The battery thing can be important. One strategy law enforcement uses is to force your phone into a high energy state and zap the battery very quickly.
No need for the law enforcement to do anything. I suspect that a large, thick crowd where everyone carries a phone creates enough radio interference that phones lose contact with the tower very often, and try to reconnect very often, especially when people send or receive messages, auto-upload photos, etc. This keeps the phones in the active state for longer, draining the batteries.
I'm guessing in this context it means drain the battery. I haven't heard of this technique, but it seems plausible, by tricking the phone into constantly transmitting over WiFi or cell.
Couldn't you achieve the same by just enabling airplane mode or similar on regular devices? I don't think niche devices with hardware killswitches should be necessary
Guessing from things I've heard, take this with a grain of salt:
- In order for most cellular protocols to work successfully, it's necessary for the transmission power level (phone to tower and tower to phone) to be lowest possible.
- So that tx power has to be constantly modulated because the phone's distance is always changing as it moves, meaning the optimum power level is always changing.
- The tower is in control of this - it tells the phone how powerful to transmit, and this can be done for each device.
- So I would suppose a malicious party in control of the tower could simply tell the phone to transmit at max power, which will drain batteries quickly, especially if the connection is being actively used I guess. This may have interference considerations but if the tower is really a box on top of a car or truck it may not really matter.
- I don't know how the phone is prevented from connecting to closer non-malicious towers.
I could hazard a guess that if someone made your phone really hot it would be able to be scanned by thermal imaging and pick you out of a crowd. Just leave phones at home, like, use 18th century methods if you have to. I dont pretend to care or know why people would be interested in this, but like, your phone probably is not your friend in a protest
(I have no information and thus no opinion on this being a thing that happens but)
constantly keeping the cell antenna and CPU awake would probably do it. it's a BIG part of why weak cell signal and lots of noise at e.g. conventions drains your phone many times faster than normal, even when you're not using it. you could probably do that just by sending junk data to everyone occasionally, or delaying valid data to prevent going into sleep modes for longer periods.
If you ever forget to put your phone in Airplane Mode when flying (and you survive the flight!), you will notice that the battery is surprisingly depleted.
I think it has to do with the phone constantly renegotiating with cell towers along the route.
I've seen similar behaviour when a hurricane took out power to a local tower, and it was intermittently restored.
It might be possible to emulate that in a controlled environment/area.
Not exactly. The phone needs to transmit with enough power to communicate with the tower. When connected to the tower, the tower is constantly monitoring the signal and sending back information to the cell phone to tell it how much power it needs (without using more than it needs and wasting battery life).
If a phone isn’t connecting to any towers (like on a plane) it assumes it is out of range and is blasting out max power trying to find something to connect to. During hurricanes, many towers are down, which can overburden adjacent towers as well (since each tower only has a certain number of slots/channels it can handle). It means that you may not be able to communicate with your closest tower, since it is down, but you also may not be able to communicate with the next nearest tower, since it at capacity for current users, which puts you in a longer distance higher transmit power situation.
From what I have heard, those Stingrays act as fake towers, so I would assume they could set them to always tell the phones it needs max transmit power.
I think both 'sap' and 'zap' work in this context, and zap might be the better option because 'sap' can have the additional meaning of moving the energy somewhere else, whereas 'zap' can just mean to remove in general.
