After I've been searching for the right DVB-T antenna, I decided for a branded product. The device makes a reasonable impression and can be installed (roof mounting on existing satellite holder) simply. Only works has not the appliance! With a home-made dipole antenna in the room I had more reception than with the receiver. The manual is an insolence and apparently there are many who have the same problem. Meanwhile, I have returned the device again.
Thanks to Amazon and the excellent telephone support.