RF Shield Turns Arduino (And PC) Into Shortwave Radio

Microcontrollers tend to consume other kinds of electronics. A project you might once have done with a 555 now probably has a cheap microcontroller in it. Music synthesizers? RC controllers? Most likely, all microcontroller-based now. We always thought RF electronics would be immune to that, but the last decade or two has proven us wrong. Software-defined radio or SDR means you get the RF signal to digital as soon as possible and do everything else in software. If you want an introduction to SDR, Elektor now has an inexpensive RF shield for the Arduino. The Si5351-based board uses that oscillator IC to shift RF signals down to audio frequencies and then makes it available to the PC to do more processing.

The board is available alone or as part of a kit that includes a book. There’s also a series of Elektor articles about it. There’s also a review video from Elektor about the board in the video, below.

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All Band Radio Uses Arduino And Si4730

It is getting harder and harder to tell homemade projects from commercial ones. A good case in point is [Mirko’s] all band radio which you can see in the video below the break. On the outside, it has a good looking case. On the inside, it uses a Si4730 radio which has excellent performance that would be hard to get with discrete components.

The chip contains two RF strips with AGC, built-in converters to go from analog to digital and back and also has a DSP onboard. The chip will do FM 64 to 108 MHz and can demodulate AM signals ranging from 153 kHz to 279 kHz, 520 kHz to 1.71 MHz, and 2.3 MHz to 26.1 MHz. It can even read RDS and RBDS for station information. The output can be digital (in several formats) or analog.

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DIY Radio Telescopes Hack Chat

Join us on Wednesday, February 12 at noon Pacific for the DIY Radio Telescopes Hack Chat with James Aguirre!

For most of history, astronomers were privy to the goings-on in the universe only in a very narrow slice of the electromagnetic spectrum. We had no idea that a vibrant and wondrous picture was being painted up and down the wavelengths, a portrait in radio waves of everything from nearly the moment of creation to the movement of galaxies. And all it took to listen in was an antenna and a radio receiver.

Over the years, radio telescopes have gotten more and more sophisticated and sensitive, and consequently bigger and bigger. We’re even to the point where one radio telescope often won’t cut it, and astronomers build arrays of telescopes spread over miles and miles, some with antennas that move around on rails. In the search for signals, radio astronomy has become the very definition of “Big Science.”

But radio astronomy doesn’t have to be big to be useful. James Aguirre, an astronomer at the University of Pennsylvania, spends his days (and nights) studying the radio universe with those big instruments. But he’s also passionate about down-scaling things and teaching everyone that small radio telescopes can be built on the cheap. His Mini Radio Telescope project uses a cast-off satellite TV dish and a couple of hundred bucks worth of readily available gear to scan the skies for all sorts of interesting phenomena.

Dr. Aguirre will join us on the Hack Chat to discuss all things radio astronomy, and how you can get in on the radio action on the cheap. Chances are good your junk pile — or your neighbor’s roof — has everything you need, and you might be surprised how approachable and engaging DIY radio astronomy can be.

join-hack-chatOur Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, February 12 at 12:00 PM Pacific time. If time zones have got you down, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about. Continue reading “DIY Radio Telescopes Hack Chat”

Fallout-Inspired Clock Radio Helps You Party Like It’s 2077

Since its first release seven years ago, Raspberry Pi single-board computers have become notoriously ubiquitous in compact and portable builds. They’re used in many different applications, but one of the most interesting has got to be how it can turn just about any old thing into a Linux computer. [xito666] writes in with his own build, a portable retro computer inspired by the retro-futuristic stylings of the Fallout games.

For true aesthetic accuracy, [xito666] used an old discarded Crown 5TV-65R portable TV and radio combo. The unit hails from the 1970s, so a bit newer than Vault technology, but it still gives off a great retro charm with its CRT screen and knobs. Sadly, the original components couldn’t be reused, and the shell was stripped empty so that the new hardware could take its place. This includes an off-the-shelf HDMI LCD screen with resistive touchscreen and new potentiometers and knobs that still fit in with the overall look of the machine.

