renluop: yes, you are right. I've heard there are frequiences used by amateur radio, however I've gathered information that nobody broadcast radio on these frequiences in my town. Moreover, my phone line is underground. Moreover, my QLN is strange. On unused frequiences I have also very low noise.
My ISP annoys me. They continously say it is normal for long lines (obviously it is not true and also my line is no such long).