Something that you generally don’t expect as a North-America-based enthusiast, is to listen in on Russian military communications during their war in Ukraine via WebSDR, or that these communications would be passing through US military satellites that are happy to just broadcast anything. Yet that’s the situation that the Saveitforparts YouTube channel recently described. As it turns out, there is a gaggle of UFOs up there, as the US DoD lovingly calls them.

Between 1979 and 1989 eight FLTSATCOM launches took place, with FLTSATCOM 7 and 8 still operating today. They were later joined by their successor UHF Follow-On (UFO) with 11 launches between 1993 and 2003. All of these operate in the UHF spectrum, with some UFO satellites also covering other bands. Their goal is to provide communication for the military’s forces, with these satellites for the most part acting as simple repeaters. Over time non-military parties learned to use these satellites too, even if it’s technically illegal in many jurisdictions.

As described in the video, if you listen in on WebSDR streams from Ukraine, you can not only find encrypted military comms, but also unencrypted Russian radio traffic. It seems that in lieu of being provided with proper (encrypted) radio systems, Russian forces are using these US military satellites for communication much like how US (and NATO) forces would have. This is reminiscent of how Russian troops were caught using Discord via Starlink for communication, before Russian command shutdown Discord.

Thanks to [Stephen Walters] for the tip.

One of the problems with quantum bits, or “qubits”, is that they tend to be rather fragile, with a high sensitivity to external influences. Much of this is due to the atoms used for qubits having two distinct spin states of up or down, along with the superposition. Any disturbing of the qubit’s state can cause it to flip between either spin, erasing the original state. Now antimony is suggested as a better qubit atom by researchers at the University of New South Wales in Australia due to it having effectively eight spin states, as also detailed in the university press release along with a very tortured ‘cats have nine lives’ analogy.

For the experiment, also published in Nature Physics, the researchers doped a silicon semiconductor with a single antimony atom, proving that such an antimony qubit device can be manufactured, with the process scalable to arrays of such qubits. For the constructed device, the spin state is controlled via a transistor constructed on top of the trapped atom. As a next step a device with closely spaced antimony atoms will be produced, which should enable these to cooperate as qubits and perform calculations.

By having the qubit go through many more states to fully flip, these qubits can potentially be much more stable than contemporary qubits. That said, there’s still a lot more research and development to be done before a quantum processor based this technology can go toe-to-toe with a Commodore 64 to show off the Quantum Processor Advantage. Very likely we’ll be seeing more of IBM’s hybrid classical-quantum systems before that.

Sometimes you come across a purported scientific paper that makes you do a triple-check, just to be sure that you didn’t overlook something, as maybe the claims do make sense after all. Such is the case with a recent publication in the Langmuir journal by [Budlayan] and colleagues titled Droplet-Scale Conversion of Aluminum into Transparent Aluminum Oxide by Low-Voltage Anodization in an Electrowetting System.

Breaking down the claims made and putting them alongside the PR piece on the [Ateneo De Manila] university site, we start off with a material called ‘transparent aluminium oxide’ (TAlOx), which only brings to mind aluminium oxynitride, a material which we have covered previously. Aluminium oxynitride is a ceramic consisting of aluminium, oxygen and nitrogen that’s created in a rather elaborate process with high pressures.

In the paper, however, we are talking about a localized conversion of regular aluminium metal into ‘transparent aluminium oxide’ under the influence of the anodization process. The electrowetting element simply means overcoming the surface tension of the liquid acid and does not otherwise matter. Effectively this process would create local spots of more aluminium oxide, which is… probably good for something?

Combined with the rather suspicious artefacts in the summary image raising so many red flags that rather than the ‘cool breakthrough’ folder we’ll be filing this one under ‘spat out by ChatGPT’ instead, not unlike a certain rat-centric paper that made the rounds about a year ago.

Determining that a cable has a broken conductor is the easy part, but where exactly is the break? In a recent video, [Richard] over at the Learn Electronics Repair channel on YouTube gave two community-suggested methods a shake to track down a break in a proprietary charging cable. The first attempt was to run a mains power detector along the cable to find the spot, but he didn’t have much luck with that.

