[TowerTalk] Radials how deep is too deep?

[Jim Lux]

On 12/6/15 8:58 AM, John V wrote:

>
> #3. How deep in the soil can a radial be and still operate properly, how
> deep is too deep?
>

It depends (hows that for a vague answer)..

I'll write here about the RF effects: lightning and electrical safety is 
different.

There's a huge difference between buried radials, which really includes 
radials lying on the surface, and elevated radials.

Once you're buried, what you're really doing is improving the effective 
soil conductivity.

So the question you have about "too deep" is whether the skin depth of 
the soil is so shallow that your radials are below the level of 
significant current in the soil.

Rudy, N6LF, happens to have calculated all this
http://www.antennasbyn6lf.com/files/ground_skin_depth_and_wavelength.pdf

For reasonable conductivity (i.e. you don't live in a dry sandy area), 
skin depth at HF is going to be "meters".

For areas covered by concrete, the concrete is a bit higher in 
conductivity than most soil.  That will shallow the skin depth a bit, 
but not much.

So, unless you buried your radials in a 6-10 foot deep trench, they're 
probably helping.  How much is very hard to tell.


One general observation..
You'll not be able to measure the improved soil resistance (and the 
related improvement in antenna system performance) in any meaningful way.

It's all buried now. Be happy, brag about your ground network, use it to 
explain how you made DXCC in 3 months, etc.