On Thu, 16 Feb 2017 01:52:24 +0000 (UTC), Stijn De Jong wrote:

Q: Which app do you use on iOS or Android to figure out all the cellular
towers and signal strengths of the cellular signal (CDMA or GSM) in your
area?

Summary of the freebie app selected after a few days of testing.

I've dumped the freeware version of Network Signal Info because it kept
hanging, and opted to use as my primary real-time app "Network Cell Info
Lite" (The best logging app was NetMonitor).

One nice thing about Network Signal Info payware is that it reports not
only the current (aka registered) cell, but also the neighbor cell
strengths.
http://wilysis.com/networkcellinfo

Here are some screenshots of today's scan to help you see what it reports.

The good news is that I've brought my signal strength in the mountains,
miles from the nearest T-Mobile tower, up from around minus ninety to minus
one hundred decibels to consistently better than minus fifty-five to minus
sixty-five decibels (which is astounding!).

Here are the results of a scan this morning from my new "gsm" folder:
http://i.cubeupload.com/lgDafB.jpg

In this scan are the unique cell tower identification numbers:
http://i.cubeupload.com/5H7qmX.jpg

The second tab shows the ever-changing raw data in text format:
http://i.cubeupload.com/3gMofW.jpg

While the third tab shows a time-sequence graph showing consistency:
http://i.cubeupload.com/3rDsHX.jpg

There are multiple plots of multiple types of signal strengths:
http://i.cubeupload.com/4HQqh8.jpg

And a quick table of DATA ON/OFF connection percentage statistics:
http://i.cubeupload.com/NQ0xJU.jpg

You can export the entire database in multiple file formats:
http://i.cubeupload.com/W1AAaK.jpg

And there is a nice summary page of the device & sim card information:
http://i.cubeupload.com/hCXKXJ.jpg

I may end up getting the payware if I can't find a freeware app that
reports the neighbor cell strengths, which would also be useful
information.

But there are plenty of freeware apps to explore, e.g., this MIT app:
http://people.csail.mit.edu/bkph/CellTracker.shtml