Copasetic Flow

2012-01-16T02:51:00.000-08:00

Ham Radio Practice Exams from KD0FNR

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Agnew Hunter Bahnson's Namesake

2012-01-16T02:45:00.000-08:00

I'm doing a presentation later this year on the role Agnew Hunter Bahnson Jr. played in founding the Institute of Field Physics at the University of North Carolina at Chapel Hill. On a recent trip to the Philadelphia Museum of Art, I lucked onto a painting, ("The Agnew Clinic" by Thomas Eakins), of Bahnson's namesake, Dr. David Hayes Agnew. Dr. Agnew was the long time friend of Bahnson's grandfather and performed the excision of his elbow joint.

Thomas Eakins is a famous American painter who lived in the Philadelphia area. The "Agnew Clinic" was his largest painting. The picture below is of another painting by Thomas Eakins.

Tesla's Wardenclyffe Lab Special Event Stations!

2011-10-06T01:51:00.000-07:00

November 5th of this year, three special event stations will operate to help raise awareness of the efforts of TeslaScienceCenter.org to save Nikola Tesla's last existing laboratory, Wardenclyffe, in Shoreham, NY. W3T will transmit from the Wardenclyffe site itself. N3Y will operate from the New Yorker Hotel in downtown, NY, one of Tesla's residences. YU0TESLA will operate from the Tesla museum in Belgrade, Serbia. There may be other stations as well, stay tuned!

The special event stations are operating in conjunction with a conference that will be held by the Tesla Science Center at Brookhaven National Laboratory, (a few miles away from Wardenclyffe), on the same day. There will be several great speakers including William H. Terbo, engineer and great-nephew of Nikola Tesla.

If you have any questions or comments, please feel to contact me at hcarter333@gmail.com Keep watching here for more information on the special event stations, QSL cards, and all that kind of great stuff!

Alpha Decay as Quantum Tunneling

2011-09-15T05:19:00.000-07:00

We're covering tunneling in my quantum mechanics class. I did a little bit of research and was surprised to find out that Gurney and Condon made one of the first practical application of quantum tunneling to accurately predict alpha decay of various radioactive elements. They describe alpha decay as alpha particles tunneling through the attractive potential barrier of the nucleus. I found three very interesting journal articles on the subject. The first is a historical summary by Condon. The second and third are the initial journal articles by Gurney and Condon in Nature and Physical Review. All three of these articles can be accessed for free from most university libraries.

EU Condon, Tunneling - How it all Started, Am. J. Phys., 46, 319, (1978)

Gurney and Condon, Wave Mechanics and Radioactive Disintegration, Nature, 122, 439, (1928)

Gurney and Condon, Quantum Mechanics and Radioactive Disintegration, Phys. Rev., 33, 127, (1929)

Luna Moth on Long Island

2011-08-11T06:41:00.001-07:00

This little, (kinda big actually), was hanging out at the gas station today.

Boulder in Scarecrow and Mrs. King!

2011-08-08T02:10:00.000-07:00

Why is Boulder, CO cast in the part of Washington D.C. in Scarecrow and Mrs. King, Season 3, Episode 19, "The Boy Who Could Be King"? 11:32 into the episode a panning shot that is supposed to be in downtown DC is actually the Pearl St. mall, in Boulder, CO. Here's the shot from the episode, (scroll down for the same view of the Pearl St. mall in Google Earth):

Here's the view of the Pearl St. mall in Google Earth. Google Earth is a bit strange, you may have to reload the page to get the correct picture, (or click the 'View Larger Map' link below:

View Larger Map

Later at 23:14 an assay report is shown from the Stagler Mining Co. of Bolder Colorado.

Anybody know if there was any rhyme or reason to all this?

It's Obvious... Not: Knowing When not to do the Math

2011-08-03T13:25:00.000-07:00

I'm still studying for quals. I got stuck for awhile on problem 2.11 of Griffith's Introduction to Quantum Mechanics first edition. The problem involves manipulating raising and lowering operators to perform a normalization. The problem I was having was doing too much of the math too early. I tried to expand all the operators and got stuck. I tried to apply integration by parts as the book suggests and applied it to the wrong term the first time, and carried the operation too far on a second try. The series of conservative steps that finally did the trick is shown in the video below.

Satellite Tracking adds Bearings

2011-08-01T03:30:00.000-07:00

The satellite tracking tool now displays the bearing from your location to the first and last visible points on each satellite pass as well as the bearing of the maximum elevation. For elevation, the number in the upper row is the number of degrees above the horizon, and the number in the lower row is the bearing.

Geometry, Trigonometry, and Amateur Satellites

2011-07-26T14:20:00.000-07:00

Back to Part III. I'm still playing around with building a satellite tracking application. I'm helping with a special event station to help raise awareness for the Friends of Science East's effort to restore Tesla's last lab, Wardenclyffe, in Shoreham, NY.

First, the good news, the satellite pass finder and viewer is up and running at

http://copaseticflows.appspot.com/findsat!

Just drag the yellow thumbtack to your location and click the 'Passes' button and all the radio visible satellite passes for your location will be listed. By clicking on the map checkbox for any pass, you can display it on the globe. You can see how visible a pass will be from a city building by positioning yourself near the building and looking up for the pass. The app is still very beta, so please let me know if you see anything that could be better.

One of the big steps in getting the application to work was determining if a satellite would be visible over the horizon. To do this took some geometry and a little bit of trigonometry. The very same rules that they tell you to memorize in high school, but you can't see where you would ever use them. This is where!

For the mathematically curious, here's what I had to do. It follows from the proof drawn up by the folks at the Northern Virginia Community College. If you think about where you can see a satellite from on earth, it's where the earth, (the horizon), isn't getting in the way. If you draw a line from the satellite that's tangent with the earth, then, where that line meets the earth, anyone to the left of it in the picture below won't be able to see the satellite, and anyone to the right will.

The question is, given the height of the satellite the radius of the Earth, and the location on the Earth directly below the satellite, how do you figure out where the line meets the earth? The queston framed another way is how do you draw a line from a point so that it is tangent to a circle? First, draw a line from the point, (the satelite), to the center of the circle. Then, draw a second circle that has the new line as its diameter.

Where the second circle meets the first circle is where the tangent line from the satellite will just meet the Earth. How do we know that? This is where a few geometry rules come in handy. First, we should know that to find the tangent line of a circle, we draw a radius from the center of the circle to the point where we want to find the tangent. The tangent will be a line that forms a right angle with the radius line. Second, any triangle drawn inside a circle so that one of it's sides is the diameter of the circle and all three of its points touch the circle is a right triangle.

To prove that we actually found the tangent location, first draw a line from the intersection of the two circles back to the center of the smaller circle, (the Earth). Since it touches the edge of the smaller circle, and its center, this is a radius line and the tangent will be perpendicular to it. Next, draw a line from the intersection of the two circles back to the far side of the diameter of the bigger circle, (the location of the satellite). This newest line, the radius line and the diameter form a triangle. The angle that is opposite the diameter is a right angle. Remember, the tangent line makes a right angle with the radius of the small circle. That same angle is the right angle between the radius of the circle and our line back to the satellite, that's our tangent line!

If we can find out the distance from the location directly below the satellite, (remember, that's one of our givens), to the horizon, we can compare that to the distance between our location and the location directly below the satellite. If we're closer to the satellite ground location than the horizon, then we can see the satellite. If we're not, we can't, (ignoring diffraction effects we're not going to talk about yet).

To figure out the distance to the horizon, we'll go back to trigonometry. If we know the angle from the location on the ground directly below the satellite, then we can figure out the distance. The distance along a circle is the angle swept out by the circumference of the circle times the radius of the circle. We're in luck because we still have our tangent right triangle and it will let us solve the problem.

The short side of the triangle is the radius of the earth which we know. The hypotenuse is the radius of the earth plus the altitude of the satellite which we also know. We can plug those two numbers into the formula for the cosine of an angle and solve. The cosine of the angle is equal to the short side divided by the hypotenuse. The value for the angle is the arccosine of the same quotient, the Earth's radius divided by the hypotenuse, (the Earth's radius plus the satellite's altitude). Finally, by multiplying the angle by the radius of the Earth, we get the distance from the point directly below the satellite to the horizon.

Amateur Satellite Tracking Part III

2011-07-22T08:09:00.000-07:00

Part I, Part II. I'm still playing around with building a satellite tracking application. I'm helping with a special event station to help raise awareness for the Friends of Science East's effort to restore Tesla's last lab, Wardenclyffe, in Shoreham, NY.

When reading through the Google Earth API documenation on linestrings, I noticed that they could be 'extruded'. This means that a plane is drawn down from the line to the ground. This seemed like an odd option at the time, but now I see the use for it. It turns out that it's difficult to tilt the view back far enough on Google Earth to see the satellite above from ground level. A wall that extends from the satellite to the ground though? Well, that's a different matter! (See the video below).

There are two next steps. One is to identify the horizon for a satellite. With this information, we can make a sort of automated siting scope to determine if a satellite is worth investigating further. The other thing to finish is making all 61 amateur satellites visible instead of just the one.

Making all 61 satellites visible requires pulling the data from the Amsat site and parsing it correctly. This step is all done and you can see the map with all the satellites at
http://copaseticflows.appspot.com/sattrack

Satellite Tracking: Initial Succeess

2011-07-21T01:13:00.000-07:00


New Tracking App	N2YO site

As I mentioned yesterday, I'm playing around with building a satellite tracking application. I'm helping with a special event station to help raise awareness for the Friends of Science East's effort to restore Tesla's last lab, Wardenclyffe, in Shoreham, NY. After a few very minor issues, the first satellite is being tracked! First, the satellites in the AMSAT Keplerian data are named in a different fashion than they are on N2YO's site, (the site I'm using to verify my results). So, LO-19 in Amsats Keplerian data table:

LO-19
1 20442U 90005G 11187.94329143 -.00000024 00000-0 64087-5 0 01550
2 20442 098.3466 141.1781 0012855 097.5464 262.7179 14.32152423120621

is designated as Oscar19 (LUSAT) on the N2Y0 site.

