Mileage estimates are not based on a standard method or procedure. They are sometimes conservative, under-stating the performance of an antenna in many real world applications. Sometimes a mileage 'estimate' is wildly over-stated and only the most rare and extreme installation would hope to obtain the claimed results.
TV Fool offers a mathematical approach to predicting the signal strength at your location. Using the data in your customized estimate along with the measured and or calculated performance data available for reputable antenna system products, we are able to be far more accurate predicting the performance of an antenna system.
We simply ignore the marketing departments ad copy in favor of the engineering departments science based information.
http://forum.tvfool.com/showthread.php?t=109