The K5GO contest station is located on a mountain south of Harrison, Arkansas with a peak elevation of 2060 feet. Since about 2005 we have used the terrain analysis program HFTA to determine best heights and best locations for our antennas. While we are on top of a mountain our shot to Europe for 10, 20, 80, and 160 meters is relatively flat for the first half mile and then begins a steep drop off:
According to HFTA this terrain is nearly identical to flat terrain as far as signal response to angle of radiation. Beginning with our 40 meter project in 2006 we realized that we could get some terrain advantage by locating the tower a few hundred feet away and gain some advantage towards Europe. This meant locating the new 40 meter tower approximately 300' to the west of its original position. It doesn't sound like much but below you can see the difference in terrain toward Europe:
The above terrain file shows approximately 200' of drop over the course of 2000'. The chart below shows the difference between the 5 element 40M Yagi at its current location 135' (blue) vs. a 5 element Yagi over flat ground at 135' (red).
As you can see, at lower angles we have more than 2 S-units of gain over flat ground. As you move counter clockwise from the Northeast our terrain improves even more. Below is the shot to Japan:
We do well in this direction and the band is always super quiet. Below is a 15 meter antenna at 30' (blue) vs. the same antenna over flat ground at 90' (red).
