Tvheadend

Hi folks, as i could not find this topic on the boards and only some outdated sites on google, i am asking you here for help. I apologize in advance if i overlooked forum entries that descibe my topic exactly.

I want to use tvheadend to view japanese tv streams, but i can not find a good usb tv tuner that works on raspberrypi.
The MyGica products that are mentiond to work are no longer available to buy anywhere. If you could give me some hints which usb tv receiver to buy/use that works with rapsberrypi and can tune in ISDB-T i would be very happy.