piecat
@piecat@lemmy.world
- Comment on Half Life: Alyx is Five Years Old Today 1 day ago:
That is why those other VR sets are so cheap.
With valve, you’re paying for the hardware. With Meta, you’re the product
- Comment on Bernard 1 day ago:
Kinda looks like larry david
- Comment on Wikipedia not rendering math formulas? 2 days ago:
It’s happening on multiple people’s devices, seemingly only the same equations.
Is it possible wiki caches the rendered latex on some event like page edits saved, ran into an error during that, and is now serving the errors from a cache?
Otherwise there must be an issue with these specific equations?
- Comment on How can a military buy fighter jets that the seller has kill switches for? 1 week ago:
Can it not be removed? Or cracked?
- Comment on Come one come all, it's time to unblock !conservative@lemmy.world and bring your best memes of conservatives! 3 weeks ago:
when in reality it results in murderous regimes that oppress their people, their neighbors and everyone else there is to oppress.
Huh TIL that the USA is communist.
- Comment on Come one come all, it's time to unblock !conservative@lemmy.world and bring your best memes of conservatives! 3 weeks ago:
Communists aren’t destroying the US government as of now. Unless you consider the Russian assets on the right as communists?
- Comment on If a mysterious force secretly changed EVERY clock worldwide one minute forward, how long would it take until people notice, and how would people/governments react? 4 weeks ago:
So do we need to take time dilation into account?
1 minute forward in all reference frames? Is there an 81pSec difference in the time jump?
- Comment on My Honest Opinion 1 month ago:
- Comment on How is TikTok being blocked in the US? 2 months ago:
Why do they care enough to listen? It isn’t a US based company. I understand if they remove their US servers, but why do they have to block IPs?
Can’t US users just get a VPN? Is this whole situation a ploy to ban VPNs and privacy?
- Comment on Canva charges you to make a circle 2 months ago:
What downsides?
- Comment on Hypothetically, if some mysterious force started to jam every radio frequency, how would modern day society adapt to this? 2 months ago:
Thank you!
And yes I do!
- Comment on Hypothetically, if some mysterious force started to jam every radio frequency, how would modern day society adapt to this? 2 months ago:
Thank you :)
- Comment on Hypothetically, if some mysterious force started to jam every radio frequency, how would modern day society adapt to this? 2 months ago:
Chill out. I was interested in the “how” and thought I would share.
- Comment on Hypothetically, if some mysterious force started to jam every radio frequency, how would modern day society adapt to this? 2 months ago:
Their transmitting power they use is so powerful, its jamming signals are 1000 times stronger than the strongest radios we have
Strongest (declassified) radio transmitter is (likely) the Eglin AFB Site C-6. en.wikipedia.org/wiki/Eglin_AFB_Site_C-6. Peak radiated power is 32 megawatts, it operates at a bandwidth of 10MHz.
32MW is about 105dBm. Times 1000 will add 30 dB, so the alien transmitter will be at least 135dBm, which corresponds to 32GW.
Given the Friis Transmission Equation, 135dBm with a transmit antenna gain of 1dBi, at a distance of 12,756km (diameter of earth), a receive antenna with a gain of 1dBi, will receive a signal of: 22.44dBm at 1MHz, 2.44dBm at 10MHz, -17.56dBm at 100MHz, -37.56dBm at 1GHz, -57.56dBm at 10GHz, adding an additional 20dB of loss per decade. This is completely ignoring all effects like atmosphere and ionosphere, signal traveling through or around the earth, reflections, any funky propagation, or constructive/deconstructive interference patterns that may occur. Also ignoring antenna gain.
A rule of thumb is that the signal-to-noise ratio (SNR) should be at least 5x (or about 7dB) in general and some digital modes will tolerate it. 20dB is usually the minimum recommended in general, with 25dB or more being recommended for voice.
AM radio at about 1.5MHz will still work- but only for about 1km from the tower. At this point the AM signal from a 100kW transmitter would be about 46.03dBm for a specially designed antenna and receiver, but the noise level would be about 22.44dBm. Realistically, AM will not work and may even blow out a receiver front-end. Television at about 88MHz will be usable for only about 1km using a specially designed receiver, normal TV likely won’t work at all.
GPS is around 1.5GHz and the typical levels received are about -130dBm. Our noise is about 90dB or 1,000,000,000 times stronger than the received signal. No chance of GPS working at all. Wifi is around 2.4GHz or 5GHz and a “perfect” signal is about -30dBm. The received noise at 2.4GHz would be about -45.17dBm, and at 5.6GHz this would be -52.53dBm, so feasible that wifi could still work if you are close to your router/antennas.
Cell Phones have an extremely wide range of frequencies. On the lower frequency end, they likely won’t work. For something like K band at 10GHz, the phone itself would be transmitting about 33dBm. At a distance of 2 km, the cell tower will be seeing about -83dBm from your phone, while the the noise received will be far higher at about -57dBm.
