Re:Radiation from TV towers, > TV Towers

["John Moulder" <jmoulder@post.its.mcw.edu>]

> Hocking et al Med J Aust 1996; 165: 601-605.   Cancer incidence 
> and mortality in proximity to TV Towers. 
> This is an ecological study comparing cancer incidence and mortality 
> in nine municipalities  The population was divided in to two groups 
> living within 4 km of the geographic centre of three towers and 
> greater then the 4 km radius.

This is a rather odd definition of exposure.  The RF levels 4 km from a TV 
tower will be highly variable, depending on antenna design, station power and 
antenna height.  Note also that all other sources of exposure are ignored.  
This is like measuring ionizing radiation as "distance from source" and 
simultaneously ignoring background.

Nevertheless, for a typical single station antenna, power levels at 4 km will 
be in the 0.02 - 0.10 microW/cm-sq range.  You could get similar RF levels 
standing 10 meters from an operational cell phone or standing within 600 
meters or so from a cell phone base station.

If you assume that any cancer risk will depend on the level of RF exposure, 
then many people counted as "exposed" in this study will get lower exposures 
than many people in the "unexposed"populations.

"Ecological" study designs such as this are effectively useless, particularly 
when exposure is heterogeneous and the populations are mobile.



John Moulder (jmoulder@its.mcw.edu)