Loop-on-ground question, regarding 1 or more turns

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JELAIR

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For receiving only! Not for transmitting.

Would you rather...

A:
1 loop of wire equivalent to 1 full wave-length at desired reception-frequency (So the wire has the length of 1 full wave-length)

B:
2 turns of wire, so the wire is technically double the wave-length (2 times longer than desired wave-length)

or

C:
3 turns of wire, so the wire is thrice the wave-length.

when

the loop-diameter is the same in all 3 cases (Same size antenna in terms of width and depth, but 3 different lengths of wire laid out in 1, 2 or 3 turns around the loop-circumference)

AND

the entire construct will be passive and directly connected to the feed-line without any type of impedance-matching devices or anything else at any point.


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I plan to experiment with laying out some cable in my garden (Urban area, no high-rises nearby though), for a 'loop-on-ground' antenna, and I would like to avoid cutting the cable unless a single-turn loop is far superior to simply rolling out the entire cable in 3 turns.

The roll of cable is currently 3 times the full wave-length I'm going for (So basically there's enough cable for 3 full-wavelength antennas)

But I'm unsure if using it like that is much better or much worse, or not making much difference, compared to cutting off a third of the cable which would give me enough wire for a single turn loop at the full wave-length.

When I google I get different answers.
Some say 'longer is always better', others say multi-turns won't enhance anything but also won't be detrimental, others say 1 single turn will cause the directional-lobes to be more along the horizon rather than straight up (Though others dispute that by saying a loop-on-ground is always just straight up)

So I'm not sure what might be better here and can't really try all options without cutting the cable, and I would obviously prefer the final solution to not involve a cable having been cut unnecessarily.

I know there are no easy answers and other things, such as soil-composition and so on, play in on which may be the better approach.
But I'm just interested in what people speculate might be the better option here.
 

jonwienke

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Inductance is proportional to the square of the number of turns, and impedance at a given frequency is a function of inductance and capacitance and resistance. So adding turns has a nonlinear effect on resonant frequency and other antenna characteristics.
 

JELAIR

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Inductance is proportional to the square of the number of turns, and impedance at a given frequency is a function of inductance and capacitance and resistance. So adding turns has a nonlinear effect on resonant frequency and other antenna characteristics.

So the antenna won't be resonant on X kHz on 1 turn, and X/2 kHz on 2 turns and X/3 on 3 turns?
 

prcguy

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Antennas laying on the ground are not resonant anywhere near the same frequency as when in the air. I don't think you need to make a loop on the ground a full wavelength anyway, I've heard a square about 15ft on each side fed with a 9:1 balun is a good compromise for VLF through HF. Other balun ratios like 4:1 might also work. Connecting an antenna analyzer right to the loop wire might help choose the best balun ratio.
 

JELAIR

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Antennas laying on the ground are not resonant anywhere near the same frequency as when in the air. I don't think you need to make a loop on the ground a full wavelength anyway, I've heard a square about 15ft on each side fed with a 9:1 balun is a good compromise for VLF through HF. Other balun ratios like 4:1 might also work. Connecting an antenna analyzer right to the loop wire might help choose the best balun ratio.

Thank you.

Yes, I've been reading this page as well, where the 15' square-shaped loop-on-ground is mentioned: The Loop on Ground Antenna - the "LoG"
 

ka3jjz

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There was a very extensive discussion of the LoG here...


and would you believe there is a Facebook group for it...


Mike
 

JELAIR

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There was a very extensive discussion of the LoG here...


and would you believe there is a Facebook group for it...


Mike

Great, thanks :) I will be doing some reading in the near future then and try to educate myself further on this :)
 

JELAIR

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There was a very extensive discussion of the LoG here...


That was a long read, but worthwhile :)
Thanks again for that link.
 
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