I do not exclude that this already the problems begin in the cabling throughout the home and even extend the extremely poor coax cable rather inconvenient places and hardly have a good shielding. But the fact is that the amplifier in my case was no help here. Amazon has but the device taken back without hesitation.
PS: The blister packaging is catastrophic. One can get the product only with the complete destruction of the box. This Hama should finally think about to take the path of Frustration-Free Packaging.