qjkxbmwvz

joined 2 years ago
[–] qjkxbmwvz@startrek.website 2 points 2 days ago

Your numbers seem reasonable


more intuitive for me to work in terms of pressure. Atmosphere is (roughly) 1e3 Torr, good UHV can be around 1e-10, so that's 13 orders of magnitude, which is (roughly) the same difference that you calculated.

[–] qjkxbmwvz@startrek.website 34 points 2 days ago (4 children)

I am becoming increasingly more appreciative of the fact that I have root access to "my" company provided work device.

[–] qjkxbmwvz@startrek.website 33 points 2 days ago* (last edited 2 days ago) (7 children)

Aluminum foil is very common in physics labs. And a main use for it is "baking"! To get ultra high vacuum (UHV)* you generally need to "bake out" your chamber while you pump down. Foil is used same as with baking food


keep the heat in and evenly distributed on the chamber.

Sadly, it's usually not food grade aluminum foil, as that can contain oils, and oils and vacuum are generally a big no-no.

*Just how good is UHV? Roughly: I live in San Francisco, which is ~7 miles by ~7 miles (~11km). Imagine you raise that by another 7 miles to make a cube. Now, evacuate every last molecule of gas out of it. Now take a family sedan's trunk, fill it with 1 atmosphere of gas, and release that into the 7 mile cube. That's roughly UHV pressure.

[–] qjkxbmwvz@startrek.website 42 points 3 days ago (4 children)

From TFA:

"I have failed you completely and catastrophically," Gemini CLI output stated. "My review of the commands confirms my gross incompetence."

[–] qjkxbmwvz@startrek.website 6 points 3 weeks ago

ZigBee router thing:

I've been happy with the SMLIGHT SLZB-06M. You can easily flash firmware, and it has PoE which was important for me. I believe it also supports Thread, but I haven't tried this yet (and I'm not sure if it supports it at the same time as Zigbee).

Zigbee smart plugs from Third Reality have been pretty solid in my experience, and they report power usage.

For circuit breaker level monitoring, I have an Emporia Vue2. I have it running esphome, completely local


unfortunately this requires some simple soldering and flashing, so it's not turnkey. But it's been rock solid ever since flashing it. (Process is well documented online.)

I've had decent luck with cheap wifi Matter bulbs, but provisioning them is finicky, and sometimes they just crap out and need to be power cycled; Zigbee bulbs (e.g., Ikea) have generally been reliable, though sometimes I've had difficulty pairing them initially. After power cycling a Matter WiFi bulb, it takes a while for it to respond to Home Assistant; Zigbee bulbs generally respond as soon as you power them on.

I have a wired smart light switch from TP-Link/Kasa (KS205), and it's been completely hassle free (and totally local


Matter over wifi). The Kasa smart switch dongles I have work flawlessly but need proprietary pairing, and I'm afraid to update firmware in case they lose local support.

Good luck! Fun adventure :)

[–] qjkxbmwvz@startrek.website 12 points 1 month ago (1 children)

I think a lot of companies view their free plan as recruiting/advertising


if you use TailScale personally and have a great experience then you'll bring in business by advocating for it at work.

Of course it could go either way, and I don't rely on TailScale (it's my "backup" VPN to my home network)... we'll see, I guess.

[–] qjkxbmwvz@startrek.website 2 points 1 month ago

Sawyer filter inline with a camelback is awesome. I'd just fill up my camelback in a stream using a (clean) handkerchief to get the large debris out and then let the filter do the rest.

[–] qjkxbmwvz@startrek.website 3 points 1 month ago

Yep, you're right


I was just responding to parent's comment about fiber being best because nothing is faster than light :)

[–] qjkxbmwvz@startrek.website 13 points 1 month ago* (last edited 1 month ago) (3 children)

That's...not really a cogent argument.

Satellites connect to ground using radio/microwave (or even laser), all of which are electromagnetic radiation and travel at the speed of light (in vacuum).

Light in a fiber travels much more slowly than in vacuum


light in fiber travels at around 67% the speed of light in vacuum (depends on the fiber). In contrast, signals through cat7 twisted pair (Ethernet) can be north of 75%, and coaxial cable can be north of 80% (even higher for air dielectric). Note that these are all carrying electromagnetic waves, they're just a) not in free space and b) generally not optical frequency, so we don't call them light, but they are still governed by the same equations and limitations.

If you want to get signals from point A to point B fastest (lowest latency), you don't use fiber, you probably use microwaves: https://arstechnica.com/information-technology/2016/11/private-microwave-networks-financial-hft/

Finally, the reason fiber is so good is complicated, but has to do with the fact that "physics bandwidth" tends to care about fractional bandwidth ("delta frequency divided by frequency"), whereas "information bandwidth" cares about absolute bandwidth ("delta frequency"), all else being equal (looking at you, SNR). Fiber uses optical frequencies, which can be hundreds of THz


so a tiny fractional bandwidth is a huge absolute bandwidth.

[–] qjkxbmwvz@startrek.website 5 points 1 month ago

80% of the USA lives within urban areas (source). Urban "fiberization" is absolutely within reach.

Agree that running fiber out to very remote areas is tricky, but even then it's probably not prohibitive for all but the most remote locations.

[–] qjkxbmwvz@startrek.website 8 points 2 months ago* (last edited 2 months ago)

So the irony is

I see what you did there...

[–] qjkxbmwvz@startrek.website 11 points 2 months ago (1 children)

I think you mean more scrupulous, not less.

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