles. . . . 5

Using H.F. Pentodes. . . . 9

Pre-Amplifier Tone Control. . . . 11

12-Valve Communications Receiver. . . . 13

Signal-Strength Meters. . . . 17

Among Our Readers. . . . 21

A Four-Valve Battery Portable. . . . 23

Calling CQ. . . . 27

Amateur Transmitting Licences. . . . 29

SHORTWAVE REVIEW —

Notes From My Diary. . . . 31

THE SERVICE PAGES —

Speedy Query Service. . . . 34

P.03 - Editorial
EDITORIAL

I must have been feeling glum when I wrote last month's editorial. Since then I have been going over the accounts and things aren't quite so black as I expected. It now seems that, there will be no need to increase our price, in spite of increased printing and block costs. Just a little more advertising support and it will be possible to turn out improved issues at our present price. First step in the right direction has been the appointment of Paul Stevens as Technical Editor and my personal representative in Sydney. The fine articles which Mr. Stevens has contributed over the past six years have been widely appreciated and he can be counted on to do even better work in this direction in future. He is also a keen businessman and will soon get things organised so that the issues will be out on their due date. It may take a while to get into top gear, but the first of the improved issues should be the September issue, which will take the form of a special "Data & Handbook Issue" which will contain lots of information you'll want to keep handy, such as colour codes for different brands of coils, specifications of components available on the market at present, and so on. Another bright prospect has been provided by some experimenting which has been going on over the past few weeks. It looks as though I have in hand the logical successor to the old "1933 Standard," the most successful set I ever designed. Further testing is being made to probe every possibility, but so far it has shown nothing but the greatest possibilities. — A. G. HULL.


text:
History of wireless telegraphy and broadcasting in Australia/Topical/Publications/Australasian Radio World/Issues/1948 08

P.01 - Front Cover
The Australasian Radio World

Registered at the G.P.O., Sydney, for transmission by post as a periodical.

1/-

Vol. 13 - No. 3; AUGUST 18, 1948

P.03 - Contents Banner
THE AUSTRALASIAN RADIO WORLD

Devoted entirely to Technical Radio

and incorporating

ALL-WAVE ALL-WORLD DX NEWS

VOL. 13 - AUGUST, 1948 - No. 3

P.03 - Publication Notes
Published by the Proprietor — A. G. HULL, Balcombe St., Mornington, Vic. Phone: M'ton 344.

Technical Editor — Paul Stevens, 21 Fletcher's Av., Bondi, N.S.W. Phone: FW6157

Short-wave Editor — L. J. KEAST, 7 Fitzgerald Rd., Ermington, N.S.W. Phone: WL1101

Ham Notes By — Don B. KNOCK (VK2NO), 43 Yanko Av., Waverley, N.S.W.

Advertising Representatives —

In N.S.W.: Amalgamated Publications Pty. Ltd., 83 Pitt St., Sydney. Phone: B1077

In Victoria: R. L. McKillop, Regency Advertising Contractors, 60 Market St., Melbourne. Phone M1279

In Queensland: John Bristoe, Box 82, Maryborough, Q.

In New Zealand: H. Barnes & Co., 4 Boulcott Terrace, Wellington.

In England: Anglo Overseas Press Ltd., 168 Regent St., London, W1.

Distributed throughout the World by Gordon & Gotch (A/asia) Ltd.

Subscription Rates: 12 issues - 10/6; 24 issues - £1; To N.Z. and Overseas - 12 issues, 12/-; Post free

Address for all correspondence - Australasian Radio World, Box 13, Mornington, Vic.

Printed by Bridge Printery Pty. Ltd., 117 Reservoir Street, Sydney, N.S.W., for the proprietor of the "Australasian Radio World," Balcombe St., Mornington, Vic. (Footnote P.35)

