I've used N6BV's HFTA for over 15 years, love it and found it very useful.
Recently I downloaded the terrain from K6TU for a new planned station in V31
and found some strange numbers. All latitude and longitude numbers were double
checked so that is not an issue. From being in the area where the station will
be located and from the Google Earth terrain numbers, things don't agree. I'm
talking about 50 foot hills that don't exist. From observation, I know there
is a steady slow slope to the ocean from an elevation of 45 feet to ocean level
2500 ft away. No hills, and Google Earth confirms this, but the terrain
numbers from K6TU claims there is one
I manually downloaded the numbers for several different directions and compared
the output between the numbers from K6TU and the ones from Google and there are
differences. No gross changes, but enough to change the output by 3 or more dB
in many cases. I'm not badmouthing K6TU and appreciate his work, but this is
quite puzzling. I've never had this happen before. In low flat sugar cane
areas, Google gives numbers that conform, but the numbers I got from K6TU show
rises of almost 40 ft.
My guess is that the numbers outside the US are not quite as accurate and
perhaps thick jungle gives an artificial height. Any thoughts?
Bill K4XS/KH7XS
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