Re: WWZN 1510 Signal Coverage

[dan.strassberg@att.net]

WWZN's coverage of Acton is at best fair during the day 
and nonexistent at night. In the design of the night 
pattern, there was never any intent to provide coverage 
much further northwest of the RX than Lexington. 1510 
protects WLAC, the dominant station on 1510, with a very 
deep and fairly broad null to the west-southwest. There 
is also a lesser null to the north to protect a now-dark 
station in Sherbrooke PQ.

It was the Sherbrooke station in particular that 
necessitated siting the TX _north_west of Boston and not 
west or southwest. The combination fo the high 
frequency, the poor soil conductivity in New England, 
and the then-existing requirement to put 25 mV/m over 
the principal business district of the COL necessitated 
a site only 8 airline miles from the Boston waterfront.

As for coverage maps, don't confuse coverage maps with 
polar plots of field intensity vs azimuth (which is what 
John Kodis' site provides--although the plots are now 
badly screwed up with apparently no hope of anyone 
unscrewing them). Polar pattern plots are NOT coverage 
maps, although with enough information (a soil-
conductivity map the FCC curves of signal strength vs 
distance with soil conductivity as a parameter), you can 
use the pattern plots to construct coverage maps. In 
general, the poorer the soil conductivity and the higher 
the frequency, the more the pattern nulls and maxima are 
de-emphasized.

> I know there is that sight that generates a station's pattern based on the
> FCC file info..but it doesn't show it in context to the milage, geography,
> cities, towns, roads, mountains, etc.