P.03 - Contents
CONTENTS

TECHNICAL —

Converter For Amateur Bands. . . . 5

History of "1933 Standard". . . . 9

"The Bedside 5". . . . 13

Loudspeaker Baffling. . . . 17

The American Radio Industry. . . . 19

Exceptional 20 Watt Amplifier. . . . 21

"Long Shot" Economy Beam. . . . 23

Calling CQ! . . . . 27

SHORTWAVE REVIEW —

Notes From My Diary. . . . 31

THE SERVICE PAGES —

Speedy Query Service. . . . 34

P.03 - Editorial
EDITORIAL

The next issue will be the special Radio Handbook and Data issue, which will be something quite out of the ordinary, with a great collection of tables, tabulations and lists which you will find useful as a handy reference for many months to come. A large number of extra copies are being printed and circulated but if you are not a regular reader I would strongly recommend you to make a point of placing a definite order for this issue with your local newsagent. Whereas some of our issues have been a few days late in the past, the big September issue is due to come out on time, in fact it is scheduled to reach every part of the Commonwealth by the 15th of the month, which is the date on the cover. Subscribers' copies should be in their hands about a week earlier. The special issue marks the start of a series of improved issues and we have some fine technical articles lined up to follow on in the October and November issues. Among these might be mentioned the mantel model to outdo all mantel models, designed by Paul Stevens and described in detail with full photographs and diagrams, the 1948 World Standard, which gives terrific power with exceptional fidelity, yet costs only a few shillings more than an ordinary set, a new 45-watt super-quality amplifier, and last, but not least, the sweetest of low-powered amplifiers. This last item is a modest affair but has the following performance when laboratory checked: frequency response flat with half a decibel from 10 c.p.s. to 18,000 c.p.s., and total distortion less than .15 per cent, when delivering an actual 2.7 watts to the voice coil! This is the answer to those who deplore the use of high-powered amplifiers for home use. — A. G. HULL.


text:
History of wireless telegraphy and broadcasting in Australia/Topical/Publications/Australasian Radio World/Issues/1948 09

P.01 - Front Cover
The Australasian Radio World

Special Data and Handbook Issue

Registered at the G.P.O., Sydney, for transmission by post as a periodical.

1/-

Vol. 13 - No. 4; SEPTEMBER 18, 1948

P.03 - Contents Banner
THE AUSTRALASIAN RADIO WORLD

Devoted entirely to Technical Radio

and incorporating

ALL-WAVE ALL-WORLD DX NEWS

VOL. 13 - SEPTEMBER, 1948 - No. 4

P.03 - Publication Notes
Published by the Proprietor — A. G. HULL, Balcombe St., Mornington, Vic. Phone: M'ton 344.

Technical Editor — Paul Stevens, 21 Fletcher's Av., Bondi, N.S.W. Phone: FW6157

Short-wave Editor — L. J. KEAST, 7 Fitzgerald Rd., Ermington, N.S.W. Phone: WL1101

Ham Notes By — Don B. KNOCK (VK2NO), 43 Yanko Av., Waverley, N.S.W.

Advertising Representatives —

In N.S.W.: Amalgamated Publications Pty. Ltd., 83 Pitt St., Sydney. Phone: B1077

In Victoria: R. L. McKillop, Regency Advertising Contractors, 60 Market St., Melbourne. Phone M1279

In Queensland: John Bristoe, Box 82, Maryborough, Q.

In New Zealand: H. Barnes & Co., 4 Boulcott Terrace, Wellington.

In England: Anglo Overseas Press Ltd., 168 Regent St., London, W1.

Distributed throughout the World by Gordon & Gotch (A/asia) Ltd.

Subscription Rates: 12 issues - 10/6; 24 issues - £1; To N.Z. and Overseas - 12 issues, 12/-; Post free

Address for all correspondence - Australasian Radio World, Box 13, Mornington, Vic.

Printed by Bridge Printery Pty. Ltd., 117 Reservoir Street, Sydney, N.S.W., for the proprietor of the "Australasian Radio World," Balcombe St., Mornington, Vic. (Footnote P.60)

P.03 - Contents
CONTENTS

F.M. — Minus Boloney. . . . 5

Starting Off In Radio. . . . 9

New Broadcast Wavelengths. . . . 15

Buyers' Guide. . . . 25

Students' One-Valve Experimental Set. . . . 39

Calling CQ. . . . 47

How To Become a "Ham". . . . 49

The Morse Code. . . . 50

International Amateur Prefixes. . . . 52

The "Q" Code. . . . 53

Index to Volume 12. . . . 54

Short-Wave Review. . . . 55

Bargain Corner. . . . 58

P.03 - Editorial
EDITORIAL

As you will have noticed already, this issue is a special one, with more pages than usual and a number of new ideas embodied in it. The main purpose of the issue is to help us catch up with our publication date, as the strain of the war and its after-effects brought us into a position where our issues were not actually on sale until a week or more after the date on the cover. By bringing out three issues in two months we hope to catch up again. In fact future issues should be on sale all over the Commonwealth by the 15th day of each month. We have taken the opportunity of making this issue somewhat different in structure, mainly with the idea of giving you an issue which will be a handy source of reference for many months to come. Data charts have been prepared with a view to having them essentially practical; the sort of data which I myself will pin up over my work bench to save time when I am in doubt about the colour code for an odd resistance value or the socket connections for an unfamiliar valve. In some ways the arrangement is experimental, and I would like expressions of opinions about it. If it appears to meet with a favourable reception it is quite possible that we will make a regular feature of the catalogue section, for example. The lists in this issue are far from complete, and I feel sure that there will be ample material available to keep this feature going for many months, especially with additions and amendments. — A. G. HULL.


text:
History of wireless telegraphy and broadcasting in Australia/Topical/Publications/Australasian Radio World/Issues/1948 10

P.01 - Front Cover
The Australasian Radio World

Registered at the G.P.O., Sydney, for transmission by post as a periodical.

