I developed Tinnitus shortly after a Cell phone tower was erected across the street from where I live. I am sure this is the cause. I now have the ringing in my ears 24 x 7. The day I developed it, I spent walking around the cell tower with an EMF meter to measure the radiation in different areas. That night I heard the ringing for the first time and it has been non-stop ever since (over 1 year later). The only relief I have found is when I am away from civilization where there is no wi-fi, cell phones, cell towers, etc, it almost goes away entirely. Unfortunately, when I come back to civilization, it returns. I have also found that sleeping under a Faraday canopy which blocks all RF/Microwave radiation helps considerably and when I wake up in the morning, it is barely there.
