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photon_rancher

29 karma · joined August 15, 2023

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photon_rancher··on Electric cars produce less brake dust pollution than combustion-engine cars
Most autos have an override to shift manually and engine brake more, hardly ever see people use them except if they tow frequently though.

A lot of CVTs have virtual gears for that even, although others like the prius only have B mode.

photon_rancher··on Electric cars produce less brake dust pollution than combustion-engine cars
There’s a few luxury cars that use the same or larger engines for the hybrid. Lexus did it with the LS, hybrid 600h had a larger engine (5L) than the gas 460 (4.6L).

Those are super rare though.

photon_rancher··on More than 50% of Australian voters now rely on government for their main income
There’s always the risk of economic collapse lol
photon_rancher··on Why top posting has won (2018)
Yeah and it prevents issues if the subject line changes in an unexpected way that confuses the email client, or issues where an email chain goes on for a long period of time but retention policies delete old emails. Etc…
photon_rancher··on A Tektronix TDS 684B Oscilloscope Uses CCD Analog Memory
The PCB is easy to screw up, so are the cables. And scopes that go that high are expensive but customers expect USB3 even on low volume low cost products so there’s definitely advantages.

There can even just be manufacturing defects the FR4 weave that mess up SI that you might want to check for as a QA step on the assembly line. For hi volume that gets slow or expensive

photon_rancher··on A Tektronix TDS 684B Oscilloscope Uses CCD Analog Memory
Yeah, this is a well known technique for boosting resolution.

For example: You add a dithering signal which can be processed out. If the signal has the right properties (for example, random but evenly distributed noise bounded to one LSB), you can then average out multiple samples to get more effective resolution than the ADC has. The additional number of bits scales something like 2^n samples, although if you don’t take sufficient samples this mainly just reduces your SNR. It also requires a periodic input.

However you can also pull similar tricks in the time domain or using simultaneous sampling with multiple ADCs. You can also interleave slower ADCs with a phase shift. This produces stitching artifacts unless you average them out though because ADCs generally are not well matched at the limits. You can bin or calibrate this out somewhat if you can characterize the error.

You can do a similar thing in the frequency domain if the ADC sample window is narrow enough but it has arguably the worst artifacts. Lo-pass the first ADC around N/2. The second ADC use a bandpass from N/2 upto N. The third is N upto 3N/2 etc… but the fourier transform will have a bunch of junk at the stitching points.

Or you can take the sampling scope approach using a fast but low sample rate ADC and many triggers.

I’ve seen most of these done on commercial instruments if you dig into the settings. Some of them you can see in normal operation (like the stitching in the frequency domain).

But I think the other poster was suggesting the first case applies - if you think about it there are certain periodic signals you can add instead of a random signal. That has the advantage of limiting SNR degradation and can also be filtered out easier/ detected i n the data.

photon_rancher··on Switch bouncing reference traces for a variety of different switches
Did some similar testing with an on-off rocker switch for a project last year.

Traces were highly predictable if you pressed it just gently past the detent. But if you did it too slowly (restricting the detent force) or used too much follow through (adding to the detent force) the result was very chaotic. Sometimes you could get the bounce period to extend by 10x if you took enough samples.

And if there’s too much current or other problems i saw decent ground and supply bounce too. That definitely makes it toucher to measure the behavior- in some respects a diff or current probe gave even more interesting results.

photon_rancher··on Hybrid AC/DC distribution system with a shared neutral (2020)
I don’t see a world where this is possibly cheaper than just putting a AC-DC supply at the point of load. Looks like a big safety hazard too.

IDK, but I wouldn’t even want to debug circuits for this thing.

photon_rancher··on Windows RDP lets you log-in using revoked passwords. Microsoft is ok with that
This is true for basically any AD windows login. If you log in with an account on a machine on your domain, then take that machine offline and change the password elsewhere- you can login with the old password.

If you instead restore network access after it’s been offline long enough - depending on the exact process it will still accept the old password. Entering the old password isn’t enough to trigger domain check in. However, if I recall correctly entering an incorrect password will cause the login window to hang for 30+ seconds while it attempts to perform such a check in to see if your password changed in the interim. This will usually fail - but not always.

