Depends on your country.? In the US, the max is 100W PEP ERP.? If you are using a 1/4 wave vertical, and a 100W RIG, you could not achieve 100W ERP without an amp.
FWIW, mine works fine on 60m, just have to be careful with the drive power so you do not exceed the 100W ERP which in my case, is 200W output with my antenna.
N5GGG