The second method involved using the capacitance of the wires, or specifically treating two wires in the cable as the electrodes of a capacitor. Since the broken conductor will be shorter, it will have less capacitance, with the ratio theoretically allowing for the location of the break in the wire to be determined.

In the charging cable a single conductor was busted, so its capacitance was compared from both sides of the break and compared to the capacitance of two intact conductors. The capacitance isn’t much, on the order of dozens to hundreds of picofarads, but it’s enough to make an educated guess of where the rough location is. In this particular case the break was determined to be near the proprietary plug, which ruled out a repair as the owner is a commercial rental shop of e-bikes.

To verify this capacitor method, [Richard] then did it again on a piece of mains wire with a deliberate cut to a conductor. This suggested that it’s not a super accurate technique as applied, but ‘good enough’. With a deeper understanding of the underlying physics it likely can be significantly more accurate, and it’s hardly the only way to find broken conductors, as commentators to the video rightly added.

Thanks to [Jim] for the tip.

On February 13th of 2023, ARCA of the kilometre cubic neutrino telescope (KM3NeT) detected a neutrino with an estimated energy of about 220 PeV. This event, called KM3-230213A, is the most energetic neutrino ever observed. Although extremely abundant in the universe, neutrinos only weakly interact with matter and thus capturing such an event requires very large detectors. Details on this event were published in Nature.

Much like other types of telescopes, KM3NeT uses neutrinos to infer information about remote objects and events in the Universe, ranging from our Sun to other solar systems and galaxies. Due to the weak interaction of neutrinos they cannot be observed like photons, but only indirectly via e.g. photomultipliers that detect the blue-ish light of Cherenkov radiation when the neutrino interacts with a dense medium, such as the deep sea water in the case of ARCA (Astroparticle Research with Cosmics in the Abyss). This particular detector is located at a depth of 3,450 meters off the coast of Sicily with 700 meter tall detection units (DUs) placed 100 meters apart which consist out of many individual spheres filled with detectors and supporting equipment.

With just one of these high-power neutrinos detected it’s hard to say exactly where or what it originated from, but with each additional capture we’ll get a clearer picture. For a fairly new neutrino telescope project it’s also a promising start especially since the project as a whole is still under construction, with additional detectors being installed off the coasts of France and Greece.

Good news for everyone who cannot get enough from improbably shaped boats that get referred to as a bench: the current owner (NTI Group) of the copyright has announced that 3DBenchy has been released into the public domain. This comes not too long after Prusa’s Printables website had begun to purge all derived models to adhere to the ‘no derivatives’ license. According to NTI, the removal of these derived models was not requested by NTI, but by a third-party report, unbeknownst to NTI or the original creator of the model. Recognizing its importance to the community, 3DBenchy can now be downloaded & modified freely.

NTI worked together with the original creator [Daniel Norée] and former Creative Tools CEO [Paulo Kiefe] to transition 3DBenchy and the associated website to the public domain, with the latter two having control over the website and associated social media accounts. Hopefully this means that the purged models on Printables can be restored soon, even if some may prefer to print alternate (literal) benches.

The unfortunate part is that much of this mess began courtesy of the original 3DBenchy license being ignored. If that point had been addressed many years ago instead of being swept under the rug by all parties involved, there would have been no need for any of this kerfuffle.

Car infotainment systems somehow have become a staple in today’s automobiles, yet when it comes down to it they have all the elegance of a locked-down Android tablet. In the case of the Honda infotainment system that [dosdude1] got from a friend’s 2016/2017-era Honda Accord, it pretty much is just that. Powered by a dual-core Cortex-A15 SoC, it features a blazin’ 1 GB of RAM, 2 GB of storage and runs Android 4.2.2. It’s also well-known for crashing a lot, which is speculated to be caused by Out-of-RAM events, which is what the RAM upgrade is supposed to test.

After tearing down the unit and extracting the main board with the (Renesas) SoC and RAM, the SoC was identified as being an automotive part dating back to 2012. The 1 GB of RAM was split across two Micron-branded packages, leaving one of the memory channels on the SoC unused and not broken out. This left removing the original RAM chips to check what options the existing pads provided, specifically potential support for twin-die chips, but also address line 15 (A15). Unfortunately only the A15 line turned out to be connected.

