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OpenVOGEL/User's guide/Guide 3 Part 2

Introduction
While the classic approach in flight mechanics is to decompose the model and the aerodynamic actions (like for instance "the change of lift on the empennage due to down-wash") and then write complicated equilibrium equations, we will here take advantage of the aerodynamic method we have and propose a few numerical simulations that will only use the resultant aerodynamic forces and moments. This will let us focus on the final behavior of the model, without having to think about the interactions.

These examples will serve as an illustration of what the software can do in real life problem solving. Nothing prevents you from creating your own customized analysis for other situations different than the ones we will expose here. It is hard (or almost impossible) to build software that fits to everyone's needs, so we take for granted that you will be preferring to do so. This is the maximum freedom that we can provide, and it relays on the power and flexibility provided by the Console and the scripts.

Before starting with the standard batch analysis that will help us solve different design aspects of the aircraft, we will see how to run the simplest simulation on the console. The raw data that results from that simulation can be used in customized post-processing, so it is maybe interesting to see.

Steady analysis for a single simulation
In the simplest form of automatic analysis through the Console, you have to create yourself (in Tucan) the set of *.vog files you need. Then you open the Console and enter, for each file: load enter file name:   [there comes a message describing what has been loaded] steady [the calculation starts]

Scanning the incidence angle
If you want to quickly analyse the aerodynamic loads and the previous method seems too tedious, there are faster alternatives. The first automation procedure we will see is called "alfa scan" and will let you run a series of simulations in one go for a predefined range of incidence angle.

The first thing you need to do is to create in Tucan the model at what you consider is a zero incidence angle. When you are ready, open the Console and load the file: load enter file name:   [there comes a message describing what has been loaded]

Next you need to specify that you want to run an alfa scan: alfa_scan;;; [the calculation starts for each incidence in the given set] The starting incidence alfa_1 and the final incidence alfa_2 will always be included, and the alfa_step is the increment that is maintained until alfa_2 is reached.

As result of the scan, an output file is written in the same directory as the input file named _batch.dat. Here is an example of the output file: OpenVOGEL alfa scan A = 1.485717E+000m² L = 1.485717E+000m q = 1.159693E+004Pa Alfa  CL             CDi            CDp 0.000 7.443804E-001  4.707133E-002  1.146459E-002 2.000 8.550402E-001  6.360122E-002  1.446163E-002 ... Alfa  Fx             Fy             Fz             Mx             My             Mz              0.000  1.004243E+003  1.317944E-014  1.278442E+004  1.558601E+004 -1.781820E+003 -1.224195E+003 2.000 8.247472E+002  1.538323E-014  1.470960E+004  1.793306E+004 -2.047669E+003 -1.005339E+003 ...
 * 1) Force coefficients
 * 1) Forces and moments ([N] and  [Nm])

Longitudinal control performance in straight flight
While the alfa_scan is intended for a simple performance analysis, if the airplane is equipped with control surfaces, it does not tell much about the static equilibrium. In practice, when we compute the polar curve of an airplane with the goal of studying its performance, we need to refer to an equilibrium state. Therefore, the equilibrium and the performance must be analyzed together.

When we design an airplane, one of the many basic questions that arise is: where will the center of gravity be allowed to be so that the aircraft is stable and in static equilibrium throughout the desired flight envelope Some aircraft are designed in such a way that the equilibrium is obtained by displacing the center of gravity (the most common example being hang gliders). However, all other aircraft normally include either a flap or an extra surface (called empennage) equipped with a flap (called elevator) to provide longitudinal control. In this later case, the empennage itself increases the stability of the model while the deflection of the flap provides for control. The size and position of the empennage and elevator play a key role, so the previous question translates into an optimization problem with many variables involved.

One of the things that only a few books about flight mechanics make readers aware of is that the deflection of the elevator not only affects the pitching moment, but also the lift and the drag. For wing-empennage configurations the influence on the lift is less accentuated than for a flying wing, were the effect is very strong. So even for the simplest analysis of longitudinal stability (finding the equilibrium states for straight and leveled flight), we require dealing with many variables. Because the lift and the moment are coupled through the incidence and control deflection angles, finding the equilibrium states is not so straightforward as solving a simple set of uncoupled equations. If only the lift and moment are included in the equilibrium equations, and for both actions the associated coefficients are considered as a linear function of alpha and delta, then at most we can reduce the problem to a system of two linear equations and run only four simulations. You can do that (and save calculation time), but we don't enforce it here to preserve generality. If you want to add propulsive forces, then the problem gets even more complex and it is probably easier to move to a multi-variables graph and brute calculation force.

OpenVOGEL offers you a basic tool to find the equilibrium states in straight flight, and is called alfa_delta_scan. The approach is quite simple: for a range of incidence angles, simulate flight in a range of elevator deflections. Since both angles are limited by nature (the stall and the flap hing constraints respectively), by providing the right ranges the analysis can cover the whole flight envelope. The resulting air loads are then transferred to a scrip in Scilab to make a plot. There, the airloads (lift and pitching moment) are interpolated within the given ranges and contour lines are drawn for the center of gravity and lift coefficient. The resulting graph (in the alpha-delta space) provides the answer to three basic questions:

What is the forwardmost CG position that can still be held at maximum lift?

This state is represented by the CG curve that crosses the maximum alpha and delta values (upper-right corner of the alpha-delta plot for a trailing empennage, and lower-right corner for a forward empennage). If the CG position is limited to that coordinate, the aircraft will still be able to maintain leveled flight at the minimum [stall] speed (or said differently, if the CG exceeds that limit, the aircraft will not be able to fly at the minimum [stall] speed -and imagine how cruel that situation would be for the pilot that is trying to land-). Positioning the CG after that coordinate is a typical mistake for amateur air modelers. Be careful, because you normally will not realize of the issue until you are about to land! (because that is when you want to trade some air speed for extra circulation around the wing -call it CL-). Actually, the most critical condition for this state is when the pitching moment is at its maximum, and this typically occurs when recovering from a dive at maximum lift with all [main wing] flaps down. In OpenVOGEL you can simulate that condition using flow rotation. However we will leave that case for another section.

What is the rearmost CG position that makes the control too sensitive or totally unstable?

This state is represented by the CG curve that is (almost) horizontal. If the CG is located too close to that coordinate, the aircraft will be completely unstable because even the smallest elevator deflection will cause huge variations in the [equilibrium] incidence angle. Now even that is theoretical, because flight dynamics will make the equilibrium simply impossible, so the aircraft will end up following an erratic path (unlike the previous issue, this you would notice from the moment you try to take off). A correct design (for an aircraft that is free of any kind of computer-based control) will limit the CG to a point that is sufficiently far from that coordinate. This CG coordinate is commonly referred to as neutral point or aerodynamic center. Many accidents in civil aviation (and a lot more in air modelling!) have been sadly attributed to the CG exceeding this point, so it is worth understanding it well. Normally, certification norms for civil aircraft will put an upper limit to the g-factor to stick force gradient for the different aircraft categories. This magnitude can be obtained from the slope of the CG curves (but also requires knowing the elevator hing moment and control mechanism properties). For air models or drones, this last value is useless (because the pilot doesn't feel the onboard rigidity of the control) and the limit can be set directly from the slope.

What are the required elevator deflections for a given lift coefficient and center of gravity?

These states are given by the points where a given CG curve crosses the CL curves. Since the CG normally only changes a bit during flight, these points are important to understand the aircraft performance regarding range and autonomy.

Note that because the equilibrium is considered using the Z force component and the Y moment component, the center of gravity must lay along the X axis for the solution to be valid. Also, because the throttle is not included, the throttle force should also be acting on the X axis. For the rest, the method makes no assumptions about how the actions behave and it even includes the contribution of the drag to the moment, so it can be used for any configuration. If you need to add throttle or any other action, you could include it manually on the Scilab script.

To execute an alfa delta scan, you would enter the next command:

alfa_delta_scan;;;;;;;;

The first three arguments are the same as for the alfa scan. The following two arguments are the identification of the flap that will be deflected: the name of the lifting surface (case insensitive) and the index of the region (1-based). The last three arguments are similar to the first three ones, but they control the flap deflection range.

If after entering the command the surface or the flap are not valid (not found), the procedure will be aborted.

