THE SPARK GAP

A monthly publication of the Meridian Amateur Radio Club March 2018

 

 Bible Verse

Psalms 46:1-11 / God is our refuge and strength, an ever-present help in trouble. Therefore we will not fear, though the earth give way and the mountains fall into the heart of the sea, though its waters roar and foam and the mountains quake with their surging. There is a river whose streams make glad the city of God, the holy place where the Most High dwells. God is within her, she will not fall; God will help her at break of day. Nations are in uproar, kingdoms fall; he lifts his voice, the earth melts.

The Lord Almighty is with us; the God of Jacob is our fortress. Come and see what the Lord has done, the desolations he has brought on the earth. He makes wars cease to the ends of the earth. He breaks the bow and shatters the spear; he burns the shields with fire. He says, “Be still, and know that I am God; I will be exalted among the nations, I will be exalted in the earth.” The Lord Almighty is with us; the God of Jacob is our fortress. NIV

 

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President's Report

Hello all,

As I come to you this month before the March meeting. I would like to say that February has been a month of ups and downs for sure. As we look at the good, our community has had two birthdays. Gary White KF5MWE and Steve Blackwell K5DAD, Happy birthday to you both.

With a heavy heart I mention that we have another silent key, Thomas Bolivar (Buddy) Crane WD5DX, formally KB5LYU. Buddy was in Amateur Radio for many years before I received my license. He was a member of REACT back in the early days and helped with many things throughout the area. As I think back, Buddy was with my dad and me at the Birmingham Hamfest years ago when I bought my first radio, an Icom W32a. I have many memories of him from back in the day. He is survived by his wife and children, and if I'm not mistaken one of his kids has an amateur radio license as well and maybe the other one will get theirs soon.

I know at the last meeting we had tried to finalize the field day site. We'll our plans have changed due to the State Games Group taking the entire Bonita Lakes. We did manage to get a last minute place to operate, LEMA will let us use their facility. I don't know about you but I have to say they came to the rescue just at the right moment.

Please join me at the meeting on Saturday March 3rd at the Checkerboard 10am.

73's Charles Grisham KB5SZJ

 

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Next MARC Business Meeting

The next business meeting will be held at the Checker Board Restaurant on Saturday, March 3rd beginning at 10 A.M. Come join us for breakfast, coffee and fellowship.

 

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ARRL Alabama Section Convention

Birmingham Ham Fest

http://birminghamfest.org/

 

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Northeast Louisiana Hamfest

Mark your calendar! The Northeast Louisiana Hamfest in Monroe, Louisiana, is coming up on April 21, 2018. We will once again be at the West Monroe Convention Center.

Go to http://nelarc.org/hamfest.html for more information.

Thanks and 73, NorthEast Louisiana Amateur Radio Club http://nelarc.org

 

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HAMS EATING CHICKEN

If you have not visited the web site "HAMSEATINGCHICKEN.COM" lately you probably will be surprised at all the great information posted there. One thing I wanted to make everyone is aware of is a post there about 2018 Skywarn classes available online. All times, access and other information is included. Look around and you will more than likely find something of interest.

73' John Buckley K5DDT

 

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Which way does current really flow?
By Dan Romanchik, KB6NU

I was recently taken to task by one of my blog readers regarding my description of current flow in my No Nonsense Technician Class License Study Guide. He wrote:

"You casually say that current flows from Positive to Negative (with cool accompanying directional arrows), without any accompanying qualifying statement. Over the years I have looked at ALL the views on the subject. Positive to Negative is NOT what I was taught 48 years ago, and I have never seen a good reason to change my view."

Current Flow

In a subsequent email, he pointed me to a Nuts ‘n Volts article, “Which Way Does Current Really Flow?” (http://www.nutsvolts.com/magazine/article/which-way-does-current-really-flow) and asked my opinion. In the article, the author, who is a ham by the way, does a good job of explaining the various types of current flow.

I agree that in electronic circuits electrons flow from negative to positive, but it really doesn’t matter. I agree with one the article's commenters who says,

"This is a silly argument. It’s like comparing apples and oranges and challenging people to take sides.

"Electron flow is not current flow. Electron flow is easy to understand, an actual physical property, and a real help in understanding vacuum tube operation. But it falls apart when one needs to understand complex electronic systems.

"[Conventional] current flow is a mathematical abstraction. It is defined as a net flow of positive charge, irrespective of the polarity of the physical charge carriers — whether electrons, holes, positive or negative ions, or whatever.

"When looking at any circuit containing a resistance with a voltage across it, conventional current through that resistor says that the voltage drop occurs as the current through it meets resistance. On the other hand, in negative (electron) flow, a voltage INCREASE will correspond to the ‘current’ flow through it, clearly violating physical laws. Conventional current flow is consistent with the laws of physics and those of other engineering disciplines.

"You are correct that engineers, professors and scientists use conventional current flow. That is not because they are too obtuse to understand electron flow; I assure you they fully understand it. It is because in their world they have to solve more general problems involving complex math and science, and, again, conventional current flow is consistent with physical laws.

"It is unfortunate that electron flow and current flow are so often confused. They both have their place."

After reading that article, I thought I’d see what the ARRL Handbook has to say about current. In the 1963 edition, they don’t mention electron flow at all. They have one diagram showing the direction of current flow in both series and parallel circuits, but the voltage source has no polarity. It’s simply labeled “Source of E. M. F.” Diagrams giving practical examples of series and parallel circuits do include a battery, and if the reader were to mash up the two diagrams, they would conclude that current flows from the positive terminal to the negative terminal.

The most recent edition of the Handbook that I have is the 2005 edition (it might be time to get another copy!). It says,

"Electrons move from the negative to the positive side of the voltage, or EMF, source. Conventional current has the opposite direction, from positive to negative. This comes from an arbitrary decision made by Benjamin Franklin in the 18th century. The conventional current direction is important in establishing the proper polarity sign for many electronics calculations. Conventional current is used in much of the technical literature. The arrows in schematic symbols point in the direction of conventional current, for example."

Having said all that, I really don’t see that there’s much of a controversy here. I did learn to think of current as conventional current in college, although it was mentioned that electrons actually flow in the opposite direction. Using the concept of conventional current has never seemed to hold me back. I’ve been able to design circuits and repair electronic equipment thinking that current flows from positive to negative.

Although it's a departure from my “no nonsense” style, I am thinking of including a sidebar, similar to the paragraph above from the 2005 Handbook explaining the two ways of looking at current flow. What do you think?

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When he's not trying to figure out which way current flows, Dan blogs about amateur radio at KB6NU. Com, teaches ham radio classes, and operates CW on the HF bands. Look for him on 30m, 40m, and 80m. You can email him at cwgeek@kb6nu.com.

 

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Quote of the Day

A cloudy day is no match for a sunny disposition. William Arthur Ward

 

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Have a great month

 

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