This left double capacity (1 GB) chips as the sole option, meaning a total of 2 GB of RAM. After installation the infotainment system booted up, but only showed 1 GB installed. Cue hunting down the right RAM config bootstrap resistor, updating the boot flags and updating the firmware to work around the LINEOWarp hibernation image that retained the 1 GB configuration. Ultimately the upgrade seems to work, but until the unit is reinstalled in the car and tested it’s hard to say whether it fixes the stability issues.

Thanks to [Dylan] for the tip.

Like many pieces of lab equipment, oscilloscopes are both extremely useful and rather intimidating to a fledgling user. Unlike a digital multimeter with its point-and-measure functionality, digital storage oscilloscopes (DSOs) require fundamental knowledge before they can be used properly. Yet at the same time nobody likes reading manuals, so what is one to do? Try the Absolute Beginner’s Guide to DSOs  by [Arthur Pini]

[Pini’s] Cliff’s Notes version of your scope’s manual isn’t half bad. It covers the basic user interface and usage of a (stand-alone) DSO. Unfortunately, it focuses a bit too much on a fancy touch-screen Teledyne LeCroy MSO rather than something the average hobbyist is likely to have lying around.

We rather like the PSA-type videos such as the classic ‘“How not to blow up your oscilloscope” video by [Dave] over at EEVBlog. Many guides and introductions cover “what to do,” but covering common safety issues like improper grounding, isolation, or voltages might be a better place to start.

What tutorial or reference work would you hand to an oscilloscope newbie? We can endorse a hands-on approach with a suitable test board. We also enjoyed [Alan’s] video on the topic. Even if you are an old hand, do you know how to use all those strange trigger modes?

The MP3 file format was always encumbered with patents, but as of 2017, the last patent finally expired. Although the format became synonymous with the digital music revolution that started in the late 90s, as an audio compression format there is an argument to be made that it has long since been superseded by better formats and other changes. [Ibrahim Diallo] makes that very argument in a recent blog post. In a world with super fast Internet speeds and the abstracting away of music formats behind streaming services, few people still care about MP3.

The last patents for the MP3 format expired in 2012 in the EU and  2017 in the US, ending many years of incessant legal sniping. For those of us learning of the wonders of MP3 back around ’98 through services like Napster or Limewire, MP3s meant downloading music on 56k dialup in a matter of minutes to hours rather than days to weeks with WAV, and with generally better quality than Microsoft’s WMA format at lower bitrates. When portable media players came onto the scene, they were called ‘MP3 players’, a name that stuck around.

But is MP3 really obsolete and best forgotten in the dustbin of history at this point? Would anyone care if computers dropped support  for MP3 tomorrow?

Alternatives

It’s hard to disagree with [Ibrahim]’s point that MP3 isn’t quite as important anymore. Still, his argument of AAC being a good alternative to MP3 misses that the AAC format is also patent-encumbered. Specifically, there’s a patent license for all manufacturers and developers of “end-user codecs,” which involves per-unit pricing. Effectively, every device (computer, headphones, smartphone, etc.) incurs a fee. That’s why projects like FFmpeg implement AAC and other encumbered formats while leaving the legal responsibilities to the end-user who actually uses the code.

While FLAC and Vorbis (‘ogg’) are truly open formats, they’re not as widely supported by devices. Much like VGA, MP3 isn’t so much sticking around because it’s a superior technological solution but because it Just Works^® anywhere, unlike fancier formats. From dollar store MP3 players to budget ‘boomboxes’ to high-end audio gear, they’ll all playback MP3s just fine. Other formats are likely to be a gamble, at best.

This compatibility alone means that MP3 is hard to dislodge, with formats like Ogg Vorbis trying to do so for decades and still being relatively unknown and poorly supported, especially when considering hardware implementations.

Audio Quality

Since the average person is not an audiophile who is concerned with exact audio reproduction and can hear every audio compression artefact, MP3 is still perfectly fine in an era where the (MP2-era) Bluetooth SBC codec is what most people seem to be content with. In that sense, listening to 320 kbps VBR MP3 files with wired headphones is a superior experience over listening to FLAC files with the Bluetooth SBC codec in between.