It’s probably bad behavior but it’s probably configurable in the domain settings. But it makes the user experience terrible because logging in gets super slow, because domain syncs in azure/ Active Directory are super slow.

photon_rancher··on A study of lightning fatalities inside buildings while using smartphones [pdf] (2024)
No, unplugging works because cables are antennas. Power cables being disconnected dramatically reduces the ability for the lightning to couple into the device

The device itself usually has shielding, capacitors, transient suppressors, etc… as well as usually designed to make a poor antenna so on it’s own it will be affected much less than when charging

Surge protectors do work, mind you - but only for weaker storms or pulses coming in from the outside power lines. Just by physically being separated from the final device they are limited in how much they can protect from direct coupling

photon_rancher··on Energy Department cuts university overhead rates to 15% on research grants
Interest, military, and social security are the only things big enough to cut to fix the deficit much less pay down the debt.

The entire rest of the government could be free and we would still be screwed if we don’t make cuts where it counts.

photon_rancher··on The PS3 Licked the Many Cookie
I mean commodity hardware usually did ok in games consoles prior to then too. NES was a modified commodity chip
photon_rancher··on Building the System/360 Mainframe Nearly Destroyed IBM
What’s the average IPC of these chips for a reasonable workload?

Early processors were typically 1 or lower. Modern stuff is all superscalar piplined and out of order and can do way more than you’d expect. Not to mention SIMD operations and other technologies. Branch prediction is probably better on the new chips too.

And with more RAM and cache algorithms can be chosen with different tradeoffs for less instructions.

16 cores at 4ghz was a thing like a decade ago - chips today might have the same specs but are definitely far faster.

photon_rancher··on Ask HN: Where are the Mac ergonomic keyboards?
Logitech makes them. Ergo k680 is sitting on my desk right now and has both cmd and option in the correct spots.

Wireless tho so you’ll have to get over that one. Not a lot of options with usbc wired - unless you look at the custom or boutique space most wired keyboards have permanent cables. Battery easily lasts a year.

It’s kinda a weird list of requirements imo - most mac users are exclusively on wireless options. And even the wired ones only have usbc if they’re mechanical with like a teensy or something. Not that you’re wrong to want it but its unusual.

photon_rancher··on Oracle attempt to hide cybersecurity incident from customers?
Yes that sort of stuff happens all the time in the business side of things. There’s a reason it’s a trope.

Not to every company per se but it’s been commonplace well probably for as long as business itself has been.

Just an example - nothing that happened in wolf of wall street was original to them - just the getting famous for being caught part. And that was only a few decades ago.

The defense and finance industries are famous for that sort of thing. I’m sure it’s pervasive elsewhere too.

There’s nothing special about software or tech or clouds that makes schmoozing impossible.

photon_rancher··on Anatomy of Oscillation
Looks like inversion
photon_rancher··on New electrical code could doom most common EV charging
Over 100nF of unbalanced Y-caps is needed at 60Hz/120V to see 5mA gnd current. That would be a big Y capacitor (2.2n or lower is common) and they’re usually used in a balanced configuration which would reduce it further. If a Y capacitor fails on one leg, you have a problem. If a Y capacitor fails is only present on one leg, you have a problem.

And if it’s resistive leakage, that’s almost a watt of dissipation - also huge and probably a short in a cable and potentially a fire risk.

5mA is a massive threshold for well designed devices

photon_rancher··on Narcolepsy is weird but I didn't notice
That exit strategy sounds suspiciously similar to a technique I’ve heard for lucid dreaming.

Wonder if they’re related?

photon_rancher··on You don't have to pay the Microsoft 365 price increase
Your estimate is late by almost 20 years - the first of that generation graduated high school ten years ago.

But the problem is that over those ten years google docs mostly feels like it’s been enshittified. Today’s office suites all suck I just want office 2007 or the google docs beta experience back - those were snappy and obvious how to use. Even basic stuff like linear regression in excel is terrible UX these days

And so mostly they don’t care to push it and if they do it’s not a material over modern office anyway.

photon_rancher··on Consumer-grade routers on puny power supplies (2024)
There’s oscillators out there that slowdown as they brownout. That would cause those symptoms. A lot of logic families have slower edges and longer delays too, not that there would be much asynchronous logic in a router.

