http://www.geocities.com/zbtaz/
found that... doesnt really sound like what your looking for...
might just drive around town and see where the pirate station covers the other one most completely... and mark it on a map... then drive around town more... find another point that has the same reception as the first... and repeat over and over... then the point in the middle of the other points should be close to the broadcast area... assuming everythings flat and there arnt geographic features that would interfere with reception...