Back to Basics: Practical Antennas and the Beauty of Simplicity
When I first started in electronics back in the mid-’80s, one of the first things I learned was that good design doesn’t always mean complex design. Nowhere is that truer than with antennas. Chapter 8B of the RAC Basic Certificate Course reminded me of something many of us tend to forget: the simplest antennas often work the best.
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This week in the RAC Amateur Radio course, we dug into one of the most fundamental — and fascinating — parts of radio communication: antennas. For many hams, the antenna is both the most visible and most mysterious part of the station.
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Riding the Waves: Reflections on Radio Propagation
This week’s class on radio-wave propagation took me right back to my roots. It’s hard not to smile when I see diagrams of skywaves, ground waves, and skip zones — things I first learned about nearly forty years ago at Sheridan College, when we were still using analog oscilloscopes and scientific calculators. Back then, I was an electronics engineering technology student just getting ready to start my career, and the idea that invisible waves could circle the globe felt almost magical.
Now, as I sit in class once again — decades later, after a long career in electronics and electrical control system design — I see those same principles through a different lens. What once seemed like mysterious phenomena now feel like old friends whose habits I know well. The theory hasn’t changed, even though the tools and applications have evolved beyond what I could have imagined in 1985.
The story of radio propagation is as much about curiosity as it is about science. When Guglielmo Marconi proved in 1901 that a wireless signal could cross the Atlantic, he didn’t know why it worked — only that it did. He thought the waves were following the Earth’s curve, but in reality, they were bouncing off the ionosphere — a discovery that wouldn’t be fully understood for decades.
That experiment, conducted from Signal Hill in St. John’s, Newfoundland, still captures my imagination. It’s a reminder of how experimentation often leads the theory, and how the physics that govern our communication systems today are the same ones that guided those first transatlantic dots and dashes of Morse code.
Of all the layers of the atmosphere, the ionosphere remains the most fascinating. The D, E, and F layers — invisible, dynamic, and ever-changing — are what make global communication possible.
During the day, the D layer absorbs low-frequency signals, muting AM stations that roar back to life at sunset. The higher F layers, split into F1 and F2 in daylight, refract HF signals over thousands of kilometres, bending them back toward Earth like a mirror made of charged particles. [1], [3]
Even after years of working with EMI and high-frequency noise in control systems, it still amazes me how the same physics in a factory floor’s PLC cabinet also govern how a signal from halfway around the world reaches a simple dipole antenna in my backyard.
As engineers, we tend to think of “weather” as something that affects reliability through temperature or humidity. But this week’s class reminded me that space weather plays an equally critical role. Solar flares, coronal mass ejections, and sunspots — the restless activity of our nearest star — shape the ionosphere daily [2], [5].
The Dominion Radio Astrophysical Observatory in Penticton, BC, has been measuring the Sun’s radio emissions at 2800 MHz since the 1940s, producing the Solar Flux Index we still rely on. Seeing that connection between a Canadian observatory, solar physics, and real-world radio performance renewed my appreciation for how deeply our communications depend on phenomena far beyond our control.
In my work over the years, I’ve seen signal dropouts caused by everything from ground loops to induction noise, but ionospheric fading has a kind of poetry to it. The way signals strengthen and vanish as the ionosphere shifts with time and sunlight reminds me that all communication — whether through copper, fibre, or free space — is ultimately about timing and conditions.
Skip zones, backscatter, and multipath effects are more than textbook curiosities; they’re metaphors for the real-world challenge of designing systems that perform reliably despite an unpredictable environment. Our ability to predict, compensate for, and even exploit those effects is a testament to a century of accumulated engineering wisdom.
Near Vertical Incidence Skywave (NVIS) propagation especially caught my attention. It’s used today for short-range HF communication, where terrain or disasters might block line-of-sight signals. I couldn’t help but think how that same principle could apply to robust emergency communications or even industrial networks in remote regions.
NVIS signals are propagated at a high elevation (greater than 60°). They are reflected down from the ionosphere (principally the F2 layer) over an area of a few hundred kilometres from the source. [4]
Using trigonometric calculations, we can estimate the NVIS coverage to be about 350 kilometres. Because the diagram represents a two-dimensional view, it’s essential to understand that this range extends equally in all directions from the transmitting station. In other words, if we imagine a circle centred on the transmitter with a radius of 350 kilometres, any receiver positioned within that circle should be able to detect the NVIS signal.
