the further back you go the reading goes lower of course, at 100ft it's about 0.4mG
It seems a bit high compared to other places I have found. The powerline has 3 conductors at the top and one below.. seems to be a higher tension than most others.
Not sure if it's a good idea or not. I have found neighborhood lines that measured 0.2mG right underneath, and close to zero a little further away..