I then positioned the 546E on the ground floor in the desired location. There was almost nothing. It was not a stable connection possible. He has always had a connection times short, if you wanted to use them, but they collapsed. At another point on the ground floor it was a bit better. There was, after all, a stable connection, but this was very slow and not much better than my previous wireless solutions.
My current cabling is actually fairly new (about 7 years old) and a neighbor has a PowerLAN solution run successfully on at all times. In defense of the unit I must say, however, that the circuit in the basement and the ground floor hang with me each on a separate RCD. This means that the powerline signal passes through two RCDs. I suspect that this is the cause of the problem.
I have returned the equipment and I bought instead an AVM FRITZ! WLAN Repeater 300E. So now I get along quite well.