From my Twitter feed: X-Band, QRP, Handi-Ham podcast

January 2, 2013 by Leave a Comment

moleculo
Here, try this one:http://t.co/Fq6MAXg1 that I did with Gordon West this summer

I would like to fool around with 10 GHz some day.

w7dtg
Affordable radio – a full QSK CW transceiver with built in keyer for $40 !http://t.co/RScQZyPr #hamr #qrp

The PigRig is just the things for the Flying Pigs of ham radio!

yv5venet
Handiham World Weekly E-Letter for the week of Wednesday, 02 January 2013: Courage Center Handiham World Weekly …http://t.co/rNz0fNG0

Handi-Hams does a great thing for hams with disabilities.

Filed Under: Kits, Microwave

Save 75% on MAKE: e-books

December 27, 2012 by Leave a Comment

Just got this offer from MAKE: and thought you all might like to know about it. I’m thinking of purchasing Getting Started with Raspberry Pi. They also have a primer on how to make your own PCBs. That should only cost 75 cents with 75% off…….Dan

Thanks for a Great Year!

To celebrate the end of 2012, we’re offering our newsletter subscribers 75% off every PDF in our e-book category. They’re all on sale – from the brand-new Getting Started with Raspberry Pi to MAKE’s Ultimate Guide to 3D Printing, from the Arduino Cookbook to Make: Electronics. It’s time to stock up! Just add any (or all!) of the PDFs in our e-book category to your cart and enter coupon code PDF75. Sale ends when our year does — at midnight PST Dec 31, 2012.

Filed Under: Building/Homebrew

Wire and cable throughout the ages

December 20, 2012 by Leave a Comment

The German Wire Museum (Deutsches Drahtmuseum) in Altena is all about wire and cable—from its use in chainmail in the Middle Ages through superconductors today. Just reading the story about the museum is a real eye-opener. As hams, we tend to think of wire and cable as electronic components, but wire has been used down through the centuries in jewelry, in pianos, in bridges, and many other applications. Interesting stuff.

Filed Under: Electronic Components Tagged With: ,

From my Twitter feed: QRP rigs, logging program, SW digital text

December 16, 2012 by Leave a Comment

DTL
@Stefano_NVR Have you seen G3XBM’s simple transceivers? https://t.co/egG5MtYKcan mod to be on other band than 10m.

These really do look like fun little projects.  The G3BXM website has lot of other cool stuff, including a one-transistor regen receiver project and reviews of the QRP gear that G3BXM uses.

 

OY3JE
Check out DX Logger, looks to be an excellent logbook for portable use etc.http://t.co/fQDPKOWn #hamr #dx

A friend and I had talked about doing something like this several years ago. Kudos to the DXLogger people for actually doing it!

 

More shortwave digital text (and the reason behind it) http://t.co/M50ed1tO
Interesting idea. I guess if amateur radio operators can use digital modes, why shouldn’t broadcasters? I’m still wondering exactly what they’d send, though.
Filed Under: Building/Homebrew, QRP, Software

Circuit prototyping tip

November 27, 2012 by 2 Comments

I found this in my inbox this morning. It’s from the Make: newsletter.

Prototyping on florist foamFoam is Your Friend

When prototyping perfboard layouts, long component leads can be a pain, sticking out on the underside of the board. I don’t want to cut them off yet, because I might need long leads. Solution? Green florist foam. The leads stick into the foam, which holds them securely enough that you can turn the board over and nothing will fall out. But they’re also easy to pull out and rearrange as needed. [Sean Ragan]

Filed Under: Building/Homebrew

On the Internet – 11/26/12

November 26, 2012 by 1 Comment

WITCHWITCH gets a reboot. The world’s oldest digital computer was brought back to life by engineers at The National Museum of Computing in Buckinghamshire, England. The computer was first turned on in 1951 and uses 480 relays and 828 vacuum tubes called Dekatrons, which store ten discreet values. EETimes also ran a story on this computer.

First Visible LED Demoed 50 Years Ago. Since we’re doing history today, here’s a link to a Wired article marking the first demonstration of an LED that emitted visible light. The article notes, “In the February 1963 issue of Reader’s Digest, Holonyak predicted that the LED would eventually replace incandescent bulbs. Bold words from a man who worked for GE, a company founded by Thomas Edison.” We’re finally getting around to this 50 years later.

