Wait for it at 00:20. With funny sounds I don't mean bird-like sounds. Those are produced by real birds.
Parameter 28.06 was set to 100 metres. Actual cable length is 60 m. Above 80 m the drive changes switching frequency at low rpm (less than 20% of motor nominal).
N.B. this is not normal behavior of the generator, allthough is does no harm, your neighbours might beg to differ ;-) Normally it is as silent as in the first few seconds. The high pitched wissle you might not even notice, is caused by little damage to the blades.