This leads to another point made by [Ibrahim]. The average person does not deal with files anymore. Many people use online applications for everything from multimedia to documents, which happily abstract away the experience of managing file formats. Yet, at the same time, there’s a resurgence in interest in physical media and owning a physical copy of content, which means dealing with files.

We see this also with MP3 players. Even though companies like Apple abandoned their iPod range and Sony’s current Walkmans are mostly rebranded Android smartphones with the ‘phone’ part stripped out, plenty of portable media players are available brand-new. People want portable access to their media in any format.

Amidst this market shift back to a more basic, less online focus, the MP3 format may not be as visible as it was even a decade ago, but it is by no means dead.

These days, rolling your own MP3 player is almost trivial. We’ve seen some fairly small ones.

As great as silicon is for semiconductor applications, it has one weakness in that using it for lasers isn’t very practical. Never say never though, as it turns out that you can now grow lasers directly on the silicon material. The most optimal material for solid-state lasers in photonics is gallium-arsenide (GaAs), but due to the misalignment of the crystal lattice between the compound (group III-V) semiconductor and silicon (IV) generally separate dies would be produced and (very carefully) aligned or grafted onto the silicon die.

Naturally, it’s far easier and cheaper if a GaAs laser can be grown directly on the silicon die, which is what researchers from IMEC now have done (preprint). Using standard processes and materials, GaAs lasers were grown on industry-standard 300 mm silicon wafers. The trick was to accept the lattice mismatch and instead focus on confining the resulting flaws through a layer of silicon dioxide on top of the wafer. In this layer trenches are created (see top image), which means that when the GaAs is deposited it only contacts the Si inside these grooves, thus limiting the effect of the mismatch and confining it to within these trenches.

There are still a few issues to resolve before this technique can be prepared for mass-production, of course. The produced lasers work at 1,020 nm, which is a shorter wavelength than typically used, and there are still some durability issues due to the manufacturing process that have to be addressed.

As a general rule of thumb, anything that has some kind of display output and a processor more beefy than an early 90s budget PC can run Doom just fine. As [John] AKA [Nyan Satan] demonstrates in a recent video, this includes running the original Doom on an Apple Lightning to HDMI Adapter. These adapters were required after Apple moved to Lightning from the old 30-pin connector which had dedicated pins for HDMI output.

As the USB 2.0 link used with Lightning does not have the bandwidth for 1080p HDMI, compression was used, requiring a pretty beefy processor in the adapter. Some enterprising people at the time took a hacksaw to one of these adapters to see what’s inside them and figure out the cause of the visual artifacts. Inside is a 400 MHz ARM SoC made by Samsung lovingly named the S5L8747. The 256 MB of RAM is mounted on top of the package, supporting the RAM disk that the firmware is loaded into.

Although designed to only run the Apple-blessed firmware, these adapters are susceptible to the same Checkm8 bootROM exploit, which enables the running of custom code. [John] adapted this exploit to target this adapter, allowing this PoC Doom session to be started. As the link with the connected PC (or Mac) is simply USB 2.0, this presumably means that sending keyboard input and the like is also possible, though the details are somewhat scarce on this aspect.

Soldering irons and their tips come in a wide range of formats and styles, with the (originally Hakko) T12 being one of the more interesting offerings. This is because of how it integrates not only the tip and heating element, but also a thermocouple and everything else in a self-contained package. In a recent video [Big Clive] decided to not only poke at one of these T12 tips, but also do a teardown.

These elements have three bands, corresponding to the power supply along with a contact for the built-in thermocouple. After a quick trip to the Vise of Knowledge, [Clive] allows us a glimpse at the mangled remnants of a T12, which provides a pretty good overview of how these tips are put together.

Perhaps unsurprisingly, most of the length is a hollow tube through which the wires from the three contacts run. These power the ceramic heating element, as well as provide the soldering iron handle access to the thermocouple that’s placed near the actual tip.

With a simple diagram [Clive] explains how these T12 elements are then used to regulate the temperature, which isn’t too distinct from the average soldering iron with ceramic heating element, but it’s still nice to have it all integrated rather than having to try to carefully not damage the ceramic heater while swapping tips with the average soldering iron.