How to Listen to Real Spy Broadcasts Now. Lifehacker shows you how to dial in to numbers stations and the like. The article says, “The behavior of shortwave radio in the atmosphere makes it ideal for long range radio transmission. You can send messages on a given frequency all over the world, and most people who use shortwave radio use it to communicate with ships at sea and people in locations all over the world.”

Filed Under: Computers, Electronic Components, SWLing

KB6NU finally builds an end-fed, half-wave antenna

November 13, 2012 by 13 Comments

I’ve posted about end-fed, half-wave antennas before, but until this weekend, I’d never built one. One of the reasons for this is that most designs are for QRP antennas and not made to handle more than 5 – 10 W of power.

A couple of months ago, I ran across a design rated at 100 W. The design seemed relatively simple to build, requiring only a single toroid and a capacitor made with a short length of RG-174 coax. Well, it just so happens that I bought 100-ft. of RG-174 at Dayton this year, and I found the toroid cores online from the  “Toroid King” for a very reasonable price, so I decided to make my own.

All told, the parts cost about $10, the biggest part of that the plastic junction box I got from Lowe’s for $6.41. Compare that with the $60 that LNR wants for their end-fed antenna.

Sunday was a beautiful day here with temperatures in the 60s, so I decided to put up the antenna. I’d love to report that everything worked perfectly, but this antenna is going to need a little more work. The SWR is 2.6:1 at 14.000 MHz, dropping to about 1.5:1 at 14.900 MHz.

Since the internal tuner on my IC-746PRO is supposed to be good to 3:1, I did use it and made a couple of contacts. The guy in MA even gave me a 599 signal report. I’d be a little more comfortable about using it, however, if I could get the SWR down a bit.

I e-mailed the guy who published the design and asked why he thought the resonant frequency was so high, and he said that all I had to do was add a couple feet of wire to the antenna. He also suggested that adding a turn or two to the coil would bring the SWR down. I did some more reading about end-feds and I’m thinking that perhaps adding a short counterpoise might be something to try, too.

So, while the results so far have been mixed, I’m hopeful that with a little tweaking, I’ll have another antenna to add to my arsenal. It’s been a good learning experience, and I’ve certainly saved a bunch of money over the commercial versions.

UPDATE 11/18/12:
I added 24-in. to the antenna  and it did indeed bring down the SWR of the antenna to below 2:1 in the CW portion of 20m.  I’m happier with this. I still do plan to try a counterpoise. Not so much to improve the SWR, but to see if it makes the antenna a little more efficient.

The box I used for this project is the Carlon E989NNJ, a 4-in. x 4-in. x 2-in. plastic junction box.  This is a very nice box. Not only is it completely enclosed. The screw down cover is gasketed, making it waterproof.

I liked the box so much, I went back to Lowe’s to get a couple more. Not only were they out of stock, when I searched their website for that part number, it came up with no results. It kind of looks to me as though they’re not planning to stack this box anymore.

I Googled the part number and found several places online that had them, but they wanted more money, plus I would have to pay shipping. Fortunately, I was able to find some at a local Home Depot. They wanted $6.88, compared to $6.41 at Lowe’s, but at least I was able to purchase a couple more of them.

Filed Under: antennas, Building/Homebrew Tagged With: , ,

Book tells you not only how to use components, but what can go wrong when you do

November 11, 2012 by 3 Comments

Encyclopedia of Electronic Components – Volume 1
By Charles Platt
O’Reilly Media, 2012, 278 pages.

The Encyclopedia of Electronic Components is the latest from Make: magazine, part of the O’Reilly empire. Like all of their publications, this book is well-written, well-illustrated, and if you’re just getting started in amateur radio or electronics, it would make a great addition to your library.

The nice thing about this book is that it not only talks about what a component does and show you the schematic symbol for a particular type of component, it also talks about typical applications for a component and what can go wrong with that type of component. Let’s compare how the 2005 ARRL Handbook (the latest version that I have) discusses resistors  with how The Encyclopedia covers resistors.

The 2005 Handbook devotes about a page and a half total to resistors, including:

  • four paragraphs on the fundamentals of resistance in the chapter Electric Fundamentals,
  • twelve paragraphs on different resistor types in the chapter  Real World Component Characteristics, and
  • a half page on resistor markings in the chapter Component Data and References.

