Say, some alien just wanted to mess with us, but doesn’t invade, or even care enough to want to kill us, but seeing how everyone is on their phone all the time, they decided to just jam all our radios to watch us suffer. Their transmitting power they use is so powerful, its jamming signals are 1000 times stronger than the strongest radios we have, so there’s no way we can overpower the jamming.
What does the immediate aftermath look like?
What does it look like in the long term?
(Please don’t say “kill the aliens” they have tech so advanced, its impossible to do it)
I’m just going to go with the scenario of ‘the specific part of the EM spectrum that we use for comms is no longer accessible to us’.
So, mobile data and GPS are out. A heck of a lot of people suddenly get very lost, and the immediate aftermath would include a lot of car crashes- mostly from people trying to play with their phone while driving, or just generally being distracted. Long term, people would get used to having to find themselves on a map. I doubt street directories would make a comeback, as it’s relatively straightforward to download a map to a phone by plugging it into to a computer, or USB to Ethernet. Oh, in that regard- The shortage of USB to Ethernet adaptors would probably hit before the toilet paper shortage.
There’s a large portion of the world’s population who like to stay inside and listen to the radio or watch TV, the internet still being an unwieldy thing that the yung’uns use. These people will start getting their entertainment and news by walking outside and congregating - At least until they get a computer or phone setup wired. Hopefully, many will continue to go for walks around town to see their friends and eat a meal. A lot of households are going to have a whole lot of Ethernet cables run all over the floor for quite some time. People will start buying switches and routers to get more outlets next to the couch, for example.
Massive queues will form around the few existing payphones, until businesses and homes at central locations will start offering up ethernet ports. Because this started soon after the Blackout, rooted in generosity and helpfulness, this will just become a free service.
Taxi drivers will start congregating at these spots, plugging in and updating their location, moving to other locations where there is few drivers- and hoping that others aren’t getting the same idea, unable to know that until they arrive. The old guard of taxi drivers, who worked pre-Uber and have an encyclopedic knowledge of the local streets are in high demand, and people seek them out.
A lot of scientists are out of a job. People who worked with radio astronomy are suddenly having to peer through optical telescopes again, and keep talking about the good old days. Whole divisions of people at space agencies, responsible for things like monitoring and control of satellites, space probes, and rovers are suddenly retasked to creating ways to create autonomous return probes to find out what the fuck just happened. Some start trying to work out ways to replace radio by using giant scaled up versions of television remote controls, putting giant infrared lights on mobile phone towers, with smaller repeaters on top of houses and cars. (For funsies, I’m assuming point to point microwave comms are out- which has the implication that microwave ovens don’t work any more, with the associated knock on effects of house fires from people melting microwave dinners in ancient, unmaintained conventional ovens).
People who worked with wireless stuff- from FM radio DJs to antenna design engineers are all out of work. Perhaps they start selling coffee to people stopping by those public ethernet locations? Unfortunately, there’s a noticeable economic downturn from so many vacant jobs, people being out of work suddenly, and commerce becoming so much more difficult. Cash becomes much more useful, and those handy dandy wireless payment terminals don’t work so good anymore, and while waiting for wired replacement terminals to arrive, people get used to cash again. There’s a knock on effect of people keeping cash to themselves, despite the government being almost completely unchanged. This downturn, along with jobs that don’t exist any more, puts a lot of people out of work. However, they are likely to start filling the jobs left vacant by the thousands of people who perished in the utter chaos that was every aircraft on the planet trying to land at the same time in utter confusion.
A couple might make it safely down, but it only takes one accident- say a little Cessna coming in low, not seeing the 747 coming in faster from above, to turn the runway into a total mess of burning jet fuel, wreckage, and stunned people slowly bleeding out, surrounded by smashed bodies and assorted socks. Aircraft block major highways attempting to use them as runways, often causing huge multi-car pileups by giving already already distracted drivers a totally insane thing to have to deal with. Many pilots take the opportunity to ‘do a Sully’. Hundreds die as waterways around major airports become congested with crashed aircraft, with many potential rescue personnel sleeping through the whole thing, because who the heck has their landline phone number, even if they have an actual phone plugged into the wall?
In short, I’d watch that movie. Maybe a series in three parts, immediate, a few months later, and then years after. Great question OP, thanks!
Oh, also- people who made special effort to get a phone that has a headphone jack will be smug as fuck for a very long time.
Many modern cars will stop working and there will be a huge demand for cars from the 90s, due to the anti-theft authentication in the key not working.
In America, not being able to drive is basically a death sentence. Especially for the few people living rurally with no fixed internet or phone line to be able to call for help.
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. https://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.
I think you’re being intentionally obtuse here and betraying the spirit of the question?
Your meta analyzing the question instead of just taking the questions as it is, and in the process failed to actually address the core question. It’s a hypothetical scenario where most of our radio communication is jammed and unusable.
The mechanics of how the question got there don’t really matter, that’s not part of the question, it’s pointlessly pedantic to pick it apart. Just imagine the scenario with the mechanics you can consider plausible for such a scenario, and roll with it 🤦
“Aliens have technology beyond our means and largely render radio communication impossible by way of jamming”
What I like about these kind of questions is how different people take things in a totally different direction. I find it absolutely fascinating to see detailed replies about connotations I never thought of. It’s the whole reason why I love xkcd’s What If. If you’re unfamiliar, do yourself a favour and have a read. I particularly enjoy his answer to the question of everyone standing in one spot and jumping at the same time. He more or less ignores the core question and focuses on the societal & environmental impact of a mass human migration to one point, resulting in a fantastic read.
Wired communications would take over immediately and it would be a massive pain in the ass, but we’d ultimately adapt.
If the EM jamming is enough to also degrade the signal in copper lines, which at 1000x the strongest signal, might happen, then basically all modern society would collapse within 48 hours
If the jamming was spread spectrum and affected wired signals, it would also be strong enough to cook every living thing on the planet.
I guess if the aliens were carbon-based, it would let them cook planets and then sample the biological products at leisure.
The oceans and lakes would boil off, of course.
Interestingly in Ukraine they are beginning to use drones with huge spools of fibre optic cable to transmit control and video signals. They’re doing this because of the jamming.
Not nessasarilly. U can reletivly easily block signal jamming for a confined area with a Faraday cage and most long distance is fibre optic nowdays.
In addition to wired you’d probably also see an uptick in line of sight optical transmissions via laser. Both of those options would really be the only two ways around it.
For me, since my entire house is wired, I’d just lose use of my cell phone. Most all internet infrastructure is wired too, so all that would continue to operate.
What does it look like in the long term?
If they don’t stop, we’ll start using their jamming as a source of power for small mobile devices. It’s free energy at that point.
Pulls out my big box of old CAT5 cables… Who’s the packrat now?!
