Why don’t cell phones work in airplanes?
The short answer is that when you’re 35,000 feet in the air going 500 miles per hour,
you’re just too far from a cell tower. But that got us thinking: how does wifi work in
an airplane? Hi there! This is Amy for DNews, and the question
“Why don’t phones work in planes while they’re in the sky?” came to us through Twitter.
Some of you know that they CAN work, if you’re on a plane with wifi. From the passenger’s perspective, in-flight
wifi is as simple as turning on your computer and connecting to the network. But there’s
a lot more going on than we see. There are a couple of ways to connect to the
Internet in a plane. One is by a ground-based system sort of like a cellular network. Stations
set up around the country provide overflying planes with contact points. An antenna on
the plane’s underside transmits and receives signals to and from these ground-based towers,
bringing wifi into the plane. But of course, this doesn’t work when you’re flying overseas
or out of range of the ground network. The alternative is a satellite-based system
that uses an antenna on top of the plane that talks to satellites in orbit sometimes in
conjunction with that antenna on the bottom of the plane that talks to ground based towers. In both cases, the wifi signal you request
from your seat gets to the plane. But that’s only half the battle since the information
has to get to you in your seat. And here’s where things get a little more complicated. Wireless signals bounce around in small spaces
like airplanes, and not just off the walls. The seats, luggage, and even the passengers
in their seats can disrupt the electromagnetic environment in an airplane and affect the
way a wireless signal moves. And if people are up out of their seats moving around, and
the drink cart is being pushed down the aisle, well, that just disrupts the environment more.
This translates to a spotty internet connection, one that not only varies from seat to seat,
it can vary depending on where your laptop is placed on that tray table in front of you. Manufacturers are working on the problem.
In 2012, Boeing filled an airplane’s seat with potatoes — spuds apparently mimic the
electromagnetic disturbance of human flesh — to try and understand how wireless signals
bounce around to bring stronger and more reliable wifi signals to future flights. And providers
are doing their part, too, beefing up ground networks and developing new systems that can
transmit more data. Do you guys use in-flight wifi, or do you
like having an excuse to go offline when you fly?
Let us know in the comments, and for more DNews every day of the week don’t forget