At first, I thought there just weren't actually any amateur satellites in the Amsat data, but soon realized the different naming after performing a 'Search By Satellite Name' on N2YO's site. I'll try to get a table that lists the associated names into one of these blog posts.

After looking into the naming issue, it only took a few minutes to disect the baseline code, (because it is very clear and well written as mentioned before), and feed it the Keplerian data for Oscar19.

And a few seconds later, there was Oscar19 on my screen just tracking along! Using N2YO's site as a reference, Oscar19 is showing up in about the right place as can be seen in the pictures above.

Now, I'm off to understand the time progression code and to add buildings to the map.

Buildings were no problem. Using the Google Earth API docs for layers, it took one line of code to add the buildings of Manhattan!

I ran into what I thought might be the first problem while perusing buildings. It's difficult to know where to look for the satellite without a good old 2D representation of it's position, (or by zooming way out), and it would be handy to have a 2D inlay of where the horizon is at the current position to know if the satellite was behind the horizon.

The time progression code for the satellite animation has an ingenious member called g_speed. By setting this to 1, you can see the satellite move in real time. By setting it to more than one, you speed up time and watch the satellite track for the entire day in just a few seconds.

Each satellite has a Icon member which is responsible for drawing the satellite on the screen. I'll be adding a LineString geometry member to the satellite that will store the locations on the satellite track and draw the line corresponding to the track as it progresses.

And it worked! As of this writing, one satellite is being tracked with it's trail streaming out behind it. I've sped time up 20 using the g_speed variable. You can see the current demo at:

http://copaseticflows.appspot.com/examhelp/sattrack.html

You'll probably need to rotate the earth a bit to find the satellite at first, but it's there!

Or watch a brief movie of it here.

Getting Started with Amateur Satellites and Satellite Mapping

2011-07-20T14:51:00.000-07:00

Progress! See Part II.
I'm helping to plan an amateur radio special event on November 5th to raise awareness of the effort by The Friends of Science East to save Tesla's last lab, Wardenclyffe, in Shoreham, NY. One idea for the event is to operate from some of the buildings that Tesla occupied either as labs or as homes in Manhattan. I'm thinking an easy means of operation from there might be satellite. This brings up the interesting question of "which satellites are visible from which rooftops?" I've perused the net a bit and haven't found a program that will display amateur satellite orbits in relation to the NYC skyline, so I decided to plunk around and see if I could come up with my own. So far, I have a list of references I intend to start with and I know what technology I'm going to try to use.

Google Earth is now avaiable on web pages as a JavaScript plugin. I'll be using that as the programming framework. The docs for the portion of the API I plan on using can be found at:
http://code.google.com/apis/earth/documentation/geometries.html

Satellite trajectories are described by Keplerian data. The Keplarian data for amateur satellites is availabe at:
http://www.amsat.org/amsat/ftp/keps/current/nasa.all

Amsat also has an fb explanation of the Keplerian data elements at:
http://www.amsat.org/amsat/keps/kepmodel.html

The author of the site http://www.barnabu.co.uk has already written a great satellite debris tracking framework I'll be using as a code basis. To see more about it, go to:
http://www.barnabu.co.uk/satellite-collision-debris-tracking-in-the-google-earth-plug-in/

For an in-depth description of the algorithms used in the code, check out Wikipedia at:
http://en.wikipedia.org/wiki/Simplified_Perturbations_models

Finally, if you just absolutely positively have to find an amateur satellite right now, then the site you want is the excellent one by N2Y0.

Hiam Percy Maxim's Dad in Mecanno Magazine

2011-07-18T04:14:00.001-07:00

Prior to reading all about Hiram Percy Maxim on Dashtoons, I'd never heard of the original OM of ham radio. So, while perusing the December, 1927 issue of Meccano Magazine, I was surprised to find an article extolling the inventive brilliance of Sir Hiram Stevens Maxim, Hiram Percy's dad! In addition to highlighting Sir Maxim's childhood work ethic, the article points out that he was almost the inventor of Cordite except for one flawed sentence in his application that was filed fourteen days before the ultimately accepted application of Sir Dewar, (inventor of the Dewar flask), and Sir Abel. The article further details Maxim's invention of the machine gun, (an early model is shown below), and includes a quote from the Lord of Salisbury to the Prince of Wales:
"I have just been telling Mr. Maxim that he has prevented more men from dying of old age then any other person that ever lived!"

Help Index for Ham Radio Practice Exams at Copasetic Flows

2011-07-15T03:52:00.000-07:00

You can now look up the available study material for the Copasetic Flows ham radio practice exams by subelement and group. The study material index can be found at:

http://copaseticflows.appspot.com/helpindex

Just click on the exam you're studying for using the tabs on the left-hand side of the screen. Then, you can select the subelement and group you're interested in using the buttons in the application window.

Subelement Progress Reports

2011-07-05T14:41:00.001-07:00

Thanks to Dave, W4YDY, who remembered that the ham radio practice tests used to have a feature that created tests containing all the questions from a single test subelement.

For folks new to ham radio license tests, each of the three United States amateur license exam question pools, (technician, general, and extra), is organized into 10 subelements. Each of the subelements covers a particular subject area in amateur radio. For example, subelement 2 of the technician class exam covers 'Operating Procedures'.

Dave pointed out that his grandson used the subelement feature to practice the questions corresponding to a subelement as he was reviewing the same subelement in his study guide. When he took his exam he: "Only missed 3 questions and is now W4DWA."

The subelement focus feature and subelement progress charting has been added back to the U.S. ham radio practice exams at http://copaseticflows.appspot.com/hamtest. Now, in addition to tracking your practice test scores over time, you can also scroll down the scores tab to see your scores broken out per subelement. Each subelement score graph has a button directly below it that will setup a practice test of only questions from that subelement. You can also start a test for a particular subelement on the 'Test' tab by clicking one of the subelement buttons below the question and answer area.

Subelement Study Focus Added to Practice Exams

2011-07-04T12:33:00.001-07:00

Subelement specific practice tests have been added to the free ham radio practice exams at http://copaseticflows.appspot.com/hamtest for the United States amateur exams. To study a specific subelement press the button, (look below the question area), that corresponds to that subelement. A new test will start specific to that subelement. The questions that appear in the exam will be only the questions for that subelement in numerical order. The exam header will have a message reminding you that you are studying for that subelement and not practicing a full exam.

As always with new features, if you see anything new or old that looks broken, please contact me at hcarter333@gmail.com. Have fun!

Dr. H.T. Barnes of Mecanno Magazine Fame

2011-07-02T07:47:00.000-07:00

The September, 1929 issue of Mecanno Magazine briefly outlined Dr. H.T. Barnes efforts to destroy icebergs with thermite. Thermite is a mixture of aluminum powder and iron oxide, (rust), that burns at temperatures up to 5000 F, but does not normally explode. Dr. Barnes discovered that thermite embedded in ice would in fact explode. He patented the process as a method to destroy ice jams and icebergs. Decades later, the guys at Mythbusters would explore exploding thermite as urban myth, (see the video below), apprently unaware of Dr. Barnes' research. Here’s an excerpt from the Mecanno magazine article detailing Dr. Barnes' research:

"From ice jams to icebergs is a very natural step, and the inventor of the thermit method, Professor H.T. Barnes of Montreal, decided to try to blow up an iceberg by this means. For his first trial, he chose one that was nearly 100 ft. in height. Into a hole bored just above the waterline he placed 160 lb. of thermit and fired the mixture with a slow-burning fuse. Flames shot 125 ft. into the air and the berg was so badly cracked that one-third of it broke away completely a few hours later"

In addition to exploding icebergs, Dr. Barnes worked with Ernest Rutherford at McGill University in Montreal on the radio-chemistry experiments

that would eventually earn Rutherford the 1908 Nobel Prize in Chemistry "for his investigations into the disintegration of the elements, and the chemistry of radioactive substances". Dr. Barnes became Macdonald Professor of physics at McGill University in Montreal after Rutherford left the post to relocate to England.

Professor Barnes most publicized work however was his work on detecting and destroying icebergs. In addition to being featured in Mecanno Magazine, it was also featured in "Popular Mechanics" and "Popular Science" at the time.

Thermite is a mixture of powdered aluminum and iron oxide, (rust), that burns at temperatures up to 5000 degrees F. It doesn't normally explode, but when put in contact with ice as in Dr. Barnes' experiment, it will. As it turns out, the guys from the Mythbusters show unknowingly replicated Dr. Barnes experiment recently. You can watch the resulting explosion below:

Dr. H. T. Barnes Reading List:
Experiments with wireless telegraphy on trains

Engineering News Volume 67, 1912 Iceberg Detection

Ice Breaking Patent

Map for H. T. Barnes

View HT Barnes in a larger map

General Class Practice Exam Gadget Update to New Question Pool

2011-07-01T13:25:00.000-07:00

The General class practice exam gadget has been updated to the new general question pool that took effect today.

Lecture 24 of MIT Freshman EM

2011-06-29T08:11:00.000-07:00

I'm back to studying for the Physics quals at New Mexico State. Today I reviewed lecture 24 of the Freshman EM class there. You can watch it below. Timestamps and additional notes follow.

At the end of the video, there's a very cool explanation and demonstration of a Ruhmkorff, (shown at left). It works in a similar manner to a car's induction coil and can make sparks in air between terminals separated by 10 cm. To read more about it, check out the Wikipedia article on indicution coils.

Timestamps and notes
RC circuit charging over time

7:00 derivation of differential equation for RC circuit.

8:34 Solution

21:48 Transformers
33:00 Cool transformer demo
39:00 Induction heater demo with a nail
43:00 car transformer
49:00 Rumkorf spark generator

Mecanno Magazine Archive

2011-06-29T00:57:00.000-07:00

Check out this great resource of scientific and engineering articles written for kids between 1916 and 1981! The covers are fascinating! They were printed by the manufacturers of the Mechanno building sets, which are known as Erector sets here in the States. Each issue contains articles about interesting technologies of the time and the future of technology as the authors saw it then.

