Radio receivers (and the LNA component of such) are incredibly sensitive... that's what allows all the radio systems we use daily to work at all. If a signal is

Radio receivers (and the LNA component of such) are incredibly sensitive... that's what allows all the radio systems we use daily to work at all. If a signal is strong enough to have a physiological effect on the human body it is many many orders of magnitude stronger than can be measured with off-the-shelf instruments (i.e. an antenna and spectrum analyser). Even if you make an effort to concentrate the effect in a specific spot (e.g. phased array antennas), you can only achieve a moderate reduction (e.g. 1-2 orders of magnitude) outside the central lobe. It will be easily detectable outside the effective area.