SteveHiker said:
I read the warning sign, but don't remember exactly what it said. The gist was that it exceeded acceptable values for workplaces. So I would think that the danger would be minimal for a brief visit like ours was. If you worked up there, that would be a different story. .
IIRC, workplace exposures would be for 8 hrs.
Presumably, someone walked around with a field strength meter and the boundary marks the allowable 8 hr field strength. Radio wave power densities drop off with the inverse square of the distance (ie half the distance, four times the power; third the distance, nine times the power etc). So field strengths inside the boundary could be much higher than the 8 hr limit.
RF radiation damage exhibits reciprocity failure. (That is, twice the exposure at half the time may not be equivalent to a level of exposure for one unit of time.) Thus a short exposure to a higher field may induce more damage than might be expected. Yes, for a constant field strength level shorter exposures may induce less damage than longer exposures, but you do not know what the exposure levels are inside the boundary.
RF radiation damage can include burns, heating, cataracts, temporary sterility in males, and is suspected as a cause of cancer. (An individual may not feel anything while exposed and the effects may only appear after a long delay.) For instance, when you put a piece of meat in a microwave oven* you expose it to a few hundreds of watts of RF confined in a shielded box. Commercial radio and TV transmission powers can be up to ~500KW.
IMO, the prudent course of action is to stay outside the marked boundary and to minimize my time in the general area.
* The frequency used by microwave ovens (2.4GHz) is chosen to maximize the heating of objects containing water. The shielded box is designed to keep the leakage to acceptable limits--the primary risks would be cataracts and temporary sterility. FWIW, I prefer to keep some distance between my microwave oven and my body when using it.
Doug