The early motto of the magazine is my favorite:
"To Help Meccano Boys to Have More Fun Than Other Boys"

SDR Construction Notes from Jeri Ellsworth

2011-06-16T01:23:00.000-07:00

Jeri Ellsworth posted an interesting video on youtube outlining her software defined radio construction. This is a pretty slick example of what can be done with SDR.

Television Inventor Worked on Fusion

2011-06-12T03:35:00.000-07:00

While plunking around Wikipedia this morning, I came across an article on Wikipedia about Philo T. Farnsworth, one of the inventors of the television system. It turns out he also invented a table-top fusion device. It never took off as a power source, but the basis of the invention serves as a commercially available table-top neutron source. For more details, see the link below:
http://en.wikipedia.org/wiki/Fusor

Scoring fixes to embeddable free ham radio practice tests

2011-06-06T18:29:00.000-07:00

Several scoring bugs and one multiple test bug were fixed on the embeddable google gadget free ham radio practice exams today. The scoring bugs fixed should make for reliable tracking of your unanswered and unpassed exam questions. There was also an issue where taking a test a second time didn't always work correctly. That's fixed now. Finally, if you were having trouble using the tests with IE8, they're up and running! If you run into new or the same issues, please let me know at hcarter333@gmail.com and I'll get it fixed.

Have fun!

73 de KD0FNR Hamilton

Extra Class Rectangular Impedance Video Help... by Pirates

2011-06-06T02:10:00.001-07:00

There's a new video help topic available for the free ham radio practice exams at: http://copaseticflows.appspot.com/hamtest. Feedback is welcome!

Study the Correct General Pool

2011-06-03T13:26:00.000-07:00

If you're taking the general class test after on or after July 1st of 2011, be sure to not use the google gadget practice exam and do use the practice exams at:

http://copaseticflows.appspot.com/hamtest

Your same user account will work on either practice exam, but the exam set at Copasetic Flows has the new general question pool as well as the current one. Just select the 'NEW General' tab on the practice exams. The question pool on the google gadget will change over to the new one on July 11th.

SWR explained by AT&T

2011-06-01T10:20:00.001-07:00

Thanks to soldersomke for pointing this out. Here's an excellent film made by Bell Laboratories in 1959 explaining SWR.

Inventor of the crystal set worked on global warming... prior to 1902

2011-05-30T07:08:00.000-07:00

While researching the Beverage antenna which was tested in part at Otter Cliffs Naval Station, I cam across an interesting article in Popular Science from 1922 about the inventor of the crystal detector, George W. Pickard. It turns out that OM Pickard was at the Blue Hills Observatory in Milton Hills, MA working on the apparently age-old problem of global climate change when he heeded the call of the Smithsonian Institution to experiment with kites to determine the dependence of radio propagation on the height of the transmitting aerial.

Incidentally, at the time, it was thought that gathering a sufficient amount of data to prove or disprove the hypothesis of global climate change would take the work of 'countless generations'. In the same issue, there are articles about the 'dwindling supply of gasoline' and charging batteries using windmills.

Google App Engine and Windows 7 Snipping Tool Incompatability

2011-05-28T05:32:00.000-07:00

I saw an issue in the last two days with app engine that took me awhile to fix. I was saving pictures using the 'Snipping Tool' in Windows 7 as .png files and then uploading them to my Google app engine site. The pictures were subsequently not available on the site. I was never able to make the pictures available. However, after pasting pictures into Microsoft Pain on Windows 7 and then saving them as .png files and uploading to my Google app engine site, they became available online. I don't know what causes the issue, but it seems easy enough to avoid once it's known.

Have fun!

Help Topic on RLC resonance added and congrats to KK4CDL 98% on extra exam!

2011-05-27T09:56:00.000-07:00

First, congrats to KK4CDL! He passed his extra class exam with an FB 98%!

A new help topic has been added to the extra class exam about the RLC resonance frequency. If you have any feed back, it would be greatly appreciated either here, or at hcarter333@gmail.com

New Help Topic and a Few Bug Fixes on the Free FCC Ham Radio License Practice Exams

2011-05-25T13:36:00.000-07:00

A new help topic on gray-line propagation has been added to the extra class practice exam. Any feedback would be very appreciated.

The ham radio practice exams have been updated again. There was a bug that was causing some tests to hang up on their last question. It's fixed! The figure E5-2 was missing, and has been added to the tests.

If you spot anything else, please contact me at hcarter333@gmail.com

Tesla's Wardenclyffe Lab Restoration Featured in RASL 10

2011-05-20T04:32:00.000-07:00

The restoration effort to save Tesla's last existing laboratory in Shoreham, NY got a mention in RASL #10. To learn more about what's going on and how you can help go to:

http://teslasciencecenter.org/about.html

There will be a conference at Brookhaven National Laboratory on Saturday November 5th to support and raise awareness for the effort. If you're interested, you can find out more at:

Conference Call for Papers

About the Tesla Science Center

We're also working on setting up an amateur radio special event station to transmit from somewhere near Wardenclyffe that day. Any interest from the hams?

FCC Commercial Operator License Element 5 Free Practice Exam

2011-05-18T12:44:00.000-07:00

The Element 5 practice exam is ready to go at http://copaseticflows.appspot.com/hamtest. The grid below shows which elements are required for the different FCC Comercial Operator Licenses.

The Flying Rockmite on Dashtoons!

2011-05-17T04:46:00.000-07:00

The flying rockmite that uses official Dash! dogbone antenna insulators is featured on Dashtoons.com this week! Jeff K1NSS also waxed poetic about wire antennas. Check out the awesome cartoon!

FCC Commercial Operator License Element 3 Free Practice Exam

2011-05-16T12:40:00.000-07:00

The Element 3 practice exam is ready to go at http://copaseticflows.appspot.com/hamtest. The grid below shows which elements are required for the different FCC Comercial Operator Licenses.

FCC GROL Element 1 Free Pracitce Exam

2011-05-15T06:42:00.000-07:00

I'm adding the FCC commercial license exams to the free exam site. So far Element 1 is up. This element is required for the GROL as well as other commercial licenses. To find it go to:

http://copaseticflows.appspot.com/hamtest

and click on the Comm E1 tab on the left of the exams.

Please let me know about any feedback you might have at hcarter333@gmail.com

New General Question Pool Available!

2011-05-15T06:40:00.001-07:00

The new General class question pool, (effective July 1, 2011), is available one the free practice exams at:
http://copaseticflows.appspot.com/hamtest

Four New Cosponsors for HR 607

2011-05-12T12:22:00.000-07:00

On May 10th four more representatives cosponsored HR 607 which impacts amateur radio frequency allocations in the 70 cm band. They are:

Rep Wittman, Robert J. [VA-1] - 5/10/2011
Rep Mica, John L. [FL-7] - 5/10/2011
Rep Buchanan, Vern [FL-13] - 5/10/2011
Rep Reichert, David G. [WA-8] - 5/10/2011

If you're an amateur radio operator from one of these districts, you might want to write your representative.

iHAB-2 Launch Video

2011-05-11T02:40:00.000-07:00

Sounds like the recent iHAB-4 launch went well! Here's a video the iHAB-2 launch we helped out with:

First Flying Rockmite QSO!

2011-05-10T02:25:00.000-07:00

I made my first QSO with WD8AFB of Orlando, FL with the new Rockmite 20 yesterday. That's 974 miles from Sound Beach, NY on about half a watt. The antenna design is a little different. Instead of running coax from the radio up to the antenna, the radio is part of the antenna and hijacked length of cat-5 ethernet cable brings the control and power lines down from above.

I used Dashtoons brand antenna insulators as quick disconnects so I can take the radio down during our frequent rains here on Long Island.

The keyer was a bit primitive for this first QSO:

Map of the QSO:

New Goslings!

2011-05-08T10:52:00.001-07:00

The new batch of goslings hatched out here! Scroll down for a video!

Extra Class Exam Video Help Begins!

2011-05-07T02:50:00.000-07:00

It seems like some of the topics for the US extra class exam would be better served by help videos instead of long detailed written help pages. So, here's the first video help topic for Copasetic Flows free ham radio practice exams. It covers direct digital synthesizers. Please let me know what you think and what could be improved or changed.

Video seems to have been in the air for ham radio this weekend. Here are some of my favorite ham radio blogs that also posted videos this weekend:

SolderSmoke: WSPR the Movie
G4ILO: Installing APRSISCE/32
W2AEW's Dorkage Blog: Delayed Timebase operation example
and
GOKYA: GB0CMS, Caister Marconi Station

Foggy Beach Walk and some Waves

2011-05-06T07:27:00.000-07:00

The Waves:

The walk:

MIT Thermo... Studying for Quals... Notes and Video

2011-05-02T02:51:00.000-07:00

Lots of cool stuff! This lecture has nice clean explanations of:
1. How a heat engine diagram is used
2. What adiabiatic means, (doesn’t exchange heat outside the system)
3. Why work examples are inexact, (they’re path dependent)
4. van der Waals equation of state

NOTES:

Adiabatic: No transfer of heat between the system and the outside world. Can be reversible and not.

Isobaric: constant pressure
Isothermal: constant temperature

triple point of water is used as a reference point for the Kelvin scale because it is the same everywhere.

Ideal gas law only holds for a very small range.

21:00 van der Waals equation of state

derivation of van der Waals, b is the volume consumed by the hard sphere molecules. a is the attractive force that slightly reduces pressure. a is divided by the molar volume squared because it is more likely to affect things in smaller volumes and less likely in larger volumes.

31:00 Convention in the definition of work. The environment compressing the gas is called positive work. Work done by the system on the environment is called negative.

The amount of work that you put in depends on the path to change the system. The state variables in the initial and final state do not care about the path.

45:00 heat engine first demonstrated
The differential of work used here is not an exact differential. The integral around a closed pat is not 0.
Heat flowing out of the system is called negative Q.
48:00 Adiabatic temperature change is the change of temperature without transfer of heat to or from the environment. Heat and work are really the same thing.

iHAB-4 Launches This Morning!

2011-04-30T03:07:00.000-07:00

iHAB-4 a high altitude baloon complete with qrp beacon and student science exerpiments will launch this morning! We helped chase iHAB-2 back in October and had a great time! You can read more about the fb work by W0OTM and team at the iHAB-4 web site.

