Microwave Journal
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View from Below

A View from Below

November 6, 2018

Last week I was privileged and honored to address the Radio Society of Great Britain (RSGB) National Convention, via Skype.  My topic was the art and science of technical writing, which was very well received, and it was gratifying to be able to give back some encouragement to a venerable organization which had once inspired me.  In my early radio and electronics career, it was largely the publications of RSGB and the American Radio Relay League (ARRL) which compelled me to pursue a technical writing career, in parallel with my hands-on careers in broadcast engineering, military radio and RADAR, and ionospheric research. 

The latter part of my talk progressed into some exciting new developments in American amateur radio, the allocation of two brand new amateur radio bands, in the 630 meter and 2200 meter regions.  England and parts of Europe have had these bands for many years, so we are, in effect, playing catch-up.  U.K. radio amateurs have been enthusiastic about the lower frequency bands for quite some time, I discovered.

Now, it may seem a bit out of place, or at least anachronistic, to express any excitement in the nether regions of the radio spectrum in a publication dedicated to pushing the frontiers of shorter and shorter wavelengths.  Sometimes it’s good to see where you’ve been to extrapolate, to some degree, where you’re going. 

But beyond that, there are some truly amazing technologies available now that weren’t available, or even dreamed about, back when all radio was in the long wave spectrum.  It was only a few short months ago that a new digital mode, FT8, was introduced, the latest in a long string of digital methods developed by Nobel laureate, Joseph Taylor, K1JT, a mode that allows reliable communications at signal-to-noise levels far below the noise floor.  If history serves as a guide, methods developed by radio amateurs to make practical use of difficult regions of the radio spectrum will eventually find their way into commercial and military applications.   One of the forgotten advantages of extremely low radio frequencies is their invulnerability to many propagation ills that plague higher frequencies.   Low frequency radio can serve as a viable backup when higher frequencies fail, for whatever reasons.

The current generation of RF and microwave engineers may not be aware that it wasn’t all that long ago that the high frequencies were once deemed impractical, or even useless.   Every radio engineer should read 200 Meters and Down, by Clinton DeSoto, which has been reprinted numerous times by the ARRL.  So now we have come full cycle, as we discover high-tech, digital methods of exploiting the “useless” frequencies below the A.M. broadcast band.

Radio Science for Fun and Profit
With all the recent buzz about 5G technology, as just one example, it’s very easy to be overwhelmed by the sheer practicality of radio technology, regardless of the frequency.

I am reminded of the amazing story of Michael Faraday when he first demonstrated magnetic induction to the Royal Society.  After his brilliant presentation, one grizzled sceptic approached him and said, “That’s all very interesting, Mr. Faraday, but of what practical value is it?” Without missing a beat, Faraday retorted, “Of what practical value is a baby?”

It was the perfect answer then, and it is still the most appropriate answer today.  There are doubtless innumerable as-yet-unconceived applications for radio technology, from “DC to Daylight.”  Many of these applications may not seem immediately practical…or necessary.   As is the case with any unexplored technology, it’s usually the squeaky wheel that gets the grease.  And dollar signs generally squeak more loudly than mere scientific curiosity…often to our great detriment. 

For many years, I worked at HIPAS Observatory, an ionospheric research facility near Fairbanks, Alaska, which was operated by the UCLA Plasma Physics department.   HIPAS was the predecessor to HAARP (High Frequency Active Aurora Research Project), a few hundred miles to the south.   Between HIPAS and HAARP, we did some truly amazing radio science.  Now, the “holy grail” of this kind of ionospheric research was for the purpose of ELF submarine communications.  It was the Office of Naval Research (ONR) which funded most of our studies, and we were indeed able to produce practical ELF signals capable of being received by submarines, using the ionosphere as an intermediary.   And, as an added bonus, we helped the Navy develop some unique weak-signal detection technology.

But it was really the side projects at HIPAS that were the truly fun stuff.   I don’t have space to go into detail on these pure radio science projects in this short article, but suffice it to say, it was these “rabbit trails” that really led us to the most interesting discoveries.   And yes, we did use a lot of microwave technology for basic radio research, primarily as a diagnostic tool, even for our ELF experiments, ironically enough.

STEM-ing the Exodus from RF Engineering
It is probably preaching to the choir to point out that RF engineers for the most part, are “well-seasoned,” present company being no exception.   Despite all the publicity about cutting edge 5G technology and its ilk, it is a minuscule percentage of electrical engineering students who are going into RF engineering, and the trend doesn’t seem to be changing.  It’s mainly older guys doing most of the development in this area.   I’m certainly not complaining that I am currently overemployed as an RF technologist at an age when many of my peers are retired or retiring.   I’m having far too much fun to even consider retiring…and that is precisely my point.

We need to convey to “kids” that RF engineering is a blast….and that includes wavelengths from thousands of kilometres to nanometers….and we really haven’t been doing a very good job of that, on the whole.  Kai Siwiak, editor of ARRL’s QEX Magazine recently pointed out that the average reader was over the age of 60, and this magazine is focused on folks doing bleeding edge RF and microwave technology.

 We hear a lot about STEM these days: Science, Technology, Engineering, and Math.  What we don’t hear much about is how radio, in one form or another, is one of, if not the main portal into all four of these branches.   On a universal, galactic level, radio is our only access to the universe outside of our back yard.  (I might have to modify this assertion if it is proven that gravity is propagated, but for the time being, this truth stands).  All that we know about the universe is what we’re able to glean from radio propagation, whether it’s in the form of X-rays or ELF.   When it comes to Technology and Engineering, most students are fixated on computer science.   As useful and necessary as this is, to confine ones thinking to the digital domain is not only a disservice to our youths…but also somewhat boring!

