John McAfee, libertarian politician and former computer programmer, tweeted this:

The "Presidential alerts": they are capable of accessing the E911 chip in your phones - giving them full access to your location, microphone, camera and every function of your phone. This not a rant, this is from me, still one of the leading cybersecurity experts. Wake up people!

Leading cybersecurity expert status aside, is any of this based in reality? Could the Presidential Alerts system give any government agency, body, or official, any level of control over cellular devices beyond sending alerts?

  • If he's talking about Enhanced 911(which isn't a specific 'chip' or based on the alerts), then yes the government can get access to your location by requesting your location from your local carrier. The full specifications of the upcoming version of this system can be found here, so are the specifications an answer to the claim or is there some implication in the claim that the government managed to sneak in extra software?
    – Giter
    Commented Oct 4, 2018 at 18:07
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    @Giter I'd assume by E911 chip, the claim means the various GPS chips, which is how wireless carriers comply with FCC location accuracy rules.
    – De Novo
    Commented Oct 4, 2018 at 18:45
  • @DeNovo: I doubt he meant just GPS chips, because if he did then the real question is how manufacturers have been able to cram so much non-GPS related hardware and software into the chips without anyone noticing.
    – Giter
    Commented Oct 4, 2018 at 20:04
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    Kind of a meaningless claim. All apps and the os have access to that data. Whether the app and os are trustworthy when they say they don't misuse it is the question. Do you trust FEMA and your wireless carrier? Well, I trust FEMA, but not my carrier, for whatever that's worth. Lots of people near and on the conspiracy spectrum don't trust FEMA either. McAfee is one of those.
    – user11643
    Commented Oct 4, 2018 at 23:26
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    @IMSoP people should attempt to find out what Snowdon actually made public domain. These kinds of discussions are a joke.. the government's can access at any moment.. pictures and sound from your location..the name of your best friend's mother and how many times you've bought bread in the last 5 days.
    – Richard
    Commented Oct 7, 2018 at 9:41

2 Answers 2


The presidential alerts are part of a bigger system that also includes AMBER alerts and alerts for bad weather and "other threatening emergencies". These alerts are called Wireless Emergency Alerts (WEA).

FEMA explains how it works:

Does WEA know where I am? Is it tracking me?

No. Just like emergency weather alerts you see on local TV, WEAs are broadcast from area cell towers to mobile devices in the area. Every WEA-capable phone within range receives the message, just like TV that shows the emergency weather alert. WEA, like the TV station, doesn't know exactly who is tuned in.

The FCC also says "WEA is not designed to – and does not – track the location of anyone receiving a WEA alert". Verizon Wireless says something to the same extent.

If you're on a phone call, the message will wait until you're done (you won't get a message if you get off when the message is no longer being broadcasted), but I see no evidence this is done by the broadcaster. It seems far more likely that it's the phone itself that does this.

  • I was going to ask for a reference for the Presidential Alerts using that same system, but the FEMA FAQ you linked for the quote actually includes that information as well. There might be a better way to organize things to better indicate the reference for the first paragraph. Commented Oct 5, 2018 at 14:57
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    I don't think the analogy FEMA uses is accurate. I don't believe TVs report their location to a location server. Mobile phones do. As described in RFC6280, sharing of location information is restricted, but that's very different from a TV receiving a broadcast signal and not reporting location at all.
    – De Novo
    Commented Oct 5, 2018 at 16:30
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    It is of course also technically a lot simpler to broadcast a message to all devices logged in to a limited number of towers than to collect gazillions of location data, process them for applicability, and unicast each of them from a central Commented Oct 6, 2018 at 10:07
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    I think it would be good to also address what the E911 system is, and how it relates (or doesn't) to these broadcasts.
    – IMSoP
    Commented Oct 6, 2018 at 10:54
  • @HagenvonEitzen sure, it would be simpler to act like a radio, but that's not how mobile phones work. Your phone does report its location to a location sever.
    – De Novo
    Commented Oct 9, 2018 at 16:36

This isn't a complete answer to your questions, but I'd like to point out that the government doesn't need access to the E911 chip to locate you. Traditionally mobile phone networks were switched networks. They work by locating where you are in the world, and routing your telecoms through a microcell / macrocell transmitter.

It's been some time since i worked in telecoms, some of this might have changed now and I've forgotten some of it, but this is how it used to work.

Each cell transmitter has a fixed number of channels much like a television has. Once the channels are all in use, no further calls can be placed through that cell. Although, there may be special provisions for emergencies like police and ambulance calls.

Due to the limited number of channels each cell has and the very limited broadcasting range of a cell, it's necessary to work out your position accurately. This is done periodically by a regular update that notifies the nearest cell where you phone is. The cell sends back the information to a central database, for the mobile phone provider. They store all this information in a database called a HLR (home location register). This keeps accurate information of where you are to within a few hundred meters if your phone has the battery installed.

So essentially, mobile phones always were personalized tracking devices since day one. Not necessarily because they were meant to be, but because of the way the networks functioned. So the government absolutely can find out where you are at any time, if you take your phone with you. They don't need an E911 to do this.

I should also point out that there's something now called a VLR, which suppliments the HLR's functionality.

Description of the Ericsson HLR. I can't find a public description for the HLR at Nokia where i used to work.

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    Hey there, and welcome to Skeptics! Your answer is pretty interesting, but it would be way nicer if it had sources for us to check this in more detail. Could you add references to your text?
    – T. Sar
    Commented Oct 8, 2018 at 15:36
  • "Due to the limited number of channels each cell has and the very limited broadcasting range of a cell, it's necessary to work out your position accurately." It seems to me that the more salient issue is that when someone calls you, the network has to route the call to the cell tower of the cell that you're in, so the network has to know what cell you're in. Commented Oct 8, 2018 at 19:22
  • @T. Sar: I can add some references to Wikipedia on this, but obviously I can't reveal company proprietary references; even though i don't work there anymore.
    – Owl
    Commented Oct 9, 2018 at 13:45
  • @Acccumulation: yes exactly. It's not that they wanted these devices to be tracking devices, it's more than mobile phone networks evolved from landline networks which were also switched circuits. There were physical limits of the technology at the time. These days things are moving to VoIP because it works out cheaper and more standard to use TCP/IP, so maybe a lot of these issues will disappear?
    – Owl
    Commented Oct 9, 2018 at 13:47
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    It isn't necessary to work out your position exactly, but it is necessary to determine which cell towers you can connect to, and which available cell(s) will give you the best connection. From the data acquired in this process, e.g., transmission time between cell tower and your phone, your position can be estimated. How well depends upon many criteria, including the density of cell towers in your vicinity. For example, the advertised geoanalytics component of this product, which I work on. Commented Oct 31, 2018 at 22:32

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