Time travel thread, Hey ho let's go!

if you were to produce 'something' akin to a magnet...however not as simple as a household magnet (because the earths field fluctuates, so you would need to be able to change its frequency) that was in tune with the earth...ie 440hz...you would be able to make it fall slower...as it would be able to repel the field...

Is there anywhere I could read more about this idea ?