Despite all our modern connectivity, there’s still a place for understanding how nature itself moves information from one point to another.
For me, studying propagation again isn’t about relearning the formulas — it’s about rediscovering the elegance behind them. The same electromagnetic principles that may have carried Marconi’s letter “S” across the Atlantic in 1901 still underpin the wireless links in a factory, the telemetry in a wind farm, or the Wi-Fi in our homes.
After four decades in the field, it’s humbling to be reminded that no matter how advanced our technology becomes, we’re still riding the same waves — reflections from the same sky, governed by the same physics, and inspired by the same human drive to connect across distance.
[1] D. Tal, “Region vs. Layer: Earth’s Atmosphere and Ionosphere”. Accessed: Oct. 10, 2025. [Online]. Available: https://www.qsl.net/4x4xm/Region-vs-Layer-Earth’s-Atmosphere-and-Ionosphere.htm
[2] ‘Space Weather’, spaceweather.com. Accessed: Oct. 10, 2025. [Online]. Available: https://www.spaceweather.com
[3] D. Tal, ‘Skywave Propagation Basics’, Understanding HF Skywave Propagation. Accessed: Oct. 21, 2025. [Online]. Available: https://www.qsl.net/4x4xm/HF-Propagation.htm
[4] John VA3KOT, ‘The NVIS Illusion’, Ham Radio Outside the Box. Accessed: Oct. 21, 2025. [Online]. Available: https://hamradiooutsidethebox.ca/2023/06/19/the-nvis-illusion/
[5] N. R. C. Government of Canada, ‘Current regional magnetic conditions’. Accessed: Oct. 21, 2025. [Online]. Available: https://www.spaceweather.gc.ca/forecast-prevision/short-court/regional/sr-1-en.php?region=ott&mapname=east_n_america
Every so often, a class reminds me that the fundamentals never really change. This week’s topic — Waves, Wavelength, Frequency, and Bands — was a trip back in time for me. As someone who trained as an electronics engineering technologist in the 1980s, this material feels like old territory. Yet, revisiting it in today’s context, with modern software-defined radios (SDRs) and digital signal processing, highlights just how enduring these basic principles are.
The lecture opened with the essentials: amplitude, wavelength, and frequency — the vocabulary of every waveform, whether it’s a sound wave in air or a radio wave racing through space. Back then, we learned these on oscilloscopes with green phosphor traces, adjusting time bases and triggering circuits to freeze those elegant sine waves in time. Today, the same principles remain, but the scopes are digital, and the waves are simulated, captured, and analyzed by software.
What hasn’t changed is the relationship between wavelength and frequency — the beautiful simplicity of ( c = f \λ ), where the speed of light ties them together. It’s still the same 300 × 106 metres per second in free space, as it was for Heinrich Hertz when he first proved Maxwell’s equations right. The numbers might scale from kilohertz to gigahertz now, but the physics hasn’t changed a bit.
Thinking about waves and bands always takes me back to the early history of radio — to the days of spark-gap transmitters, longwave Morse signals, and men like Hertz, Marconi, and Fessenden. Those pioneers were dealing with kilohertz frequencies, with antennas and capacitors the size of ships, yet they were manipulating the same invisible medium we use today.
I’m pretty sure my neighbours would be unhappy with me if I built an antenna array that resembled Marconi’s Glace Bay installation!
By 1907, the Marconi station at Glace Bay, Nova Scotia, was operating on remarkably low frequencies for its time — around 70 kHz. That range was chosen for the transatlantic service linking Glace Bay with Clifden, Ireland, inaugurated in October 1907.
Earlier experiments at the site had been conducted on higher frequencies — roughly 182 kHz in 1902 and 272 kHz for some later trials — but Marconi’s engineers soon discovered that lower frequencies provided far greater reliability over long distances. By 1907, they had moved down to around 70 kHz, and eventually as low as 45 kHz.
These very long wavelengths (VLF) proved ideal for transatlantic work. The signals could travel enormous distances, reflecting between the Earth and the ionosphere, and remained stable both day and night — something that higher frequencies of the day simply couldn’t achieve. Considering the limits of early transmitters and receivers, this was an extraordinary technical accomplishment, and a milestone in the development of reliable global communication.
