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Ground losses, wet soil (dirt) vs dry soil..
- Thread starter TheBlaster
- Start date
Probably more than you wanted to know.
https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=2590&context=etd
https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=2590&context=etd
I went straight to the conclusion and I think it said, signals were up when earth was wet.
To quote: "In almost all measurements an increase in soil moisture content gave a substantial increase in signal strength."
Although I cannot work out if that is due to less ground losses, which I imagine RF that goes in the ground and dissipates as miniscule amounts of heat.
To quote: "In almost all measurements an increase in soil moisture content gave a substantial increase in signal strength."
Although I cannot work out if that is due to less ground losses, which I imagine RF that goes in the ground and dissipates as miniscule amounts of heat.
Be better if it rained in your area for two days. Ground conductivity which does indeed affect signal strength do a degree, lower the frequency the more noticeable the difference, is not just dependant on the quality of your ground system but rather on the quality of THE ground ie sand and rocks versus river bottom or dyke land.
In many ways, "Earth" is Return, Ground, Shield - many things. So with soil moisture and conductivity - they pretty much go hand in hand.
The more you can provide for the Image to form in the "Earth" the more propagation effects you will be able to participate in as well as remove levels of noise that would otherwise occur if the ground image was left floating at atmospheric ionization levels - referring to Wind Static and Air Ions from things like Power line losses, Ozone and or local thunderstorms, even trans-atmospheric effects like ducting and even ground currents that change when the Magnetosphere gets "pinged" by an interstellar event.
You also have the Galvanic and Electrolytic events that help transfer (the process of reduction) your bare, base metal radiator and ground spikes into a working circuit using earth. This process accelerates when water - slightly acidic (carbonic or sulfuric - salts found in soils) is present to help with this reduction cycle. (Yes to your Question)
When the Earth and your antenna are more closely coupled together - meaning they are as a unit - no matter the height in between - the noise effects like above are less likely to cause issues. The loss is then as one unit of conductivity in both ohmic and radiative effects (your true relativistic resistive working value against your system) which is dependent on the soils' ability to conduct RF interactively as an image or counterpoise.
Water works against the system as a reduction - but it is a necessary process in order to have the ability to even form an image in soil.
I have found that dirt and vegetation requires the rule height is might. Rock not as much. I have had many contacts with the fed point 8' above rock top hill ( ok mountain). Soiled topped I go min of 20' and 4 x the power.
You will always have contacts for sure. I made a contact from Nova Scotia to Florida on 11m with a dipole in my basement. Doesn't get much lower than that LOL. We could actually see a difference in field strength on our AM signals from spring when everything was saturated in water to the middle of summer when it was dry as a bone. You could see the signal was lower and you could tell in the weak signal areas. The difference was not dramatic but noticeable if you knew what to look for. Like I said, the lower the freq. the more noticeable it is and this was on AM broadcast freqs. I am sure a detailed study in azimuth and elevation angles would reveal changes over the year oh HF but they may not be that noticeable.
That seems to go against the premise that soil is "better" ground than rock. Rock being more like desert (i.e. the worst ground) ?
Thanks for that deep reply Handy Andy and nice anecdote Captain kilowatt. The old make a contact on a "wet bit of string" saying.
When atmospheric conditions allow everyone has a "POWER STATION" lol. It is when the going is not so good you need the edge to cut through.
On my line of sight contacts over 150-250miles (high ground at both ends) I am acutely aware 1-2dB differences on SSB are a copy or "not heard". Small tweaks add up and why I check connectors mate well, coax is shortest possible and best quality possible, I use a good external speaker, sand paper my poles so they connect well, and do my best to make any install (all my installs are temporary as static mobile even using a vehicle mounted whip) as best as it can be. When set ups are going up and down a few times a week you need to do maintenance on your set up. (even checking your 259's/239's are in good shape as they wear)
Only a CB'er here but I am bang into it !
I get satisfaction form that side of it, even if some of things in themselves make virtually no difference.
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For my inverted L on 160 meters (77feet vertical section) i put in 3000 feet of radials in the ground, have 9 10 feet long earth rods in the silty sea clay here connected to each other and the radial net and house ground.
Over that radial network is my OCF and other antenna's so it looks like I'm good with the radials.
