I add this to the frey.
The globe we live on called Earth, is enveloped with a HUGE system of magnetic belts that form the Van-Allen belts.
These will affect your readings.

I fail to see how it is that people can say they feel the effects of Electro-magnetic fields.
There has been monitoring of people that work with HV bare wires since the 1950's.
There is no conclusive evidence that there are any causitive factors in the health of these workers.

It is the same with the hysteria that is quite prolific when a new cell tower goes up, it seems to be the emotive response from those that are complaining, rather than actual REAL science from those that are looking to install the tower that the media takes on board.

We've all read the headlines "Tower will kill our children" or "Families protest against new tower site"

Many of the people have nothing but pseudo-science to back their claims up, without having read or understood the original technical report on the tower and the emitters.

But one thing I have seen here, is that the same people that are complaining about cell towers are the ones that are also complaining about poor reception.

Work that one out for yourself.