The posting to GQRP announcing the launch is copied below:

The Iowa High Altitude Balloon project is making it's 4th launch
tomorrow morning at 10Am Central, 1500z, from Cedar Rapids, Iowa.

A major milestone is that science student's cannister experiments will
be carried aloft and analyzed upon recovering the payload.

One of the goals of this launch is to do a remotely triggered cut down
at 75,000 feet, or over the Mississippi River, whichever comes first.
The tether between the payload and the balloon will be severed from a
ground command. A test of the cutdown circuit at low temperature can
be viewed here http://www.youtube.com/watch?v=S4voKhzUflM

As on the last flight, a 2M simplex repeater will be operatiing on
147.500 PL TONE 100.00.

The 20M CW beacon will be operating again on 14.058 sending IHAB4
W0OTM Feel free to post signal reports on www.QRPSPOTS.com

You can monitor the flight path at http://aprs.fi/?call=a%2FW0OTM-4

Enjoy the flight.
----------------------------------------------------------
I love this radio stuff !
72, 73 Terry, WAØITP
www.wa0itp.com
www.4sqrp.com
www.qrpspots.com

Biot Savart Notes

2011-04-27T07:07:00.000-07:00

Still watching MIT Freshhman EM lectures in preparation for quals. Notes and time stamps follow the video.

Biot Savart

C = mu0/4pi = 10 ^ -7

9:40 Magnetic field from current loop

15:00 Dual of current loop magnetic field and electric dipole electric field

Magnetic flux through a closed surface is always 0.

37:30 Leiden jar disassemble and discharge example
Demonstrates corona discharge from metal to the insulating glass
Removing charge from the insulating glass is difficult

MIT Freshman EM... Magnetism ... Studying for Quals

2011-04-26T03:11:00.000-07:00

In getting ready for quals next January, I found out that MIT provides several of their courses online. I watched the freshman physics lecture on magnetism today and it's awesome! There are demos of the forces created on wires by magnetic fields, (car batteries are apparently the key to getting this demo right), as well as simple electric motor demos. There are also several everyday applications that make the Lorentz force equation immediately applicable. The video is embedded after the notes.

Notes:

Force on a wire due to a B field

SSB Internet Reader: History

2011-04-18T10:29:00.001-07:00

I mentioned before that I was doing some research on the history of SSB in amateur radio and promised my reading list. Here it is.

ARRL "Amateur Radio and the Rise of SSB" [pdf]

GE Sideband Handbook Chapter 2 detailing the SSB Junior among other things [pdf]

GE Ham News detailing the "Signal Slicer" SSB receiver from July 1951 [pdf]

How Donald Noorgard's SSB Junior inspired Wes Schum's Central Electronics Model 10A.

Historical reference on the RCA transmitting station at Rocky Point, NY, site of the first transatlantic SSB transmission

Rocky Point Historical Society essay on the RCA transmitting station

Wikipedia entry for Rocky Point, NY mentioning the RCA transmitter site

Modern pictures of what is left of the RCA transmitting site at Rocky Point, NY

WB9IPA QRP SSB project with its own great reading list

Studying the Tenna Dipper Deluxe

2011-04-16T04:36:00.000-07:00

I saw an interesting new kit from Hendricks QRP Kits yesterday called the Tenna Dipper, (designed by KD1JV). It tells you the 50 ohm resonant frequency of an antenna. Basically, you scan the frequency from the Tenna Dipper until an LED goes out and the read the resonant frequency from the display.
What I thought was even cooler was learning how the kit worked. I’ve included the links I used for research below.

The schematic is available on the Hendricks site as a pdf.

The kit uses a Wheatstone Bridge to cause the LED to go out when the antenna resonates at 50 ohms. The bridge is the workhorse circuit that provides antenna match information. It’s actually fairly easy to understand, check out the explanation at:
Wikipedia Wheatstone Bridge article.

A voltage controlled oscillator, 74HC4046, is used to generate the square wave sent to the antenna.
74HC4046 datasheet [pdf]

A 74HC4017 decade counter is used as frequency counter to feed the kit’s frequency display.
74HC4017 datasheet [pdf]

The frequency display is driven by an Atmel ATTiny2313 microcontroller.
ATTiny2313 microcontroller datasheet [pdf]

NOTE: I’m not associated with Hendricks QRP kits, I just thought this was a cool design to learn about.

Another Five Representatives Cosponsor HR 607, NY, PA, AK, GA, and IA

2011-04-15T05:40:00.000-07:00

Yesterday two more representatives cosponsored HR 607 which impacts amateur radio frequency allocations in the 70 cm band. They are:

Rep Lowey, Nita M. [NY-18]
Rep Gerlach, Jim [PA-6]]
Rep Young, Don [AK]
Rep Barrow, John [GA-12]
Rep Loebsack, David [IA-2]

If you're an amateur radio operator from one of these districts, you might want to write your representative.

SSB Internet Reader: Technology

2011-04-14T02:54:00.000-07:00

Soldersmoke 132 inspired me to look up Donald Norgaard, one of the engineers who worked on and promoted SSB transmission early on. I found a wealth of material about early SSB available on the internet. Here's a list of the more technically minded articles:

Amateur Radio and the Rise of SSB[pdf]: Nice historical overview of SSB. This article references a 1948 QST article, (see below), by Norgaard that has a very nice explanation of phasing SSB.

"A New Approach To Single Sideband", Donald Norgaard, QST June, 1948
This is the article referenced above. If you're an ARRL member, you can pull it from the QST archives.

"Notes on the Design of the SSB Jr. Rig"[pdf] Another article by Donald Norgaard that appears in the GE Ham News. Be sure to check out the FB http://n4trb.com/AmateurRadio/GE_HamNews/ge_ham_news.htm from N4TRB.

"A QRP SSB Transceiver" by WB9IPA This page has plenty of other links to SSB articles on the web as well as a very interesting chronicle of WB9IPA's SSB transceiver project.

Coming soon, the historically oriented list.

Have fun everybody!

First Tran-Atlantic SSB Transmission Made in Rocky Point, NY

2011-04-13T09:35:00.000-07:00

View TeslaTwain in a larger map>

Apparently Long Island is rife with radio history! While listening to Soldersmoke #132 I noticed N2CQR mention Don Norgaard as one of the pioneers of SSB modulation. Interested, I looked up Don, W2KUJ and came across a lot of interesting information on the history of SSB, including a great ARRL article[pdf]. It turns out that the first trans-Atlantic SSB transmission was sent from the RCA Transmitter Laboratory in Rocky Point, NY just a short distance from Tesla’s last laboratory!

Dash! The Dog Faced Ham at MOCCA 2011

2011-04-11T01:27:00.000-07:00

We went to the Museum of Comic and Cartoon Art Festival this weekend and met Jeff K1NSS of Dash! The Dog Faced Ham fame! It was great to run into another ham at a comic book fest! Jeff is a super, super nice guy! He supplied us with the first two issues of Dash and three Official Dash Insulators which will go into the backyard dipole just as soon as the new Rockmite is finished.

After we got home, I tore through the first dash book and got half-way through the second. Dash is the story of a dog-faced kid growing up with ham radio. The book chronicles Dash's adventures with vacuum tubes, fox-hole radios, and all sorts of other exciting and arcane technology! The art in the book is pretty to look at and the story is great fun to read! There are plenty of ham radio in-jokes for those in the know, and secret morse code messages as well!

There were a few other cool and pretty things around the fest. I'll add more as time allows:

The Center for Cartoon Studies, from White River Junction, VT.

Spring Turkeys

2011-04-09T03:53:00.000-07:00

These guys turned up yesterday.

Higgins: Amateur Radio Operator!

2011-04-08T05:56:00.000-07:00

Just finished watching season 3 of Magnum PI and I saw that Higgins is an amateur radio operator with the callsign WP6RNA. I quick search of the FCC database showed that the callsign has never been issued. Higgins callsign in a later season changed to N6DBZ and that callsign is in use now!

HR 607: Two New Cosponsors Sign On (Minnesota and North Carolina)

2011-04-07T05:00:00.000-07:00

Yesterday two more representatives cosponsored HR 607 which impacts amateur radio frequency allocations in the 70 cm band. They are:

Rep Cravaack, Chip [MN-8] and
Rep Shuler, Heath [NC-11]

If you're an amateur radio operator from Minnesota or North Carolina, you might want to write your representative.

Nice Note on the Ham Radio Practice Tests and Congrats to KD8GEH

2011-04-03T04:34:00.000-07:00

I just received a nice note about the ham radio practice tests. Great job on your exam Dave!

"
Hamilton,

Just a note to let you know the I used your practice exam and got my extra. Thanks so much for the work! Much appreciated.

Keep up the good work, and the interesting jokes :)

Hope to catch you down the log,

73 De Dave KD8GEH
"

Groups and Their Graphs: Clarifications of Normal Subgroup Theorem and Test for Normal Subgroup Elements

2011-04-03T03:59:00.000-07:00

On page 123 of “Gropus and Their Graphs” by Grossman and Magnus I struggled understanding Theorem 6 and the test it provides. The theorem read more clearly for me with the following substitution:

“the set K that contains all elements of G such that...” becomes

“the set K containing every element of the group G such that...”

The following paragraph that contained the test was easier for me to understand with the following substitution:

“If f maps all elements onto I...” becomes

“If f maps all elements of G onto I...”

Hope this helps! Any comments or questions?

Easy HR607 Letter Creation

2011-03-31T01:47:00.000-07:00

The ARRL is encouraging all amateur radio operators to write the congressional representatives about a bill before congress that would reduce frequency privleges on the 70 cm band, HR 607. KD4PYR has created an FB web application that creates a letter for you based on the ARRL's sample letter. Just input your call sign and a letter will be created with your name and address. The application even uses your call sign address to automatically fill in information about your specific representative!

