There was a study with mice, where the scientists wanted to reach the inner core of the brains.
(With humans that is a very difficult and tricky thing.)
They managed to do that with very low frequencies. High frequencies did not have any effect.
It is my opinion that the most harmful frequencies are not the RF, but the low to mid frequencies , expecially from 1Hz to 5kHz up to 10MHz.
Be aware that the RF do have
components of these frequencies. For instance Wifi has 10Hz, GSM mobile 211Hz, GSM masts 1733Hz. I have measured nice 100kHz frequencies in UMTS senders.

The inhabitants of this house could not live on the front of the house, because of mobile phonemasts on topof the building across the street.
I could measure the aforementioned frequencies in the front of the house, and so a grounded catch-antenna was constructed against the outer wall (a copper pipe with plastic covering).
Since then, the furniture was replaced to the front of the house, and they evenj copuld work for hours in the garden, which was not possible before that. On the mobile phone masts, nothing was done.
Placing a BioProtect card under the cables of a mobile phone masts can also have a positive effect, like a strip of adhesive aluminium tape around the cable.
See:
http://www.milieuziektes.nl/Pagina600.htmlAt the moment I am now trying to tackle a new problem.
Persons who do
not react to *normal* elektrosmog anymore, like masts, DECT, Wifi, etc. do now react to very subtle energies, like coming from an (empty) honey comb. (Grebennikov)
Even meters away through concrete walls.