hi lana,
have similar aversion to electro smog, we spent some time on this important issue you raise
can only speak for ireland, im sure its possible to get maps of mast locations in other countries such as
http://siteviewer.comreg.ie/#explore, then you can be sure your at least not near a mast,
getting locations with no coverage at all will be more difficult, most will be remote areas, you will see that coverage map for ireland is mostly all blanked out
https://n.vodafone.ie/network/coverage.html
otherwise its possible to use a pendulum, i use an electrosmog index 0-100% to assess areas/houses remotely,
even when no electro smog there still may other issues such as geopathic stress and negative entities,
we spent sometime looking for vacation locations with optimal
energy, not easy to find,
we never stay in hotels cause wifi, just rental houses with good energy in wild coastal locations, offshore islands are our favourite
overall better to have an energy tool, that boosts your own biofield, you carry everywhere as its difficult to avoid exposure all the time,
not a fan of faraday cages they do work but restrict the astral body at night