HR607 in the news

2011-03-30T05:12:00.000-07:00

HR607, the bill proposed by Representative Peter King, received some interesting coverage regarding it's effect on amateur radio in USA Today yesterday. It seems the letter writing campaign suggested by the ARRL may be working. The following excerpt is taken from the USA Today article:
--------------------------------------------------------------------

"America's first responders, including law enforcement officers and firefighters, these front-line heroes still do not have a national interoperable public safety wireless broadband network," King said.
He added that efforts are underway to address concerns of ham radio operators and others.
Rep. Billy Long, R-Mo., a co-sponsor of the bill, said he will work "to ensure that we are not cutting any vital emergency services and not adversely affecting ham radio operations."

----------------------------------------------------------------------

Find out how you can help.

Amateur Radio and HR 607

2011-03-28T10:18:00.000-07:00

The ARRL and AMSAT have recently pointed out that a bill before the House of Representatives would adversely affect frequencies used by amateur radio. The video below describes the ARRL's stance and what you can do. Scroll down for links to a template letter for your representative and the address to send it to.

A sample letter can be downloaded from:
ARRL Sample Letter

For those without Microsoft Word, the letter is copied below.

You can send your letter to the ARRL's Washington Representative:

John Chwat
Chwat & Co.
625 Slaters Lane
Suite 103
Alexandria, VA 22314

who will expedite its delivery to your representative.

=========================Copy of sample letter===============================

The Honorable ____________________
United States House of Representatives
______________ House Office Building
Washington, DC 20515

Dear Representative ________:

As a voter in your district and as one of the nearly 700,000 federally licensed Amateur Radio operators across the nation, I ask that you oppose H.R. 607, the "Broadband for First Responders Act of 2011" in its current form. H.R. 607 was introduced by Congressman Peter King (R-NY) and referred to the House Committee on Energy and Commerce.

H.R. 607 proposes to allocate the "D-Block" of frequencies (frequencies previously occupied by analog television) to be developed into an interoperable Public Safety wireless network. Earlier, it had been expected that the D-Block would be auctioned by the FCC for commercial use, but there is now substantial support for the allocation of the D-Block to Public Safety. H.R. 607 also provides for the reallocation of other spectrum for auction to commercial users, in order to offset the loss of revenue anticipated by the auction of the D-Block.

While I strongly support the work of the Public Safety officials who put their lives on the line for our safety, my opposition to the bill stems from the inclusion of the 420-440 MHz spectrum (the UHF 70-cm band) as part of a frequency swap and auction. Very little of this spectrum is allocated to Public Safety, and only in very limited areas. Rather, it is allocated to government radiolocation services on a primary basis, with Amateur Radio allocated on a secondary basis. The Federal government uses this band for critical defense purposes, including Pave Paws radars for detecting surface-launched missiles aimed at the United States, and for airborne radars used for drug interdiction. The Amateur Service carefully coordinates its uses of this band to insure compatibility. The two services have a very good record of sharing this spectrum successfully, putting it to good use for both military and civilian purposes in the national interest.

Amateur radio emergency communication relies heavily on our limited frequency allocations in the VHF and UHF radio bands. The loss of access to the 420-440 MHz spectrum would make it very difficult for us to maintain this capability and would mean we could no longer use numerous systems that have been constructed on our own time and at personal expense to provide this important communications support.

Amateur Radio operators across the country repeatedly demonstrate our commitment to public service and emergency communications. Through our work with FEMA and other Homeland Security activities, state and local Emergency Management offices, and numerous charitable relief agencies, volunteer Amateur Radio operators assist the first responders, doing so at no cost to the agencies we support. The role of the Amateur Radio Service as a partner to Public Safety in providing supporting public service and emergency communications necessitates our retention of full access to the entire 70-cm band.

As an Amateur, I understand and support that Public Safety officials must have the spectrum they need to do their jobs. However, it is not necessary to do so in the ill-conceived manner proposed in this bill. Other pending legislation provides for this important goal to be realized without the proposed reallocation of non-Public Safety spectrum for commercial auction that is included in H.R. 607. I urge you to oppose H.R. 607 in its current form. Thank you for your consideration.

[Your Name]
[Your Address]

Beach Hinges: What are They?

2011-03-26T03:56:00.001-07:00

Anyone know what these are for? Found on a beach in NY.

Notes on Emmy Noether and Group Theory

2011-03-25T03:19:00.000-07:00

Just a few quick notes on historical trails I'm finding as I study group theory and Emmy Noether's theorem. The people involved are a bit of a group themselves. The first person I found is Lagrange. He introduced the Langrangian, one of the key concepts of analytical mechanics. It's used today, well, everywhere, from plain old mechanics to quantum mechanics, to quantum field theory. He also laid some of the foundations of group theory working on permutation groups and their use in solving polynomials.

That brings us to Évariste Galois. Galois read Lagrange's papers at the age of 15. He later went on to develop Galois theory. Galois theory relates permutation groups of the roots of polynomials to their solvability.

Sophus Lie developed Lie groups, provide a framework that is similar to Galois theory for studying the symmetries of differential equations.

And that brings us to Emmy Noether. Her paper on "Invariant Variation Problems" applied Lie's work to variational calculus revealing conservation laws applied to Lagrangians.

Emmy Noether and Women's History Month

2011-03-24T04:49:00.000-07:00

Coincidentally, during Women's History Month, I'm studying Emmy Noether's work on symmetric groups and conservation laws in physics. There's a great Wikipedia entry on her life and work. I found links to her conservation paper in both English and German at UCLA's Women in Physics site. There are a few books about her life and her theorem that look interesting. I'll be reading "Emmy Noether's Wonderful Theorem" later this month.

She spent her last few years at Bryn Mawr College a few miles from Philadelphia. Her ashes are scattered below the cloisters there. If you'd like to travel to the college, a map and transit information is included below. It turns out that it's pretty simple via SEPTA once you get to Philadelphia.

View Emmy Neother in a larger map

New Mexico Sunset

2011-03-23T13:11:00.001-07:00

6th and 7th Grade Math Champs Build Ham Radios... You Can Help!

2011-03-21T10:57:00.000-07:00

The following announcement about an awesome program for 6th and 7th graders came through on the RockMite mailing list this morning. Read on to find out how you can help out!

Thirty two "Math Champs" honor students from the 6th and 7th grades at Blaine Middle School in the state of Washington will be building and operating Small Wonder Labs Rock-Mites. The Math Champs represent their school in the Washington State Math Championships. They have finished the first week of their amateur radio program, which is a regular part of their schoolwork – not just an optional after-school activity.

The 32 students each belong to a work group of four students representing a DX country, and they have corresponding mock callsigns which are not currently assigned to any real hams:

Joseph: 3A2JSA, Gavin: 3A2GM, Monika: 3A2MK, Lauren: 3A2LKO, Candace: 9N7CO, Delaney 9N7DN, Kaylee 9N7KM, Darien 9N7DJ, Logan: ET3LN, Chase: ET3CL, Sawyere: ET3SH, Allan: ET3AL, Sarah: HH6SD, Holly: HH6HJ, Andy: HH6AB, Chloe: HH6CF, Kavish: JW5KC, Tayah: JW5TT, Emily: JW5ER, Riley: JW5RF, Jakob: S21JF, Kolby: S21KWS, Spenser: S21SDO, Ian: S21IM, Michael: XW1MB, Jalen: XW1JK, Matt: XW1ME, Zack: XW1ZO, Preston: ZP4PB, Parker: ZP4PB, Greg: ZP4GA, and Ben ZP4BH. Their math teacher sports EY8NH.

The students can recite the Alpha, Bravo, Charlie, Delta alphabet, thanks to instruction from Wayne McFee NB6M. They have started practicing ten Morse characters at a character speed of 20 WPM. For "transmitting" practice, they are singing "dits" and "dahs" for E I S H 5 T M O Ø and sos. Next week, they will add A U V 4 and F to that list. Outside of class, they are listening to those same characters on their home computers using the free G4FON Koch Morse trainer program: http://www.g4fon.net/CW%20Trainer.htm .

So far, the Math Champs have been learning about radio waves, about the relationship between RF wavelength and frequency, and about the whole RF spectrum from ELF through EHF, with special attention to MF, HF, VHF and UHF, where most hams hang out. The Rock-Mite will be their practical window into the world of radio and electronics. They will study the circuit diagram in detail in addition to building their own rigs. Making contacts on equipment which they understand and have built themselves should be especially meaningful.

All of this costs money. Some of you have already made contributions which we very much appreciate. These eager youngsters need your help. If you are wondering how much would be appropriate for this group of 32 students:
$30 will buy one student a Rock-Mite, associated connectors, and a simple wire antenna.
$15 will pay one student's required exam fee.
Whatever you can afford, you will be giving a big boost to these eager future hams.

Lyle Johnson KK7P and Heather Johnson N7DZU have generously offered a dollar-for-dollar challenge grant which will match contributions received at the Blaine Middle School by April 15 up to a total of $500.

All 32 students will be earning their Tech tickets. We'll make sure of that. Some especially ambitious ones who get a big kick out of studying are considering tackling both the Tech and the General Class exams in the same sitting. Most of those aspiring Generals will be building the 14.060 MHz version of the Rock-Mite. The rest will build the 7.030 MHz Rock-Mite.

All contributions are tax deductable.

Please make out your check or money order to Blaine Middle School designated for Math Champs Amateur Radio Program. If you include your name, callsign and mailing address, the school will send you a tax receipt, plus you will receive a special thank you from one of the students after the FCC has issued them callsigns. Maybe you can make a sked to chat with that new ham on the air.

Please address the payments to:
Blaine Middle School
975 H Street
Blaine, WA 98230

Attn: Math Champs Amateur Radio Program

Thanks and 73,
Bruce N7RR

Groups Made Easy: Group Definition

2011-03-20T04:26:00.000-07:00

Just recording my notes on learning group theory into a series of short highlight videos.

Around the Lab: Diamagnetic Levitation and the levitating pan

2011-03-15T02:59:00.000-07:00

What you're watching below is an example of diamagnetic levitation. The little bench that the coil is sitting on top of is solid aluminum. The coil is about three inches in diameter and contains a few hundred turns of magnet wire. A variac is used to drive the coil with AC current.