The next data is an example of an automatically generated Scilab script created by OpenVOGEL alfa delta scan. You can try running it on Scilab to have an idea of how the results look like.

Circular path recovery performance
In the alpha-delta analysis we focused our attention in the longitudinal control characteristics during steady straight flight. However, we mentioned in that section that there is a more restrictive forward-most limit for the CG, and that this happens when the airplane rotates following a circular path (in practice: when it recovers from a dive) at low speed. Imagine the airplane is flying on approach close to the stall airspeed, and therefore the lift coefficient and incidence angle are at the maximum allowed. Now imagine that the airplane needs to go around as soon as possible in an emergency situation. The pilot will push the gas lever to full throttle and gradually pull the elevator up at full [permitted] deflection, trying to bend the trajectory upwards as much as possible. How will the aircraft behave for a given mass configuration?

Simulation approach
OpenVOGEL lets you simulate the rotation of the airplane by adjusting the stream angular velocity (the vector called Omega). Now lets figure out a simple mathematical description of this situation. The aircraft moves in the XZ plane, so some components of the velocity and angular velocity are null:

$$\omega_x = \omega_z = 0$$

$$V_y = 0$$

Then, the curvature of the trajectory depends on the angular velocity to speed ratio:

$$\kappa = \frac{\omega_y}{V} $$

with the airflow velocity as:

$$V = \sqrt{V_x^2 + V_z^2} $$

Since the kinematics of the flow will be the same for a same curvature, we can fix a reference velocity and adjust only the angular velocity to obtain a range of curvatures (different circular paths). This is the basis of what we call omega_scan.

With the aid of a free body diagram (see picture) we can write the equilibrium equations of the aircraft at the lowest point of the trajectory. In the vertical axis aligned with the lift force (not to be confused with the Z axis!) we have:

$$L = m (g + \kappa V^2)$$

Note that here we did not include the propulsive forces. Around the Y axis we have the moment equilibrium equation:

$$M_y + x_{cg} F_z = 0$$

Note that we have simplified the dynamics by introducing a steady circular path, however the situation will still resemble the original problem.

From the moment equation we can directly obtain the CG coordinate for each circular path. For this simplified approach, this coordinate will not depend on the velocity nor on the mass, so to make it clear, there is a functional relationship between the curvature and the CG coordinate.

From the force equilibrium equation we can obtain the necessary aircraft velocity for a given mass. Here we have to take into account that the lift depends on the dynamic pressure, and so it is also a function of the square of the velocity. By doing some arithmetic hocus-pocus, we obtain:

$$V = \sqrt{\frac{2mg}{\rho S C_L - 2 m \kappa}}$$

and the associated g-factor (the total acceleration as fraction of the gravitational acceleration) will be:

$$n = 1 + \frac{\kappa V^2}{g}$$

What does this all mean? If you got lost in the math (it can happen), this means that by taking the results of our omega_scan set of simulations at maximum lift and maximum elevator deflection, we can draw a diagram of contour lines where the maximum g-factor is plotted for a range of mass and a range of CG coordinates. If we then pick a minimum target g-factor for high incidence maneuvering, the plot will give us the forward-most allowed CG position for a given mass. Extremely useful, isn't it? This also means that by running an alfa_delta_scan and an omega_scan, you will be able to understand most of the longitudinal control of your model at [quasi] steady flight (not the dynamic response! we have not been there yet!).

We can bring an example in numbers to make it clearer. In the model of the depicted diagram, if the landing mass is 1200kg and we still want to be able to recover at 1.3g, the CG should not be placed behind X=0.94. The more gees we want, the closer the CG must be placed to the aerodynamic center.

Command
The omega scan analysis requires calling the omega_scan command (no surprise). A typical script for this simulation would be as follows:

readback load;C:\...\omega_model.vog set_velocity;80 set_alfa;12 set_delta;empenage;1;20 set_altitude;1000 pause omega_scan;0.4;10;2000;4000;50

As you see, the script allows you to easily adapt the incidence and deflection angles, which are not part of the arguments of the omega_scan function. The signature of this functions is as follows: omega_scan;;;;;<Mass range refinement>

The first argument is the maximum Y component of the angular velocity and the second one the number of aerodynamic simulations (which equals the number of evaluated CG coordinates). The scan will cover the range from 0 rad/s (straight path) to the provided value. The next two following arguments are the minimum and maximum mass respectively, and the last one is the number of control points in the mass range. As result, the command will return the Scilab script that can be executed in the Scilab environment to obtain a design diagram. The name of the script file is equal to the name of the original OpenVOGEL project file, with the string _script appended and a new .sce extension.

Ultimate state (sharpest recovery)
Maybe you have already noticed that the velocity equation is a bit tricky, because it has a singular point and might adopt complex solutions above a certain path curvature or mass. In fact, this means that the aircraft will not be able to exceed a certain path curvature for a given mass (or put the other way around, it will not be able to exceed a certain mass if you want it to be able to pull up with a certain curvature). This is logic, since the lift is not unlimited, and the $$C_L$$ value that we provide is the maximum for any possible air speed. So you will have to be careful with the range of mass and curvature (in the form of angular velocity and airspeed) you provide.

If you provide an unrealistic mass range, the Scilab script will warn you that the maximum range has been exceeded and it will reduce the upper limit to 90% of the critical mass. That way you don't get to see the mess on the diagram.

Shortcomings
Lets now be critic about the shortcomings of this approach:
 * The center of rotation is not exactly at the CG, it is at the origin, so this can affect the pitching moment. So when you run this simulation, try to locate the origin close to where you think the CG will be located (you can loop to refine if you like).
 * The real path in recovery is not perfectly circular and the speed is not constant. A hard recovery involves an unsteady transit, during which the aerodynamic forces evolve differently.
 * The aerodynamic forces are obtained for a single reference velocity (the Reynolds number is constrained).
 * We didn't include the propulsive forces (although for most situations the effect might be negligible).

These negative points do not mean that this analysis is useless. For most practical applications, it will give you a fast an relatively accurate description of the aircraft performance. In principle, it should be better than most traditional mathematical descriptions.

title: OpenVOGEL/User's guide/Guide 3 Part 2


text:
History of wireless telegraphy and broadcasting in Australia/Topical/Publications/Australasian Radio World/Issues/1947 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. 11 - No. 12; May 15, 1947

P.03 - Contents Banner
THE AUSTRALASIAN RADIO WORLD

Devoted entirely to Technical Radio

and incorporating

ALL-WAVE ALL-WORLD DX NEWS

VOL. 11. - MAY, 1947. - 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 Vic. — W. J. LEWIS, 20 Queen St., Melbourne, 'Phone MU5154

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

Subscription Rates: 6 issues - 5/3; 12 issues - 10/6; 24 issues - £1; Post free to any address in the world.

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 —

Problems of Trade Discount. . . . 5

Double Superhet for Ham Use. . . . 9

Preamplifiers for Talkie Work. . . . 11

Starting a Radio Business. . . . 13

Visual Tuning Indicators. . . . 16

Photo-Electric Cells. . . . 24

Disposal Bargains — And Otherwise. . . . 26

Service Problems in U.S.A. .. . . 30

SHORTWAVE REVIEW —

Notes From My Diary. . . . 38

THE SERVICE PAGES —

Answers. . . . 42

P.03 - Editorial
EDITORIAL

In the April issue of a contemporary magazine are advertisements from various firms offering the Cosmocord pickup at prices of 59/6, 66/-, 67/11 and 75/-. The same item was advertised a few months ago at 77/6. The cartridges for this pickup are advertised in the same magazines at prices of 31/-, 37/6 and 45/-. The "Young Atom" pickup is also advertised at widely varying prices of 57/-, 57/6 and 70/9. A number of our readers, who also read the other magazine in question, have written to me to ask if I can offer any explanation for the terrific difference in prices quoted. Some of them actually purchased pickups at the higher prices prevailing a few months ago; now they feel that they have been robbed. Knowing that my little publication is completely independent, without any trace of trade association or obligation, and that I will give them the honest "low-down" on the position, they have come to me with confidence. I cannot betray that confidence, although it puts me in a tight corner. I feel that the only way to handle the problem is to explain to my readers the whole background of the position. I feel sure that they have sufficient intelligence and logic to be allowed to know about these things. Most of them already know that Father Christmas does not necessarily climb down the chimney. Some even know that babies are not found under cabbage bushes. They are old enough to know about radio trade prices and discounts without being shocked. So the first article of a series covering this subject appears in this issue. — A. G. HULL.

