Sciencemadness Discussion Board

Looking for an ionic salt that is good for soil

Sulaiman - 5-5-2023 at 03:27

For my amateur radio hobby I want to use something that is cheap and easy to apply over an area of about 20m x 20m that is long term beneficial to soil/plants and will make sandy soil electrically conductive.
eg NaCl is cheap and would make soil conductive
but it is toxic to plants in the required concentration.

Any ideas that I can research?

Rainwater - 5-5-2023 at 03:50

For the plants, you really need a soil analysis to see what is missing.
Sandy soil usually needs clay add.

For your antenna you just need a ground plane.
Ideally a circular piece of conductive material with a radius equial to the antenna height with a quarter wavelength antenna.
But 20% of the ideal radius will provide over 80% of the desired effect.

Grounding kits are available as attachments to antenna bases, usually just adjustable metal fingers in the horizontal plane.

Copper wire arranged in a grid pattern is the roof top standard.

Some steel concrete mesh, properly painted and bonded, buried a few inches underground made my tv antenna go from 150 miles to over 1200. I get tv stations from Matamoros mexico to Virginia usa

Sulaiman - 5-5-2023 at 04:49

The idea is to have a 5m vertical for 1/4 wavelength on the 20m band (my favourite)
with some (tbd.. maybe 16 or more) radials,
then make the surrounding soil more conductive to see if it lowers the take off angle.
I'll use WSPR to try and verify any improvement.

Here there is an average annual rainfall of 2.5m so soluble salts are soon washed away if not bio-accumulated.

PS what frequency is your TV receiving ?
Usually a yagi antenna many wavelengths above ground is used so I'm surprised that the ground makes much difference,
I'm also surprised that vhf or uhf skips well enough for 1200 miles range,
Can you receive that TV station easily or does it need special conditions?
eg only on the grey line.
And, are you sure it was not WZTD-LD or similar ;)

[Edited on 5-5-2023 by Sulaiman]

Rainwater - 5-5-2023 at 06:18

I got an old pole mount UHF/VHF yagi with a swivel, it came with the house. Unmodified i picked up the local stations, around 22 channels DTV and no analog. Not sure what band they are in but wiki says alot.
https://en.m.wikipedia.org/wiki/Television_channel_frequenci...
I tossed on a tv amplifier from the hardware store, local signals got stronger but weaker ones completely vanished. Ripped that out then added a ground plane with painted rebar mesh. Had to play with getting the plane level/perpendicular to the antenna as well as distance from the antenna, for best performance. The distance is the stonger performance variable. Again 1/4 wavelength is best.
Broadcast overlap is an issue but i can turn the anntenna to focus on a station i want to watch.

If you'll be transmitting off the same antenna you need to consider the extra gain your antenna will have so your in compliance with what ever government body you have to deal with

Sulaiman - 5-5-2023 at 07:44

Quote: Originally posted by Rainwater  

Some steel concrete mesh, properly painted and bonded, buried a few inches underground made my tv antenna go from 150 miles to over 1200. I get tv stations from Matamoros mexico to Virginia usa
............
I got an old pole mount UHF/VHF yagi with a swivel, it came with the house. Unmodified i picked up the local stations, around 22 channels DTV and no analog. Not sure what band they are in but wiki says alot.
https://en.m.wikipedia.org/wiki/Television_channel_frequenci...
I tossed on a tv amplifier from the hardware store, local signals got stronger but weaker ones completely vanished. Ripped that out then added a ground plane with painted rebar mesh. Had to play with getting the plane level/perpendicular to the antenna as well as distance from the antenna, for best performance. The distance is the stonger performance variable. Again 1/4 wavelength is best.
Broadcast overlap is an issue but i can turn the anntenna to focus on a station i want to watch

What you described is inconsistent because if the ground mesh was buried a few inches underground and the antenna was 1/4 wavelength above that, it would only be inches above the ground.

In any case, you were probably receiving this on channel 34 (or something similar not too far away)
https://en.wikipedia.org/wiki/WZTD-LD
_______________________________________
Back to chemistry.. Any suggestions for a suitable salt?

(my default so far is a few bags of commercial fertiliser)

Tsjerk - 5-5-2023 at 08:53

So you want a none soluble conductor? I don't think we can think of a liquid that would fit your budget. Steel is probably going to be cheapest.

Fulmen - 5-5-2023 at 09:45

Yeah, no. You could try ammonium nitrate or similar fertilizers, but I suspect it will become toxic to plant life before you notice any improvement. And it will wash out pretty fast if the plants don't absorb it.

unionised - 5-5-2023 at 09:59

I had a look at a hydroponics page to see how much stuff plants actually "want" in solution.

