Jahova or Jahovah could be considered an incorrect way of spelling Jehovah. However the name of God is unknown. Since we don't know how God pronounces his name, we also don't know how to spell it. Therefore Jahova is just as correct as Jehovah. Certainly if you belong to the Jehovah's Witnesses, Jahova is not correct, but from the standpoint of God, some say that anything goes.
Jahovah is merely a label we as humans use to refer to God. For some reason people seem to need labels when it is likely that God does not. God's name has nothing to do with God himself. Just like your name could be John, Mike, or Suzy. Your name is not who you are. Your name is merely a label to distinguish you from other people.
Does God need a name? Why not call him God instead of YHWH, Yahweh, Jehovah, or Jahova, etc? Some may argue that there are several 'gods'. Jehovah's Witnesses say that Satan the Devil is the god of this world, for example. Also other people refer to their God by a different name.
Is it true that there is more than one God? Some say there is only one God. They say there is only one intelligence that created the heavens, earth, plants, animals, birds, and humans. One being did it all. Jehovah's Witnesses believe this to be true. They call their God Jehovah. Calling him by any other name is not acceptable. Yet in other religions, people believe their God created everything as well. To distinguish him from Jehovah, Jahova, or Jahovah, etc, they might call their God, Adi Purush, Bhagwaan, or Allah.
The fact of the matter is this. If one believes there is only one true God that created everything, there is no need to label him or argue about the name's spelling or pronunciation. All of us are referring to the same God. It's kind of silly to say my God is better than yours because his name is Jahova, if in fact we were referring to the same timeless being.
It is interesting that many of the names for God have a 'ah' or 'oh' sound to them. Consider the names Jehovah ... aaahhhh, Jahova ... aaahhh,, Allah ... aaahhhh, etc. Some say the name is a path to God. Why? Because they say that God cannot be explained. He cannot be understood by the rational, thinking mind. The way to know God, is to go into a field of nothingness in between our thoughts. That place is now. It knows no past or future. It is pure consciousness. Ego does not exist in this place. All are one. There is no disconnection, separation, or individualism. We are one in this place of complete acceptance and love.
How does the name act as a path to understanding God? Some say it's because if we focus on the 'ahhhhhhhh, ....' or the 'ohhhhhh,...mmmm' and use this sound as a mantra repeated over and over again, we go into a sacred place where there is no beginning and no end. We are eternal in this moment. We cannot live in the past. It is not real. It is merely a memory. We cannot live in the future because it has not yet arrived. All we have is this instant in time.
In the silence between our thoughts, a door opens to hear God and understand his true nature. As long as our mind is busy thinking, it's impossible to understand God. However when we take our left brain out of the picture and live in the present, there is no judgment, no disconnection, no separation. Love is all there is and this is the place where God lives. 1 John 4:16