[BC] Ground system

[Mike McCarthy]

The radials can be a component in an effective lightning or static energy dissipating ground system if the surrounding soil composition is conducive (not necessarily conductive in a RF sense). Such as where the water table is just below or at the surface and/or the soils is very mineral rich (hearty black top soil).

As Curt knows all too well, the energy of lightning goes looking for the moisture layer/water table to disperse out through it's mineral rich composition.A swamp or river basin floodway are two examples where the radial system could assist in lightning or static energy dissipation.  
The radials are immersed in that type of environment will become a component in the dissipation array below and beyond the primary current conductors and electrodes closely spaced to the tower.Never the less, I would never in a million years suggest relying only on a RF radial system for earthing static or lightning energy.  The surge current is simply too high and the radial array will saturate quickly.

However, I have seen radial systems completely detached and removed from the inner ground electrode system (first 5 degrees or so) and very little change in RF performance has occurred.  Both in terms of base impedance and efficiency.

But Curt is right...ground is not always "earth".  And "earth" is not always ground.  But you have a better chance at achieving a stable long term tower with the deep earthing system than a radial ground system alone.

MM