The reason you hear almost nothing at the beginning is supposably due to the massive radiation of the alexander platz tv tower. I walked from close range (50m) of the tower to Radisson Hotel Karl-Liebknecht-Straße 3. You can clearly hear a shift of infoscape when the detektor entered the radisson hotel starting at 03:12 and left the hotel lobby at 10:05 and entered again around 10:30.
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