In regards to Gods at least. If we are talking all powerful, no limits etc. Then I would require them to be able to convince me pretty easy, so that would be my requirement for them at least.
In regards to supernatural beings and we disregards Gods, so we are talking ghosts, spirits etc. That would probably be a lot more difficult, as at least from my understanding of them, they are not all powerful and therefore unable to just convince me.
A good start would be for someone to actually put forward an experiment that could demonstrate that they exist and that we are actually talking about such things. Obviously after having given a clear definition of what exactly a spirit or soul is suppose to be.
But also in regards to what you are writing, I would start by asking you to demonstrate that a frequency of which you are talking about actually exist and if you could define that for me as well, as I have no idea what you mean.