"Bob Haberkost" wrote in message
news:LIBee.16270$c86.2254@trndny09...


David - I take exception to this assertion. Sure, low-end ground wave is
better...MUCH better...than the high end, but it's more like a factor of
5,
maybe 10...not 50. In fact, referenencing the FCC graphs available as
PDFs, the
560kHz graph shows that, for the 20mmhos conductivity curve, for example,
the
curve intersects 10mV/m at 9.6km, whereas for the 1550kHz graph, this
point is
at 7.6km....hardly even a factor of 2, and when squared (for coverage
area) only
a factor of 1.5 or so. So, sure, a 1kW station may have decent coverage
at
550kHz of perhaps 1000 sq.km, but a 50kW operation at 1600 kHz is still
going to
have much, much more.
--

I actually ran maps of a 5 kw below 600 and a 50 kw above 1500. Both located
in areas of the same conductivity, within a few miles of each other. The low
frequency station covers slightly less than the 50 kw right above 1500.

A good practical example is the 5 kw coverage of WMT and the 50 kw of KXEL,
a few miles apart in identical high conductivity areas in Iowa. one on 600.
The other on 1540. A run on the coverage of each reveals 600 with slightly
better coverage than 1540. Or, take the 550 real coverage of KFYR in Bismark
or the daytime 5 KW of KNAX in Yankton, and compare with WHO on 1040. Both
cover greater areas for comparable signal levels. In fact, KWMT, a 5 kw on
540 in Ft. Dodge, IA, used to advertise in the 50's as having the largest
land coverage area in the USA, and the ads were certified by one of the
major consulting engineering firms of the day.