Why wrapping a cellphone in foil leaves it uncovered and untraceable, like in the Maracena kidnapping

The Andalusian municipality of Maracena has become a protagonist in the middle of the electoral campaign, but for undemocratic reasons. In case of kidnapping of Councilwoman Vanesa Romero took a step forward with the investigation of the number 3 of the Andalusian PSOE and the mayor of the city. The investigating judge considers that there are indications of the two’s participation in the events that took place on February 21, although the sentimental couple are in prison as the main suspects of being the author of the material.

One of the most surprising details of the car to which EL ESPAÑOL has had access is the fact that the culprit he wrapped his phone in aluminum foil, or “papel albal”; all in an attempt to avoid police follow-up, something he said he “saw in a movie” and verified at home that it worked. The logic was that, if the mobile phone lost its coverage, it would not be possible to obtain the location of the device and, therefore, of the hijacker.

But is it true that it is possible to block location using this simple technique? As often happens, the answer is a bit more complicated and largely depends on circumstances and technical details over which the user does not have full control.

From myth to reality

Logic dictates that such a thing is not possible; in fact, aluminum foil is the protagonist of many “hoaxes” that have no scientific basis. A simple Internet search reveals that, indeed, this is not possible, and in fact there is already precedent in a similar case. In 2020, prosecutors in the case of Ghislaine Maxwell, the romantic partner of Jeffrey Epstein, revealed that she tried to avoid tracking his mobile using aluminum foil; However, the “trick” didn’t work, and Maxwell was captured without much difficulty.

And yet the myth is true. At least in part. A mobile wrapped in aluminum foil can not be able to receive calls, and the location features that Apple and Android devices often have will not work. After completely wrapping it in foil, the phone will disappear for convenience, and until it’s unwrapped, those basic mobile functions won’t return: as soon as it gets its cover back, you receive missed calls and messages.

EL ESPAÑOL – Free Android has been able to verify firsthand that this is true with several experiments. In none of the cases were the foil-covered mobiles able to receive calls, even in places where they had good phone coverage. In the same way, iPhone search function not working and it only showed the last known location of the device.

Mobile and white paper: the science

The reason the aluminum foil blocks cell phone coverage is that the structure has been made into a simplified version of a Faraday cage, which blocks the electromagnetic field from the outside. Being a highly conductive element, aluminum remains positively charged when it receives electromagnetic waves from the mobile signal; in response, an identical and opposite electric field is generated; the sum of the two fields is zero and this is what prevents the waves from continuing inside the packaging and up to the antenna of the mobile phone.

But it’s not as simple as that. And it’s that not being able to make a call to a mobile does not show that you are completely disconnected from the network mobile. To demonstrate this, it helps to remember what happens when you try to make a call in an elevator or in an underground car park; the call will most likely drop out and stop, but not completely. Likewise, communication does not die as soon as the device is wrapped in this version of the cage.

Although calls are not possible, other methods of communication (and follow-up) would be possible. The order does not explain whether the police were ultimately able to find Maracena’s kidnapper despite the measures he took, but it would be very likely. A mobile phone constantly communicates with nearby cell towers and calculates signal strength; If the user moves away from a coverage area, the mobile can increase the power of your antenna to better capture the waves, as happens when one enters the Faraday cages that everyone encounters on a daily basis.

In these cases, obstructing this communication only results in increased battery consumption. Another important detail is that communication is only affected if the mobile is completely covered with aluminum foil; just leave a part exposed for the coating to do nothing.

Therefore, while it is true that wrapping the mobile phone in foil blocks calls and some services, it is not able to absolutely block all signals. In this case, only a true Faraday cage created to expressly block the wavelength used by mobile antennas would be capable of something similar. And in this case, it is easier not to take the mobile.

You may be interested

Follow the topics that interest you