What makes this build unique, however, is that it also includes custom software to turn it into a clock and music player, with the deliciously Pip Boy-like UI being controlled entirely with the front buttons and knobs. The whole project is well written up in the Reddit post, in it [xito666] explains some of their choices and planned improvements. One that we would suggest ourselves is replacing the menu scrolling selector dial with a rotary encoder rather than a potentiometer, for that added knob feel. We also think that with the addition of a keyboard, it would easily pass for one of those luggables from the 1980s, a style of project we’ve featured once or twice here before.

Keeping Ham Radio Relevant Hack Chat

Join us on Wednesday, February 5 at noon Pacific for the Keeping Ham Radio Relevant Hack Chat with Josh Nass!

It may not seem like it, but amateur radio is fighting a two-front war for its continued existence. On the spectrum side, hams face the constant threat that the precious scraps of spectrum that are still allocated to their use will be reclaimed and sold off to the highest bidder as new communication technologies are developed. On the demographic side, amateur radio is aging, with fewer and fewer young people interested in doing the work needed to get licensed, with fewer still having the means to get on the air.

Amateur radio has a long, rich history, but gone are the days when hams can claim their hobby is sacrosanct because it provides communications in an emergency. Resting on that particular laurel will not win the hobby new adherents or help it hold onto its spectrum allocations​, so Josh Nass (KI6NAZ) is helping change the conversation. Josh is an engineer and radio amateur from Southern California who runs Ham Radio Crash Course​, a YouTube channel dedicated to getting people up to speed on ham radio. Josh’s weekly livestreams and his video reviews of ham radio products and projects show a different side of the World’s Greatest Hobby, one that’s more active (through events like “Summits on the Air​​”) and focused on digital modes that are perhaps more interesting and accessible to new hams.

Join us on the Hack Chat as we discuss how to make ham radio matter in today’s world of pervasive technology. We’ll talk about the challenges facing amateur radio, the fun that’s still to be had on the air even when the bands are dead like they are now (spoiler alert: they’re not really), and what we can all do to keep ham radio relevant.

join-hack-chatOur Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, February 5 at 12:00 PM Pacific time. If time zones have got you down, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about. Continue reading “Keeping Ham Radio Relevant Hack Chat”

[Eric] Talks Crystal Radios

The AM broadcast band doesn’t have a lot of mainstream programming on it across much of the United States today. That’s a shame because a lot of kids got their first taste of radio and electronics by building simple crystal radios. [Eric Wrobbel] has a well-done page discussing some of the crystal radio kits and toys that have been around.

[Eric] should know, as he’s written two books on toy crystal radios. The pictures range from a 1945-era “Easy Built Radio Kit” which looks like a piece of masonite with a coil, some Fahnestock clips, and a cat whisker, to a very slick looking Tinymite from 1949. Honestly, though, the one we really want is the X-50 Space Helmet Radio that comes in a box marked “For Young Moon Travelers.”

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Full Duplex Radio Claimed Easier With Analog Module

There’s an old saying that we have one mouth and two ears so you can listen twice as much as you talk. However, talking and listening at the same time is fairly difficult and doing it with radio signals is especially hard. A company called Kumu Networks has an analog module that can use self-interference cancellation which allows transmitting and receiving on the same frequency with around 50 dB of the transmitted signal in the transceiver. You can see a video about Kumu’s claims its technology below.

You may think that cell phones and ham radio repeaters transmit and receive at the same time, which of course they do, but usually on different frequencies to avoid direct interference. A diplexer is a device that sorts out the two frequencies while a duplexer sorts them out by the direction of the signal, but they are tricky to use. A duplexer can operate on a single frequency in applications such as radar, and even then it is still very difficult to prevent leakage from the transmitter from overloading and desensitizing the receiver.

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