Here are the recommended nutrient solutions for some plant types

Crop N P K Ca Mg
Concentration in mg/l (ppm)
Tomato 190 40 310 150 45
Cucumber 200 40 280 140 40
Pepper 190 45 285 130 40
Strawberry 50 25 150 65 20
Melon 200 45 285 115 30
Roses 170 45 285 120 40

Those figures are in ppm So the highest total is less than 1%

A 1% solution of anything in water is not going to be a good conductor.
You won't get good conductivity until you are at levels that are bad for plants.
I'm told that burying an old sprung mattress works as a ground connection.

Sulaiman - 5-5-2023 at 10:05

Looks like a non-starter then.
Thanks

Fulmen - 5-5-2023 at 11:48

Quote: Originally posted by Sulaiman  
Usually a yagi antenna many wavelengths above ground is used so I'm surprised that the ground makes much difference


The ground plane is integral to the 1/4-design. Basically it generates a reflection plane that makes it work like a 1/2 wave center fed dipole. The yagi simply doesn't have or need that. But ground effects can still affect the radiation pattern, especially close to ground.

You might want to check out the 5/8-wave design. It has a distorted radiation pattern that produces higher gain near the horizontal plane.

violet sin - 5-5-2023 at 17:29

What about a few Kg of BB or bearing tossed in the grass. They aren't soluble and prone to relocation. But close enough might count. Slag, dross from a cutting torch might be cheaper, could be nearly free if you're cleaning someone's foundry

Sulaiman - 5-5-2023 at 21:12

This (thought) experiment would only require the earth to be conductive for a day or two.
It is (now) clear to me that it is not a viable experiment.
Thanks for all of the comments.

unionised - 6-5-2023 at 01:28

Quote: Originally posted by violet sin  
What about a few Kg of BB or bearing tossed in the grass. They aren't soluble and prone to relocation. But close enough might count. Slag, dross from a cutting torch might be cheaper, could be nearly free if you're cleaning someone's foundry

I suspect that would be hellishly "lossy".
It would make better shielding than transmission.

unionised - 6-5-2023 at 01:29

Quote: Originally posted by Sulaiman  
This (thought) experiment would only require the earth to be conductive for a day or two.
It is (now) clear to me that it is not a viable experiment.
Thanks for all of the comments.

How impractical is a paddling pool?
Or even a ring of (un-cemented) bricks and a tarpaulin with water in it.

[Edited on 6-5-23 by unionised]

violet sin - 6-5-2023 at 10:46

So, I've been around antennas since I can remember. My father's a HAM operator and always had something going on. From yearly events where he would set up wire in trees up on the mountain, and sit at a little table all day making contacts with as many people as possible, to his daily use of home based shack/garage setup. But we never did anything to the ground. No buried wire or conductive salts.

I'm familiar with a few types of antennas, like the standard whip off a cars roof, free standing ground versions and the hoisted up guys what usually have several(4) horizontal elements below the vertical element. I my understanding, all these had the same function performed by the hood of the car, the ground itself and finally the horizontal array of elements, to reflect the radiated energy up and out.

If the ground is giving a lossy signal with it's current level of coupling to the antenna, I don't understand why seeding the ground plane with additional, insoluble, conductive bits would create more loss. The only example above where a fully conductive base is used, is in the cars hood with a magnetic whip.

Not trying to be contentious here, because frankly I've only a little time invested myself in learning about antennas. Most everything else is from years of observations and questioning the old man. KB6LZW by the way. I've had kilo bravo 6 Lima zulu whiskey living in my head for decades.

Could better impedance matching and then amplification work out more favorably? He's on the coast and conditions changed often with fog and such. I always remember the hand wound balun on ladder line leading out to his tower. A nice 50' triangular tower with the rungs welded in. We climbed those things for him to get wires up when they got snagged. He had a huge yagi atop it, and several wires from tree-> tower-> house, below that. He'd have to dial it in before playing. Turning up the matched signal was easier than ignoring a boosted noisy one.

What am I missing or overlooking, if you don't mind me asking. Improvement in wear areas never hurts, so if you've the time, please share some knowledge

Rainwater - 6-5-2023 at 12:15

https://www.google.com/search?q=nanovna
If your serious, spend the 75 dollars,
its worth its weight in gold

Once the transmitter, receiver, antenna and connecting cables are impedance matched then fine tuning the antenna can begin

I can not explain it better than this guy
https://m.youtube.com/@w2aew
This guy has 100s of videos. Anything about analog electronics you could ever want to know, i learned more from his videos than 6 years of school

To isolate any problems and properly solve them more information is needed
These videos may be of particular interest

https://m.youtube.com/watch?v=Il_eju4D_TM
Use a scope to measure the length and impedance of coax

https://m.youtube.com/watch?v=9thbTC8-JtA
Use NanoVNA to measure coax length - BONUS Transmission Lines and Smith Charts, SWR and more

https://m.youtube.com/watch?v=xa6dqx9udcg
How to use the NanoVNA to sweep / measure an antenna system's SWR and optimize its tuning

[Edited on 6-5-2023 by Rainwater]