It is close. The sense of "I am" awareness is that. Can you see or grasp or measure it?
In fact, it is so close, it is in the brain. And no transmission is required at all.
I see several assumptions made here that I find to be quite unlikely.
1. That awareness is a singular thing. I see it as much more likely to be a collection of interconnected processes.
2. That the circuitry that determines 'I am' will forever be out of reach of our measurements. Again, I find it likely that we will uncover several different aspects that fall under this heading of 'I am' with it only being an illusion that they are a unity.
3. We can certainly measure various degrees of consciousness through a variety of means.
4. The focus on subjectivity, to me, seems like a serious red-herring. A detector doesn't detect itself directly, but that doesn't mean it isn't material. There are many things we don't know about how the brain works, but all available evidence is that it can and does manage all the aspects of consciousness.
5. How can I know if I am conscious in the same way you are? I *think* I am conscious, but it seems from what you and others describe, my experiences may be different in kind from yours. maybe even to the place that what I 'experience' isn't really 'experience' from your point of view. How can I know?
6. To me, subjectivity is the least important part of discovering how reality works. OK, so such and such happened to me. That is a single event that may or may not give any hint about more general truths. It's on the order of saying that detector picked up red light. Without context and a physical background, that isn't very meaningful as far as i can see.