In the photo above, Marconi Operator L.R. Johnstone is shown transmitting the first official messages of the commercial wireless telegraph service from Marconi Towers, near Glace Bay, Nova Scotia, to Clifden, Ireland, on October 17, 1907. Ten thousand words were exchanged between the stations on the first day of operation.
The rotary spark discharger was the heart of the spark transmitter at Marconi Towers. In the upper-right background, the three large ring-shaped loops are the three turns of the antenna transformer’s primary coil, which fed the spark’s electrical energy into the high-mounted antenna.
At the Marconi station in Glace Bay, Nova Scotia, six steam boilers powered dynamos that generated the 15 kV power supply, which charged a capacitor composed of 288 metal sheets, each measuring 60 feet by 20 feet, separated by approximately 6 inches. The sheets were suspended from rafters at the top of the building and hung vertically almost to ground level. This capacitor (or “condenser,” as it was originally called) occupied most of the 160-foot-long transmitter building. As a result, the building became known as the condenser building.
This extensive array of plates offered only 1.7 microfarads of capacitance, with a voltage rating of 15 kilovolts. An “air-insulated” design was selected over a more compact glass dielectric design because it was relatively trouble-free and easy to build using locally available materials. If a draft caused the plates to shift and short-circuit, the “spot-welded” plates could be knocked apart with a sledgehammer.
One story that sticks in my mind is Weather Station Kurt, a German automatic transmitter secretly placed in Labrador during the Second World War. It operated on 3940 kHz — smack in what we now think of as the amateur 80 m band — sending weather reports back to Germany every few hours. Even in wartime, radio’s reach was both strategic and scientific, and its physics — the propagation of electromagnetic waves through atmosphere and ionosphere — governed everything.
When I first learned about LC circuits, we tuned them with physical coils and capacitors, feeling resonance through the sound in a speaker or the flicker on a meter. The “bands” we talked about then — HF, VHF, UHF — were as much about practical limitations as they were about regulation. Antenna length, wavelength, and atmospheric reflection all dictated what was possible.
Today, when I look at a modern software-defined radio (SDR), I find it astonishing to think that an entire superheterodyne receiver now fits in a USB drive. Instead of a coil and a capacitor, we use algorithms to shift and filter signals in code. But the foundation — waves, frequencies, and harmonics — is the same. Whether it’s a spark-gap transmitter, a vacuum-tube superhet, or a LimeSDR, every one of them lives by the same electromagnetic laws.
There’s a certain poetry in knowing that a 7 MHz signal — the classic 40 m amateur band — still bounces off the ionosphere just as it did when I first listened to shortwave broadcasts as a teenager. The gear has changed; the spectrum hasn’t. Even in a world dominated by Wi-Fi, Bluetooth, and cellular links operating in gigahertz ranges, it all still comes down to waves oscillating in time and space.
So while the students around me might be seeing this material for the first time, I find myself smiling at how familiar it feels. The math is old, the physics immutable, and yet the applications keep evolving. From sparks to software, from the hiss of AM static to the crisp digital decoding of an SDR waterfall, it’s all the same story — one wave at a time.
As the course continues, I’m looking forward to diving deeper into how these timeless wave fundamentals shape the communication technologies we rely on every day. Understanding them through both the lens of experience and modern tools like SDRs bridges the gap between the analog world in which I first learned and the digital systems that define today’s engineering practice. It’s a reminder that while technology evolves, the language of physics remains beautifully consistent — and that makes every new concept feel like an old friend revisited.
[1] Marconi – Krause House Info-Research Solutions
[3] List of Marconi wireless stations
[5] List of Marconi wireless stations – Wikiwand
[6] Frequency Spectrum Management Overview
[7] Radio’s First Message – Fessenden and Marconi
[8] An Historical and Technological Survey
[9] ULTRA TCS – Canadian Marconi History
[10] VE1DEW – Callsign Lookup by QRZ Ham Radio
[11] M. Rosano, “Throwback Thursday: Nazi weather station in Labrador”, Canadian Geographic. 2015. Available: https://canadiangeographic.ca/articles/throwback-thursday-nazi-weather-station-in-labrador/ [Accessed: 2025-10-16]
[12] ‘The First Transatlantic Wireless Stations in Cape Breton’, Cape Breton Wireless Heritage Society. Accessed: Oct. 13, 2025. [Online]. Available: http://www.cbwireless.ednet.ns.ca/cbwirelessp3.html
Over the past couple of classes, we’ve been exploring two interconnected concepts in electronics: capacitance and resonance. For me, these aren’t new ideas—I first studied them at Sheridan College back in the 1980s, when oscilloscopes still had CRTs and breadboards came with point-to-point wiring. Even so, it has been rewarding to revisit these foundational topics with a fresh perspective and a few more decades of practical experience under my belt.
