Category Archives: spectrum

Crowdfunding Is Now A Contract Between Company And Backer

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Kickstarter is not a store. Indiegogo is not a store. Crowdfunding is not buying something — you’re merely donating some money, and you might get a reward for your pledge. Caveat emptor doesn’t apply, because there is no buyer, and no one can figure out what the correct Latin translation for ‘backer’ is. These are the realities that have kept Indiegogo and Kickstarter in business, have caused much distress in people who think otherwise, and have been the source of so, so many crowdfunding follies.

Now, finally, crowdfunding is being legally recognized as a store. The Register reports a court …read more

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Lamp Analysis Tells Sad Truth Behind The Marketing Hype

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Here in the northern hemisphere, winter has wrapped us in her monochromatic prison. A solid deck of gray clouds means you need a clock to tell the difference between night and day, and by about the first week of February, it gets to feeling like you’ll never see a blue sky again. It’s depressing, to be honest, and the lack of sunlight can even lead to a mood disorder known as SAD, or seasonal affective disorder.

SAD therapy is deceptively simple — bright full-spectrum light, and lots of it, to simulate the sun and stimulate the lizard brain within us. …read more

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Tapping into a Ham Radio’s Potential with SDRPlay

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Software-defined radios are great tools for the amateur radio operator, allowing visualization of large swaths of spectrum and letting hams quickly home in on faint signals with the click of a mouse. High-end ham radios often have this function built in, but by tapping into the RF stage of a transceiver with an SDR, even budget-conscious hams can enjoy high-end features.

With both a rugged and reliable Yaesu FT-450D and the versatile SDRPlay in his shack, UK ham [Dave (G7IYK)] looked for the best way to link the two devices. Using two separate antennas was possible but inelegant, and switching …read more

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Cleaning up a Low-Cost Buck-Boost Supply

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Cheap DC-DC converters have been a boon on the hobbyist bench for a while now, but they can wreak havoc with sensitive circuits if you’re not careful. The problem: noise generated by the switch-mode supply buried within them. Is there anything you can do about the noise?

As it turns out, yes there is, and [Shahriar] at The Signal Path walks us through a basic circuit to reduce noise from DC-DC converters. The module under the knife is a popular buck-boost converter with a wide input range, 0-32 VDC output at up to 5 amps, and a fancy controller with …read more

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Cascade LNAs and Filters for Radioastronomy with an SDR

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It may not be the radio station with all the hits and the best afternoon drive show, but 1420.4058 MHz is the most popular frequency in the universe. That’s the electromagnetic spectral line of hydrogen, and it’s the always on the air. But studying the H-line is a non-trivial task unless you know how to cascade low-noise amplifiers and filters to use an SDR for radio astronomy.

Because the universe is mostly made of hydrogen, H-line emissions are abundant, and their distribution can tell us a lot about the structure of galaxies. The 21-cm emission line is so characteristic and …read more

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A Multicore ZX Spectrum

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From the blog of [telmomoya] we found his latest project: a hardware based multicore solution for a ZX Spectrum Emulator. It’s not the first time we feature one of his builds, last year we was working on a ARM Dual-Core Commodore C64. Luckily for Speccy fans, it seems a ZX Spectrum project was just unavoidable.

At its heart is the EduCIAA NXP Board, a Dual Core (M4 & M0) 32-bit microcontroller, based on the NXP LPC4337. It’s an Argentinan-designed microcontroller board, born from an Argentinian academic and industry joint venture. [telmomoya] took advantage of  the multicore architecture by running the …read more

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A Multicore ZX Spectrum

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From the blog of [telmomoya] we found his latest project: a hardware based multicore solution for a ZX Spectrum Emulator. It’s not the first time we feature one of his builds, last year we was working on a ARM Dual-Core Commodore C64. Luckily for Speccy fans, it seems a ZX Spectrum project was just unavoidable.

At its heart is the EduCIAA NXP Board, a Dual Core (M4 & M0) 32-bit microcontroller, based on the NXP LPC4337. It’s an Argentinan-designed microcontroller board, born from an Argentinian academic and industry joint venture. [telmomoya] took advantage of  the multicore architecture by running the …read more

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Power For An Amstrad Spectrum

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If you were an American child of the early 1980s then perhaps you were the owner of a Commodore 64, an Apple II, or maybe a TRS-80. On the other side of the Atlantic in the UK the American machines were on the market, but they mostly lost out in the hearts and minds of eager youngsters to a home-grown crop of 8-bit micros. Computer-obsessed British kids really wanted Acorn’s BBC Micro, but their parents were more likely to buy them the much cheaper Sinclair ZX Spectrum.

Sinclair Research was fronted by the serial electronic entrepreneur [Clive Sinclair], whose love …read more

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Making a Spectrum Analyzer the Wrong Way on an ATtiny85

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Everyone’s a critic, but it’s hard to argue with success. And that’s exactly what [agp.cooper] has with his ATtiny85-based spectrum analyzer devices.

The “normal” way to build a spectrum analyzer is to collect a bunch of samples and run a Fast Fourier Transform (FFT) on them all in one shot. As the name implies, the FFT is fast, and the result is the frequency components of the sampled data. [agp.cooper]’s “wrong” way to do it takes the Goertzel algorithm, which is used for detecting the intensity of a particular frequency, and scanning across the frequency range of interest. It’s a …read more

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The Tribe Protesting the Dakota Pipeline Is Ready to Defend Its Wireless Network

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“We as tribal nations have never given up our airspace.” Continue reading The Tribe Protesting the Dakota Pipeline Is Ready to Defend Its Wireless Network→