Sissipaska

Hi Have searched for this without result. My rooftop aerial (radioantenna) has cracked in half and the plastic has perished. I've removed just the aerial and left the base in place. Do anyone know if I can replace the antenna with a aftermarket one like this: www.ebay.de/itm/SKODA-FABIA-OCTAVIA-ROOMSTER-STAB-ANTENNE-16V-M6-40CM-/271041572799?pt=DE_Autoteile&hash=item3f1b562fbf It has adapters in different sizes to screw in to the base so that part is clear to me. What puzzles me is that the original antenna, which also screws in to the base, has an extension with a small edge (see orange arrow in picture). I wonder if this extension is essential for connection or if it's just an anti-theft invention? Note that this part is molded in to the original aerial and I have painted how the aerial sits over the screw-part-thingy So will a normal screw give enough signal or do you need a original aerial with the extended screw? Sorry for bad english guys, I'm only 24 Thanks!