Things I found while twittering

February 6, 2012 By Leave a Comment

Just some things I found while twittering. I found them interesting, so I thought you might, too…….Dan

Tworse Key:  a tweeting Morse key. An open design exercise in interface archaeology, that decodes the input from a classic Morse key to send twitter messages. The source code and hardware schematics are available online http://modin.yuri.at/tworsekey/

Design analog chips. According to the website, this freely downloadable book is “a comprehensive introduction to CMOS and bipolar analog IC design. The book presumes no prior knowledge of linear design, making it comprehensible to engineers with a non-analog background. The emphasis is on practical design, covering the entire field with hundreds of examples to explain the choices. Concepts are presented following the history of their discovery.”

DashToons.Com. Jeff, K1Nss presents the illustrated adventures of Dash!, the dog-faced ham.

 

Filed Under: CW, Electronics Theory, Everything Else

From the Twittersphere

January 14, 2012 By Leave a Comment

The Twittersphere is kind of like the ionosphere. It helps you make contact with other hams and brings you news from far and wide. Here are a few interesting links that I found on Twitter in the last day or so:

Global Pirate HF Weekend 14-15.1.2012.  This station lists pirate SW radio stations that it expects to be on the air this weekend. They include one using the callsign WEMP. Look for it between 15.005 – 15.095 MHz. They’ll be broadcasting with 100 W to Europe: 12.00 – 16.00 UTC – (check 15.010 or 15.040 or 15.090 MHz).

The Evil Mad Scientist Laboratories Zener Diode Tutorial. Confused about zener diodes and how they work? Read this.

Monitor your Ham Radio transmitter with an oscilloscope. In this video, Alan, W2AEW builds a little adapter that lets you connect your transmitter output to a scope input so that you can see how clean its output is.

Filed Under: Electronic Components, SWLing, Test Equipment

Ham Radio Finally Jumps on the Maker Bandwagon

January 12, 2012 By 6 Comments

Over three years ago, I wrote that ham radio should do more to associate itself with the Maker movement. Well, it finally looks like it is going to do just that.

Just before the first of the year, the ARRL unveiled its DIY campaign. It mostly consists of the video below, but there’s also a flier designed to be a hand-out to go along with the video. A PowerPoint presentation and speaker’s notes also are available, as well as ‘Ask Why I DIY with Ham Radio’ buttons.

CQ  magazine is also jumping on the bandwagon. They recently annnounced that they will run a quarterly “Maker” column, written by Matt Stultz, KB3TAN. Stultz is the founder of “HackPittsburgh,” a “hackerspace” or community workshop for makers in Pittsburgh, Pennsylvania. He has been a ham since 2009 and has integrated amateur radio into many of HackPittsburgh’s activities.

Stultz’s first column, titled “We Are Makers,” will appear in the March issue of CQ. It provides a general introduction to the maker/hacker community for hams, as well as a description of a high-altitude balloon project that brought the two groups together in Pittsburgh.

Filed Under: Building/Homebrew

Rugged Transistors, Designing Radio Systems

December 22, 2011 By Leave a Comment

Here are a couple of links to articles in electronics engineering trade magazines that I’ve run across lately that I think are of interest to amateur radio operators:

  • Some new transistors can withstand VWSRs up to 65:1.Gauging Ruggedness In RF Power Transistors. This article, written by editor Jack Browne, who is himself a ham, covers some of the new power transistors on the market. Some of them are capable of withstanding VSWRs on the output of up to 65:1!
  • The Radio Link: A Tutorial. This series of articles is a bit heavy on math for most radio amateurs, but the point of the series is to think of radio communication as a system whose behavior can be predicted. Thinking about how we use radio in this way could help us to become better radio amateurs.

And here’s something entirely out of left field. Scientists have published a paper that shows that random noise can actually make signals clearer. The process is called stochastic resonance, and while the article doesn’t explain the theory in much depths, and I’m not sure that it’s something that’s applicable to radio communication, it seems like it might be something to look into.

Filed Under: Books and Magazines, Building/Homebrew, Propagation

Easy PCB Holder

December 13, 2011 By 1 Comment

Ken, WA4MNT, posted this to several QRP mailing lists and gave me permission to post it here….Dan

WA4MNT PCB HolderAre you ready for a useful tool that you can assemble with a hammer? I came up with this after I got tired of chasing around PCBs on the bench top during construction and testing. I have one of those gimbaled pcb vises, but it takes up too much room on the bench.

This is perfect for secure holding of PCBs during soldering, prototyping, and testing. A dovetail groove prevents any slipping of the board from the fixture, with minimal clamping pressure. The jaw opening will easily accommodate and securely hold boards from 1/4-in. to 5-in., easily extended with longer rods. The jaws are fabricated from UHMW, (ultra-high-molecular- weight polyethylene), rods are Nylon. Easily replaceable elastic band for many years of service.

