Listening to police and fire calls used to be a pretty simple proposition: buy a scanner, punch in some frequencies — or if you’re old enough, buy the right crystals — and you’re off to the races. It ...

With as cheap and versatile as RTL-SDR devices are, it’s a good idea to have a couple of them on hand for some rainy day hacking. In fact, depending on what signals you’re trying to sniff out of the ...