The new graph view (in version 1.16) shows for GSM the strengths of the neighbouring cell towers. It also shows clearly when hand-offs happen – this is when you are passed from one tower dealing with your voice/data off to another of the towers. Poor hand-offs are a big cause of dropped calls.
To see a graph of multiple towers (or in wifi mode multiple routers) click on the graph in the graph-tab to bring up the options, choose “show-detail”. If you want the graph to continue loggin data when you exit out of the app, choose “Allow graph to run in the background”.
The connected tower is shown as a thick line
So in the above image you can see two hand-offs occurring. CLicking on the graph will bring up a key showing you the identities of these towers.
Note for CDMA signal strength is only available for the connected tower.