Topband: Ground rods vs radials

Donald Chester k4kyv at hotmail.com
Sat Aug 21 11:21:54 EDT 2004



>...And I'm not sure I buy into the 'penetrate the soil very far' either.  
>"Very Far" is clearly not a technical term, but the suggestion is that a 
>few inches is all you get.  I'm not buying it. ...>Basically, unless you 
>can prove this 'thickness' issue in some way, I'm banking on 3' - 4' 
>apparent ground depths being relevant in my wet pasture soils of central 
>Minnesota.  A 4' rod would just poke into it...  >

It would depend on the soil conductivity.  By "very far" I was thinking in 
terms of feet, not inches.  Except for soil of the lowest conductivity I 
don't think you get much rf down at 8ft, though.  To me, the 8' ground rod 
always seemed a waste of effort.  Maybe it would be more effective to cut it 
in two, and run two 4' rods in parallel.

The capacitance, or counterpoise effect of even a small radial field should 
connect to the (virtual) ground plane better than one single rod driven into 
the soil.

I'm not even sure that a deep rod is particularly useful for lightning 
protection, since the pulse duration of a lightning surge is so short that 
it behaves essentially like rf.  I added some 20' radials to the ground rod 
at my service entrance for better protection.

Any other thoughts or opinions on this issue?

Don K4KYV

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