Could also be affecting the analog circuitry more if the droop is too bad or its browning out. That could be loss of gain, SNR, etc.. that could cause packet loss and retransmissions

photon_rancher··on Soldering the Tek way
Chipquik works fine. There’s probably better stuff but it is consistently good and doesn’t seem to go bad (i can’t tell much performance stuff between a roll that’s old enough to have the label rubbed off and a brand new one).
photon_rancher··on Soldering the Tek way
1) board preheat. In a pinch, heat gun or old hairdryer. But ideally get a cheap ceramic one off amazon or something. Typically set it to 75C for delicate components. For sturdy boards i start there and if that still sucks you can usually go up to ~150C. Usually its the heating element or air temp not the board temp.

2) Flux and thin solder. Solder should contain flux too. Use solder paste whenever possible and keep it refrigerated when not in use as it dries out

3) you need a high wattage iron and usually a thicker tip with more heat capacity. A slightly higher temp helps a little, but the wattage helps it stay a consistent temperature from the start to end of the joint.

4) when designing boards use ENIG and not HASL

5) remove any old solder before attempting to add more to a joint (older than a day or two).

6) sometimes an air gun on a arm helps too on thick copper

7) get really good lighting with a mix of diffise and directional sources. Brighter than you’d think

photon_rancher··on PCIe trouble with 4TB Crucial T500 NVMe SSD for >1 power cycle on MSI PRO X670-P
They probably just provide extra power over the port. It costs extra to design an extra supply for a specific port so it’s probably shared, and likewise also costs extra to current limit each port. So more than likely a cost saving measure
photon_rancher··on Coercing a Magic MIFARE credential into being an iPhone-compatible NFC tag
Seconded. There’s almost certainly NXP IP used in nearly all NFC implementations which makes them subject to their terms.

Those terms are in turn set by the partners that asked for these technologies to be developed in the first place. And so any development gets slowed to a crawl in this space.

photon_rancher··on Failure analysis of the Arecibo 305 meter telescope collapse
I was on the suspended section about a year before collapse - everyone could tell it was about to fail. Visible stress in rusty beams, old cables, and failing concrete. I think it just came down to underfunding at the end of the day - there was no money available to ask for even if the alarms were louder.

And for most applications it was obsoleted by the larger new telescope in china, so there was no large push to turn that ship around from the wider scientific community.

photon_rancher··on A Physicist Reveals Why You Should Run in the Rain
Likewise the minimum amount of rain you could catch would only be on your front from moving at an infinite speed. You’d leave behind a tunnel of missing raindrops in the shape of your profile along your path.

As you move slower or faster you approach one limit or the other.

photon_rancher··on Intel stock dropping toward 50 year low amid restructuring news
Lol not competitive cost or efficiency wise is what people said about the iPhone compared to blackberry, and here we are - people bought them anyway.

Not trying to argue with you just a funny parallel. I don't really have a horse in this race but it’s clear there’s a lot of uncertainty out there for intel right now.

photon_rancher··on 2 GHz Active Probe
Realtime scopes exist at this bandwidth but are crazy expensive, and then they have frequency-stitching artifacts all over the fourier plane. (Because they use mixing techniques)

Sampling systems are about $20k - 50k without probes in this bandwidth.

Keysight DCA-M and picoscope have the best public prices, and exfo has an eye analyzer in that price range. There’s also DCA-X but nobody wants to pay 10k extra for a touchscreen.

Unfortunately tek doesn’t make electrical sampling systems anymore, just optical.

photon_rancher··on Do not buy a Hisense TV (or at least keep them offline)
Cars pretty much all do this now.
photon_rancher··on usbredir: A protocol for sending USB device traffic over a network connection
I mean you could sign it yourself. Or donate to a maintainer so they can sign it. Open source or other community windows drivers usually aren’t signed unless they have donors paying for it, certs aren’t free :)

If anything it’s on windows for not having a way to allow just one unsigned driver.

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