ianburrell (u/ianburrell)

ianburrell commented on What if every city had a London Overground? dwell.com/article/what-if... · Posted by u/edward

nkrisc · 17 hours ago

> people are being whisked through a network of tunnels, deep below the bustling city

Also compared to London or many metro systems, Chicago’s is not deep underground at all. As a Chicagoan I was very surprised the first time I saw some of the escalators in London or Washington.

In some parts Chicago’s is almost literally just basement level with nearby buildings.

ianburrell · 14 hours ago

The big innovation for the Underground was the tunneling shield. It kept the tunnel from collapsing and has places for people to dig out the face.

The reason that the Underground uses small tunnels was because expensive even then to pay people to dig out tunnels by hand.

ianburrell commented on World Wide Lightning Location Network wwlln.net/... · Posted by u/perihelions

perihelions · 2 days ago

20th-century navigation used to operate like that, except using artificial radio sources—fixed beacons. I guess you could answer a lot of technical questions by looking at OMEGA, which, similar to lightning-generated RF, used the VLF range (3–30 kHz), and had global range bouncing off the ionosphere,

https://en.wikipedia.org/wiki/Hyperbolic_navigation ("Hyperbolic navigation")

https://en.wikipedia.org/wiki/Omega_(navigation_system) ("Omega (navigation system)")

> "OMEGA was the first global-range radio navigation system, operated by the United States in cooperation with six partner nations. It was a hyperbolic navigation system, enabling ships and aircraft to determine their position by receiving very low frequency (VLF) radio signals in the range 10 to 14 kHz, transmitted by a global network of eight fixed terrestrial radio beacons, using a navigation receiver unit. It became operational around 1971 and was shut down in 1997 in favour of the Global Positioning System."

ianburrell · 2 days ago

There is eLoran which is upgrade to LORAN-C and as accurate as GPS. I saw link here that China is deploying eLoran system. The range is only 1200 mi so it won't cover the middle of the oceans, but would provide backup to GPS.

ianburrell commented on Making Your Own Merchant Service Provider voidfox.com/blog/payment_... · Posted by u/progval

flopsamjetsam · 9 days ago

> This is because in the US, anyone can pull money out of your account with only the ACH numbers

Whoa, I don't blame people for not wanting to provide ACH numbers in that case. Is there any groundswell to provide a system where this doesn't happen?

ianburrell · 8 days ago

FedNow is that system. It only sends money. Can request money but it needs to be approved.

However, I'm not sure if it uses different account numbers from ACH. It could be that sharing account numbers could be secure with FedNow and dangerous for ACH.

ianburrell commented on Passkeys are just passwords that require a password manager danfabulich.medium.com/pa... · Posted by u/dfabulich

dboreham · 20 days ago

Passkey is literally a software emulation of a yubikey.

ianburrell · 20 days ago

Passkey is a security key used as password. Yubikey implements security key in hardware, it can store passkeys. Password managers implement security key in software, they can store passkeys.

ianburrell commented on Cellular Starlink expands to support IoT devices me.pcmag.com/en/networkin... · Posted by u/teleforce

lupusreal · 20 days ago

Starlink by the nature of how it works, knows exactly where receivers are. Perhaps even more accurately than GPS.

ianburrell · 20 days ago

This isn't regular Starlink, it is Direct-to-Cell. Direct-to-Cell uses regular LTE/5G. There is no way for the phone to tell the satellite where it is.

Direct-to-Cell probably can't resolve smaller than the cell. I found mixed results if they use the 25 mi cells or if they use the whole dish, hundreds of miles.

ianburrell commented on Telephone colophon: Or, how I overengineered my call audio (2020) noahliebman.net/2020/12/t... · Posted by u/mafro

perching_aix · 24 days ago

It still positively mystifies me why the only actually lossless codec used for getting data to and from a headset / earpiece wirelessly is the extremely underadopted and proprietary aptX Lossless. Like I just cannot for the life of me understand why is it so difficult to push ~2.3 megabits/sec (48 KHz, 16-bit stereo listen + same but mono mic) wirelessly in the big 2025.

ianburrell · 22 days ago

Bluetooth has low bandwidth. Classic Bluetooth is 1 Mbps. Bluetooth LE can do 2 Mbps. LE Audio was introduced in Bluetooth 5.3 and starting to show up in headphones. I think LE Audio supports high quality bidirectional so that should solve the poor headset problem.

ianburrell commented on Brazil central bank to launch Pix installment feature in September reuters.com/technology/br... · Posted by u/CXSHNGCB

c0wb0yc0d3r · a month ago

It’s a shame that it isn’t used.

ianburrell · a month ago

It is brand new, released in 2023. It is a backend protocol, it requires every bank to implement the protocol. And there are some big changes compared to ACH, like having to present requests to the user. Or how to deal with reversals.

ianburrell commented on CO2 Battery energydome.com/co2-batter... · Posted by u/xnx

eldaisfish · a month ago

If lithium was as abundant as you claim, why is the Lithium Triangle a thing?

The largest exporter is Australia and the largest importer is China. Were lithium abundant, why does China import most of its lithium?

ianburrell · a month ago

Abundant doesn't mean available in location. It can be concentrated in one spot and more economic to mine there and ship where needed.

Australia also exports a billion tons of iron ore to China. Iron ore is everywhere, but easier to mine good ore in Australia and ship it. Shipping is really efficient.

ianburrell commented on It's a DE9, not a DB9 (but we know what you mean) news.sparkfun.com/14298... · Posted by u/jgrahamc

arjvik · a month ago

Doesn't VGA use DE-15?

ianburrell · a month ago

Edit: I was wrong, it is DE-15 connector. They squeeze 15 smaller pins into 9 pin housing.

ianburrell commented on Starlink is currently experiencing a service outage starlink.com/us... · Posted by u/throwmeaway222

oskarkk · a month ago

I wondered how much energy could pass through some area 1000 miles away from the explosion, so I made some rough calculations.

Assumption: all energy of the nuclear explosion is radiation uniform in every direction.

The energy E would be spreading in a sphere with area 4*pi*R^2. Area A being a part of that sphere would capture E*A/(4*pi*R^2) of energy. So with:

  energy E = 209 PJ (Tsar bomba for an extreme example)
 
  area A = 1 m^2

  radius of the sphere R = 1000 miles (1609 km)

That would give:

  2.09 * 10^17 J * 1 m^2 / (4 * pi * (1.609 * 10^6 m) ^ 2) = 6.4 kJ

So at the distance of 1000 miles an 1 m^2 object would be exposed to 6.4 kJ of radiation. I don't know how destructive would that be. That energy would be equivalent to 6 seconds of sun irradiating a 1 m^2 area above the Earth's atmosphere, but of course sun's radiation is less dangerous (very little gamma/x-ray), and all of that radiation would be almost instant.

From what I'm reading about high-altitude nuclear testing, it can cause artificial radiation belts around the Earth (composed of high-energy electrons). I think that may be more dangerous to satellites at distances like 1000 miles (or at any distance) than the immediate gamma/x-ray radiation.

ianburrell · a month ago

Radiation is measured in gray, which is 1 J absorbed by 1 kg. I can't find the conversion between flux to absorbed dose. 5 gray is fatal. If even a fraction of that energy is absorbed, it would be fatal.

I found that satellites get 100-1000 rad per year. Getting that much in a moment would cause problems.