[TowerTalk] Vertical and radials

[Robert Harmon]

Thanks Dave,   

I will look into it.

Bob
K6UJ

> On Jan 22, 2022, at 9:36 AM, Dave Sublette <k4to.dave at gmail.com> wrote:
> 
> Do you have an agriculture extension office or a Farm Services Admin office in your area?  You might try calling them and asking if they have that data.  As much grape growing as there is in your area, one would think that all of the soil data is available.
> 
> 73,
> 
> Dave, K4TO
> 
> On Sat, Jan 22, 2022 at 12:22 PM Robert Harmon <k6uj at pacbell.net <mailto:k6uj at pacbell.net>> wrote:
> I love your perfect QTH description.   A hill of salt water, sloping gently in all directions.   hihihi
> 
> I am having trouble finding ground conductivity fro my area in the north San Francisco Bay Area.  Napa county.
> Looks like my area shows a number 8.  Where is he chart to find out what this means in conductivity ?
> Wish I could find a map that I could drill down closer to my QTH.  I know it is pretty good right now, we have had 
> lots of rain the last few weeks.
> 
> Bob
> K6UJ
> 
> 
> 
> > On Jan 22, 2022, at 3:58 AM, John Langdon <jlangdon1 at austin.rr.com <mailto:jlangdon1 at austin.rr.com>> wrote:
> > 
> > The other thing that K5IU was clear about is that the ground under the
> > antenna is the dominant factor in performance regardless of the radials you
> > use.  
> > 
> > 
> > 
> > If you have really low conductivity soil under the antenna, even if you
> > mount a vertical on a 1/4 wavelength radius copper disc, essentially an
> > infinite number of buried radials, you are going to get poor performance.
> > Elevated radials will be as good or better in that situation, and are less
> > work, but a high dipole, over poor soil, will be equal or better.
> > 
> > 
> > 
> > If you have really high conductivity soil, a modest number of buried radials
> > or a set of 4 1/8 wavelength elevated radials tuned with an inductor will
> > probably give you good performance.
> > 
> > 
> > 
> > If you are over salt water, a single resonant radial will work very well.
> > 
> > 
> > 
> > BTW the ground conductivity maps most of us have access to, like
> > https://commons.wikimedia.org/wiki/File:United_States_Effective_Ground_Condu <https://commons.wikimedia.org/wiki/File:United_States_Effective_Ground_Condu>
> > ctivity_Map.png , are from data averaged over a large area  and any given
> > location within an area on the map may vary widely from the average. The
> > perfect QTH is a hill of salt water, sloping gently in all directions.
> > 
> > 
> > 
> > 73 John N5CQ
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > _______________________________________________
> > 
> > 
> > 
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