Large language models (LLMs) are wholly dependent on the quality of the input data with which these models are trained. While suggestions that people eat rocks are funny to you and me, in the case of LLMs intended to help out medical professionals, any false claims or statements dripping out of such an LLM can have dire consequences, ranging from incorrect diagnoses to much worse. In a recent study published in Nature Medicine by [Daniel Alexander Alber] et al. the ease with which this data poisoning can occur is demonstrated.

According to their findings, only 0.001% of training tokens have to be replaced with medical misinformation to order to create models that are likely to produce medically erroneous statement. Most concerning is that such a corrupted model isn’t readily discovered using standard medical LLM benchmarks. There are filters for erroneous content, but these tend to be limited in scope due to the overhead. Post-training adjustments can be made, as can the addition of RAG, but none of this helps with the confident bull excrement due to corruption.

The mitigation approach that the researchers developed cross-references LLM output against biomedical knowledge graphs, to reduce the LLM mostly for generating natural language. In this approach LLM outputs are matched against the graphs and if LLM ‘facts’ cannot be verified, it’s marked as potential misinformation. In a test with 1,000 random passages detected issues with a claimed effectiveness of 91.9%.

Naturally, this does not guarantee that misinformation does not make it past these knowledge graphs, and largely leaves the original problem with LLMs in place, namely that their outputs can never be fully trusted. This study also makes it abundantly clear how easy it is to corrupt an LLM via the input training data, as well as underlining the broader problem that AI is making mistakes that we don’t expect.

The [Denki Otaku] YouTube channel took a look recently at some stepper motors, or ‘stepping motors’ as they’re called in Japanese. Using a 2-phase stepper motor as an example, the stepper motor is taken apart and its components explained. Next a primer on the types and the ways of driving stepper motors is given, providing a decent overview of the basics at the hand of practical examples.

As great as theoretical explanations are, there’s a lot of value in watching the internals of a stepper motor move when its coils are activated in order. Also demonstrated are PWM-controlled stepper motor drivers before diving into the peculiarities of microstepping, whereby the driving of the coils is done such that the stator moves in the smallest possible increments, often through flux levels in these coils. This allows for significantly finer positioning of the output shaft than with wave stepping and similar methods that are highly dependent on the number of phases and coils.

As demonstrated in the video, another major benefit of microstepping is that it creates much smoother movement while moving, but also noted is that servo motors are often what you want instead. This is a topic which we addressed in our recent article on the workings of stepper motors, with particular focus on the 4-phase 28BYJ-48 stepper motor and the disadvantages of steppers versus servos.

In his most recent article, [Ken Shirriff] takes a break from putting ASICs under a microscope, and instead does the same in a proverbial manner with the word ‘mainframe’. Although these days the word ‘mainframe’ brings to mind a lumbering behemoth of a system that probably handles things like finances and other business things, but originally the ‘main frame’ was just one of many ‘frames’. Which brings us to the early computer systems.

We have all seen the photos of early computer systems, which not only filled rooms, but which also tended to consist out of multiple units. This was something which the designers of the IBM 701 computer seem to have come up with, to make it possible to transport and install computer systems without cranes and the breaking out of walls. Within the IBM 701 system’s internal documentation, the unit containing the core logic was referred to as the ‘main frame’, alongside the ‘power frame’, the ‘core frame’, etc.

From this [Ken] then traces how the word ‘main frame’ got reused over the years, eventually making it outside of the IBM world, with a 1978 Radio Electronics magazine defining the ‘mainframe’ as the enclosure for the computer, separating it seemingly from peripherals. This definition seems to have stuck, with BYTE and other magazines using this definition.

By the 1960s the two words ‘main frame’ had already seen itself hyphenated and smushed together into a singular word  before the 1980s redefined it as ‘a large computer’. Naturally marketing at IBM and elsewhere leaned into the word ‘mainframe’ as a token of power and reliability, as well as a way to distinguish it from the dinky little computers that people had at home or on their office desk.

Truly, after three-quarters of a century, the word ‘mainframe’ has become a reflection of computing history itself.

Is fire conductive? As ridiculous that may sound at first glance, from a physics perspective the rapid oxidation process we call ‘fire’ produces a lot of substances that can reduce the electrical insulating (dielectric) properties of air. Is this change enough to allow for significant current to pass? To test this, [The Action Lab] on YouTube ran some experiments after being called out on this apparent fact in the comments to an earlier video.

