Hi,
If you can plug a Voodoo 3 in your Amiga, you can use on of the PC TV cards based upon those chipsets (if you have the GREX bus):
Brooktree BT848
Brooktree BT878
Brooktree BT879
Conexant Fusion 878a
Conexant Fusion 879
Microtune Tuner
Philips Tuner
Visionary for G-REXand only (?) Bt878 for the Mediator...
But which is your version of MorphOS 1,1.3 or 1.4 ?? :-o