For far off help the rest of our province has the same salty sea clay adding to the reflection.
I worked the world in phone on 160, the same inverted L fed by the MFJ 998 autotuner at the botton also works fine on 80/40/20.
The Imax 2000 is on the roof, used for 10/12/15/18, also worked the world with that all continents., mostly with 100 watts, didn't need the Heathkit SB-1000 most of the time.
Retired my FT 2000=D, and got the new FT991A, so playing around with that.
For 2/70 i use the Diamond X510N, 3/4 inch low losss cable and N connectors from antenna to N connector on the FT 991A.
all my antennna's are above the radial field, so they wil benefit from that.
Over that radial network is my OCF and other antenna's so it looks like I'm good with the radials.
For far off help the rest of our province has the same salty sea clay adding to the reflection.
I worked the world in phone on 160, the same inverted L fed by the MFJ 998 autotuner at the botton also works fine on 80/40/20.
The Imax 2000 is on the roof, used for 10/12/15/18, also worked the world with that all continents., mostly with 100 watts, didn't need the Heathkit SB-1000 most of the time.
Retired my FT 2000=D, and got the new FT991A, so playing around with that.
For 2/70 i use the Diamond X510N, 3/4 inch low losss cable and N connectors from antenna to N connector on the FT 991A.
all my antennna's are above the radial field, so they wil benefit from that.
Sounds like a powerful and elaborate setup you have that works well. Well I can say I have worked the world as well, not every island and country of course but every continent and usually with a $200.00 radio and a $160.00 antenna only on 11m.
Right now I am struggling a bit, verticals are difficult to cross the Atlantic with in Sunspot minima (of which I think we are slowly coming out of) so I am just shooting the Sporadic E skip. Which is not working like I remember it 5 years ago, most days I speak to 3-4 stations often from the same places, Spain, Italy and Portugal very commonly.
Maybe 5 years ago there was a mix of F2 and Sporadic E and so the band appeared more filled up... in fact the last week it even seems like the Sporadic E is tapering off a bit compared with June which is expected. I had better get out there whilst it lasts.
Right now I am struggling a bit, verticals are difficult to cross the Atlantic with in Sunspot minima (of which I think we are slowly coming out of) so I am just shooting the Sporadic E skip. Which is not working like I remember it 5 years ago, most days I speak to 3-4 stations often from the same places, Spain, Italy and Portugal very commonly.
Maybe 5 years ago there was a mix of F2 and Sporadic E and so the band appeared more filled up... in fact the last week it even seems like the Sporadic E is tapering off a bit compared with June which is expected. I had better get out there whilst it lasts.
Blaster,
Attached is a picture of my idea of rock.
Very different idea compared to many may envision
Pretty much like desert just by looking. I suspect the "I am up a mountain" part is somewhat mitigating the "I have poor soil" part : ) The height gain will be very, very significant. At great altitude the ground losses will pale into insignificance at a guess.
Also if land slopes away from you your lower angles of radiation in the direction land that slopes away are fortified by default. i.e. at the top of a ridge. This is because the ground reflections that recombine with your main radiated signal (their phase relationship) combine constructively at a lower angle than on flat land.
http://on5au.be/Cebik-2/ThePseudo-brewsterAngleRevisited.pdf
I am never ceased to be amazed how slat water gives your incoming and outgoing signal massive gain from the get go.I think it is something like 6-9dB gain coming in and out.
Someone near me has amazing ears and he is on salt water / marsh inlet on a ex military metal boat. This is as close to ideal ground as exists. He hears things on DX I could only wish for on just a vertical.
Also if land slopes away from you your lower angles of radiation in the direction land that slopes away are fortified by default. i.e. at the top of a ridge. This is because the ground reflections that recombine with your main radiated signal (their phase relationship) combine constructively at a lower angle than on flat land.
http://on5au.be/Cebik-2/ThePseudo-brewsterAngleRevisited.pdf
I am never ceased to be amazed how slat water gives your incoming and outgoing signal massive gain from the get go.I think it is something like 6-9dB gain coming in and out.
Someone near me has amazing ears and he is on salt water / marsh inlet on a ex military metal boat. This is as close to ideal ground as exists. He hears things on DX I could only wish for on just a vertical.
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