Hackaday Links: January 15, 2023

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It looks like the Martian winter may have claimed another victim, with reports that Chinese ground controllers have lost contact with the Zhurong rover. The solar-powered rover was put into hibernation back in May 2022, thanks to a dust storm that kicked up a couple of months before the start of local winter. Controllers hoped that they would be able to reestablish contact with the machine once Spring rolled around in December, but the rover remains quiet. It may have suffered the same fate as Opportunity, which had its solar panels covered in dust after a planet-wide sandstorm and eventually gave up the ghost.

What’s worse, it seems like the Chinese are having trouble talking to the Tianwen-1 orbiter, too. There are reports that controllers can’t download data from the satellite, which is a pity because it could potentially be used to image the Zhurong landing site in Utopia Planitia to see what’s up. All this has to be taken with a grain of dust, of course, since the Chinese aren’t famously transparent with their space program. But here’s hoping that both the rover and the orbiter beat the odds and start doing science again soon.

Click to enlarge — you won’t regret it. Image credit: NRAO/GBO/Raytheon/NSF/AUI

Closer to home, you may have heard that there’s a place in West Virginia that really, really doesn’t like extraneous RF noise, to the point where the cafeteria microwave oven is inside a Faraday cage. It’s the National Radio Quiet Zone, a 13,000-square-mile electromagnetic radiation safe zone around the Green Bank Telescope. But the rule against microwaves is apparently negotiable, as the enormous radio telescope has now been equipped with a 700-Watt microwave transmitter that was used to take a fantastically detailed picture of Tycho Crater. The GBT transmitter, which is less powerful than the caged microwave in the cafeteria, painted the Moon with signals that bounced back toward the Very Long Baseline Array, a radio telescope with dishes at ten locations across the United States. The photo returned was amazing, and with a 5-meter resolution, the crispest picture of the Moon ever taken from Earth. They also used the system to image a potential planet-killing 1 km asteroid at a distance of 2.1 million km. Not bad for half a microwave oven.

If you’ve got someone in your life who just doesn’t grok electronics, you’re in luck. Our friend Leo Fernekes has started a new video series on learning electronics. His first episode covers the fundamentals of current flow and resistance and we found it to be very well done. Bear in mind that Leo is self-taught, and his teaching style flows from that. So yes, he uses the “marbles in a pipe” metaphor for electron flow, which always seems to cause some people distress, but is a useful model nonetheless. He’s also quick to dismiss electron flow, as opposed to conventional “plus to minus” flow, as unimportant to a practical understanding of electronics, as in being able to build fun and useful circuits. We’re excited to see the rest of this series, and looking forward to a fresh perspective from someone who has done the hard work of teaching himself a complex subject.

Also for your further viewing pleasure, we’d like to draw your attention to a channel called Inheritance Machining. It’s run by a fellow named Brandon, a trained machinist with the good fortune to inherit his grandfather’s complete machine shop. He’s now using the tools and machines to do what every machinist does, which of course is to make more tools and machines. But he’s got a great style, and everything he does is pretty much within the constraints of the setup his grandfather left him. So no CNC, no lasers or plasma — just making chips the old-fashioned way. He even eschews CAD tools, opting instead for real drafting using Grandad’s old drafting table and tools. That alone is worth the price of admission — very relaxing. Check it out.

And finally, this is something that cropped up in the Hackaday Discord tip line that was so clever we thought we’d pass it along. It’s a short video describing how Australia provides cell phone service in remote areas of the Outback. These aren’t phone booths in the traditional sense, but rather dish reflectors set up to capture signals from distant cell towers and focus them onto a single point. There’s a stand for your phone at the focus, where the boosted signal is strongest. It’s completely passive, but still provides enough amplification to boost a “none-to-one bar” signal to something more usable. Pretty clever!

18 thoughts on “Hackaday Links: January 15, 2023

      1. Couldn’t you use a metal mesh to reflect the phone signal and let (some) of the wind through? But I suppose the bigger it gets the more expensive it gets and then there goes the cost effectiveness of the whole thing.

  1. Ever since that Bond villain blew up Arecibo, radio telescopes have lacked transmitting capability. So I guess they had to add it elsewhere. But they know when they are transmitting.

  2. Hmm? I get one bar and know others too at home in the city. Cheap plan carriers to blame. I’ve got an old Direct-TV dish around here somewhere…

    The good question is where is the antenna on any particular cellphone? On the top right next to your head or at the bottom which is often free of hand blockage and farther away from your head. If on the bottom the metal arm and holder of these sites would block the antenna rather well. Top or bottom? I kinda miss those old pull up the antenna phones and remember standing on a chair for a boost when indoors. As a ham I want to know where the real antenna is.

  3. Passive reflectors for all kinds of telecommunications can be found in the alps, they first appeared many decades ago to bring TV to small valleys, often privately erected and well disguised for legal reasons. Nowadays they are primarily used for mobile phone or to get microwave links round the bend.
    Here is a not so old one on top of Piz Boè in the Dolomites (Italy):

    1. It says “He’s also quick to dismiss electron flow, as opposed to conventional “plus to minus” flow”. Electrical Engineers draw current flow from plus to minus, so “hole” flow, unlike physicists and technicians who view current flow from minus to plus.

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