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


text:
Planet Earth/6g. Common Rock Identification

What are Rocks?
All rocks can be classified into one of the three major groups, igneous (for rocks that cooled from molten materials), metamorphic (for rocks that were subjected to intense heat and pressure, but did not melt), and sedimentary (for rocks that form from Earth’s surface processes, such as transported grains, organic material and evaporation). All rocks can be grouped within one of these three types. Rock names on the other hand, are classifications that organize the many different varieties of rocks found in each of these three major types. There are many different ways that geologists name rocks, but it comes down to two things; the mineralogy and texture of the rock. In other words, the percentage of each mineral present in the rock (the mineralogy), and the nature of the crystal or grain sizes and shapes, or texture of the rock. There are many ways in which geologists name rocks, and several competing ideas and active research. The basic rock names are listed below for each type of rock.

Igneous Rocks
All igneous rocks are divided into two major divisions based on the minerals they contain. Felsic igneous rocks are composed mostly of feldspars (plagioclase/orthoclase) and quartz, while mafic igneous rocks are composed of mostly pyroxene, amphibole and olivine. Some rocks, particularly enriched in olivine, are called ultramafic, and have very little silica (quartz). Felsic minerals tend to be white, pink and clear (transparent) in color, and hence these rocks will be a lighter overall color, while mafic minerals tend to be dark black, dark red, or dark green colors, and these mafic rocks will be a darker color, often black. All igneous rocks are formed by crystals that form as the molten material cools. If the rock cooled very slowly (deep in the Earth or plutonic), the rock is called intrusive, while if the rock cooled very quickly (such as from lava on the surface of the Earth), the rock is called extrusive. The length of time the molten material cooled results in different sizes of the crystals in the rock. Intrusive rocks have large crystals that formed slowly, while extrusive rocks will have very tiny crystals. The size of the crystals in igneous rocks is called texture. We can generally divide all igneous rocks based on these two characteristics, whether they are mostly composed of felsic minerals or mafic minerals, and the texture of the rock.

Granite (Felsic Intrusive Igneous Rock)
Granite is the name of igneous rocks that are both felsic and intrusive, which form from cooled molten magma deep inside the Earth. Because these rocks form from the slow cooling of molten material, crystals can be very large. Granite is almost exclusively composed of quartz, feldspars (plagioclase/orthoclase) and mica (muscovite/biotite). When crystals are exceptionally large, geologists called this a pegmatite, or pegmatitic granitic rock. If the individual crystals can be seen by the naked eye, then it is called phanerite, or phaneritic granitic rock. Most granite is phaneritic granitic rock, with visible speckles of individual crystals of felsic minerals. Granite is typically found in the core of mountains and exclusively in continental, silica-rich crust. Granite is a useful building material, although its hardness makes it more difficult to carve and sculpt compared to other softer types of rocks.

Diorite (Intermediate Intrusive Igneous Rock)
Diorite is rock that contains slightly more mafic minerals than felsic granite, with an increase in darker colored minerals include biotite, pyroxene and amphibole. These minerals give the rock a black and white speckled appearance, when compared to the light-colored granite. Sometimes geologists will refer to granodiorite, a rock that is between a diorite and granite in mineral composition.

Gabbro (Mafic Intrusive Igneous Rock)
Gabbro is a rock that contains mostly mafic minerals including pyroxene, amphibole, and olivine, with less quartz and feldspar. Gabbro is black in color, but as an intrusive plutonic rock contains large crystals of these minerals. Gabbro is a common rock found in subduction zones and deep in oceanic crust. In continents, gabbro is often found in ophiolites, which are regions of oceanic crust that has been accreted or emplaced into continental crust. If the rock is composed of more olivine, and exhibits a dark green color, with little silica (quartz) the rock is considered ultramafic. An ultramafic rock name used for olivine-rich rocks is peridotite. Peridotite is a common rock found in the deeper mantle of the Earth, and exhibits more olivine and less quartz than gabbro, although both are considered mafic igneous rocks. Many of the lunar rocks brought back to Earth through the Apollo missions are classified as gabbro, with high amounts of olivine and other mafic minerals.

Rhyolite (Felsic Extrusive Igneous Rock)
Rhyolite is the name of igneous rock that is composed of felsic minerals (quartz and feldspars (orthoclase/plagioclase)), but also contains tiny crystals (only seen through magnification). These tiny uniform crystals that form the matrix of the rock is called aphanitic texture. Rhyolite tends to be a white to pink color, with a similar uniform color and texture with the presence of these tiny aphanitic crystals that compose the entirety of the rock. Extrusive rocks form from rapid cooling, usually associated with abrupt volcanic eruptions. Rhyolite is a common rock found in volcanic regions emerging from silica-rich continental crust, like that found around Mount Saint Helens, and other subduction zones. Rhyolite and other extrusive rocks can also be described as porphyritic. A porphyritic rock is an igneous rock that underwent two stages of cooling, an abrupt cooling event that lead to tiny crystals (aphanitic texture), and a slower cooling event that lead to larger crystals (pegmatitic/phaneritic textures). A porphyritic igneous rock is any igneous rock that contains both tiny and large crystals. These larger crystals often freeze at lower temperatures, for example the mineral quartz, but can also be due to intrusive rocks that had cooled slowly, but suddenly were cooled more rapidly during a volcanic eruption, resulting in both tiny and large crystals (porphyritic texture).

Andesite (Intermediate Extrusive Igneous Rock)
Andesite is an extrusive igneous volcanic rock of intermediate composition (between felsic and mafic) like diorite, but with aphanitic to porphyritic texture. It tends to be greyish in color, with speckles of small crystals, stemming from rapid cooling of magma. Andesite tends to exhibit large crystals of plagioclase, amphibole, and pyroxene. These large crystals are known as phenocrysts, which are large crystals surrounded by a matrix of smaller crystals in porphyritic rock. Andesite is named for the Andes Mountains in South America, a prominent region of active subduction, but andesite is also common in many volcanically active regions of the Earth, especially on continents.

Basalt (Mafic Extrusive Igneous Rock)
Basalt is one of the most common types of igneous rocks on Earth, formed from the rapid cooling of mafic-rich magma and lava. Basalt is especially common in oceanic crust that forms the seafloor, and found in island volcanic systems, like Hawaii. Basalt is common in continental volcanic regions where deeper mafic minerals are brought up in massive lava flows that can cover large regions. Basalt is molten rock that has cooled very rapidly, resulting in tiny aphanitic crystals of amphibole, pyroxene, and olivine, but can contain smaller amounts of quartz, biotite and feldspars. Basalt is nearly always black, dark green, to dark reddish in color. Since basalt forms from cooling lava flows that contain many gases, basalt often exhibits vesicular texture. Vesicular texture is where bubbles of gas have left behind holes or pores within the rock. These holes are often uniform in their distribution, and are left behind when volcanic gas escapes from the rapidly cooling lava. Sometimes these can be filled in with phenocrysts of quartz. Scoria is a rock name used for reddish vesicular basalt that is popular in landscaping. Not all basalt is vesicular, as much of the basalt found on Earth is aphanitic in texture, with a dark black color. Obsidian is a silica-rich rock formed from extrusive, rapidly cooling molten rock, and is often found in association with basalt. Obsidian is a silica rich rock, forming a glass like texture due to an increase in molten quartz, which can pool and rapidly cool within lava and magma flows, between mafic-rich basalt.

Nearly all igneous rocks can be grouped into one of these six subdivisions; granite, diorite, gabbro, rhyolite, andesite and basalt. Although there is often debate among geologists where these strict divisions should be defined as, especially regarding the proportions of various minerals and texture. These definitions are useful for a quick identification of igneous rocks that you are likely to encounter.

Sedimentary Rocks
All sedimentary rocks form from surface processes on Earth, including 1) cemented grains/sediment transported by wind and water, 2) burial of organic matter produced by living organisms, and 3) evaporation and recrystallization of minerals from a solution. All these processes occur only on the surface of the Earth, and through a process of lithification these materials will turn to stone.