When the coil is energized, the alternating current creates an alternating magnetic flux. This flux sets up a counter-emf, (electromotive force) in the space occupied by the aluminum plate. This counter-emf creates a current in the aluminum plate that in turn creates a magnetic field opposing the one created by the coil. The two magnetic fields repel and the coil is levitated. Check out the videos and then check out the newspaper article from the '60s describing the levitational stove.

NEW YORK HERALD-TRIBUNE: Monday, November 21, 1951, pp. 1 & 6

PAN FLOATS IN AIR

In it seven coils of wire on laminated iron cores are contained inside a plywood cabinet of blond mahogany. The magnetic field from these coils induces 'eddy currents' in an aluminium cooking pan nineteen inches in diameter, which interact and lift the pan into space like a miniature 'flying saucer.'

The cooking pan floats about two inches in tha air above the stove in a stabalized condition; 'eddy currents' generate the heat that warms it while the stove top remains cold. The aluminium pan will hold additional pots and it can be used as a griddle. It is, of course, a variation of several other more familiar magnetic repulsion gadgets including the 'mysterious floating metal ball' of science hall exhibits.

Superconductor Meissner Effect Levitation

2011-03-11T18:33:00.000-08:00

I came across this video illustrating the Meissner effect with a high temperature superconductor from one of my labs today. Pretty fun! Magnetic fields cannot penetrate a superconductor. In order to prevent the magnetic field of the suspended magnet from entering, the superconductor sets up and opposite magnetic field that suspends the magnet.

Groups Made Easy

2011-03-09T12:21:00.000-08:00

If you’re taking quantum mechanics, QCD, quantum field theory, electricity and magnetism, or any of the other physics courses where group theory is often used, but rarely explained, then Groups and Their Graphs by Israel Grossman and Wilhelm Magnus is the book for you. It lays out the basics of group theory in simple easy to understand language. For the more esoteric minded, it even covers quaternions.

I just found this book a few weeks ago and finally picked up my own copy. It’s from a seemingly brilliant series of books called the New Mathematical Library that was started in the ‘60s. The series takes advanced or less than common mathematical concepts and explains them in a manner that is targeted at an audience with high school level math skills. Here’s a quote from the book:

"This book is one of a series written by professional mathematicians in order to make some important mathematical ideas interesting and understandable to a large audience of high school students and laymen. Most of the volumes in the New Mathematical Library cover topics not usually included in the high school curriculum; they vary in difficulty, and, even within a single book, some parts reuire a greater degree of concentration than others. Thus, while the reader needs little technical knowledge to understand most of these books, he will have to make an intellectual effort."

The book uses geometric operations such as rotations and flips on an equilateral triangle to illustrate concepts so far. While it’s easy to understand, it never talks down, or dumbs down concepts. More on this later.

Understanding Spherical Gradients

2011-03-05T19:22:00.000-08:00

Previously we looked at where the 1/r term comes from in the gradient in cylindrical coordinates. This time, we're looking at the gradient for spherical coordinates.

The spherical coordinate values are shown in the figure below. The new theta coordinate is another angular coordinate similar to the phi coordinate introduced in the cylindrical system. It's angle sweeps down from the positive z axis of the Cartesian coordinate system to the negative z axis. Theres a another change. Instead of being anchored on the z axis and moving up and down, the r coordinate is anchored permanently at the coordinate origin.

In this coordinate system, the the angle theta and the radial direction sweep out circles in vertical planes similar to the horizontal plane circles discussed in the cylindrical case. Because of this, the theta coordinate has the same 1/r multiplier discussed in the cylindrical case.

phi and r sweep out circles in horizontal planes exactly as in the cylindrical system. But now, the radius of the circles are not just dependent on the value of r anymore. They also depend on the value of theta. If theta is zero radians, then the circle swept out by r and phi is a point, a circle with 0 radius. If theta is pi/2 radians, then the circle swept out by r and phi actually has a radius of r. The figure below shows a view of the relation ship between r and theta. The phi circles are swept out by the radial line with lenght r and angle theta from the z axis.

Because phi no longer sweeps out circles with radius r, but with radius r sin theta, it's element of length change must be modified in the same manner and we get the length factor assciate with the phi coordinate shown in the gradient above.

Understanding Cylindrical Gradients

2011-03-04T03:20:00.000-08:00

We’ve previously looked at how to derive divergence for cylindrical coordinates. If you’re like me though, knowing the rather lengthy derivation won’t help you understand or memorize the resulting formula. So, let’s take a look at why the result makes sense.

The formula for the gradient of a function in cylindrical coordinates is:

Why is the factor of 1/r in the phi term? Remember what question the divergence is asking. We want to find out the amount the function changes vs. a small change in distance along each coordinate’s direction. For coordinates that actually correspond to distances, like x, y, and z of Cartesian coordinates, or r and z of cylindrical coordinates, this is straightforward. The change in the coordinate corresponds to the change in distance along the coordinate.

For coordinates that correspond to angles in the cylindrical coordinate system, there’s an extra twist. The direction of phi always points tangent to a circle centered on the z axis. The small change in distance along the phi or theta coordinate direction is actually a distance measured along the circumference of a circle. The figure below helps me see the issue more clearly. A small change in phi at a radius of 1 means a change of distance of phi times the radius, or 1 phi. At a radius of 2, the same small change in phi results in a change along the circumference of 2 phi.

The distance used in finding the amount the function changes per small change in distance along the phi or theta coordinate is equal to the change in phi times the radius where the change in phi or theta occurs.

So, to properly account for the distance along the phi direction, the divergence has to be written as:

Foundation for Amateur Radio Scholarships

2011-02-23T21:35:00.000-08:00

It's time to apply for the Foundation for Amateur Radio Scholarships again! Applications are due April 15th. Several of the scholarships require the recommendation of a club member, so start early. If you have questions, you can contact Dave Prestel, W8AJR, at dave.prestel@gmail.com or by phone at (410) 552-2652.

Anyone else remember self-healing GaAs transistors?

2011-02-19T07:29:00.000-08:00

On episode 130 of SolderSmoke, N2CQR wondered why the transistors on the Venus Magellan probe were mentioned as self-healing. I remember a reference being made to self-healing GaAs transistors for use in radiation environments when I worked at a paticle accellerator during my MSEE studies, but I can't find a solid reference to this usage now. The explanation I remember went something like this:

"Radiation can damage transistors by breaking the crystalline lattice inside the semiconductor. Self-healing transistors run very hot so that when a lattice site in the semiconductor crystal is broken by radiation it is 'fixed' by the crystal effectively melting around the broken site."

Does anyone else have a solid reference to this or more information?

Thanks!

Share QSO Maps!

2011-02-16T01:11:00.000-08:00

The QSO mapper at http://copaseticflows.appspot.com/newqso now provides sharable QSO maps! Just enter the callsigns from your QSO:

Click the Map It! button and notice the sharing toolbar:

Choose the social site you'd like to share your map on, Facebook for example, and click that button on the sharing toolbar. You'll be asked for a comment for your map link:

And a link to your map will appear on your profile like this one.
Want a link without using another site like Facebook? Click on the 'Map Link' under the sharing toolbar to go directly to your map.

Adding Google Friend Connect: Scriptaculous collision

2011-02-15T08:05:00.001-08:00

I recently added sign-in via Google Friend Connect to the ham radio practice exams. It took a few days longer than I had planned. Using the example at: http://www.ossamples.com/api/ seemed like it should be simple enough, for an even more stripped down example try http://copaseticflows.appspot.com/glogin.
I could see that initAllData was running and sending the opensocial.newDataRequest(), but there was never a response that executed the callback function. After a few days of isolating code, it turned out that there is a conflict between Google Friend Connect and Prototype version 1.6 that ships with Scriptaculous. You can read all about it here, but the short version of the story is use the new version of Scriptaculous with Prototype 1.7.

Ham Radio Exams now have Google Sign-in

2011-02-15T06:59:00.000-08:00

You can sign-in to save your scores and customize ham radio practice exams at copaseticflows using your Google account! Look for more ways to interact with your Google and Facebook friends coming soon. Is there anything you'd like to see? Leave a suggestion in the comments section below.

Physics Tour of New York

2011-02-10T14:41:00.000-08:00

I came across an interesting article on the history of Physics in New York City titled, "The Physical Tourist Physics and New York City", (you can download the article for free at the preceding link. At the end of the article, the author outlines a tour through Manhattan of Physics landmarks. It sounds like fun and I hope to do it one of these days. A map of the stops on the route follows.

View Manhattan Physics Tour in a larger map

Add a mapping ham radio log book to your web page

2011-02-09T03:30:00.000-08:00

I've written a gadget that adds a mapping ham radio log book to any web page. Just go to the gadget's customization page. copy the code from the bottom of the page and add it to your web page. You'll get a log book like the one below. It can also be added to your igoogle home page at the gadget's igoogle page.
The QSOs tab shows all the recently logged calls. Use the logger tab to enter your own QSO. Use the search tab to search for QSOs from any callsign, frequency, or mode.

Crystal Oscillator Design: Parallel and Series

2011-02-06T22:22:00.000-08:00

On the Rockmite yahoo group today, Chuck Carpenter, W5USJ posted a very nice explanation of series vs. paralel resonant crystals along with a link to a FAQ on crystal oscillator design at:

http://www.foxonline.com/techfaqs_cry.htm#a4

Chuck' post follows:

RMers,

Here's some info sent to me by Rich at ESS.

Chuck,

The group that requested 7114 requested it in Series Resonant crystal. Most
of the other crystals that I sell are Parallel Resonant. I have included an
explanation from Fox Crystal Co. web site. They are not my supplier but the
information applies to all crystals and their manufacturers. This should
get you where you want to be.

The information that everyone needs to know is #6. 4 and 5 will help people
make a circuit oscillate where they want it.

This is from: http://www.foxonline.com/techfaqs_cry.htm#a4

More information can be found at:
http://www.oscilent.com/spec_pages/PNDescrpt/Load_Cap.htm

4. The load capacitance (CL) of my parallel resonant crystal is rated at
20pF. How do I calculate the value of the load capacitors used in my
parallel resonant oscillator circuit?

