[TowerTalk] Follow up {Re: Measuring RF ground characteristics}

[Artek Manuals]

Thanks to all who replied

The Hagan paper sited in the ARRL Antenna  handbook was eventually 
located and turned into a scavenger hunt. Hagan published several papers 
on the subject and the math for using the OWL probe approach is in yet 
another paper by Hagan.. (publish or perish I guess).

As it turns out the Rudy N6LF has a much easier path to follow ( should 
have known ..tnxs Rudy). At any rate I eventually Googled my way back to 
Rudy's home page and then subsequently to this page.

https://www.antennasbyn6lf.com/measurement_of_soil_characteristics/

( Tnxs to Carl K9LA who clued me into the N6LF papers to begin with)

Towards the bottom of this page is a section titled "Soil parameter 
measurements at HF", and at the bottom of that paragraph is a link 
highlighted in blue "ground parameter measurements 
<https://www.antennasbyn6lf.com/files/ground_parameter_measurements_2.pdf>" 
which in turn takes you to a paper by Rudy which among other things 
addresses the construction and math involved in an OWL ( open wire line) 
Probe.

For those of you who have a decent VNA the assembly and use of an OWL 
probe is discussed. Not for everyone depending on your soil type (and  
the time of year for you guys in Minnesota) but for my sand bar in 
Florida just what the doctor ordered, Also the need for a BALUN should 
be noted if your VNA is connected to the power mains eventually as the 
all that becomes part of your "ground" if not isolated from the 
measurement field.

73
Dave
NR1DX
manuals at artekmanuals.com

On 2/13/2021 12:59 PM, Artek Manuals wrote:
> In the process of trying to correlate actual measured R+jX values vs 
> NEC models for an 80M inverted L with elevated radials, I was directed 
> to a paper by Rudy N6LF in QEX from 2009. I have used Rudy's approach 
> and have after many iterations achieved reasonable correlation between 
> actual and modeled numbers. The numbers were not what I expected but 
> are "believable"
>
> It would be intellectually far more satisfying to be able to measure 
> conductivity and dielectric values through direct means.The ARRL 
> Antenna Handbook ( 22nd edition , page 3-21) references some work done 
> by George Hagan back in the 1980's using probes and a VNA. . The ARRL 
> in its infinite wisdom of course does not show the math involved in 
> using this method to directly measure and calculate conductivity and 
> dielectric constant. I have "probes" and a decent VNA ( AIM4300)
>
> I am looking for a copy of:
>
> HF Ground Measurements at the Lawrence Livermore National Laboratory 
> Field Site; /Applied Computational Electromagnetic's Society Journal 
> and News Letter, Vol. 3,Number 2, Fall 1988"
> /
> Any help appreciated with either a copy of the paper or a pointer to 
> where it might be downloaded. So far Google has not been my friend./
>
> Dave
> NR1DX
> manuals at artekmanuals.com
> /

-- 
Dave Manuals at ArtekManuals.com www.ArtekManuals.com

-- 
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus