There are lots of completely unused frequencies is in the higher frequency bands. The problem with them though is that they go long all the time so NVIS is impossible. The only NVIS band not used by many stations is the 120 meter band which requires huge antennas. But, if you are far from your audience there are lots of good in-band frequencies available in the 22, 19, 16, 15, 13, and 11 meter bands.