Use this formula to approximate the value of capacitors needed:

CL=((C1 x C2) / (C1 + C2)) + Cstray

Cstray is the stray capacitance in the circuit, typically 2-5pF. If the
oscillation frequency is high, the capacitor values should be increased to
lower the frequency. If the frequency is low, the capacitor values should be
decreased, thus raising the oscillation frequency. When CL =20pF, C1 and C2
will be approximately 27-33pF each, depending on the amount of stray
capacitance.

5. What is load capacitance?

Load capacitance is defined as being the total capacitance present in an
oscillator circuit as measured or calculated across the pins of the crystal
socket. Load capacitance has the effect of increasing the frequency of a
crystal unit. Please see the tutorial section for a complete explanation.

6. Will a series crystal work in a parallel circuit and vice versa?

Yes to both, but a crystal unit manufactured as a series resonant crystal
will operate at a frequency higher than expected if used in a parallel
resonant circuit. A crystal unit manufactured as a parallel resonant crystal
will operate at a frequency lower than expected if used in a series resonant
circuit.

If you need any other information then feel free to contact me,

Rich Kennedy - N4ESS
Expanded Spectrum Systems
6645 Founders St.
Zephyrhills, FL. 33542-1828
USA

813-620-0062 Office

www.expandedspectrumsystems.com

n4ess@tampabay.rr.com

Chuck Carpenter, W5USJ, Point, -|- Rains Co., TX -|- EM22cv -|- 72/73
56 years -|- 19 as K2OFN and 37as W5USJ -|- Most fun = QRP since 1984.
Website = http://www.w5usj.com

Facebook Connect Application Login Now Simple!

2011-01-31T02:42:00.000-08:00

Writing a Facebook Connect application can be done in about half an hour using the newly updated Javascript API. No more server side code required! Here are the steps:

1. Setup a Facebook applicaiton
Go to http://www.facebook.com/#!/developers/ and click on the 'Set Up New App' button to setup a new application. On the about page, enter the application's name and a short description. On the 'Web Site' tab, enter the URL of the web domain that will serve the web page you will put your login box on. Copy the 'Application ID' from this same tab. Click on 'Save Changes'.

2. Add the Facebook javascript library to your web page
Place the following div and script on your web page. The div won't actually display anything, it's just to bring in the Facebook code. I place it at the bottom of my web pages:

3. Initialize the facebook library with your application ID
Execute the following line of code somewhere in your page's javascript.
FB.init({appId: '105604822850082', status: true, cookie: true, xfbml: true});

4. Add the facebook login button to your html
Insert the html below into your page where you would like to see the login button displayed:

Login with Facebook

5. Listen for and respond appropriately to facebook login events
//Listen for the user to login and then customize
FB.Event.subscribe('auth.login', function(response) {
// do something with response
fb_setup();
});

//If the user is already logged in and connected, then get rid of the login button
FB.getLoginStatus(function(response) {
if (response.session) {
// logged in and connected user, someone you know
fb_setup();
} else {
// no user session available, someone you dont know
}
}, true);

function fb_setup(){
FB.api('/me', function(user) {
if(user != null) {
document.getElementById('fblogin').innerHTML = '';
//alert(user.name);
var image = document.getElementById('fbimage');

image.innerHTML = ''
var name = document.getElementById('fbname');
name.innerHTML = user.name
login_user = user.id;
login_name = user.name;
}
});
}

6. You're Done!
The code above was adapted from the Facebook Developer documentation at: http://developers.facebook.com/docs/reference/javascript/fb.getloginstatus/ The documentation is getting better all the time.

For a complete working example, you can check out a flash card application I made for studying German 111 at NMSU. I got tired of having to login repeatedly to save my scores, and added a Facebook login button to let Facebook handle that work.
http://copaseticflows.appspot.com/examhelp/flashgb.html

Questions or comments? Please leave them below!

Time to Register for ARRL Scholarships

2011-01-11T08:01:00.000-08:00

Don't forget to apply for scholarships through the ARRL. The deadline is February 1st of 2011. They have college scholarships for amateur radio operators. Several of the scholarships offered are geography specific. Check out the map below and see if your state has one of these scholarships.

Scholarship Descriptions
Scholarship Application

View ARRL Scholarship in a larger map

Hacking Disney Walkie Talkies into QRP ham radios.

2010-09-30T14:27:00.000-07:00

I started a new project recently to determine if I could hack a Disney walkie-talkie into a QRP set. At first blush, it looks kind of simple, like maybe even a crystal replacement would do the trick.

Has anyone tried this? Is there a reason it specifically won't work?

Here are two pictures of the circuit board. The front looks simple enough. the back-side on the other hand... nothing by sm caps and resistors and transistors.

Ham Radio Exams Mentioned On....

2010-09-16T02:12:00.000-07:00

Just a few links to sites that use or link to the ham radio exams.
Jim's Engraving (lots of good ham radio stuff)
KB6NU's Ham Radio Blog
Northeast Weak Signal Group
Arcadiana Amateur Radio Association
ARRL
QRP Amateur Radio Club International
Mike and Key.org
Gold Coast Amateur Radio Association
W1MLK Radio
Sequoia Amateur Radio Group
New Zealand Amateur Radio Study Guide
North American DX Association
ARRL
Bluetube Project
SolderSmoke
KB7TBT
Jim's Engraving
Decatur (Alabama) Amateur Radio Club
Acadiana Amateur Radio Association
Sam's Radio Hams
Milliwatt - BRATS Newsletter"
Big Bend Amateur Radio Club
New Providence Amateur Radio Club
South Bay Amateur Radio Association
shaunlippy.org
KP4NKE
AeroARC
WC5C
Delta Amateur Radio Club
KB1VCZ
ddxa.org
N9JRV
Valley of the Moon Amateur Radio Club
Raleigh Amateur Radio Society"
G3XBM
LWRA
K6AA

Facebook Development Using AppEngine

2010-08-25T02:26:00.000-07:00

I've been porting the ham radio practice exams to facebook lately. The process for this wasn't entirely obvious to me and there were quite a few issues. This series of posts will try to make the process more obvious and highlight the issues I hit so you can avoid them. For now, I'll just point you at a list of the posts that will slowly flush out and my list of stumbleupon bookmarks I accumulated while doing research for the project.

Table of Contents

Facebook on Google App Engine Resources

Martinique on 14 and 10 MHz

2010-08-18T07:10:00.000-07:00

Click image above to go to logbook entries

FM5Ld from Martinique was spotted today.

Cool stuff about Martinique:

It's an overseas region of France.
It's part of an island arc along the Puerto Rico Trench that is the boundary between the Caribbean Sean and the Atlantic Ocean.

DX to the Azores!

2010-08-17T14:48:00.000-07:00

The DX spot of the day on copaseticflows was a QSO from OZ4Z to CU3HQ in the Azores. Not a bad looking place!

New Logbook and Spotter on Copasetic Flows

2010-07-29T09:01:00.000-07:00

There's are two new applications at copaseticflows. The front page now geographically displays the most recent calls from both dxsummit.fi and the copaseticflows logbook. That brings us to the second new application, the copaseticflows logbook. You can log, store, search, and map your calls for free. The new front page can be seen at:

copaseticflows.appspot.com

and the new logbook application can be used at:

copaseticflows.appspot.com/cflogbook

Have fun!

Gadget Google Math Formula Tester

2010-07-09T08:13:00.000-07:00

The Google Chart Formula API Tester is now available as a gadget!

You can install this gadget on your own iGoogle home page, or on any web page by using the installer from Google.

Google Mathematical Formula API Tester

2010-07-08T13:31:00.000-07:00

Google has come out with a handy URL based API for adding mathematical formulas to html documents. I haven't seen a GUI tester for this yet, so I'm adding one here.

All formula image links start with the address

http://chart.apis.google.com/chart?cht=tx&chl=

The code that follows the link describes the formula to be displayed. For example, the tester on this page loads with the quadratic formula. Documentation on the TeX codes used to create formulas can be found on Wikipedia at:

http://en.wikipedia.org/wiki/Help:Displaying_a_formula

To use the tester, place your formula tags in the text field labeled 'Formula'. Then click, 'Test Formula' to see the formula as it will be displayed. The 'Formula URL' box will contain your formula encoded into the proper web address.

Formula
Formula URL

App Engine and long Post URLs Error 414

2010-07-02T11:30:00.000-07:00

I've been working on an applciation utilizing Google's App Engine. The fist version of my application sent about 500 bytes of information along with each user POST request. The second version up this to around 100 bytes and the App Engine server started giving the error:

Requested URI too long: ... HTTP/1.1" 414 –

This is the http error returned when a post request is longer than the server is configured to accept. After a little research I found this excellent article:

http://www.openjs.com/articles/ajax_xmlhttp_using_post.php

that solved my problem. The short version of the article is:

Don’t send the post parameters as part of the url, send them using the XMLHTTP object’s send method once the object has been opened using only the address, (everything before the ?), of the original post url.

So, the original code that looked like:

var my_url = "/myhandler?longstring=" +

encodeURIComponent(longstring) +

//Now send the string to the db

if (typeof XMLHttpRequest != "undefined") {

req = new XMLHttpRequest();

} else if (window.ActiveXObject) {

req = new ActiveXObject("Microsoft.XMLHTTP");

}

req.open("POST", my_url, true);

req.onreadystatechange = my_cb;

req.send(null);

Becomes code that looks like:

var my_url = "longstring=" +

encodeURIComponent(longstring) +

//Now send the string to the db

if (typeof XMLHttpRequest != "undefined") {

req = new XMLHttpRequest();

} else if (window.ActiveXObject) {

req = new ActiveXObject("Microsoft.XMLHTTP");

}

req.open("POST", '/myhandler', true);

req.setRequestHeader("Content-type",

"application/x-www-form-urlencoded");

req.setRequestHeader("Content-length", score_params.length);

req.setRequestHeader("Connection", "close");

req.onreadystatechange = log_scores_cb;

req.send(score_params);

Notice that the call to send was changed from a null argument to the POST command arguments sent in the original URL. Also notice that the length of the parameters was sent to the server ahead of time in the 'Content-length' header.

