The voltages present on a HF antenna can be rather large its caused by the black magic in the antenna tuning unit. The number insulators and size on a ground based antenna should give you a clue however for the same power the induced voltages on VHF and above are much smaller but the energy of the electron will be greater ( Lenz and Planck)
If no one can come into accidental contact with the antenna or aircraft( grounding issues) then i'd say your fine to test if your not sure leave it alone until you're away from everyone. I've known ship radio officers come up on the ham bands to test their kit
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