Surely you used several USB Ethernet adapters to rule them out as being the source as well right? Those types of dongles are well known for calling home.
Good observation :) Multiple ethernet adapters: Apple original (ancient USB2 10/100), Tier 1 PC OEM, plus a few random ones. Some USB adapters emit more RF than others.
Good observation :) Multiple ethernet adapters: Apple original (ancient USB2 10/100), Tier 1 PC OEM, plus a few random ones. Some USB adapters emit more RF than others.