General and Extra Class Free Practice Exam Gadgets

2010-06-13T11:04:00.000-07:00

The Copasetic Flow Amateur Radio General and Extra Class Practice Exams are now available as an embeddable Google gadgeta! The gadgeta shown below can be placed on your igoogle homepage, or any other web page to provide your readers with a quick practice exam. The exam gadget also works great on your igoogle page on your iPhone!

You can install these gadgets on your own iGoogle home page, or on any web page by using these links General Class and Extra Class.

Technician Class Practice Test Gadget

2010-06-10T12:54:00.000-07:00

The Copasetic Flow Amateur Radio Technician Class Practice Exam is now available as an embeddable Google gadget! The gadget shown below can be placed on your igoogle homepage, or any other web page to provide your readers with a quick practice exam. The exam gadget also works great on your igoogle page on your iPhone! The general and extra class exams will be ported into gadgets soon.

You can install this gadget on your own iGoogle home page, or on any web page by using the installer from Google.

Cool 12 Second Math Tricks: Odd Areas

2009-03-31T21:34:00.000-07:00

This one kinda speaks for itself:

Cool 12second Math Tricks: Odd Areas on 12seconds.tv

Where's 12?

2009-03-29T16:01:00.001-07:00

A map view of 12seconds.tv!

Add it to you web page! Get the code here on the Google site.

12seconds clips mapped! on 12seconds.tv

Where's 12 followup on 12seconds.tv

Introducing Cool 12 Second Math Tricks: Logging Up

2009-03-28T06:21:00.000-07:00

A big part of making math problems easier is recognizing simplification patterns.
Hence, Cool 12 Second Math Tricks! More detailed steps follow each video

Cool 12second Math Tricks: Logging up on 12seconds.tv

Details
1. The first expression is the derivative of a logarithm. It's just a matter of seeing it.
2. Remember the chain rule vernocular: "The derivative of the whole thing is equal to the derivative of the outside times the derivative of the inside". You can read every little detail here at Wikipedia.

WebQSL: KE0A de KD0FNR

2009-03-23T08:51:00.000-07:00

KE0A de KD0FNR
Radio	Rockmite
UTC	22:30
RST	559
Frequency	14060 kHz
Mode	CW
Power	0.5 Watts
QTH	Five Points Vista, Lincoln National Forest
Distance	1159 miles

QTH Pictures

QTH Map

View Larger Map

Coil Levitation with Eddy Currents

2009-03-11T22:07:00.000-07:00

I tried out a little quickie experiment in the lab this afternoon. In short: a coil with a changing current, (AC), placed on a non-ferromagnetic conductor, like aluminum, will induce an opposing magnetic field and levitate. You can read all about the effect caused by eddy currents, on Wikipedia, and watch what happened in the lab here:

Cool Math Tricks: Deriving the Divergence, (Del or Nabla) into New (Cylindrical) Coordinate Systems

2009-03-01T15:34:00.000-08:00

The following is a pretty lengthy procedure, but converting the divergence, (nabla, del) operator between coordinate systems comes up pretty often. While there are tables for converting between common coordinate systems, there seem to be fewer explanations of the procedure for deriving the conversion, so here goes!

What do we actually want?

To convert the Cartesian nabla

to the nabla for another coordinate system, say… cylindrical coordinates.

What we’ll need:

1. The Cartesian Nabla:

2. A set of equations relating the Cartesian coordinates to cylindrical coordinates:

3. A set of equations relating the Cartesian basis vectors to the basis vectors of the new coordinate system:

How to do it:

Use the chain rule for differentiation to convert the derivatives with respect to the Cartesian variables to derivatives with respect to the cylindrical variables.

The chain rule can be used to convert a differential operator in terms of one variable into a series of differential operators in terms of other variables that the first variable depends on. This is exactly what we need because we want to start out with a differential operator in terms of x,

in our Cartesian to cylindrical example and convert it to differential operators in terms of the cylindrical variables, . For x, the chain rule gives us:

NOTE: More generally, if you’re given a differential operator in terms of a variable, u, that can be expressed in terms of n other variables, v, then to convert the differential operator in terms of u to differential operators in terms of the v’s the chain rule gives:

This is explained very nicely and in more detail here and here.

OK, so let’s get to work converting the three differential operators of the Cartesian nabla into differential operators in terms of cylindrical coordinates. We start with x,

using,

We can construct the first differential term above as:

but, we really need to get all the x’s and y’s out of the mix and just have cylindrical coordinates remaining. So, using a few substitutions we get:

Now, follow the same procedure for the next differential term in the chain rule.

Remember though that r depends on x and y, so when we differentiate, we need to expand r and use the simple one-variable chain rule. Using a table of derivates for the arccosine, we get:

The final derivative is taken using the quotient rule:

We already know from our work above that

so

Now, we start the lengthy process of simplifying:

Because z is the same z as in the Cartesian system, it doesn’t depend on x, (exactly as in the Cartesian system), so we have

and our complete conversion for the x derivative term is:

Now use the same techniques to convert the differential for y:

Starting in a similar manner:

Then, evaluating the second term of the chain rule we get:

Remember again that r depends on x and y, so when we differentiate, we need to expand r and use the one variable chain rule.

The final derivative is taken using the quotient rule:

We already know from our work above that

so

Now, we simplify again:

So,

Finally, since z is not transformed between coordinate systems:

Now that we have each differential converted, we can write the nabla operator as

Which is kind of a mess! We know that when we’re finished we expect to see nicely grouped cylindrical differential terms with cylindrical unit vectors, so let’s group on the cylindrical differentials

Now remembering our original definition of cylindrical unit vectors,

We can make two more substitutions and arrive at the final result for nabla in cylindrical coordinates!

Moving Walls and Maximizing Microstates: It's Obvious. Not!

2009-02-22T13:00:00.000-08:00

This installment of “It’s Obvious. Not!” looks at:

Book: “Statistical Mechanics”

Edition: second

Authors: R.K. Pathria

Publisher: Elsevier Butterworth Heinemann

Page: 14

Section 1.3 follows the derivation laid out in 1.2, but with a variable volume to arrive at:

As in 1.2, a parameter is defined that must be equalized:

The above subscript notation indicates that N and E are held constant and that V is equal to its equilibrium value.

The basic formula of thermodynamics is then stated as:

Immediately after which, it is stated that:

But how?

First, remembering that N and E are constant, rewrite the basic formula above as:

Now, using the expression from section 1.2 relating the micro and macro states:

We can write:

However,

so,

Copasetic Flow

Agnew Hunter Bahnson's Namesake

Tesla's Wardenclyffe Lab Special Event Stations!

Alpha Decay as Quantum Tunneling

Luna Moth on Long Island

Boulder in Scarecrow and Mrs. King!

It's Obvious... Not: Knowing When not to do the Math

More on the Jeri Ellsworth SDR Videos

Satellite Tracking adds Bearings

Geometry, Trigonometry, and Amateur Satellites

Amateur Satellite Tracking Part III

Satellite Tracking: Initial Succeess

Getting Started with Amateur Satellites and Satellite Mapping

Hiam Percy Maxim's Dad in Mecanno Magazine

Help Index for Ham Radio Practice Exams at Copasetic Flows

Subelement Progress Reports

Subelement Study Focus Added to Practice Exams

Dr. H.T. Barnes of Mecanno Magazine Fame

General Class Practice Exam Gadget Update to New Question Pool

Lecture 24 of MIT Freshman EM

Mecanno Magazine Archive

SDR Construction Notes from Jeri Ellsworth

Television Inventor Worked on Fusion

Scoring fixes to embeddable free ham radio practice tests

Extra Class Rectangular Impedance Video Help... by Pirates

Study the Correct General Pool

SWR explained by AT&T

Inventor of the crystal set worked on global warming... prior to 1902

Google App Engine and Windows 7 Snipping Tool Incompatability

Help Topic on RLC resonance added and congrats to KK4CDL 98% on extra exam!

New Help Topic and a Few Bug Fixes on the Free FCC Ham Radio License Practice Exams

Tesla's Wardenclyffe Lab Restoration Featured in RASL 10

FCC Commercial Operator License Element 5 Free Practice Exam

The Flying Rockmite on Dashtoons!

FCC Commercial Operator License Element 3 Free Practice Exam

FCC GROL Element 1 Free Pracitce Exam

New General Question Pool Available!

Four New Cosponsors for HR 607

iHAB-2 Launch Video

First Flying Rockmite QSO!

New Goslings!

Extra Class Exam Video Help Begins!

Foggy Beach Walk and some Waves

MIT Thermo... Studying for Quals... Notes and Video

iHAB-4 Launches This Morning!

Biot Savart Notes

MIT Freshman EM... Magnetism ... Studying for Quals

SSB Internet Reader: History

Studying the Tenna Dipper Deluxe

Another Five Representatives Cosponsor HR 607, NY, PA, AK, GA, and IA

SSB Internet Reader: Technology

First Tran-Atlantic SSB Transmission Made in Rocky Point, NY

Dash! The Dog Faced Ham at MOCCA 2011

Spring Turkeys

Higgins: Amateur Radio Operator!

HR 607: Two New Cosponsors Sign On (Minnesota and North Carolina)

Nice Note on the Ham Radio Practice Tests and Congrats to KD8GEH

Groups and Their Graphs: Clarifications of Normal Subgroup Theorem and Test for Normal Subgroup Elements

Easy HR607 Letter Creation

HR607 in the news

Amateur Radio and HR 607

Beach Hinges: What are They?

Notes on Emmy Noether and Group Theory

Emmy Noether and Women's History Month

New Mexico Sunset

6th and 7th Grade Math Champs Build Ham Radios... You Can Help!

Groups Made Easy: Group Definition

Around the Lab: Diamagnetic Levitation and the levitating pan

Superconductor Meissner Effect Levitation

Groups Made Easy

Understanding Spherical Gradients

Understanding Cylindrical Gradients

Foundation for Amateur Radio Scholarships

Anyone else remember self-healing GaAs transistors?

Share QSO Maps!

Adding Google Friend Connect: Scriptaculous collision

Ham Radio Exams now have Google Sign-in

Physics Tour of New York

Add a mapping ham radio log book to your web page

Crystal Oscillator Design: Parallel and Series