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Morse Code: A Brief History
radio : by Tommy - October 18th 2010, 10:12PM
radio
Most people know the important life-saving phrase Di-di-dit da-da-dah di-di-dit (SOS), but that's about it when it comes to Morse Code. Many people know that Morse Code was named after its inventor, Samuel Morse but not much more. Fewer people know that the use of Morse Code still persists (unless, of course, you know someone that uses it on a semi-regular basis!).

Morse Code is the oldest form of telecommunication still in use. It got its start when the legendary Samuel F. B. Morse, an artist by trade, began to experiment with methods to communicate via the relatively new field of electricity. Morse's system of communication was not the first form of telegraphy, nor was his invention the only electric telegraph. But he did invent a language of dits and dahs that, by way of a few revisions, remains in use to this day. (The history of the telegraph, interesting in its own right, is beyond the scope of this outline.)

Ham radio operators are perhaps the most notorious users of this antiquated form of communication, but not the only users. Navy signalmen use Morse Code when manning the Signal Lamp and aviators make use of the Code as a way of identifying directional beacons.

Morse Code has undergone few revisions since its inception. Morse's original code was a bit cumbersome, but the idea was there and several letters have remained unchanged. Morse originally planned the letters to leave imprints on a printed tape, but over time the code was learned by operators and the incoming signal was able to be decoded by ear rather than on paper. In order to speed up transmission, Morse gave the most frequently used letters the shortest signals. (E gets a single ‘dit’ and T gets a single ‘dah’) Identifying the most frequently used letters, Morse counted letters in a copy of the newspaper.

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tags: morse code ham radio cw

( Comments : 2 | Full article )

 
mod_rewrite: URL modification
programming : by Corey - October 2nd 2010, 07:22AM
programming
To say that there is extensive documentation on Apache and its various plugins, including mod_rewrite, is to grossly understate the term. Documentation is voluminous to the point of beginning to wonder if the various authors had a combined total of more than five dates with actual girls in the history of their lives.

Disgruntled, then, was I to discover that on the entirety of the Internet, there was no documentation surrounding what I needed to accomplish. I've since come to realize that this is likely due to the obscurity of the issue or the availability of other commonly known tools to accomplish the task I had before me.

That task: Rewriting and redirecting a URL from my local environment using Apache and mod_rewrite.

Without delving into specifics, I needed to take an HTTP request generated by a page viewed in my browser and direct that request to another location, including a change of domain.

Now, the more seasoned among you may resolve that the very purpose of mod_alias is to perform this task. However, just because I'm a glutton for punishment, in this particular case, I also need to change the value of a query string parameter in the URL having its domain changed. Gaze upon the domain of mod_rewrite, ye mighty, and despair.

While mod_alias is designed to handle the translation of domains, mod_rewrite is designed to handle that and query string parameters (as well as a bunch of other stuff that I have no idea about). Before we can start directing URLs to and fro, we must first setup Apache.

I'll not regale the reader with the riveting tale of that process as it is rather well (and usefully) documented. The mod_rewrite module must be included in httpd.conf and the Apache instance must be configured to run as 127.0.0.1 on port 80. Do be wary of configuring the server value as localhost because sometimes the value does not translate, especially in Windows.

Continue reading...

tags: Apache mod_rewrite URL modification redirection cake pie howto

( Comments : 1 | Full article )

 
Continue Reading...
neodux : by Tommy - August 15th 2010, 11:00PM
neodux
After the success of the DUX Yagi-Uda post and it finding its way to Hack-A-Day, I decided I should probably go in to more detail with each blog entry when I'm attempting to explain something technical.

In the past, I've tried be as succinct and just-the-fact-ma'am as I can so the article doesn't make the main page a mile long. I always assumed if you wanted to know more you could just ask me. But, more often than not, I ended up with an article that I think was too shallow or too "in-passing". So, for the sake of those that don't know me personally and would like more information, and in keeping with the spirit of information exchange on the web, I think it's best if I link to and explain all relevant information. To keep the main page short I've decided to limit the amount of words in a story that gets shown at a glance.
I've broken up the links to have the "Continue reading..." link on each article if it is longer than a preset length.

I'd really like to know what my core users think of this change. Is it for the better? Should I change the wording of the link? Should I display all information, longer or shorter at-a-glance summaries? You tell me.

tags: neodux blog

( Comments : 2 | Full article )

 
DUX Homebrew Arrow Yagi
radio : by Tommy - August 7th 2010, 11:36PM
radio
This summer I attended the TI-2 Space workshop put on by the ARRL and DARA in Dayton, OH. We spent 4 days learning how to make contacts with orbiting satellites like AO-27, AO-51 and the International Space Station, just to name a few. The antenna we used was the dual-band Arrow II Antenna. I've owned one for years and really like it. I wish more people had them, but I think most people think spending $140 for an antenna that can only handle 10W is a bit much.

My aim was to make a cheap alternative to the Arrow that is easy to break down for transport and storage. I really like the idea of using aluminum arrow shafts for elements; they are lightweight, straight, weather resistant, and fairly inexpensive. Another nice feature is the #8-32 threaded insert for broad heads that almost every arrow comes with.

I spent a couple of hours reviewing all the "cheap" and "ugly" yagi designs, as well as others like the "tape measure" and even a new-to-me "backpacker" design. They each have their own advantages and loyal followers.

I finally based my antenna design on one found in the ARRL Handbook from 1999. While not an exact replica, my design is very similar. I had decided to go with the through-boom design like the Arrow, as opposed to side-mounted because it is, in my opinion, cheaper. After buying 6 arrows and a quick trip to Lowe's I had a length of #8-32 all-thread and a piece of 3/4" conduit to use as the boom. I marked a straight line down the center of the boom to give me a point of reference, measured out the spacing holes, made sure I was drilling square and level and got to work.

Continue reading...

tags: yagi radio antenna ham_radio

( Comments : 0 | Full article )

 
Kindle isn't kind anymore
books : by Tommy - June 3rd 2010, 11:29PM
books
I don't "get" the Kindle anymore. It's been almost 6 month since I got it, almost a dozen books later and I think I'm at the end of the road with this neat little device.
At first, I liked the idea of having free 3G internet available. Then low price point of books made it great for buying books without having to wait for the local bookstore to order them, or worse, paying the retail markup.

A couple months ago, Engadget broke this story which I just saw in the NYTimes: Target will begin selling the Kindle 2 in stores nationwide beginning on Sunday, June 6.

Funny, I was just at my local Target earlier this evening and found a book I've been wanting to read. I had read through the first chapter on my Kindle as a "sample", but never went beyond that. I checked the latest Kindle edition price... $12.99. Target's price for the book? $12.80!
Why would I want to buy the Kindle edition that I can't sell or share?!

To add insult to injury, I checked the same paperback on Amazon: $9.99. Amazon is selling the paperback for less than the electronic version! Now, they're going to sell the Kindle at Target in a matter of days and the electronic version of the book costs even more than the same book in the store!

I think the Kindle's business model is falling apart (and has been). I believe the Kindle is headed for the same fate as the other innovative e-ink device: The OLPC (XO) laptop. Both situations are sad, because each had so much potential. Neither will grow beyond a neat concept without completely reinventing itself (which the OLPC seems to be doing with its tablet).

Amazon has been too slow to act on customer ideas, lacked any sort of customization, and failed to cash in on an exploding community of Kindle owners.

Continue reading...

tags: kindle books amazon

( Comments : 2 | Full article )

 
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