I always include Makefiles as a way of documenting useful (short) tasks for developers that are onboarding to projects. It gives them confidence in their ability to pick things up quickly. Whether or not they want to actually use make is up to them, but it’s one more thing they can reference.
Plex focuses on having a server component that transcodes and their “Plex Pass” service for better connectivity, enabling lightweight native players for all of your devices. This way you can watch any of your content on anything even over cellular, even if it’s a weird format that the device wouldn’t easily support.
This is a departure from the traditional XBMC-on-device that also acts as the client trying to play any format of content.
Kodi is amazing and I’d use it if it weren’t for the fact that I don’t want a new interface, I simply want my “owned” content to show up as Yet Another App on my stream boxes and phones. Plex fits that bill.
Radio is part of the EM spectrum. EM waves (including light) decay under water at an exponential rate due to absorption by the medium. So data transmission underwater must rely instead on mechanical waves (sound).
This is why underwater robots mostly use tethers, otherwise you couldn't control them very well (RC control would stop working at a very shallow depth).
Note: why are folks downvoting an honest question?
I remember being told in some physics class that visible light is actually the radiation which penetrates the most, and that indeed this may be the very reason why it's visible: eyes were developed when life was still aquatic, therefore they evolved to be sensitive to the range of frequencies that could reach them.
Yeah it does penetrate the most, so you do see some communications utilizing visible light comms. But the bitrate is bad and gets worse very quickly as you go deeper. Like, sunlight will penetrate the water a lot especially since there's so much of it coming down broad spectrum, but shoot a laser into seawater and you'll find the beam dissipates rather quickly.
It's mostly water-to-surface comms that can tolerate being in the very top of the water column that utilize this tech. Unfortunately aligning the transmitter/receivers is a bit tricky -- a lot of research has gone into better ways to send and receive information from air into water.
I guess it makes sense if eyes developed aquatically first, but it doesn't seem that interesting in the sense that most things developed aquatically first. Like even if it didn't develop aquatically, seems like evolution would have found its way on land, where sight is more useful, especially since you can't use things like lateral lines to detect pressure fluctuations (I mean there's terrestrial hearing, but seems like being immersed in a dense medium makes pressure sensing that much more important).
Most water you’d drop a phone into has enough traces of salt to make it conductive. Therefore, the water acts like a faraday cage.
Theres a calculation you can do to calculate this, its pretty standard E&M stuff. Basically you calculate the skin depth of the material and thats as far as the signal can penetrate. The derivation highlights some cool things:
1. Its frequency dependent. This is why military submarines communicate at around 30 Hz.
2. Your audio cable (and all high frequency power cables) are stranded
3. Your microwave is effectively shielded with a thin layer of metal
4. An induction stove wont work with Al pans, but will quickly melt Al foil
Lots of answers already, but let me contribute this little heuristic:
Radio waves, being EM radiation, are just light - like "visible light", except our eyes can't see it. There are some peculiarities related to wavelengths (particularly when they get very large, or close to the size of a regular surface pattern of an illuminated object), but to a good approximation, you can mentally replace "radio antenna" with "a lightbulb", and make correct determinations about how radio behaves.
In this case: much like you can't see much in water, compared to air, and a submerged flashlight also doesn't shine very far, a submerged phone has a hard time seeing signals, and its emissions don't travel far either.
That's a good question, submarines use very low frequencies for communication, so I assume bluetooth/GSM might be pretty attenuated by the water? But also it might have turned off due to the water shorting something?
Yes, generally the smaller the wavelength, the worse the attenuation. Quick googling: 4g is 600Mhz to 2.5Ghz or 0.5m to 12.5cm wavelength. For comparison, the US Navy uses 80Hz or 3750km wavelength to talk to submerged submarines.[1]
> VLF waves used to communicate with submarines have created an artificial bubble around the Earth that can protect it from solar flares and coronal mass ejections; this occurred through interaction with high-energy radiation particles.
That sounds absolutely weird - how should that "...that can protect it from solar flares..." be interpreted?
4G and 5G are going to depend on the mobile carrier. In the US, at least, that's usually going to be somewhere between 850MHz and 2100MHz. I recall reading something more recent about 700MHz being opened up in some areas.
Looks like Germany is 700-2600MHz for 4G, with 5G up at 3500MHz[0].
For underwater stuff it looks like you need something much lower in the kHz range[1], at least for distances of up to a couple hundred feet. Obviously this particular situation involves a much shorter distance. The page on MF radio[2] does mention water, and talks about frequencies up to 3MHz, but that's still way lower than any LTE bands used.
Verizon has used 700MHz for a long time, its their primary band. T-mobile uses 700MHz and 600MHz in many areas (generally as range extension, not a primary band).
the same general reason why microwave band radio sees signal fade when there's rain on a point-to-point link through the air, but magnified greatly since the radio is now inside a solid mass of water. One of the problems faced by modern submarines for data communications, they use either ELF/VLF trailing antennas that are spooled out, while running 'kind of' shallow, or buoys, or antennas on periscope masts.
While it comes across as an obvious cash grab, the cassette is a compelling feature if you consider that it does 30 washes and has its own memory of how many each has left. While it is 2x-3x the cost of traditional dishwasher pods, they are focusing on convenience — all the way down to automatic delivery and return — which deserves to be recognized as innovation in end-to-end product design, service, fulfillment, and product lifecycle.
Does someone come into the house and change it out?
I spend a lot more time (still not much) loading and unloading the dishes than I spend acquiring and pouring powder, so I'm not sure what value I'm supposed to think this would provide.
You can have about the same experience with standard tablets though and none of the wasteful shipping and plastic cartridges. The dishwasher can be online (for those who want it) and report back the amount of washes (the backend can calculate the amount of washes per week to predict when you're going to run out) so that the manufacturer can send a new box in advance.
Make it last something like half year and I'm keen. Packaging in regular shops isn't particular great either. Hand soap and tooth paste being worst. The amount of packaging we throw with food is completely crazy.
Looking beyond the obvious problem here, just curious why the admin ran chkdsk /f for no reason, then did it on 6 more systems after observing it caused ntfs failure.
https://m.xkcd.com/242/ maybe. One hopes the reporter had backups (or was testing on disposable systems) before trying to reproduce a data-loss condition.
