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![]() "Bob Bob" wrote in message ... Hi Y'all! (said with a strange Australian accent!) Am doing so NEC work for my QTH and need to get an idea of the ground conditions here. I started with the "Rich soil" of DallasLincoln but was advised that it was more clay and likely to be typical of that in central VA. Any information helpful. Cheers Bob W5/VK2YQA The 4NEC2 manual extract is attached inline below; Pastoral, low hills, rich soil, typical from Dallas, TX, to Lincoln, NE 0.0303 20 Very Good Pastoral, low hills, rich soil, typical of OH and IL 0.01 14 Good Flat country, marshy, densely wooded, typical of LA near the Mississippi River 0.0075 12 Pastoral, medium hills, and forestation, typical of MD, PA, NY (exclusive of mountains and coastline) 0.006 13 Pastoral, medium hills, and forestation, heavy clay soils, typical of central VA 0.005 13 Average Rocky soil, steep hills, typically mountainous 0.002 12-14 Poor Sandy, dry, flat, coastal 0.002 10 Bob, According to my 1977 edition of "Reference Data for Radio Engineers" Soil conductivity along the south bank of the red river is 30mS/m (Most of the OK side is shown as 15 mS/m). Since the map is not very detailed, and without going to the extent of graphic overlays, it seems that Dallas is in a region of lower conductivity at 15 mS/m. If you are interested I can scan the map for you. I went to the trouble of measuring my soil conductivity; using the "4 rod method", with 60 Hz AC, as per the ARRL handbook (Measured 52 mS/m in Calgary). I believe I have JPEGs of the relevant pages someplace. Also some guys I was working with, a couple of years ago, devised a method of measuring the complex permittivity with a capacitor structure. There were some problems with the method, which they eventually corrected. The information was required to analyze short range VHF transmission underground. 73. Frank, VE6CB |