I am looking for a free Android app (to run on an S4) that can monitor and record signal strength for my mobile phone and/or mobile data connectivity while I'm underway within a specified timespan (either explicitly indicated as times or by pressing a start / stop button).
The app should output the recorded data as something like a signal strength/time chart (a line chart, or possibly a bar chart if the recordings are chunked in defined sampling intervals). Bonus points if the average between several recordings (possibly allowing for some manual temporal alignment) can be computed.
Based upon the resulting charts, I would like to compare my connectivity of different alternative routes that I can take on my daily commute, with each chart providing something like a "characteristic line" for the respective route.
This question is very different from the seemingly similar Monitor mobile phone network signal, as I am specifically asking for recording the monitored strength over time rather than just retrieving the actual state. (Also, I am fine with something that entirely runs on Android and does not transfer its results to a computer.)