Practical Application of Soil Measurement Data

Anyone interested in ground radials, ground mounted verticals and even elevated radial verticals should visit Larry Severns, N6LF, website. he has done extenstive research om the subject and has published his results in QST and QEX with many of these articles available on the website. His article ” Experimental Determination of Ground System Performance for HF Verticals Part 4 How Many Radials Does My Vertical Really Need?” was originally published in QEX May/June 2009 edition. The following graph was taked from this paper:

This graph shows the change of signal improvement on a 1/4 wave vertical with 1/4 wave ground radials under different ground conditions. The impact of this graph is that when the ground is “good”, adding more radials results in small signal improvement vs when using a “poor” ground. I can expect a .2dB improvement if I double my radials from 8 to 16. If I double again to 32 radials my signal improvement would be only around .5dB.

There is a real economic benefit to having good soil as in general fewer radials are needed because the ground losses are less than when over poor soil.