Topband: Soil conductivity maps

[Richard (Rick) Karlquist]

On 4/1/2018 7:45 AM, Jeff Kinzli N6GQ wrote:
> So I'm looking to purchase a new QTH. I'm not particular about
> location, but would like to optimize for soil conductivity and any
> other parameters that would increase near and far field propagation
> and minimize ground losses. I've seen the US Gov M3 maps, but they are
> very coarse. They also only define conductivity, and I'm wondering
> what other quantities would be useful to look at.

Some personal experience.  My QTH is shown as 15 on the FCC map,
but is only a few miles from a 30 region.  I seem to get out on
160 very well from this QTH as if the soil is magic.  The thing
about the soil here is that it is 100% hard pan clay down to 40 feet.
Zero sand.  Zero rocks.  Terrible (Class 4) for agricultural
purposes; even the weeds don't grow well.  Unless you are growing
rice.  BTW, all the rice plantations happen to be in the 30 region.
But apparently it works for RF.  Just 5 miles to the south,
you enter the "wine country".  The soil changes drastically,
according to the local experts  That area is filled with grape orchards 
and wineries.  But the FCC map doesn't reflect this
discontinuity at all.  Possibly the soil is still good for RF
in the wine country; I don't have any data because the few hams
there don't operate on 160.  But it does bring into question
the validity of the FCC map.

Rick N6RK