How do I calculate the hysteresis losses of a straight line inductor?
Summarising the comments above, hysteresis losses will decline as your frequency increase and are not typically associated with the conductor itself.

Skin depth will start to take effect as your frequency rises, effectively increasing your impedance.  This does need to be considered, espescially if your are attempting to transfer reasonable amounts of power through the conductor/antenna.

Refer to wikipedia: http://en.wikipedia.org/wiki/Skin_effect