Ultimately what you need to make ‘fire’ conductive is to have an appreciable amount of plasma to reduce the dielectric constant, which means that you cannot just use any rapid oxidation process. In the demonstration with lights and what appears to be a (relatively clean-burning) butane torch, the current conducted is not enough to light up an incandescent or LED light bulb, but can light up a 5 mm LED. When using his arm as a de-facto sensor, it does not conduct enough current to be noticeable.

The more interesting experiment here demonstrates the difference in dielectric breakdown of air at different temperatures. As the dielectric constant for hot air is much lower than for room temperature air, even a clean burning torch is enough to register on a multimeter. Ultimately this seems to be the biggest hazard with fire around exposed (HV) electrical systems, as the ionic density of most types of fire just isn’t high enough.

To reliably strike a conductive plasma arc, you’d need something like explosive (copper) wire and a few thousand joules to pump through it.

Crystal oscillators are incredibly useful components, but they come with one little snag: their oscillation is temperature-dependent. For many applications the relatively small deviation is not a problem, but especially for precision instruments this is a deal breaker. Enter the oven controlled crystal oscillator, or OCXO. These do basically what it says on the tin, but what’s inside them? [Kerry Wong] took apart a vintage Toyocom TCO-627VC 10 MHz OCXO, revealing a lot more complexity than one might assume.

Inside the insulated enclosure there is of course the crystal oscillator itself, which has a heating coil wrapped around it. Of note is that other OCXOs that [Kerry] took apart had more insulation, as well as other ways of providing the thermal energy. In this particular unit a thermistor is attached to the crystal’s metal case to measure its temperature and provide feedback to the heating circuit. The ICs on the PCB are hard to identify due to the conformal coating, but at least one appears to be a 74LS00, alongside a 78L05 voltage regulator which reduces the 12V input voltage.

As an older OCXO it probably is a lot chunkier than newer units, but the basic principle remains the same, with a heating loop that ensures that the crystal inside the unit remains at the same temperature.

Layer adhesion is one of the weak points with FDM 3D printing, with annealing often recommended as a post-processing step. An interestingly creative method for this was published in Science Advances back in 2017, featuring the work of researchers at Texas A&M University and citing previous work by other teams. In the paper by [Charles B. Sweeney] et al, they describe how they coated PLA filament with carbon nanotubes (CNTs), resulting in this CNT being distributed primarily between the individual layers of polymer.

This is useful because CNTs are quite sensitive to microwave radiation, resulting in the conversion to thermal energy, i.e. heat. Compared to traditional annealing where the entire part is placed into an oven or similar, this microwave-based heating – or locally induced RF (LIRF) as they call this method – localizes the heat to the interface between two layers.

The advantages of this approach are that it doesn’t change the dimensions of the part noticeably, it’s faster and more efficient, and the annealing between layers approaches the strength of traditional manufacturing. Unfortunately not too much seems to have happened with this approach since then, but considering that both CNTs (single & double-walled) and microwaves are readily available, there’s not much standing in the way of replicating these results.

When considering our favorite spy movies and kin that involve deep-sea diving, we’d generally expect to see some high-end watch that costs thousands of dollars and is specially engineered to withstand the immense pressures kilometers below the ocean’s surface. Yet what about a humble Casio F91W that can be bought for about $15 if it’s the genuine article and not one of the millions of fakes? Over at the Watches of Espionage site they figured that they’d dress up one of these famous watches to give it the best possible shot at surviving the crushing pressures at a depth of 5 km.

The actual modification to the F91W was pretty mild, involving nothing but a ‘hydro-mod’ whereby oil is used to replace the air inside the watch case. Since oil is incompressible, nothing bad should happen to the watch. Theoretically at least. The Watch-Under-Test (WUT) was strapped to a US Navy’s CURV 21 remotely operated vehicle and dunked into the ocean before starting its descend into the inky darkness of the deep sea.

Although only hitting a measly 4,950 m, the watch survived just fine, showing that even if you’re a secret US operative on a deep-dive espionage mission, all you really need is one of these Casio watches.