Upcoming amateur radio events

KB6NU teaching the Jan. 14, 2012 One-Day Tech Class

Me making a point (apparently about SWR) at a recent One-Day Tech Class

Here are some upcoming amateur radio events here in Ann Arbor, MI:

  1. VE Testing. ARROW, the club here in Ann Arbor, conducts an amateur radio license test session ever second Saturday of the month at the Washtenaw County Red Cross, 4624 Packard Rd., Ann Arbor (map).

    Preregistration is recommended but walkins are welcome. Contact Mark Goodwin – W8FSA (734-944-0730) mrkgoodwin@comcast.net, Beverley Stoner – K8ZJU (734-424-9446), or Ralph Katz – AA8RK (734-663-1288) aa8rk@arrl.net, for more information, and to register for the test.

  2. University of Michigan Amateur Radio Club’s 100th Anniversary Special Event Station. The University of Michigan Amateur Radio Club is celebrating its 100th anniversary by operating a special event station on Sunday, April 14 on the Diag on central campus. Setup is going to start around 1300Z. We’re hoping to start operating around 1400Z and continue until around 2200Z. If you’re in or near Ann Arbor, please come down and operate with us. If not, listen for us on the bands.
  3. One-Day Tech Class, Saturday, April 27. I’ll be conducting the next one-day Tech Class on Saturday, April 27, at the Ann Arbor Hands-On Museum. Go to wa2hom.org for more details.

This makes me feel good


One of the nice things about writing my “No-Nonsense” study guides is that I get e-mail all the time from folks  who have used them to get their first license or upgrade to General or Extra. This is very gratifying to me. Yesterday, I found two in my inbox, one right after the other:

Mike writes:

Thank you for your license study guides!  I have been studying the Technician guide and took and passed the test today.

After passing the Technician test, they said I could try the General test without having to pay more, so I took it.  Somehow (luck), I passed it even though I hadn’t cracked open your General guide yet.  I’m still going to go through it, though, to make sure I know all the important stuff.

I’m starting to learn Morse code.  I think I want to mainly operate in CW.

I love it that he wants to operate CW. Austin, wrote:

This is just a short note to let you know I took the Extra exam today and passed with a perfect score. Thanks for your Study Guide.  I loaded the PDF on my Kindle and read each night for a couple weeks.  Today was the result.

Congratulations, Mike and Austin!  I hope to hear you on the bands one of these days.

Should we recruit truckers into amateur radio?

On the ARRL’s PR mailing list, there’s currently a discussion about recruiting truckers into ham radio. The fellow who started the discussion noted that he had talked to a trucker who not only was a ham, but also was actively recruiting other truckers by handing out information packets at truck stops.

There was, of course a lot of back and forth on this topic. Some thought this was a good idea. One fellow commented, “I think truckers would greatly benefit from our repeater systems, IRLP, EchoLink and D-STAR.  I also think it’s long past time to forget about our lost 11 meter band…We’ve had many exceptional ops who got their start on Part D Citizens Band.  We could get many more if we made the effort to be accommodating and patient.  The benefits outweigh the risks.”

Others worried that 2m might go the way of CB (as if it hadn’t already).

I’m all for it myself. I’m for recruiting nearly any group of people that could make good use of amateur radio. How about you?

My how we’ve grown: 100 years of amateur radio licensing

This morning, I was reminded that 2012 marks the 100th year of amateur radio licensing. In his January 2012 editorial, K1ZZ writes,

August 13 [2012] will mark another centenary: the approval of the Radio Acto of 1912 that required for the first time that radio stations be licensed. Today, we take great pride in being a federally-licensed radio service that can only be entered by examination, but at the time, it was regarded as the end of amateur radio. Enacted  two years before the founding of the ARRL, the legislation was intended to curb amateur activity not only by requiring licenses, but also placing severe restrictions on private, non-commercial stations. In the four months following its passage, just 1,185 amateur station licenses were issued in the United States, representing a fraction of the stations known to be active at the time.

Well, I just checked AHOA.org, perhaps the best source for licensing data, and as of November 7, 2012, there close to 707, 000 licensed radio amateurs in the U.S. My how we’ve grown!

Now, we just have to get these folks on the air…

Amateur radio in the news: 11/18/12

This edition of “Amateur Radio in the News” features a story on how a young ham in Ireland helped prevent an airline disaster and how electrical engineering students in New Mexico are getting licenses and using amateur radio as a basis for their senior projects.

