heat sink for rf ground?

[9Lives]

The amp I'm building with the erf7530 s uses a solid copper board as the common ground. Right but it's feed backing like crazy so I'm going back through the circuit and doing soon tweaking. I read somewhere that i can use the heat sink for the rf ground and tie the source pins to it to help with feed back and oscillation. If i do this should i also tie the coax shield to the heat sink? If i do this do i need to tie it into dc ground with a capacitor, or will it be good enough for the source pins?

 

[9Lives]

Common, y'all help me with everything.. some body knows. If i use the heat sink as aground i need to tie it in to dc ground some where ?

 

[Greatvalue1]

The black wire, not the red one