Let’s look at Math.  Now, I need to confess that I was a mediocre math student in high school and college.  However, it was working with radio and radio electronics that caused concepts like trigonometry and complex numbers to sink in in a practical and unforgettable way.   I believe radio is one of the best ways of teaching mathematics, which for many students, can be a very abstract, impractical topic.   Radio is the perfect interface to the physical and the abstract.  Radio yields to mechanical analogies and pure mathematics in an elegant and accessible manner.   We can be doing a whole lot more in this area to bring life into STEM programs.           

Lock Me In
When I first began working at HIPAS Observatory, back in the early 1990s, one of my tasks was to set up some instrumentation for detection of telluric currents.  These are electrical currents induced in the surface and near-surface of the Earth in response to Auroral activity.  Telluric currents are sensitive indicators of a lot of different geomagnetic phenomena, and even some solar activity.   These minuscule signals are generally in the millihertz frequency range, barely above DC, but radio nonetheless.   The primary instrument for detecting these signals was (and still is) the venerable lock-in amplifier.  The lock-in amplifier is a special phase-coherent receiver that has subsequently found application in everything from medicine to metallurgy, but began its life applied to working with natural radio phenomena.  I found the lock-in amplifier a fascinating device; it opened up a whole universe of exploration for me…a frequency range that few people knew about, and even fewer cared about.  Probably what intrigued me the most about this low-frequency stuff was how cheaply one could do some real science.  Now, admittedly, the Stanford Research Systems lock-in amplifiers we used at HIPAS were rather pricey, but I soon discovered that I could build my own, minus a few bells and whistles, for a few tens of dollars.   (There are now commercially available lock-in amplifiers that work well into the UHF range, but at the time, most of them started puttering out at a few hundred kilohertz).

The Still Small Voice
Compared to computer science (and digital technology in general), radio phenomena tend to be subtle and not so obvious.   A computer program or a robot either works or it doesn’t.  Radio signals are often minuscule, buried in background noise.  This is especially true of scientific radio. It takes a delicate touch, and sometimes some elaborate equipment to extract radio signals from the noise…and even more profoundly, it is sometimes the noise itself that is of the greater interest.  For the young student accustomed to radio communications in the form of full-quieting cellular technology, and perfect error correction, it can be difficult to convince him that the universe may have something more interesting to say than the person at the other end of the text message.  The radio technologist is perfectly at home in shades of gray, where there is no error correction.

There’s no question that we “properly-seasoned” RF and Microwave technologists have our work cut out for us, if we plan on there being anyone around to whom we can pass the baton.  We need to have a visible, active presence in our local STEM environments.  We need to show that not only is radio a whole lot of fun, but it can be highly profitable, as well.

And like Faraday, we need to show them that the path isn’t always obviously practical.   It takes some humility to acknowledge that we might have no clue how the future will look.  We do know, however, with absolute certainty, that it radio will be part of it.

Unfinished Business
If you are convinced that we need to get more young folks into radio and microwave technology (and I’m sure you are), I’d like to leave with just a few ideas about how to get STEM students engaged with the whole idea.   Some of these are projects that we began at HIPAS Observatory, but never had the time or funds to complete.   Some of these were simply just ahead of their time.                

                           1)     Radio Detection of High Energy Particles

Atom smashers are expensive.  I grew up in Silicon Valley, practically “right down the barrel” of the Stanford Linear Accelerator (SLAC).  We took a field trip there in 5th grade, before the accelerator was even finished, and it was obvious even to my young brain that this was a monumental and monumentally expensive project.  And it still is.   But atomic science doesn’t have to be monumentally expensive.  About 15 years ago, there was a conference at UCLA entitled “Radio Detection of High Energy Particles,” or RADHEP.   A number of universities and private entities came up with schemes for using radio facilities (even existing broadcast stations) for the detection of exotic particles.   As it turns out, high energy radio particles entering the Earth’s atmosphere can alter radio propagation to varying degrees.   This concept has never been fully explored however, and is wide open for more experimentation.   Who knows; there could even be a Nobel Prize in physics for this!

2)     Medical Applications

People are living longer…or at least want to.   There are countless applications for RF in medicine, from ELF and ULF (think EEGs and EKGs) to terahertz waves used for diagnosis and even cancer cell destruction.   RF technicians and engineers will be in ever-increasing demand in this field.

3)     Plasma Physics

Most of the universe is made of plasma, and for decades scientists have been exploring plasmas in laboratories in order to understand the plasmas “out there.”   Radio frequencies “from DC to Daylight” are used in every kind of plasma studies.   Radio is essentially the only means of probing this “fourth state of matter” to find out what’s really happening.

4)      Materials Engineering/High Temperature physics

One of the “side projects” we did at HIPAS Observatory was to create an inductively coupled Radio Frequency plasma.   This plasma chamber created the highest man made temperature on Earth outside of a nuclear detonation…..55,000 degrees C.  The commercial and industrial possibilities of this technology are probably limitless.  However, we never got beyond the proof of principle stage.   This technology is wide open for anyone who wants to take it to the next stage.  In fact, all the patents associated with this device have expired, so there is basically a clean slate.