I primarily use my Samsung S7* as a diagnostic tool when my Garmin and ANT+ devices don't seem to be communicating or acting weird.

There is an application called "ANT+ Plugin Sampler" that will query and report all the ANT+ devices it finds. It also dumps a lot of good information about my Powertap hub including calibration and battery status.

For actual riding, I still use the Garmin 805 head though.

I absolutely know that multiple Garmin heads can monitor the same ANT+ sensors once they are registered with the Garmin. We set up our tandem that way to read the cadence and speed sensors.



* I don't know about other mfgs, but Samsung has supported ANT+ since at least the S4.