They are small bits of rubber wrapped around the lower outer wires, not quite in the middle of the span but the same distance out on both sides.
now they where installed as part of a mount for something by the CSIRO of which is the Australian Governments national science agency as part of an experiment.
The experiment had nothing to do with aviation so don't be thinking along the lines of aerodynamics or anything.
and if you think its obvious, believe me your wrong!