All the details are here for anyone wanting to build one, or there is a complete kit of machined parts ready for assembly, now available. The kit costs $23.

Filed Under: Building/Homebrew, Kits

Ham radio on the Internet – 11/29/11

November 29, 2011 By 1 Comment

Here are some cool things I found on the Net recently:

Radio tutorial – building your first station. This YouTube video tutorial by N7FTP gives some good advice on setting up your first ham shack.

Wi-Fi and the Bad Boys of Radio (review). I haven’t yet read this book, but this review certainly makes me want to do so. The book was written by Alex Hills, who played a part in the development of WiFi technology.  Alex, AL7K, got his start in radio as a ham radio operator. From there, he went on to broadcast engineering, and then to a position with Carnegie Mellon University, where he worked on WiFi technology.

Radio hams pick up Mars rover Curiosity’s signals. This story describes how some German amateurs are working with NASA to receive telemetry from the Mars Science Laboratory spacecraft, which is heading towards Mars carrying a one-ton nuclear powered robot rover named Curiosity.

Filed Under: Building/Homebrew, Gear/Gadgets, People, Satellites

Jameco offering free shipping until Dec. 16

November 16, 2011 By Leave a Comment

If you’ve been putting off a parts order for whatever reason, now might be the time to buy…from Jameco, at least. An e-mail I just received today reads:

Buy something between now and December 16, 2011, spend at least $25, and I’ll pick up the shipping on the whole order. As the holidays approach, it would be a great time to pick up a great gift or two. Just mention or enter Offer Code RED11312M.

The fine print reads:

This offer cannot be combined with any offer. Free shipping is limited to orders for stocked products that can ship by December 16, 2011. You must place an order for $25, select the “least expensive” shipping method upon check out and enter or mention your one-time offer code. Free shipping is limited to shipments within the continental US.

Do you have any projects in the works that you need parts for?

Filed Under: Building/Homebrew

Impedance Matching 101

November 4, 2011 By Leave a Comment

electronic design magazine has just started a series of articles on impedance matching. They’re being written by ed editor Louis Frenzel, who just happens to also be W5LEF.

Filed Under: antennas, Electronics Theory

Keep electronics safe from static discharge

October 20, 2011 By Leave a Comment

Electrostatic discharge, or ESD, is perhaps the biggest danger to integrated circuits, and electronics companies spend millions of dollars each year on products to reduce static buildup and discharge and to test how susceptible their ICs are to ESD. Simliarly, when building a kit, or working on electronics that are ESD-sensitive, it’s a good idea to use a conductive  mat on your work surface and a wrist strap connected to earth ground. I use both in my shack.

Texas Instruments has a number of videos on their website that will give you a better idea why this is a good idea. They’re mostly designed to sell you their ESD protection devices, but unless you’re designing electronic systems, you can mostly ignore the sales pitch.

 

Filed Under: Building/Homebrew, Electronic Components

Construction night a success

October 14, 2011 By 2 Comments

Back when I was ARROW president, I started a tradition of using one of our monthly meetings as a “construction night.” The first year we built a little keyer kit. In subsequent years, we built ladder-line J-poles, Arduino microcontrollers, and other little projects like that.

I’m happy to say that that tradition continues today. This month’s meeting, which took place on Wednesday evening, was the 2011 episode of construction night. This year, we built the Sure PS-LP11111 5~16 VDC Linear DC Voltage Power Supply Kit.

Sure PS-LP11111 5~16 VDC Linear DC Voltage Power Supply Kit

The Sure PS-LP11111 5~16 VDC Linear DC Voltage Power Supply Kit isn't a complete power supply, but the addition of a cheap AC wall wart makes it one.

This kit met all my criteria for a club construction project:

  • It was inexpensive. PartExpress sold me 15 of them for $9 each.
  • It was easy to build. As you can see from the photo above, the kit has less than 20 parts. It took me less than a half hour to build, and most of the club members had theirs put together in less than 45 minutes.
  • Those that built it have something useful that they can actually use in their shacks.  I plan to use mine to power the little QRP radio kits that I’ve built over the years. This thing should easily supply an amp at 9 V or 12 V.

As I said, this was a real success. So much so, that several of our club members said that we should do this more often. We even discussed other projects that might we might want to tackle.

One final note: Only one of our kit builders had any problem with his kit. Despite pointing out that the electrolytic capacitor, full-wave bridge, and the LED were polarized and had to be inserted properly, this fellow managed to insert his electrolytic capacitor in backwards. It worked for about two minutes before the capacitor exploded with a loud bang. We all got a big kick out of this because this fellow happened to be one of most experienced hams. :)

Filed Under: Clubs, Kits
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