1/-

Vol. 13 - No. 5; OCTOBER, 1948

P.03 - Contents Banner
THE AUSTRALASIAN RADIO WORLD

Devoted entirely to Technical Radio

and incorporating

ALL-WAVE ALL-WORLD DX NEWS

VOL. 13 - OCTOBER, 1948 - No. 5

P.03 - Publication Notes
Published by the Proprietor — A. G. HULL, Balcombe St., Mornington, Vic. Phone: M'ton 344.

Technical Editor — Paul Stevens, 21 Fletcher's Av., Bondi, N.S.W. Phone: FW6157

Short-wave Editor — L. J. KEAST, 7 Fitzgerald Rd., Ermington, N.S.W. Phone: WL1101

Ham Notes By — Don B. KNOCK (VK2NO), 43 Yanko Av., Waverley, N.S.W.

Advertising Representatives —

In N.S.W.: Amalgamated Publications Pty. Ltd., 83 Pitt St., Sydney. Phone: B1077

In Victoria: R. L. McKillop, Regency Advertising Contractors, 60 Market St., Melbourne. Phone M1279

Representatives —

In Queensland: John Bristoe, Box 82, Maryborough, Q.

In New Zealand: H. Barnes & Co., 4 Boulcott Terrace, Wellington.

In England: Anglo Overseas Press Ltd., 168 Regent St., London, W1.

Distributed throughout the World by Gordon & Gotch (A/asia) Ltd.

Subscription Rates: 12 issues - 10/6; 24 issues - £1; To N.Z. and Overseas - 12 issues, 12/-; Post free

Address for all correspondence - Australasian Radio World, Box 13, Mornington, Vic.

Printed by Bridge Printery Pty. Ltd., 117 Reservoir Street, Sydney, N.S.W., for the proprietor of the "Australasian Radio World," Balcombe St., Mornington, Vic. (Footnote P.52)

P.03 - Contents
CONTENTS

Teleconda 4841. . . . 5

The Vibrator. . . . 13

Extension Speaker. . . . 23

Multi Channel Tracer. . . . 27

Problems With Battery Sets. . . . 29

Among Our Readers. . . . 31

Frequency Range. . . . 33

Calling C.Q. .. . . 43

A Converter For 50 Mc. . . . . 45

Shortwave Review. . . . 47

Speedy Query Service. . . . 50

P.03 - Editorial
EDITORIAL

In the English "Short Wave Magazine" I notice the following comment and I quote: "In the course of a recent airmail letter an Australian correspondent remarks as follows: 'In my opinion radio in Australia is a pricked balloon from the trading angle, though it is still good business for the commercial broadcasting people feeding moronic material to receptive illiterates. If you know of any Englishmen thinking of leaving home to start in radio here, tell them to think again; there are neither homes nor security to be had and to make more than average money one must be a lottery winner. One Englishman I know here (in Australia) rues the day he came--'." A few minutes later I was reading the local newspaper about the forming of Thom and Smith's into a public company, and of their recent turnover of about half a million pounds a year. My mind went back to the days when Freddy Thom and his pal Smith left a certain radio factory and started on their own in Woolloomooloo. They had mighty little capital and everybody seemed to agree that the time was most unsuitable to start a new business. But they had guts, plus ability and faith. They didn't ask for security. They made it for themselves. They turned out sets with performance well beyond the average, secured the services of a first-class technician, Ed Fanker (whose name is now on the list of directors, I am happy to note) and away they went. They have never looked back and I would like to offer them my congratulations. Australia needs immigrants, but they want to have guts, ability, faith and vision. I agree with the correspondent quoted only in so far as that anyone will be better off in England than seeking a home and security in Aussie. A. G. HULL.


text:
Samoan/Phrases

 * It's a nice day : manaia le aso
 * I'm hungry : ua oa fía 'ai
 * Have a good day : manuia le aso
 * Have a good evening : manuia le afiafi
 * Have a good morning : manuia le taeao
 * Have a good night : manuia le poo
 * Don't be angry : aua e ke ika
 * Go Sleep! : alu e moe!

title: Samoan/Phrases


text:
Samoan/Vocabulary

 * House - fale
 * City - a'ai
 * Star - fetu
 * Moon - maasina
 * Bread - falaoa
 * Bathroom - faletaele
 * Apple - Apu
 * Fish - i'a
 * Rabbit - rapiti

title: Samoan/Vocabulary


text:
Samoan/Adjectives

 * Happy - manuia, fiafia
 * Angry - ika
 * Worried - popole
 * Hard - faigata
 * Easy - faigofie
 * Open - mataka
 * Closed - taapuni

title: Samoan/Adjectives