My next big ham thing: Software Defined Radio

It's been a while since putting fingers to keyboard and baring my soul. I had a lengthy rationalization period that I labeled "doing nothing is good for you." Well, I'm tired of doing nothing any further. I've had plenty of time for navel-gazing and out of the blue resurrected my ham radio craving.


My next thing is called "Software Defined Radio" (SDR). For you non-hammies, SDR is a little "black box" that connects to your computer via USB, and also connects to the radio-spectrum universe via an exterior antenna. Think of it as a pair of ears that have special powers - that is, to hear signals across the entire radio frequency spectrum, and to deliver those signals to a brain that can understand them. That brain is your computer.


Technically, the SDR is merely a "front-end" for the computer. A specialized software application running on your computer interprets the SDR's signals, and displays radio activity in an intuitive, graphical manner called a "waterfall display." Below is a short movie of what this display looks like (movie credit K3RRR):



The noise is digital radio signals (that make sense to a computer that can decode them). The green area at the top represents a wide swath of radio spectrum, where the peaks are signals. The higher the peak, the stronger the signal. The blue area in the middle is the waterfall, that is "painted" by the peaks. Thus, you not only see thousands of frequencies at once (horizontally), you see a history of their activity (vertically, in the waterfall).


Compare this to an old-fashioned ham radio like the Heathkit below.


The only way to find radio activity was knowing were to tune by doing research and spinning the big dial, listening and hoping. With this method, activity could be happening right next to your frequency, and you'd never know it.


The advantage of SDR is obvious. Having a broad view of literally thousands of frequencies which you can instantly access, is enormously more effective and enjoyable that the old-school method. Some hams keep their old radios, and use SDR as their "God's-eye view" of the radio spectrum, and start spinning. Most modern radios can actually communicate with the SDR application - simply clicking on a frequency in the SDR app automatically tunes your radio to that same frequency (and vice-versa). How cool is that?


After saving $20 a week over the last seven months, I've finally got enough cash to purchase my own SDR and I can't wait! It's the SDRplay RSPdx.



More coming, so "stay tuned." (Ar!)



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