Ham radio fan saves U.S. bacon by spotting Sandy mayday call. Amateur radio fan Benny Young, from Tyrone, was tuning in on his hut-based hobby when he heard a ‘mayday’ call from a plane over the Atlantic. But the United Airlines captain, en route from Dublin to Boston, wasn’t able to reach flight controllers in the US. Benny, 29, picked up the pilot’s distress call and managed to get it passed on to emergency services. Here are a couple more reports:

Mentor guides NMSU engineering students as they construct amateur radios. Faculty adviser Robert Hull, Professor Vojin G. Oklobdzija and mentor David Hassall, WA5DJJ, mentor these senior engineering students as they complete their senior project – getting their amateur radio licenses and building QRP rigs.

EU standardizes “hamtagonistic” power line network tech. BPL just refuses to go away. I don’t know why Europe is so keen on this technology, which has failed to gain any traction at all here in the U.S.

We need some games for amateur radio

About a month ago, I was driving early on a Saturday morning, and heard a TED talk, “Gaming can make a better world,” by a woman named Jane McGonigal. She is a game designer, and she thinks that if we can somehow harness the energy that gamers put into computer games, we can solve all kinds of world problems. Now, that may be arguable, but what isn’t arguable is that computer games can be powerful motivators.

So, what does this have to do with amateur radio? Well, I think we need some amateur radio games. These games could be used to help people learn what they need to know to get their licenses. There might also be some games that teach people how to send and receive Morse Code. Remember, games are great motivators.

I developed an amateur radio game—Tech Pursuit—several years ago. I made up some question cards that could be used with a Trivial Pursuit board and markers. I tried using this with a middle school class that I was working with at the time, but it wasn’t a huge success. For one thing, the game Trivial Pursuit isn’t really aimed at kids. Whatever the reason, I decided not to update the question cards when Tech question pool was updated two years ago.

So, what do you think? Do you think a ham radio game could get more people interested in amateur radio? Could a game motivate people to get their amateur radio licenses? Could we use games to teach amateur radio skills?

KB6NU is now a columnist for World Radio Online

Amateur LicensingYours truly is now the “Amateur Licensing” columnist for World Radio Online. My first column appears in the November 2012 issue.

Each column contains three or four related questions from each of the three tests. As you might expect, I take this material from my No-Nonsense License Study Guides. I write a little intro about why you want or need to know this stuff, and voila, there’s a column.

My first column appears on page 42 of the November 2012 issue. This month, I cover  questions about repeater operation from the Tech test, digital logic questions from the General test, and questions about the RC time constant from the Extra exam.

If you’re a WRO subscriber, take a look. I’d love to hear your feedback.

11 New Amateur Radio Operators

Last Saturday, I taught another session of my one-day Tech class. Their callsigns finally made it into the FCC database today:

  • Joe,  KD8TGZ
  • Kieran, KD8THA
  • Reginald, KD8THB
  • Richard, KD8THD
  • Curtis, KD8THE
  • Judith, KD8THF
  • Robert, KD8THG
  • Ulysses. KD8THH
  • Chris, KD8THI
  • Lizabeth, KD8THJ
  • Richard, KD8THK

Eleven out of twelve passed. The twelfth was a teenage girl who really was just in the class because her father “encouraged” her to do so. As with the teenager from my last class, I’m not going to count her as part of the total and claim a 100% pass rate this time.

Extra Class question of the day: Smith Chart

NOTE: This is the last installment of the Extra Class question of the day. I’m going to be compiling all of these into the No-Nonsense Extra Class Study Guide. Watch for it real soon now.


Figure E9-3A Smith chart is shown in Figure E9-3 above. (E9G05) It is a chart designed to solve transmission line problems graphically. While a complete discussion of the theory behind the Smith Chart is outside the scope of this study guide, a good discussion of the Smith Chart can be found on the ARRL website.

The coordinate system is used in a Smith chart is comprised of resistance circles and reactance arcs. (E9G02) Resistance and reactance are the two families of circles and arcs that make up a Smith chart. (E9G04)

The resistance axis is the only straight line shown on the Smith chart shown in Figure E9-3. (E9G07) Points on this axis are pure resistances. In practice, you want to position the chart so that 0 ohms is at the far left, while infinity is at the far right.

The arcs on a Smith chart represent points with constant reactance. (E9G10) On the Smith chart, shown in Figure E9-3, the name for the large outer circle on which the reactance arcs terminate is the reactance axis. (E9G06) Points on the reactance axis have a resistance of 0 ohms. When oriented so that the resistance axis is horizontal, positive reactances are plotted above the resistance axis and negative reactances below.