It’s also very chintzy with illustrations. I only count one chart and one drawing.

The Encyclopedia, on the other hand, devotes an entire chapter to resistors, with 17 illustrations and two charts. The chapter not only covers theory, but also discusses practical applications, including how they’re used to limit current, bias a transistor, and pull up or pull down voltages in a digital logic circuit.

I also love the “What Can Go Wrong” section. This section describes how resistors can overheat, introduce noise into a circuit, and how tolerances can affect circuit operation. The book takes this approach to discussing a wide variety of electronic components, including batteries, switches, relays, encoders, capacitors, motors, and semiconductor devices, so no matter what kind of electronics you’re hacking, this book has some good info for you.

Filed Under: Building/Homebrew, Electronic Components

Interesting tidbits from the Internet – Homemade tools, more kits, a CMOS replacement

October 20, 2012 by Leave a Comment

This set of links include a website for homemade tools, another source of kits, and a report on an electronic technology to replace CMOS.

Manual pick-and-place station

This manual pick-and-place station is one of many that you’ll find on HomemadeTools.Net that are useful for amateur radio operators.

Home-made tools. This is a new site from the founder of Hotrodders.com, established to organize all of the homemade tools posted on forums and websites around the net. The site currently has nearly 3,000 different homemade tools, with new tools added regularly. Be sure to check out the electrical section, which has many tools that you can use around the ham shack. It includes a $3 battery charger, a low-cost 12 V benchtop power supply, and a manual pick-and-place station to use when building with surface-mount components.

Kits by K5BCQ, K5JHF, and the Austin QRP Club. Kees, K5BCQ; John, K5JHF; and other members of the Austin QRP Club are making available some useful kits at reasonable prices to encourage kit building and homebrewing. The kits are all based around readily available, low-cost microcontrollers, flash memory, and LCD displays. I’m thinking about buying the The Si570 Controller and Frequency Generator Kit #2. At $54 or less, I think it’s a steal.

NRI to lead new five-year effort to develop post-CMOS electronics. This article from the NIST Tech Beat describes a project to develop a next-generation electronics technology to replace the venerable CMOS technology. According to the article, new technology is needed because pretty soon IC manufacturers won’t be able to make transistors any smaller.

Filed Under: Electronic Components, Kits, Tools Tagged With:

25, 50, and 75 Years Ago in QST

October 14, 2012 by 2 Comments

QST publishes a column every month towards the back of the magazine that highlights from issues 25, 50, and 75 years ago. Now that the QST archive is online, it’s really worth taking a look at these articles. Here are a few that were interesting to me this month:

  • October 1937
    • Modernizing the Simple Regenerative Receiver by Vernon Chambers, W1JEQ. This a nicely-designed and built regen using two tubes, a 6K5 pentode and 6C5 triode. I’m going to keep this design in mind if I ever get around to playing with all the tubes I have. As an aside, W1JEQ wrote 87 articles for QST from 1936 through February 1958. This was his third article.
    • Concentrated Directional Antennas for Transmission and Reception by John L. Reinartz, W1QP, and Burton T. Simpson, W8CPC. This article describes two different antennas. The first is a  half-wave loop antenna that the author says works on 2-1/2, 5, 10, and 20m. The second is a square loop antenna called a “signal squirter” for 14 Mc.
  • October 1962
    • In the “New Apparatus” item on page 27, a key made by J. A. Hills, W8FYO, of Dayton, OH is shown under the heading, “New Key Mechanism for Electronic Keyers.” The photo clearly shows a key whose design was adopted by whoever designed the Bencher BY-1 paddle.
    • The Towering Problem by Jay Kay Klein, WA2LII clearly shows that putting up towers have always been a problem for amateur radio operators. This is a humorous take on the problem. What’s notable is that this type of humorous article almost never appears in QST anymore. Amateur radio seems to have lost its sense of humor.
  • October 1987
    • Stalking Those Fugitive Components by Doug DeMaw, W1FB. We often complain about the demise of local parts suppliers, but this article shows that this was a problem 25 years ago as well. W1FB gives some advice that I gave not long ago–stock up on parts, especially when you find a good deal on them, and you won’t have to scrounge around for them when you want them.
Filed Under: antennas, Building/Homebrew, CW, Receivers
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