The lithification process of turning buried material (such as sediment) into stone is called diagenesis. Diagenesis is the process that describes physical and chemical changes that sediments undergo due to increasing temperature, pressure, and groundwater flow as they get buried deeply into Earth’s subsurface. Diagenesis is also responsible for the petrification of fossilized bones of extinct animals such as dinosaurs. Sedimentary rocks are the only type of rock that contains fossilized remains of ancient animals and plants, but also the only type of rock that contains hydrocarbon fuels, such as petroleum, natural gas, and coal.

Sedimentary geologists divide most sedimentary rocks into two major groupings, clastic and carbonate sedimentary rocks. Clastic sedimentary rocks are those that are formed from transported grains or clasts of sediment resulting from the erosion of Earth materials by wind and water. Carbonate sedimentary rocks are those that are formed by organic carbonate minerals in the oceans, lakes, and ponds.

Carbonate sedimentary rocks
Calcium carbonate (CaCO3) easily precipitates from ocean and lake water, but is mostly utilized by aquatic lifeforms to forms shells and protective coatings. These sediments of organic calcium carbonate accumulate after burial on the ocean or lake floor, eventually turning into a rock called limestone. Limestone is a general term used to described rock composed of mostly calcium carbonate from organic matter that has been buried in ancient oceans and lakes. Limestone can be further subdivided by two classification schemes, the Folk classification and the Dunham classification, which classify limestone based on their texture. All limestone is composed of calcite or aragonite, the two naturally occurring minerals of calcium carbonate (CaCO3), however with diagenesis, the calcium (Ca) can be replaced with magnesium (Mg) forming dolomite, a harder mineral than either calcite and aragonite. Most aragonite undergoes a process of diagenesis in the subsurface to change into the more stable and compact mineral of calcite, so most naturally occurring limestone is composed of mostly calcite. Limestone easily dissolves when exposed to neutral or slightly acidic rain and ground water, producing karstification which is a terrane formed from this dissolution of the surrounding rock, including sinkholes, caverns and caves. Limestones form important aquafers for the passage of groundwater in Earth’s subsurface, as underground water will often dissolve out these layers of rock. They can also serve as important reservoirs for petroleum underground.

In Utah, along the Wasatch Mountain Range east of Salt Lake City, and within the Cache Valley in northern Utah, limestones are the predominate rock found in the region. These limestones, which today form the high mountains were deposited in a tropical shallow ocean that once covered western Utah 500 to 450 million years ago. The stacked layers of limestone were later trusted upward, forming mountains when the motion of the North American continent shifted westward, and begin to expand.

Clastic Sedimentary Rocks
Clastic sedimentary rocks are rocks composed of transported grains (called clasts), which are lithified together with a mineral glue (called cement). Grains can be either transported by wind (eolian sedimentary deposition), or by water (marine, fluvial, and lacustrine sedimentary deposition). Many rocks that you pick up from the surface of the Earth have been formed by these surface processes of erosion and re-deposition. This is due to Earth’s dynamic rock cycle, drive by water cycle and atmospheric winds. Most other planets in the solar system have rare if any sedimentary rocks on their surfaces. Sedimentary rocks are named based on their mineralogy and texture. Texture is the size and distribution of the individual grains that are glued together to form the sedimentary rock. These grains can be any size, from gigantic boulders to clay size particles, and sedimentary rock names are based on these sizes of the particles that form the rock. These grains can be well sorted (all of similar size) or poorly sorted (of various sizes), they can also be well rounded or angular in shape. Often sedimentary geologists will modify the name of the sedimentary rock based on the mineralogy of the individual grains that compose the rock. Studying sedimentary rocks can tell you how far the individual grains were transported before they were buried. Quartz is highly stable on the surface of the Earth, and will end up being transported the furthest. If a sedimentary rock contains only quartz grains, then that observation indicates that the rock is made of sediment that had travel far before burial. While if a sedimentary rock contains feldspars or lithic fragments of other rocks and minerals, then that observation indicates that the rock is made of sediment that traveled only a short distance before burial. Size and shape also are indictive of the total distance the sediment was transported before burial. Well-sorted and well-rounded sediments are found in sediment transported great distances, while poorly sorted and angular grains are found in sediment transported only a short distance, or by glaciers. You may observe that pebbles found in rivers, or beach sand will be rounded by the action of flowing water and crashing waves, while rocks that are found in alpine landslides will be angular and jumbled. Clastic sedimentary rocks are fascinating because they tell you how sediment was transported across the Earth’s surface throughout its long history, as mountains eroded and basins filled.

Clastic sedimentary rocks are typically glued together by two types of cement minerals, calcite and quartz. Calcite is a softer mineral than quartz, and will result in a weaker over all rock that more easily erodes. A few other minerals can be found in between grains, acting as a glue or cement, including many of the iron oxide minerals (such as hematite), sulfides like pyrite, as well as other minerals that may form in hydrothermal deposits through the passage of extremely hot groundwaters and dissolved minerals. Often these accessory minerals will form what are called concretions, where a strong cement mineral holds together a strangely shaped group of grains, producing unusual weathering patterns and unique colors. Concretions are often mistake for fossil eggs or fossil bones, because of their highly variable shapes and colors. This is caused by the unique way in which the individual grains of sediment are glued together by different minerals in the subsurface, and becomes evident as the rock weathers on the surface.

Claystone
Claystone is simply rock formed from clay size grains or clasts. Clay sized grains are about a thousand times smaller than typical sand grains and smaller than 3.9 μm micrometers. Clay size grains are so small that when you bite the rock with your teeth, you will not feel any grit between your teeth. This has led many geologists to bite pieces of rock they suspect is claystone, to see if they can feel any grit between their teeth (to the amusement of non-geologists). Claystone will have a smooth texture, often chalky and soft as it is frequently composed of clay minerals, that form from the weathering of silicate minerals.

Shale
Shale is sedimentary rocks deposited in low energy systems at the bottom of oceans and lakes, and forming flat tabular layers. It is most often composed of mud to silt sized clasts, which are stacked during deposition into finely laminated layers. Shale is a dominate rock found in ancient oceans and lakes, and often rich in hydrocarbon molecules, giving the rock a black color. These hydrocarbon molecules can serve as a source material for hydrocarbon fuels, such as natural gas and petroleum in the subsurface. Highly enriched hydrocarbon shales are frequently called oil shale, due to the high hydrocarbon content. Shale is often formed from marine deposits that are deeper than the carbonate composition depth, the photic zone or in colder waters, where carbonate sedimentation is more limited.

Mudstone
Mudstone is simply rock formed from mud size grains or clasts. Mud size grains are between 3.9 μm to about 62.5 μm micrometers, and somewhat more gritty texture than clay. Mud is found in soils, flood plains, river banks, and even in small ponds and wetlands. This eroded mud material when buried forms mudstone. Mudstone is often blocky or massive, when compared to shale, which is platy or thinly layered. Mudstone is the dominate rock that forms from sediments in a flood plain near meandering rivers, as well as within soils.

Siltstone
Siltstone is simply rock formed from silt sized grains or clasts. Silt sized grains are about 50 to 63 μm micrometers, which cannot be easily seen by the naked eye, but coarser than mud with more grit and can be felt as a rough texture. It is often found in a slightly higher energy system than mudstone, but in similar depositional environments.

Sandstone
Sandstone is simply rock formed from sand sized grains or clasts, and one of the most common types of clastic sedimentary rocks. Sandstone comes many different colors, but is composed of grains between 63 μm micrometers to 2 millimeters. Sandstone can be subdivided from very fine grained to coarse grained. Most sand size grains can be seen with the naked eye, giving the rock a speckled appearance. One of the challenges of identifying sandstone is that it can look like igneous rhyolite and andesite, which are composed of crystals that have grown together, whereas in sandstone the individual grains have been glued or cemented together. Sandstone forms from the burial and diagenesis of sand, which can be deposited in beach, nearshore coastal, river, lake, and eolian (desert sand dunes) environments. The study of the individual grains or clasts within sandstone can reveal key information about how the sand was transported across the Earth’s surface. Sedimentary structures, like cross beds and trace fossils are also important for the reconstruction of ancient environments. Sandstone is also an important reservoir rock for oil and water, because it tends to have more space between individual grains than in finer grained mudstone and claystone allowing the rock to behave like a sponge, with accommodation space for oil deposits, as well as an important aquifer for ground water. Most sandstone is composed of a predominance quartz sand grains, which are resistive to weathering on Earth’s surface, but other clasts of fragments of other rocks and minerals can be present as well. Sandstones are typically cemented or glued together with calcite and/or silica (quartz) minerals which grow between individual grains, binding the sand together into rock.

Conglomerate
A conglomerate is simply a rock composed of grains or clasts that are greater than about 2 millimeters in width, larger than sand grains and about the size of pebbles, but can include grains and clasts upward to the size of large boulders. Conglomerates form from deposits of river pebbles, landslides and high energy fluvial environments proximal to mountains or topographically steep environments. Conglomerates can be formed from well-rounded pebbles or clasts, but also include highly angular clasts and grains like that found in tillites, which are lithified till from sediments transported by glaciers. Conglomerates are very useful for reconstructing the Earth’s past topography, as these deposits are often adjacent to mountainous terrain which may have eroded away over long spans of time. Overall grain size will decrease in size the farther clasts are transported by water and wind, so large grains sizes tend to be found in closer proximity to their original source. Very angular, jagged or pointy large sized grains are given a unique rock name, they are called breccia.

Other types of sedimentary rocks
Beside the two major groups of carbonate and clastic sedimentary rocks are a few types of rocks that are a result of organic material and evaporation. These rocks include coal, which is composed of carbonized buried plant material, mostly ancient vegetation that has been buried and compacted, with an abundance of hydrocarbon molecules that can be combusted as a fuel source. There are different grades of coal, lignite coal is low grade brownish coal that contains the least amount of hydrocarbons, subbituminous coal is mid-grade coal with slightly more hydrocarbons, bituminous coal is higher grade coal that is shiny black and smooth and frequently mined for combustion. The highest grade of coal is anthracite coal, which is sometimes classified as a metamorphic rock, since it has been subjected to more heat and pressure. It tends to be much harder than bituminous coal. Anthracite is more common in the eastern United States, while in Utah most of the mined coal is the softer bituminous grade coal from Cretaceous rock layers. Evaporite is the name used to describe rocks formed from evaporation of ocean or lake water, leaving behind evaporate minerals like gypsum and halite. These types of rocks are common in ancient lake and ocean basins where large regions were subjected to evaporation and the deposition and burial of these minerals. One unique aspect of evaporite is that it often flows into dome like structures in the subsurface which are called a salt diapir. The upwelling of evaporite layers in the Paradox Basin of southeastern Utah gives the region around Moab some of its unique geological features, including the famous Upheaval Dome in Canyonlands National Park.

All sedimentary rocks are deposited in layers, which is referred to as bedding. These layers are stacked on top of each other over the course of millions of years of deposition. One important characteristic of sedimentary rocks is their regional layer cake appearance, which records a lengthy history of Earth.

Metamorphic Rocks
Metamorphic rocks are the product of intense heat and pressure, which makes them more difficult to name and classify, as these conditions can produce a wide range of unique mineralogy. A skilled geologist can use metamorphic rock mineralogy to not only discern the original rock, but also the amount of heat and pressure the rock was subjected to during burial to produce the observed minerals. Metamorphic rocks are ranked based on the amount of heat and pressure they were subjected to in the ground, from low-grade metamorphic rocks, which exhibit some recrystallization of their grains due to heat and pressure, up to high-grade metamorphic rocks in which minerals may have partially melted, with major recrystallization of the mineralogy of the rock. One of the most important features that identifies almost all metamorphic rocks is foliation. Foliation is a wavy pattern of differing mineral crystals resulting from differential pressure. Foliation is unique in being caused by the crushing force of the intense pressure placed on the rock as it was buried deep in the Earth. These wavy lines can be seen in most metamorphic rocks, and differ from bedding that exhibit straight horizontal lines often observed in sedimentary rocks, like sandstone. Metamorphic rocks tend to sparkle more than sedimentary rocks and igneous rocks, as the grains or crystals are partially melted under heat or recrystallized under pressure, this is true of most high-grade metamorphic rocks, which often exhibit beautiful crystals. Most metamorphic rocks are found in the cores of mountains, or in regional metamorphic belts caused by volcanic or tectonic activity, such as subduction zones, or hot spots. Metamorphic rocks are also some of the oldest rocks found on Earth. Metamorphic rocks have not completely melted into magma or lava as part of the rock cycle, and so they are exceptionally old and common within continental cratons. Cratons are the ancient core or heart of continental crust that initially formed the of today continents, and were never subjected to subduction during plate tectonic motion. These regions are rich in metamorphic rock which are very ancient with rocks that are upwards to 4 billion years old.

Metamorphic rocks are named based on their original source rock, and ranked from low-grade to high-grade. A mudstone or shale will metamorphize into slate, phyllite, schist, then finally gneiss, while limestone will metamorphize into marble. Sandstone will metamorphize into quartzite. Igneous rocks will also metamorphize with burial and pressure, with basalt changing into blueschist or greenschist, peridotite changing into serpentinite, and amphibole rich mafic rocks turning into amphibolite, and pyroxene rich igneous rocks into hornfels. Granite and other felsic rich igneous rocks will metamorphize into gneiss. Often rock names will include accessory minerals in their descriptions, for example a schist might contain garnet crystals, and the rock would be called a garnet schist.

Slate
Historically slate was used as a chalk-board writing surface and still frequently used for roofing material. It is a hard, black metamorphic rock derived from shale which has been subjected to low-grade metamorphism in the subsurface of the Earth. The rock may exhibit fine-grained foliation or be fairly homogeneous, but is harder than shale and breaks in thin sheets.

Phyllite
Phyllite is a slightly higher-grade metamorphic rock in which the minerals chlorite, biotite and muscovite start to crystallize from clay minerals. These new minerals give the rock a silver sparkle, as if covered in glitter. The rock tends to exhibit more foliation than slate, with wavy bands of parallel crystal arrangements of mica. The rock can also contain accessory minerals of garnet and staurolite at higher grade of metamorphism.

Schist
Schist is a medium-grade metamorphic rock which exhibits wavy sheet-like crystals, including crystals of muscovite and biotite, but also chlorite, talc, hornblende, graphite and quartz. Schist forms at higher temperatures with larger crystals than phyllite, but is also is silver in color and with bright sparkly crystals. Quartz becomes more liquid at these higher temperatures and can flow into foliation bands, as light colored or translucent wavy lines. Garnet and staurolite are common in schist. Garnet will form these red to black crystals, which resemble lumps like that found in chocolate chips in a cookie. Schist is often named based on accessory minerals when they occur, such as garnet schist, staurolite schist, or tourmaline schist. Schist is the common rock that is exposed in Central Park in New York City, but can be found in many continental crustal rocks in areas with a history of region metamorphism.

Gneiss
Gneiss is a high-grade metamorphic rock that closely resembles granite. This is due to the intense heat and pressure that results in the partial melting of many of the minerals in the rock, including quartz, feldspars, and muscovite. Gneiss can also form from the metamorphism of granite, which results in foliation, or bands of minerals due to differential stress and pressure subjected to the rock. Gneiss can be identified by the wavy bands of crystalline layers of minerals, often with bands enriched in quartz, while other bands are enriched in other minerals like felspar and muscovite and biotite. Gneiss can also exhibit many large pegmatitic crystals of a wide variety of minerals. Gneiss will lack the uniform texture found in granite, and feature wavy layers of differing mineralogical compositions.

Marble
Marble forms from metamorphism of limestone, as the minerals of calcite and dolomite recrystallize into a denser rock than sedimentary limestone. Because of this increase in density, marble retains its softness, but becomes more uniform in its texture, resulting in a rock that can be easily sculpted and carved. Marble is ideal for statutes and building materials, and has been used since antiquity for construction projects, from ancient Egypt to Greece. Much of the marble used in the United States is mined from Marble, Colorado, which is a rich source of a cool gray-blue color marble (called Yule Marble), that exhibits some foliation and was used in the construction of governmental buildings and monuments in the Washington District of Columbia. Italian marble comes from Tuscany (called Carrara Marble), while Greek marble comes from Attica around Mount Pentelicus, northwest of Athens (called Pentelicus Marble), both of which tend to be a warmer yellow color of marble.

Quartzite
Quartzite is the metamorphic rock of quartz rich sandstone, which results in the individual quartz crystals to fuse together removing any porosity and permeability between the individual grains, resulting in a framework of highly recrystallized quartz. A result of quartz being highly stable on Earth’s surface, quartzite is extremely resistant to any weathering. Often quartzite will form steep jagged outcrops and be commonly found as river pebbles and cobbles which are found in high energy rivers. Since quartzite contains very little other minerals, and quartz exhibits a hardness of 7 on Mohs scale, it frequently remains a common rock found on the surface of Earth due to this hardness, especially in mountainous regions. Quartzite can sometimes be enriched in gold and other rare precious metals, when the metamorphism was accompanied by hydrothermal activity, bringing dissolved metal cations through the rock with extremely hot ground waters resulting in small veins of gold hosted within quartzite rock.

Metamorphic Rocks from Mafic Igneous Material
Just as sedimentary rocks are subjected to metamorphism with intense heat and pressure, so too can igneous rocks also be subject to changes in the subsurface, leading to a diverse group of metamorphic rocks. Collectively these metamorphic rocks stem from original material of basalt, gabbro, and the ultramafic rock of peridotite. These rocks exhibit minerals that are mafic, and hence this group of metamorphic rocks formed from these types of will tend to be green to black in color, and contain many of the same minerals. Collectively geologists might refer to these mafic metamorphic rocks as greenstone, or greenstone belts. These regions form from mafic rich igneous rocks being subjected to heat and pressure, and often are thought of as rocks formed when the separation of felsic rich continental and mafic rich oceanic crust was still undivided early in Earth’s history. These rocks are given a host of different names depending on the amount of pressure and temperature they were subjected to as well as their mineralogical make up, including Greenschist, Blueschist, Amphibolite, Hornfels, Eclogite, Granulite, and Zeolite. Serpentinite is a metamorphic rock that originates from ultramafic rock with a dominate mineralogy of olivine. Greenstone belts are important precious metal ores in Australia, Canada and Africa, they also reveal a history of the early formation of continental crust.

Rock names describe a rocks mineralogy, texture and the processes that formed the rock with natural processes that work in Earth’s interior. Naming rocks in geology requires the ability to identify the common minerals present in the rock, as well as a description of the process of formation of the rock. This can be challenging when you first begin to pick up rocks and try to discern how it may have formed inside Earth. With experience, and being observant, every rock can be named and classified.


text:
History of wireless telegraphy and broadcasting in Australia/Topical/Publications/Australasian Radio World/Issues/1947 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. 12 - No. 1; JUNE 15, 1947

P.03 - Contents Banner
THE AUSTRALASIAN RADIO WORLD

Devoted entirely to Technical Radio

and incorporating

ALL-WAVE ALL-WORLD DX NEWS

VOL. 12 - JUNE, 1947. - 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 Vic. — W. J. LEWIS, 20 Queen St., Melbourne, 'Phone MU5154

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

Subscription Rates: 6 issues - 5/3; 12 issues - 10/6; 24 issues - £1; Post free to any address in the world.

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 —

The "Six-Ten". . . . 5

Unusual Condensers. . . . 13

Can You Answer These? . . . . 15

Car Radio. . . . 17

The "Voyager". . . . 19

Teleconda 3. . . . 27

Pepping up No. 4 Set. . . . 31

SHORTWAVE REVIEW —

Notes From My Diary. . . . 38

THE SERVICE PAGES —

Answers. . . . 42

P.03 - Editorial
EDITORIAL

In last month's issue there was an article on the problems of trade discounts. It is evident that the article has been misunderstood by a number of people. After glancing over my mail I have decided not to publish the second article of the series until I have been able to expand one or two points so that there can be no chance that they will be misunderstood. What I did not say, but what quite a few accuse me of having said, is that I am in favour of the public being able to buy at trade prices. I am all in favour of the recognised proper trading methods, but I do claim that many radio components are of such a nature that they need no retail price or a long discount. No ordinary man-in-the-street is likely to buy a signal generator, but neither is he likely to buy intermediate frequency transformers. Both require specialised knowledge for their proper application. Another point where several of my correspondents have gone off the track is in regard to so-called "trade" publications. Just because "Australasian Radio World" is sold over counters of bookshops as well as by direct subscription, it does not mean that it is read by those in the trade. Conversely it does not follow that the trade prices openly advertised in "trade" magazines cannot be read by "back-yarders". The wide-awake back-yarder subscribes to trade papers. So why should the trade association bring pressure to bear to stop wholesalers from advertising in the technical press? A. G. HULL.


text:
History of wireless telegraphy and broadcasting in Australia/Topical/Publications/Australasian Radio World/Issues/1947 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. 12 - No. 2; JULY 15, 1947

P.03 - Contents Banner
THE AUSTRALASIAN RADIO WORLD

Devoted entirely to Technical Radio

and incorporating

ALL-WAVE ALL-WORLD DX NEWS

VOL. 12. - JULY, 1947. - No. 2

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 Vic. — W. J. LEWIS, 20 Queen St., Melbourne, 'Phone MU5154

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

Subscription Rates: 6 issues - 5/3; 12 issues - 10/6; 24 issues - £1; Post free to any address in the world.

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 —

Natural Reproduction. . . . 5

Wave Traps. . . . 11

Great Circle Gadget. . . . 13

Grounded-Grid R.F. Stages. . . . 15

The "F.S.L." — Plus. . . . 18

Caravan Radio. . . . 20

"Little Wonder Two". . . . 24

"Europa 5". . . . 26

Technical Topics. . . . 29

SHORTWAVE REVIEW —

Notes From My Diary. . . . 38

THE SERVICE PAGES —

Answers. . . . 42

P.03 - Editorial
GUEST EDITORIAL

In New York recently the Chairman of the Federal Communications Commission warned amateurs, pointing out that the frequencies between 4 and 25 megacycles are very much in the spotlight. Following on this, "Radio News" (U.S.A.) says "— that brings us to the topic at hand; the conduct of many amateurs who are abusing their privilege to operate. The QRM situation becomes worse each day, yet many 500 watt transmitters can be heard emitting strong DX signals when merely talking cross-town. Such operators are doing little to enhance the art of Amateur Radio. When the chips are down they will only have themselves to blame if they come out on the short end of the deal— Atlantic City is sure to show pressure from foreign representatives who want amateur frequencies reallocated — every amateur should take stock of his own operating practices and make sure he is not open to criticism — it is the personal responsibility of each amateur to look jealously upon the safety of his hobby — there are many interests seeking any type of ammunition which will destroy our hobby." Those words of wisdom may well apply to this side of the Pacific, as those who listen know full well. In this part of the world there are loud-mouthed individuals who are endangering the whole future of amateur radio by spouting anything but the correct atmosphere into their microphones. There can be but one end to such malpractice. When shortwave listeners write in indignation to the Authorities it is more than obvious that the public takes note of the undesirable features of our valued hobby. — D.B.K.


text:
History of wireless telegraphy and broadcasting in Australia/Topical/Publications/Australasian Radio World/Issues/1947 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. 12 - No. 3; AUGUST 15, 1947

P.03 - Contents Banner
THE AUSTRALASIAN RADIO WORLD

Devoted entirely to Technical Radio

and incorporating

ALL-WAVE ALL-WORLD DX NEWS

VOL. 12. - AUGUST, 1947. - No. 3.

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 Vic. — W. J. LEWIS, 20 Queen St., Melbourne, 'Phone MU5154

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

Subscription Rates: 6 issues - 5/3; 12 issues - 10/6; 24 issues - £1; Post free to any address in the world.

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

CONSTRUCTIONAL —

"High Quality Six". . . . 9

"Q-Plus". . . . 17

TECHNICAL —

Ham Radio at Sea. . . . 5

Bias for Battery Sets. . . . 7

English Quality Amplifier. . . . 13

Radio on H.M.S. "Vanguard". . . . 21

Radio Reflections from Shooting Stars. . . . 24

Plastics to Revolutionise Television. . . . 26

International DX Contest. . . . 28

SHORTWAVE REVIEW —

Notes From My Diary. . . . 38

THE SERVICE PAGES —

Answers. . . . 42

P.03 - Editorial
EDITORIAL

About two hundred letters go through my office every week, and I make a point of reading each and every one of them carefully. From these letters I get impressions. Over the past couple of months my strongest impression is in regard to prices. Quite a number of my correspondents consider that prices of components are too high, and that radio is too expensive as a hobby. I cannot agree that radio component prices are too high, especially when compared to prices of complete factory-built receivers. It has recently been stated that the average price of an Australian receiver was £27 before the war and is now over £40, an increase of more than 50 per cent. I doubt very much whether component prices have risen to this extent. There are plenty of good reasons for increased costs and prices; gone are the days when there were plenty of boys who would work for 15/- per week. Pre-war radio factories were notorious for the way in which, they exploited this class of labour. There seems only one satisfactory way of getting cheaper components and that is by a greater degree of specialisation. At present some radio factories still wind their own coils, with their coil winding equipment standing idle for four days every week. If they costed their coils correctly they would find that they could get them made much more efficiently in factories which specialise in this line. So it goes for many other components. And in turn, if the coil winding specialists got all the coil winding business they would be able to make cheaper and better coils. A. G. HULL.


text:
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Warning
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text:
History of wireless telegraphy and broadcasting in Australia/Topical/Publications/Australasian Radio World/Issues/1947 09

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. 4; SEPTEMBER 15, 1947

P.03 - Contents Banner
THE AUSTRALASIAN RADIO WORLD

Devoted entirely to Technical Radio

and incorporating

ALL-WAVE ALL-WORLD DX NEWS

VOL. 12 - SEPTEMBER, 1947. - No. 4

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 Vic. — W. J. LEWIS, 20 Queen St., Melbourne, 'Phone MU5154

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

Subscription Rates: 6 issues - 5/3; 12 issues - 10/6; 24 issues - £1; Post free to any address in the world.

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.52)

P.03 - Contents
CONTENTS

CONSTRUCTIONAL —

Signal Tracer for Service. . . . 7

Build Your Own Oscillator. . . . 9

TECHNICAL —

Anisotropic Alnico. . . . 17

Beams, Beams, Beautiful Beams. . . . 21

The Kingsley "K.S.9'er". . . . 23

A Review of Ferrotune. . . . 25

Ideal Broadcast Station Console. . . . 32

Among Our Readers. . . . 34

Calling CQ. . . . 41

SHORTWAVE REVIEW —

Notes From My Diary. . . . 46

THE SERVICE PAGES —

Answers. . . . 50

P.03 - Editorial
EDITORIAL

For some weeks past the Atlantic City Allocations Committee has been fixing the future bands for amateur operation. This is a vital matter for "hams" and so a number of keen listeners have been tuning in to W1AW, the official station of the American Radio Relay League, in order to get the official announcements as they have been decided. On August 9th an announcement was made that the ten-metre band had been settled on a world-wide basis as from 28 to 29.7 Mc. On August 12th came over news that South Africa Australia and New Zealand were now pushing with the Americans for the use of the 11-metre band, shared with diathermy and electrical appliances. By August 19th the fate of the higher frequencies had been sealed, but on a complicated formula which will be explained in detail later. Apparently it is on the lines of existing allocations from 31.7 to 10,500 mC., but there will be no 220 mC. band for Australia and New Zealand. For Europe and Africa the 144 mC. band has been cut down to only 2 mC. wide. On August 25th the details were released of the popular DX band, 20 metres. The amateur frequencies were fixed at 14,000 to 14,350, in dictating that after a seven-weeks' battle the amateurs lost 50 kC. to fixed services. With the present crowding on this band the loss is a sad one, but quite a few have given a sigh of relief to know that the cut is only 50 kC. At the moment the lower frequency allocations have not yet been settled, but judging by results so far the prospects are quite bright. A. G. HULL.


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History of wireless telegraphy and broadcasting in Australia/Topical/Publications/Australasian Radio World/Issues/1947 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. 12 - No. 5; OCTOBER 15, 1947

P.03 - Contents Banner
THE AUSTRALASIAN RADIO WORLD

Devoted entirely to Technical Radio

and incorporating

ALL-WAVE ALL-WORLD DX NEWS

VOL. 12 - OCTOBER, 1947. - No. 5

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 Vic. — W. J. LEWIS, 20 Queen St., Melbourne, 'Phone MU5154

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

Subscription Rates: 6 issues - 5/3; 12 issues - 10/6; 24 issues - £1; Post free to any address in the world.

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

CONSTRUCTIONAL —

"Snug 5". . . . 5

TECHNICAL —

Kingsley Equipment for U.H.F. .. . . 11

Adjusting the Dipole. . . . 27

"Rural 4". . . . 15

Servicing by Signal Tracer. . . . 29

Calling "C.Q." . . . . 33

SHORTWAVE REVIEW —

Notes From My Diary. . . . 38

THE SERVICE PAGES —

Answers. . . . 42

P.03 - Editorial
EDITORIAL

It is indeed pleasing to note that the P.M.G.'s department has recently made certain minor changes in its rules and regulations which will be well received by amateurs. First there is the dropping of the expression "experimental" in connection with the station licence. Hams are now officially "Amateur Station Licensees." The power limit has now been raised to 100 watts all round and no probationary period necessary for new licensees. More than ten years ago I made several drives for a lifting of the power limit, but it was officially considered to be quite impossible. Now it has at last been found possible, so hams are a lot happier these days. Some radio traders are not so happy in their contact with the P.M.G. There is a regulation that dealers must send in a monthly report giving the name and address of each buyer of a radio receiver. There does not, however, appear to be a regulation which can force the buyer to reveal his name. Apparently anyone can walk into a radio shop with the pound notes in his hand and demand to be served with a radio receiver. What dealer could refuse to take the money? Yet where does he stand if the buyer hurries out of the shop muttering about having to rush to catch the tram? If the P.M.G.'s department can't manage to collect their own licence fees without the aid of the radio trade it seems apt that they should offer the trade at least 10 per cent. commission and let them do the collecting! — A. G. HULL.


text:
History of wireless telegraphy and broadcasting in Australia/Topical/Publications/Australasian Radio World/Issues/1947 11

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. 6; NOVEMBER 15, 1947

P.03 - Contents Banner
THE AUSTRALASIAN RADIO WORLD

Devoted entirely to Technical Radio

and incorporating

ALL-WAVE ALL-WORLD DX NEWS

VOL. 12 - NOVEMBER, 1947. - No. 6

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 Vic. — W. J. LEWIS, 20 Queen St., Melbourne, 'Phone MU5154

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

Subscription Rates: 6 issues - 5/3; 12 issues - 10/6; 24 issues - £1; Post free to any address in the world.

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.52)

P.03 - Contents
CONTENTS

CONSTRUCTIONAL —

"Sally". . . . 5

TECHNICAL —

A Record on Six Metres. . . . 9

Signal Tracer. . . . 11

High-Fidelity Transformers. . . . 17

Highlights of Radiolympia. . . . 19

A New Method of Tuning. . . . 23

"Transmitter, FS6 Plus". . . . 29

Among Our Readers. . . . 33

Calling CQ. . . . 41

SHORTWAVE REVIEW —

Notes From My Diary. . . . 46

THE SERVICE PAGES —

Answers. . . . 50

P.03 - Editorial
EDITORIAL

Like most new things, the advent of the "personal" set, a baby version of a self-contained battery-operated portable, brings along its crop of worries. Whilst waiting at a radio counter in town recently the customer ahead of me was trying to dispose of one of these sets. He told the man at the counter that he had only bought it a month ago, but already it had used up three sets of batteries. Having a few moments to spare, I suggested that we check the current drain, borrowed a meter and did so. The drain was still a shade over 12 milliamps, although the batteries were both down fairly low. This is a fairly normal drain for sets of the type and with it a 467 type battery will last about 15 hours. The running cost works out at well over a shilling per hour. Unless buyers are acquainted with the true position about running costs these portables are likely to earn a smelly reputation, thereby spoiling what would be a further wide application of radio if handled properly. Public reaction to the price of the minimax batteries is also easy to understand. They know that a small torch battery costs 8d. or 9d. The minimax is two or three times as big and as heavy. It is expected that the price will be, likewise, two or three times as much. Unless the running costs of personal portables can be greatly reduced, they are going to go down in history as one of the worst flops in the radio business. A. G. HULL.


text:
History of wireless telegraphy and broadcasting in Australia/Topical/Publications/Australasian Radio World/Issues/1947 12

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. 7; DECEMBER 15, 1947

P.03 - Contents Banner
THE AUSTRALASIAN RADIO WORLD

Devoted entirely to Technical Radio

and incorporating

ALL-WAVE ALL-WORLD DX NEWS

VOL. 12. - DECEMBER, 1947 - No. 7

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 Vic. — W. J. LEWIS, 20 Queen St., Melbourne, 'Phone MU5154

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

Subscription Rates: 6 issues - 5/3; 12 issues - 10/6; 24 issues - £1; Post free to any address in the world.