Lastly, Submarine communication is typically done at ELF (3-30kHz). They typically need about a whole power station dedicated to powering it, and the effective transmitted power will be something like 5 watts or less. A submarine at 100km might pick up a signal of -2.99dB on the surface (realistically, far far less when submerged due to sea-water attenuation). The noise level on the surface from noise would be 52.9dBm.
This is all assuming that somehow, the aliens have a perfectly efficient wide-band transmit antenna. And have landed on earth with their super transmitter. And all of these numbers assume that max transmit power takes up the same bandwidth as the signal of interest.
In practice, the aliens would want to be far away from us. No closer than the moon, let’s say. And they probably will want an array surrounding the earth to maximize line-of-sight. To maintain the previous numbers, they would need an additional 25dB of transmit power. And probably an additional antenna on a ship, opposite to earth from where the moon is. So that’s an additional 3dB of power required (x2 for 2 antennas).
They could probably knock off about 20dB if they used high-gain antennas. But let’s say they use that power to further overwhelm earth’s ability to use radios, even for edge-cases.
They would require 163dBm- about 20TW of power. To jam a single frequency listed above.
Let’s say to jam the TV station, they were broadcasting over a bandwidth of 6MHz. That gives a power-spectral-density of 3.4MW/Hz. To cover the entire spectrum at the same time, say 10kHz to 300GHz, they would need just over 1 exawatts. 10^18 watts. That’s a lot of power! They could use a partial dyson sphere with the sun, but we could say the aliens are nice enough to still allow the sun to illuminate the earth and other planets to keep everything else the same.
- Comment on Two in one stupidish question- Debate about United Healthcare CEO and best place to have it 2 months ago:
Vigilantism is horrible, and it’s it’s a symptom of a system that is failing. It means people feel that other non-violent options don’t work.
- Comment on Does the USA simply have no food safety standard at all? 2 months ago:
I’m willing to bet that you’ll get more microplastics from the food itself (meat, plants, water) than the bag.
- Comment on I choose innovation. 3 months ago:
And while we’re at it, why not connect the blinds at the seams? Then no water leaks out.
And honestly you could make them out of a softer plastic so it’s easier to open and close… something like sheet PVC would be perfect.
- Comment on Does anyone else think the NYPD photos of the UHC CEO shooting suspect don’t match? 3 months ago:
I bet they stop releasing info because of the public reaction. At this poiny, they want us to forget and not have copycats. They’re scared.
- Comment on Why do bugs drown themselves, what idiocy is this?! 3 months ago:
Wait- fly fishing isn’t fishing out of the back of a water plane?
- Comment on Checkmate 3 months ago:
Nope, the game ends with checkmate. The king is the only piece that can’t actually be captured. It’s in the rules, look it up.
- Comment on why is my whisky evaporating? 3 months ago:
Theres no safe level of lead, it accumulates in the body.
- Comment on flouride 3 months ago:
0.08mg per half cup serving, but may vary depending on water used.
10mg is the accepted daily upper limit. So 62.5 cups of oatmeal to reach that max safe limit.
Acute poisoning symptoms may appear as low as 10-15 mg/kg, lethal dose might be 32-64 mg/kg.
So 200 to 400 cups of oatmeal per kg you weigh for a lethal dose.
- Comment on Palworld Developer Reveals The Pokémon Patents Nintendo Claims It's Violating 4 months ago:
Patents shouldn’t exist! Mostly.
- Comment on You Pay For It, We Own It - Sony's $7.9B Lawsuit 4 months ago:
I think that’s called conversion. Or unjust enrichment.
- Comment on Dear Americans, be prepare to get screwed! 4 months ago:
FYI: companies will do 2 things to make black friday kinda suck these days
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Prices will go up before black friday so they can have an exagerated sale/discount.
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Some companies will make units specifically for black friday. Usually cheaper, less features, and sometimes less reliable.
Figure out what you want now.
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- Comment on There are Minimum Wages, Why Not a Maximum Wage? 4 months ago:
I think we should be setting these max/min wages as relative values, not absolute values. Otherwise we have to pass laws every time the min wage needs to be adjusted. And we’ll end up with stagnation.
For example, a person’s wage can only be X% higher than the lowest wage of someone a step below them in hierarchy. Including contractors and suppliers so they can’t skirt or find loopholes.
There still might be some haywire incentives that require more thought, but it should hopefully encourage labor to be valued at an appropriate proportion of value. Either everyone makes good money, or nobody does.
Should also probably deincentivize layoffs, stock buybacks, etc. at the cost of shareholder earnings / value.
- Comment on I'd have to hear her argument, but... 5 months ago:
Funny joke ?
- Comment on I'd have to hear her argument, but... 5 months ago:
Macroscopic creatures are made of different types of cells and stuff… what constitutes a living thing?
People didn’t lose half of their cells, it was all or none.
- Comment on How can I get a screw like this out? 6 months ago:
A dab of super glue in the screw hole, find a screw driver you don’t really care about, add a drop of superglue accelerator
- Comment on When was the last time you made Jello? 8 months ago:
Yeah but it’s not like you eat it anyways
