Broadcast Engineer at BellMedia, Computer history buff, compulsive deprecated, disparate hardware hoarder, R/C, robots, arduino, RF, and everything in between.
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Gathering Eclipse Data Via Ham Radio

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A solar eclipse is coming up in just a few weeks, and although with its path of totality near the southern tip of South America means that not many people will be able to see it first-hand, there is an opportunity to get involved with it even at an extreme distance. PhD candidate [Kristina] and the organization HamSCI are trying to learn a little bit more about the effects of an eclipse on radio communications, and all that is required to help is a receiver capable of listening in the 10 MHz range during the time of the eclipse.

It’s well-known that certain radio waves can propagate further depending on the time of day due to changes in many factors such as the state of the ionosphere and the amount of solar activity. What is not known is specifically how the paths can vary over the course of the day. During the eclipse the sun’s interference is minimized, and its impact can be more directly measured in a more controlled experiment. By tuning into particular time stations and recording data during the eclipse, it’s possible to see how exactly the eclipse impacts propagation of these signals. [Kristina] hopes to take all of the data gathered during the event to observe the doppler effect that is expected to occur.

The project requires a large amount of volunteers to listen in to the time stations during the eclipse (even if it is not visible to them) and there are only a few more days before this eclipse happens. If you have the required hardware, which is essentially just a receiver capable of receiving upper-sideband signals in 10 MHz range, it may be worthwhile to give this a shot. If not, there may be some time to cobble together an SDR that can listen in (even an RTL-SDR set up for 10 MHz will work) provided you can use it to record the required samples. It’s definitely a time that ham radio could embrace the hacker community.

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tekvax
3 hours ago
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Burlington, Ontario
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Modem noise spectrogram

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Scotty H created this spectrographic animation of a classic dial-up modem's startup noise. Here's a breakdown, by Oona Räisänen, of what each section concerns:

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tekvax
6 hours ago
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Burlington, Ontario
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Incredibly detailed, track-by-track analysis of the Doctor Who theme music

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Picture of Delia Derbyshire, cocreator of the Doctor Who theme music

This web site does only one thing, but does it incredibly well: It offers a nuanced, track-by-track analysis of the Doctor Who theme music originally composed in 1963.

The writers here — Danny Stewart, Ian Stewart, and Josef Kenny — break down the musical score of each track, pointing out cool details I'd never noticed (like the fact that there are two separate bass tracks that form a nifty counterpoint with each other). — Read the rest

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tekvax
6 hours ago
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Burlington, Ontario
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Vader star David Prowse dead at 85

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David Prowse, the towering English weightlifter and actor who played Darth Vader in the Star Wars trilogy, is dead at 85.

Prowse was cast as Vader for his imposing physique, even though the role was voiced by James Earl Jones.

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tekvax
2 days ago
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Rest in Peace Mister Prowse.
Burlington, Ontario
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Taking Over the Amazing Control Panel of a Vintage Video Switcher

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Where does he get such wonderful toys? [Glenn] snagged parts of a Grass Valley Kalypso 4-M/E video mixer control surface from eBay and since been reverse engineering the button and display modules to bend them to his will. The hardware dates back to the turn of the century and the two modules would have been laid out with up to a few dozen others to complete a video mixing console.

[Glenn’s] previous adventures delved into a strip of ten backlit buttons and gives us a close look at each of the keyswitches and the technique he used to pull together his own pinout and schematic of that strip. But things get a lot hairier this time around. The long strip seen above is a “machine control plane” module and includes a dozen addressible character displays, driven by a combination of microcontrollers and FPGAs. The square panel is a “Crosspoint Switch Matrix” module include eight individual 32 x 32 LCDs drive by three dedicated ICs that can display in red, green, or amber.

[Glen] used an STM8 Nucleo 64 to interface with the panels and wrote a bit of code to help map out what each pin on each machine control plane connector might do. He was able to stream out some packets from the plane that changed as he pressed buttons, and ended up feeding back a brute-force of that packet format to figure out the LED display protocols.

But the LCDs on the crosspoint switch were a more difficult nut to crack. He ended up going back to the original source of the equipment (eBay) to get a working control unit that he could sniff. He laid out a man-in-the-middle board that has a connector on either side with a pin header in the middle for his logic analyzer. As with most LCDs, the secret sauce was the initialization sequence — an almost impossible thing to brute force, yet exceedingly simple to sniff when you have a working system. So far he has them running under USB control, and if you are lucky enough to have some of this gear in your parts box, [Glen] has painstakingly recorded all of the details you need to get them up and running.

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tekvax
3 days ago
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Burlington, Ontario
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How does sound travel through space?

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Twenty Thousand Hertz is a podcast about sounds. Case in point: the latest episode, "Space Audity," which explores how, exactly, sound travels through the vacuum space, and the very practical technological complications that would make potential Martian communications difficult. — Read the rest

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tekvax
3 days ago
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Burlington, Ontario
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