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 —

Electronics in Meteorology. . . . 5

Experiment in De-centralisation. . . . 7

Better Interstate Reception. . . . 9

Theatre Sound Equipment. . . . 13

Latest American Technique. . . . 15

Among Our Readers. . . . 17

Walkie-Talkie. . . . 18

Amateur Personalities. . . . 21

Antenna Tips for the New Hand. . . . 23

Networks — and "Rag-Chew" Clubs. . . . 26

Calling CQ! . . . . 31

SHORTWAVE REVIEW —

Notes From My Diary. . . . 38

THE SERVICE PAGES —

Speedy Query Service. . . . 42

P.03 - Editorial
EDITORIAL

"What do you think about the disposals business?" is often asked. There are many angles to it. To the up-country buyer who has visions of bargains, I suggest the greatest of care. If a piece of equipment is advertised as "brand new," then it should be O.K., but there are tons and tons of stuff lying about which is simply salvage gear which was worn out in service, and then left lying under a jungle tarpaulin for a couple of years before being returned to Aussie. Next I would remind you of an old Scotch proverb about nothing being cheap if you don’t need it and can't find any use for it. So many fellows buy bargains for no other reason than that they appear to be bargains, then find no possible application for such gear. Then there is an angle of deeper ethics: what of the future? What is to become of the radio factories which make components for enthusiasts if enthusiasts are going to spend most of their money with the disposals people? When you buy a branded-line component, a portion of your money goes to the development laboratory where the components of the future are being designed. I happen to know of one large organisation which planned to market a lot of ideal "ham" gear, then decided that experimenters are putting all their money into the junk shops, so scrapped these plans. It makes a poor outlook for the future. . . . To all my readers — A Merry Christmas and a Happy New Year. — A. G. HULL.


text:
History of wireless telegraphy and broadcasting in Australia/Topical/Publications/Australasian Radio World/Issues/1948 02

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. 9; FEBRUARY 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 - FEBRUARY, 1948. - No. 9

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: 6 issues - 5/3; 12 issues - 10/6; 24 issues - £1; Post free to any address in the world.

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 —

Stir in Hi-Fi Circles. . . . 5

Walkie-Talkie. . . . 9

High Fidelity From Crystal Pickups. . . . 15

Hints and Tips. . . . 18

Home-Wound Power Transformers. . . . 19

Converters for "Six" and "Ten". . . . 24

Wanted — An Inventor. . . . 27

The "Teleconda" Powerport. . . . 31

Ham Notes. . . . 35

SHORTWAVE REVIEW —

Notes From My Diary. . . . 38

THE SERVICE PAGES —

Speedy Query Service. . . . 42

P.03 - Editorial
EDITORIAL

It is a lot of fun being a publisher of a technical radio magazine but there are one or two tight corners which you have to be careful to keep out of. To give you two examples, I might mention that quite a number of letters have been received lately which tend towards being abusive (in a nice way, of course) because I won't put down in black and white which I think is the best pick-up, and because I haven't yet published an article on how to make your own wire recorder. The pick-ups are a proper headache. For days past I have been running one of the latest type of amplifiers with triodes and inverse feedback, trying out in turn the "Lexington" and "Connoisseur" pick-ups against my old favourite crystal job which I picked out of a batch after running them on frequency test records with a v.t.v.m. in circuit. There is no doubt about the latest English pick-ups scraping highs off the records which you never hear with ordinary pick-ups, but it is hard to say whether it can be considered desirable, especially with ordinary records. By cutting the highs you can only get back to where you started. A tuned scratch filter seems to be the only answer. Making up a wire recorder at home is a far more complicated job than you might imagine from looking at a diagram which has been sketched out to show the fundamentals of the idea. You can't just use any old bits of wire and you need a lot of precision work of a mechanical nature. — A. G. HULL.


text:
Planet Earth/6h. Bowen’s Reaction Series

The Distribution of Rocks on Earth
Norman L. Bowen navigated his canoe across the densely forested Larder Lake, near the border between the Canadian Provinces of Quebec and Ontario, a sparsely populated wilderness south of the Hudson Bay in 1907. The rocks in this region are some of the oldest rocks in North America, part of the craton of North America, peppered by more recent volcanic igneous rocks leading to the possibility of rich deposits of gold and silver. Bowen was hired to explore this area, as a young student by the Ontario Bureau of Mines. During the summer alone in the field, Bowen learned to read the rocks by identification of minerals, the classification of rock names, and the quest to find regions for mining in the area. His experience in the field observing the way minerals were distributed in the rocks, underlay the rest of his life, even when he later dedicated it to laboratory experiments involved in the heating and melting of minerals to understand how they turned to liquid and how they cooled into crystals. The studies and experiments lead to a great insight into how rocks become enriched and depleted regarding different mineral compositions. His life-long work clearly explains why the oceanic crust laying near mid-ocean regions are mafic, while continental crust is felsic.

Bowen's Reaction Series
Today, Bowen’s reaction series that he came up with is a chart that illustrates how various minerals melt at different temperatures. If we think of the Earth’s rock cycle as the continue process of melting and freezing of solid matter on the planet, overtime, the minerals that melt at lower temperatures will “float” near the surface, while minerals that only melt at very high temperatures will “sink” into the Earth. This differentiation of the Earth’s outer crust results in the observed felsic minerals found in continental crust (quartz, orthoclase, albite and muscovite), while mafic minerals are resigned to oceanic crust (anorthite, biotite, amphibole, pyroxene, olivine). The solution is that felsic minerals melt at lower temperatures, while mafic minerals will remain solid, and hence sink deeper into the Earth’s magma. Over time, with the continued process of the rock cycle, Earth’s continents will become enriched in these felsic minerals, particularly quartz, while the deeper interior of Earth will become enriched in mafic minerals, particularly olivine. The remarkably young rocks that lay on the world’s ocean floors continually produced by volcanic activity along the mid-ocean ridges, the magma is enriched in mafic minerals that requires high temperatures to melt. Often students mistakenly view the ocean crust as being that crust that solely exists beneath the ocean, but this mafic rock is chemically and physically very different than the majority of continental rock found on continents, which is unusually enriched in felsic minerals. It is odd to think that the rocks that we daily pick up on the continents of Earth are fundamentally very different in their mineralogy and chemistry than the rocks found on the ocean floor.

Plagioclase Feldspar
One of the important discoveries made by Bowen was the process of how the mineral plagioclase melts with increasing temperature. Plagioclase is actually a series of minerals in the feldspar group that exhibit a white to blue color and includes two end members, albite (NaAlSi3O8) containing sodium, and anorthite (CaAlSi3O8) containing calcium. Albite melts at a lower temperature than anorthite, hence the percentages of albite and anorthite in a rock can reveal the history of the partial melting of the two minerals, and how the rock became enriched in either mineral over time. Rocks deeper in hotter magma will be enriched in anorthite, while rocks in shallow crust and cooler magma will be enriched in albite. The ratio between the two minerals can reveal the melting temperatures within the magma.

The Differentiation of Earth's Crust
Bowen’s reaction series is an important view into how felsic and mafic minerals have over Earth’s long history become differentiated forming solid felsic rich continental cratons that float over magma of increasing mafic composition. The process in building Earth’s continents is a long history of accreting felsic rich crust onto these floating solid islands in a sea of mafic oceanic crust continually being formed at mid-ocean ridges and destroyed in subduction zones. A rock cycle that continually moves these floating felsic rich continents around the Earth throughout its long history, as a result of plate tectonics.