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
to subscribe.