[BC] Why superpower? (was: WLW my take)

[Richard Fry]

"Dan Strassberg" wrote:
> It was stated that WWJ's pattern maximum (7981 mV/m @ 1 km
> by night) is equvalent to approximately 300 kW. The equivalent
> power is, in fact, almost  50% higher! If you use the pattern RMS
> --2665 mV/m @ 1 km--you find that the field-strength ratio is 2.99.
> Hence, the power ratio is 2.99^2 or 8.94, which makes the equivalent
> power something like 448 kW at the pattern  maximum. If you use
> the corresponding figures from the (five-tower) day  pattern, you
> still get an equivalent power of almost 390 kW--almost 30% more
> than the claimed 300 kW.
etc
______________

Your detailed analysis certainly is better than the rough numbers I posted. 
But my goal was to illustrate that very high ERPs don't produce as much 
coverage improvement as commonly expected.  The greater ERPs you posted for 
WWJ just underscore this point.

The coverage maps for WWJ on http://www.radio-locator.com/ show both their 
day and night 2 mV/m contours to be within those of WJR -- even at the 
peaks of WWJ's major lobes (D/N).  So all that extra ERP has done is to 
extend the distance to WWJ's contours in their major lobes by about the 
distance that separates the WWJ and WJR tx sites (maybe 15 miles?)

In other words, WWJ needs ~390 to ~448 kW in their major lobe (by your 
analysis) to approximate the same location for their 2 mV/m contour in that 
direction as WJR produces with 50 kW from a site about 15 miles down the 
radial through the center of WWJ's major lobe.

This reality about very high ERPs is not highly intuitive, and was/is the 
reason for my posts.

RF