Five-Watt SDR Transceiver For Hams

November 20, 2016 by Elliot Williams 50 Comments

The availability of cheap SDR hardware created a flourishing ecosystem for SDR software, but a lot of the hardware driving the revolution was still “cheap”. In the last few years, we’ve seen quality gear replacing the TV dongles in many setups, and down-converters designed for them to allow them to work on the ham bands.

But something that’s purpose-built might be a better option if ham radio, particularly the shortwave portion thereof, is your goal. First off, you might want to transmit, which none of the TV dongles allow. Then, you might want a bit of power. Finally, if you’re serious about short-wave, you care more about the audio quality than you do immense bandwidth, so you’re going to want some good filters on the receiving end to help you pull the signal out of all the noise.

The RS-HFIQ 5 W SDR transceiver might be for you. It’s up on Kickstarter right now, and it’s worth looking at if you want a fully open source (schematics, firmware, and software) shortwave SDR rig. It’s also compatible with various open frontends.

The single-board radio isn’t really a full SDR in our mind — it demodulates the radio signal and sends a 96 kHz IQ signal across to your computer’s soundcard where it gets sampled and fully decoded. The advantage of this is that purpose-built audio rate DACs have comparatively high resolution for the money, but the disadvantage is that you’re limited to 96 kHz of spectrum into the computer. That’s great for voice and code transmissions, but won’t cut it for high-bandwidth data or frequency hopping applications. But that’s a reasonable design tradeoff for a shortwave.

Still, an SDR like this is a far cry from how simple a shortwave radio can be. But if you’re looking to build up your own SDR-based shortwave setup, and you’d like to hack on the controls more than on the radio itself, this looks like a good start.

Make Your Eyes Louder With Bluetooth Speaker Goggles

November 20, 2016 by Richard Baguley 16 Comments

Your eyes are cool, but they aren’t very loud. You can remedy that with this build from [Sam Freeman]: a pair of Bluetooth speaker goggles. Combine a pair of old welders goggles with a Bluetooth receiver, a small amp and a couple of cheap speaker drivers and you’re well on your way to securing your own jet set radio future.

[Sam] found a set of speaker drivers that were the same size as the lenses of the goggles, as if they were designed for each other. They don’t do much for your vision, but they definitely look cool. [Sam] found that he could run the speakers for an hour or so from a small Lithium Ion battery that’s hidden inside the goggles, along with a large lever switch for that throwback electronics feel. The total cost of this build is a reasonably-low at $40, or less if you use bits from your junk pile.

The real trick is watching them in action and deciding if there’s any motion happening. Don’t get us wrong, they look spectacular but don’t have the visual feedback component of, say, the bass cannon. Look for yourself in the clip below. We might add a pair of googly eyes on the speakers that dance as they move, but that would get away from the more serious Robopunk look that [Sam] is going for. What would you add to build up the aesthetic of these already iconic goggles?

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