jamescrr

It works on the Samsung Galaxy S5 as well.

Nice, I've seen reports of it not working on the S5, but that was only VZW.

After a bit more research I've come across a neat trick that can sometimes open service mode without using a dialler code

Clearly this is for LGE phones, anyone know of other codes?

Awesome to see the maps fill up so fats for Sprint, now I need to persuade everyone on all the other networks to do the same. thanks!

I'm James from OpenSignal. We're trying to map international rollout of LTE, but very few phones can report the band and bandwidth used, so we're hoping people can help us by firing up field test mode and submitting the data to our map - all the data can be downloaded.
 
We've already got a great map of South Korea and China, there's a lot of 10 MHz and 20 MHz bands there, which explains why they're clocking some of the fastest LTE speeds on the planet.
 
You actually need to use "service mode" on Android to do this: 
Type
*#0011#
Into a dialer. 
 
You should see
 
 

 
 
Here you can read the LTE stats easily. The Band is 7 (around 2600 MHz), and the LTE Bandwidth for download (LTE DL BW) is 15 MHz. Actually the Earfcn_dl gives a more precise reading of the band, 2825, so if this available use this.
 
 
You can fill in the form here: Google docs form
Your data will appear on a map here: LTE bandwidth map.
 
This won't work for all Android phones, I'm yet to find any other codes that can bring up this info (field test modes & service modes are implemented differently on different devices.  
 
On iOS try:
*3001#12345#*[/size]
 
 
Btw if any admin has the permissions, you can embed the form and map right here:
Form:

If that works fill out this form and your information will be automatically mapped:

All the information is public, and responses are mapped immediately below – you will probably need to refresh this page before your data becomes visible. If it doesn’t appear after that there may be a problem geocoding please email me James (@ opensignal.com) with your observation and we’ll get it up.

Map of LTE bandwidth. Click on a dot to see the observation. Get the raw data here.