Dean Straw, N6BV, created a software program called HFTA for predicting the performance of antennas based on terrain. It also offers the ability to compare the expected antenna takeoff angles with the most expected angles required for HF propagation to various geographies. HFTA is included in the ARRL Antenna Book.
I am a big believer in the value of terrain modeling when planning antennas. I have found a reasonable correlation between observed performance of antennas and what HFTA predicts.
Dean kindly provided the terrain files for various directions from my three towers. Even though the three towers are only 150 feet apart, each presents different esults.
The PRO files are labeled according to tower 1, 2, or 3. E.g., K5ZD3-000.PRO = K5ZD, Tower 3, azimuth of 000 degrees, etc.
Tower 1: 100′ Rohn 45G (with 2-el 40, 5/5 on 20m, 5/5 on 15m)
Tower 2: 90′ Rohn 25G (with 7/4/4 on 10m)
Tower 3: 40′ Rohn 25G (with TH7DXX and 5-el 6m)
|K5ZD_HFTA||All files in zip archive.||24Kb|
You may need to right click on the link and select “Save Target as…” to download the file to your computer.