The process of normalization with regard to a Smith chart refers to reassigning impedance values with regard to the prime center. (E9G08) The prime center is the point marked 1.0 on the resistance axis. If you’re working with a 50 ohm transmission line, you’d normally divide the impedances by 50, meaning that a 50 ohm resistance would then be plotted on the resistance axis at the point marked 1.0. A reactance of 50 + j100 would be plotted on the resistance circle going through the prime center where it intersects the reactance arc marked 2.0.

Impedance along transmission lines can be calculated using a Smith chart. (E9G01) Impedance and SWR values in transmission lines are often determined using a Smith chart. (E9G03) Standing-wave ratio circles are often added to a Smith chart during the process of solving problems. (E9G09)

The wavelength scales on a Smith chart calibrated in fractions of transmission line electrical wavelength. (E9G11) These are useful when trying to determine how long transmission lines must be when used to match a load to a transmitter.

Extra Class question of the day: Amplifiers

There are several classifications of amplifiers, based on their mode of operation. In a class A amplifier is always conducting current. That means that the bias of a Class A common emitter amplifier would normally be set approximately half-way between saturation and cutoff on the load line. (E7B04)

In a class B amplifer, there are normally two transistors operating in a “push-pull” configuration. One transistor turns on during the positive half of a cycle, while the other turns on during the negative half. Push-pull amplifiers reduce or eliminate even-order harmonics. (E7B06)

A Class AB amplifier operates over more than 180 degrees but less than 360 degrees of a signal cycle. (E7B01) Class B and Class AB amplifiers are more efficient than Class A amplifiers.

A Class D amplifier is a type of amplifier that uses switching technology to achieve high efficiency. (E7B02) The output of a class D amplifier circuit includes a low-pass filter to remove switching signal components. (E7B03)

Amplifiers are used in many different applications, but one application that is especially important, at least as far as signal quality goes, is RF power amplification. RF power amplifiers may emit harmonics or spurious signals, that may cause harmful interference.

One thing that can be done to prevent unwanted oscillations in an RF power amplifier is to install parasitic suppressors and/or neutralize the stage. (E7B05) An RF power amplifier be neutralized by feeding a 180-degree out-of-phase portion of the output back to the input. (E7B08) Another thing one can do to reduce unwanted emissions is to use a push-pull amplifier. Signal distortion and excessive bandwidth is a likely result when a Class C amplifier is used to amplify a single-sideband phone signal. (E7B07)

While most modern transceivers use transistors in their final amplifiers, and the output impedance is 50 ohms over a wide frequency range. A field effect transistor is generally best suited for UHF or microwave power amplifier applications. (E7B21)

Many high-power amplifiers, however, still use vacuum tubes. These amplifiers require that the operator tune the output circuit. The tuning capacitor is adjusted for minimum plate current, while the loading capacitor is adjusted for maximum permissible plate current is how the loading and tuning capacitors are to be adjusted when tuning a vacuum tube RF power amplifier that employs a pi-network output circuit. (E7B09)

Figure E7-1

The type of circuit shown in Figure E7-1 is a common emitter amplifier. (E7B12) In Figure E7-1, the purpose of R1 and R2 is to provide fixed bias. (E7B10) In Figure E7-1, what is the purpose of R3  is to provide self bias. (E7B11)

Figure E7-2

In Figure E7-2, the purpose of R is to provide emitter load. (E7B13) In Figure E7-2, the purpose of C2 is to provide output coupling. (E7B14)

Thermal runaway is one problem that can occur if a transistor amplifier is not designed correctly. What happens is that when the ambient temperature increases, the leakage current of the transistor increases, causing an increase in the collector-to-emitter current. This increases the power dissipation, further increasing the junction temperature, which increases yet again the leakage current. One way to prevent thermal runaway in a bipolar transistor amplifier is to use a resistor in series with the emitter. (E7B15)

RF power amplifers often generate unwanted signals via a process called intermodulation. Strong signals external to the transmitter combine with the signal being generated, causing sometimes unexpected and unwanted emissions. The effect of intermodulation products in a linear power amplifier is the transmission of spurious signals. E7B16() Third-order intermodulation distortion products are of particular concern in linear power amplifiers because they are relatively close in frequency to the desired signal. (E7B17)

Finally, there are several questions on special-application amplifiers. A klystron is a VHF, UHF, or microwave vacuum tube that uses velocity modulation. (E7B19) A parametric amplifier is a low-noise VHF or UHF amplifier relying on varying reactance for amplification. (E7B20)