Review: LimeSDR Mini Software Defined Radio Transceiver

It’s fair to say that software-defined radio represents the most significant advance in affordable radio equipment that we have seen over the last decade or so. Moving signal processing from purpose-built analogue hardware into the realm of software has opened up so many exciting possibilities in terms of what can be done both with more traditional modes of radio communication and with newer ones made possible only by the new technology.

It’s also fair to say that radio enthusiasts seeking a high-performance SDR would also have to be prepared with a hefty bank balance, as some of the components required …read more

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An Autonomous Drone For Working Rare Squares

Amateur radio is an extremely broad church when it comes to the numerous different activities that it covers. Most of the stories featuring radio amateurs that we cover here have involved home-made radios, but that represents a surprisingly small subset of licence holders.

One activity that captivates many operators is grid square collecting. The map is divided into grid squares, can you make contact with all of them? Land-based squares in Europe and North America are easy, those in some more sparsely populated regions a little less so, and some squares out in the ocean are nigh-on impossible. As an …read more

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At 71,572 KM, You Won’t Beat This LoRa Record

A distance record for LoRa transmission has been set that you probably won’t be able to beat. Pack up your gear and go home, nothing more to achieve here. At a superficial reading having a figure of 71,572 km (44,473 miles) seems an impossible figure for one of the little LoRa radio modules many of us have hooked up to our microcontrollers, but the story isn’t quite what you’d expect and contains within it some extremely interesting use of technology.

So the folks at Outernet have sent data over LoRa for that incredible distance, but they did so not through …read more

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You All Know Reginald Fessenden. Who?

Quick, name someone influential in the history of radio. Who do did you think of? Marconi? Tesla? Armstrong? Hertz? Perhaps Sarnoff? We bet only a handful would have said Reginald Fessenden. That’s a shame because he was the first to do something that most of us do every day.

Few know this Canadian inventor’s name even though he developed quite a few innovations. Unlike Colpitts and Hartley we don’t have anything named after him. However, Fessenden was the first man to make a two-way transatlantic radio contact (Marconi’s was one way) and he was a pioneer in using voice over …read more

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Making Software Defined Radio Portable

While most smartphones can receive at least some radio, transmitting radio signals is an entirely different matter. But, if you have an Android phone and a few antennas (and a ham radio license) it turns out that it is possible to get a respectable software-defined radio on your handset.

[Adrian] set this up to be fully portable as well, so he is running both the transceiver and the Android phone from a rechargeable battery bank. The transceiver is also an interesting miniaturized version of the LimeSDR, the Lime SDR Mini, a crowdfunded Open Source radio platform intended for applications where …read more

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Repairs You Can Print: Fixing a Chewed Up Remote

What is it about remote controls? They’re like some vortex of household chaos, burrowing into couch cushions while accusations fly about who used it last. Or they land in just the right spot on the floor to be stepped on during a trip to the bathroom. And don’t get us started about the fragility of their battery case covers; it’s a rare remote in a house with kids whose batteries aren’t held in by strips of packing tape.

But [Alex Rich]’s Bose radio remote discovered another failure mode: imitating a dog chew toy. Rather than fork out $90 for a …read more

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ESP32 Makes for World’s Worst Radio Station

We can say one thing for [bitluni]: the BOMs for his projects, like this ESP32 AM radio transmitter, are always on the low side. That’s because he leverages software to do jobs traditionally accomplished with hardware, always with instructive results.

In this case, the job at hand is creating an RF oscillator in the broadcast AM band and modulating some audio onto it. From his previous experience using an ESP32 to watch video on an oscilloscope, [bitluni] knew that the microcontroller’s DACs were up to the task of producing an 800-kHz signal, and he managed to produce a more-or-less sine …read more

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Drink Lots Of Beer To Raise Your Monopole

When we published a piece about an ADS-B antenna using a Coke can as a groundplane, Hackaday reader [2ftg] got in contact with us about something with a bit more… stature.

A monopole groundplane antenna is a single vertical conductor mounted on an insulator and rising up above a conductive groundplane. In radio terms the groundplane is supposed to look as something of a mirror, to provide a reflection of what would come from the other half of a dipole were there to be two conductors. You can use anything conductive as your monopole, a piece of wire, (in …read more

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