About two years ago, a friend handed me a small blue device that plugs into a USB port on a computer. As he handed it to me, he said it would completely change the way I think about radio.
I grew up in a household where radio was important. This allowed my immigrant parents, who left Western Europe for the Antipodes after World War II, to listen to shortwave broadcasts from their homeland.
As such, the radio and antennas were common to me, and I remember building crystal kits to input any signals I could. In the end, this led me to get my amateur radio certificate in Canada.
However, as no doubt many can connect, along with it came a career, one’s own family and other requirements. My passion for radio diminished, but it always remained in my mind. A career focused heavily on Internet technology has replaced radio. After all, the Internet was like a radio without antennas.
As I approached retirement, two events piqued my interest in radio signals. The first was the gift of a small blue device made by a company called NooElec, and the second was another gift, a small handheld transceiver made by a company called Baofeng. More about the latter in the next column.
I was puzzled by both. Apparently, during my almost four-decade absence from amateur and shortwave radio, there was a major upheaval in the hobby, as I did not recognize either name.
The parts for the blue NooElec device are quite basic. The first is software-defined radio – actually a thumb or stick, originally made to convert TV channels in the UK after the transition from analogue to digital transmission. Radio enthusiasts have found that these rods have amazing properties for tuning radio signals. The rest is history and these devices now sell for about $ 25.
The other part is the antenna. In my case, for the image you see above, I used an old set of ears for TV rabbits.
My main software is called SDR #, it is pronounced “SDR sharp”. Basically, this is the software equivalent of a radio. The satellites I watch emit around 137 MHz – just above Rock 101, for example, which broadcasts at 101.1 MHz.
There is additional software that I use to track the satellite and to start the tuner program when it is on top. In addition, there is software to convert the captured signal into an image and even more software to convert the rough image into what you see here.
Basically my NooElec device is a radio on a chip, but not just any radio, mind you. This is not an FM radio. This is not a radio plane. This is not a weather warning radio. It could be all this and more. Since this is software-defined radio, it can be versatile – many radios in one if you want.
I can set up an FM station in Vancouver as easily as I can position the signal from a plane to Oregon, or download an image transmission from the International Space Station as it passes overhead. (I can even get signals from the weather stations in the backyard of the neighborhood, but don’t tell anyone.)
At first I could not understand the capabilities of the device under $ 30, which I held in my hands. In the end, I thought about how such a small and so cheap device could take the place of the mass-sized radios my father used in the 1960s.
Of course, the answer lies in the miniaturization and power of our modern computers. It all comes down to math and the ability to represent signals as waveforms that can be manipulated with software. This is the secret of SDR, software-defined radio stations.
My experimentation with SDR is really starting. I now have a few units, some slightly larger than a miniature. One is dedicated to monitoring the position of aircraft (my data is provided to an international consortium), another to tracking ships.
Two others are devoted to satellite weather data, capturing eight passes a day from both Russian and American meteorological satellites.
A fifth, more expensive, form of SDR, made by a company called SDRplay, is mostly used for so-called high-frequency bands – high frequencies from 3 to 30 MHz, essentially replacing this shortwave kit that my father listened to on Nederland radio. before all those years.
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