Capacitance is one of those elegant concepts that forms the backbone of modern electronics. A capacitor—two conductive plates separated by an insulating dielectric—resists changes in voltage by storing and releasing energy. It’s such a simple structure, but its impact on everything from timing circuits to power supplies can’t be overstated.
Revisiting the theory reminded me just how differently capacitors behave in DC versus AC circuits. In DC, a capacitor charges up to the supply voltage and then effectively becomes an open circuit. In AC, though, the constantly changing voltage makes it look as though current flows straight through—even though electrons never actually cross the dielectric. This behaviour gives rise to capacitive reactance (XC), which decreases as frequency increases. That’s why capacitors block DC but pass high-frequency signals, making them indispensable in filters and coupling circuits.
The unit of capacitance, the farad, is far too large for most real-world applications, which is why we use microfarads, nanofarads, and picofarads instead. Plate area, spacing, and dielectric material all shape a capacitor’s behaviour—details I once learned in a classroom, but now appreciate in a far deeper way after years of working with safety systems and control circuits.
Next came resonance—another familiar but fascinating topic. An inductor resists changes in current through its magnetic field, while a capacitor resists changes in voltage through its electric field. Put them together and, under the right conditions, they exchange energy back and forth in a kind of electrical echo.
Resonance happens when the inductive reactance (XL) and capacitive reactance (XC) are equal and cancel each other out. At that frequency, the circuit oscillates like a perfectly tuned pendulum, trading energy between the capacitor’s electric field and the inductor’s magnetic field. That’s the essence of every tuned circuit—from early radio receivers to modern communication filters.
One example that always comes to mind when talking about resonance is the Tacoma Narrows Bridge collapse of 1940. Although it wasn’t pure electrical resonance—it was aeroelastic flutter—the underlying principle was the same: energy reinforcing itself until a system fails. It’s a dramatic reminder of how resonance, in any form, can be both powerful and destructive if it’s not managed properly.
Reviewing series and parallel RLC circuits brought back memories of long lab sessions and breadboards filled with coils and capacitors. In a series circuit, resonance minimizes impedance, leaving only the resistance to limit current. In a parallel circuit, it does the opposite—impedance rises to a maximum.
Those two behaviours form the basis of almost every practical filter: low-pass, high-pass, band-pass, or notch. Seeing the relationships between theory and application again reminded me why I fell in love with electronics in the first place. There’s something deeply satisfying about watching a sine wave sharpen or flatten on a scope exactly as the equations predict.
We also revisited the Q factor, which describes how “sharp” or selective a resonant circuit is. High-Q circuits have narrow bandwidth and greater selectivity, while low-Q circuits are broader and less discriminating.
I built my first crystal radio as a preteen, so it was fun to see it come up again. With its single tuned circuit and diode detector, the crystal set has a very low Q—but it works. With nothing more than a coil of wire, a bit of crystal (or even a sugar cube and a sewing needle, if you’re improvising), and a pair of headphones, you can literally pull voices and music out of the air. Even now, I still find that magical.
Revisiting capacitance and resonance after four decades reminded me how enduring the fundamentals really are. These aren’t just abstract properties—they’re the building blocks of everything from radios to robotics. Capacitors don’t merely “store charge”; they make stable, responsive, and selective systems possible. Resonant circuits don’t just cancel reactances; they allow us to shape and control the signals that carry our modern world.
Coming back to these topics, I find myself both nostalgic and appreciative. The equations haven’t changed, but my understanding of their importance has deepened. It’s a reminder that no matter how advanced technology becomes, it all still rests on the same elegant principles we learned with coils, capacitors, and curiosity.
