At the Sooland Amateur Radio Association hamfest, I was the winner of $50 worth of ARRL books. After perusing the available options, and deciding that my 2010 Handbook was current enough for my needs, I decided to get Radio Science for the Radio Amateur
by Eric Nichols, KL7AJ.
The book bears the rather steep list price of $27.95, although it’s available at Amazon for a bit less. Overall, it was a good read, although I think I would have been somewhat disappointed if I had paid the list price. I suspect the price had something to do with the handful of one-star reviews on Amazon.
Nichols is a regular poster on the forums at qrz.com, and the book’s writing style is a similar level of informality. Some of the Amazon reviews point out that he seems to jump all over the place from topic to topic, and this is true. However, the book isn’t intended to be a scientific treatise about any particular subject. Nor does the book give many construction details. What the book does do, and the scatterbrained style actually does well, is give the reader some ideas about real scientific experimentation that can be done by amateur radio operators. It whets the appetite and lets the reader do some more research about what is possible. The book doesn’t really teach you how to do anything, but it does teach you that a number of interesting activities can be done.
In no particular order, here are some of the insights that I got from the book:
1. It’s possible to build a plasma chamber at home. I’m not sure exactly what I would do with it once built, but he does suggest some ideas.
2. One can purchase data acquisition modules relatively inexpensively, and these allow you to interface a computer to an analog voltage source (such as a receiver S-meter, a photocell, or a thermocouple) so that the computer can easily collect data for later number crunching.
3. Amateur radio offers some real possibilities for distributed science. My own short story, Clint’s Best DX, concludes with an author’s note saying that the story was impossible. In the story, the hero discovers extraterrestrial life with his 6-meter beam. I explain that this is impossible, because the signal strength is just too weak for earthbound antennas. (For an explanation of why, see this interesting NASA article, which also explains whether there are aliens watching reruns of I Love Lucy.) The book got me re-thinking that conclusion. If properly synchronized, it’s possible to distribute an antenna over widely separated points on earth. If Clint were to use such a distributed antenna instead of his 6-meter Yagi, then perhaps he could listen to the farm reports from Canis Minor after all.
4. Even the lone ham can do quite a bit of ionospheric research in his own back yard, and can probably do much more with some sort of distributed data collection.
The conspiracy buffs will be disappointed by this book, because it turns out that HAARP (the High Frequency Active Auroral Research Program) has a pretty mundane purpose, but makes use of some pretty interesting science. It turns out that a lot of mixing of radio signals can take place in the ionosphere. This is due to something called the “Luxembourg Effect”, which is explained pretty well in this 1935 article. The powerful longwave transmitters of Radio Luxembourg (and Gorky, Russia) were found to cross-modulate the signals of stations on a higher frequency located further away along the same path. The strong longwave signals were modulating the signal of the higher frequency station in the ionosphere as it passed over the longwave transmitter.
HAARP, as it turns out, was mostly involved in using this phenomenon as a cheap (by military standards) method of generating low-frequency signals. It can be quite a task to generate a strong low frequency signal in order to communicate with submarines. But if you want to generate a 20 kHz radio signal, one way to do it is to generate two HF signals 20 kHz apart. The ionosphere will serve as the mixing stage, and the result is a 20 kHz signal being transmitted from the edge of space. Since this signal penetrates sea water, the submarines can copy it. Unfortunately for the conspiracy buffs, I can’t think of any easy way to use this phenomenon to generate earthquakes, hurricanes, or any of the other phenomena that are associated with HAARP in the minds of some.
I think the best use of this book is to inspire aspiring young mad scientists. While not disclosing too many details, I think this book suggests a number of science projects that are well within the capabilities of a bright high school student. So if you are a bright high school student looking for an interesting science fair project, I think you’ll get some good ideas from this book. While your classmates are busy building their potato battery clocks or making a volcano out of vinegar and baking soda, you can be doing some actual science. What do you think your teacher will find more interesting, a homemade model of a volcano, or your measurements of the motion of the ionosphere? If you need to build some tangible device, then I suggest that a homemade plasma chamber, made out of a plexiglass tube, nails, and a pump from an old refrigerator, will probably be a bit more impressive than the potato clock that your classmate offers.
The price of the book is indeed a bit steep for the impoverished student. If you can’t find a used copy on Amazon, you can speak to your friendly librarian and ask them to order a copy. If your local library is also too impoverished to buy it, you’ll impress your local librarian to no end if you walk up to the reference desk and ask them to get a copy through “interlibrary loan”. You simply print out the listing from WORLDCAT, which shows the closest library with a copy. Your local librarian will request a copy from that library, and in a couple of weeks, it will be delivered for you to check out. Librarians thrive on doing this sort of thing, and they will be absolutely thrilled to learn that a student actually knows what interlibrary loan is, and actually gives the librarian the excuse to engage in the process.
For now, I glossed over the chapters on Smith Charts and wave polarization. There appears to be a lot of good material there, but it will require a bit more study than the quick read I was able to give most of the other chapters. For once, however, I do have some understanding of what is meant by the “characteristic impedance” of a feedline. A feedline is nothing more than in infinite number of tiny inductors in series, along with an infinite number of capactiors in parallel. This tiny components have both an inductance and a capacitance. And, of course, any time you have an inductance or capacitance, you also have an inductive reactance and capacitive reactance. And when I re-read that chapter, I have no doubt that I’ll have some understanding of how those give the characteristic impedance of the feedline.
Perhaps I would have been a bit disappointed if I had shelled out $27.95 for the book. But overall, I got some good ideas from the book and I’m pleased that I selected it as my hamfest door prize.