Beacons with EARS aren't counted in the number of beacons on buildings. They still transmit their effects, but with no diminishing returns.

https://imgur.com/oSecom6

Thanks for the report. EARS beacons and normal beacons are counted separately for diminishing returns calculation (because they are 2 different beacons). So two EARS beacons will have diminishing returns, two normal beacons too, but one EARS and one normal will not diminish.
I could change EARS beacons to get diminishing returns from all beacon types, but that would still keep normal beacons full returns even with an EARS beacon nearby.
Since this is even more confusing I think it should stay as it is right now. The difference is not that big, so if you know about it you can choose to exploit it for a bonus.

Got it, they just don't show up in the information window as being counted.

Is that window editable, to display the number of EARS Beacons affecting a structure, and what their effective rate is?

Oh I see, missed that. They will be shown in that list with the next update.