LoG antenna trick

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Andrew (grayhat)
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Joined: Sat May 28, 2022 5:56 am
Location: JN63pn

LoG antenna trick

Post by Andrew (grayhat) »

What follows is a small trick which allows to maximize the performance of the LoG (Loop on Ground) antenna, I won't add details about the antenna since it has been discussed on SWLing, but if one doesn't know about it, the infos about such an antenna can be found on Matt Roberts' page, here

http://www.kk5jy.net/LoG/

anyhow, let's start with the antenna topology shown on Matt's page

Image

now, let's say we hold the antenna on ground using four plastic stakes, but instead of locking the antenna wire to the stake, we'll use four nylon cable tiers to form some loose loops tied to the stakes at one end and the antenna wire passes through those loops, now, let's refer to the image below, the red dots are our stakes with tiers, notice that one of the stakes (the #1) is moved to one side, this has a reason to be; remember that we used the tiers to hold the wire, so the wire itself is free to slide through the looped tiers, now, let's say our LoG antenna main lobes (the side arrows at #2 and #4) are oriented toward E/W, if we gently pull/slide the antenna wire moving the feedpoint from point #1 to point #4 (refer to image) the main lobes of the antenna will be rotated by 90° (toward #1 and #3) so they will now point to N/S, and, given the quite wide lobes of the LoG, using such an approach we'll be able to cover the whole 360° horizon and aim our LoG toward the direction of interest, sure it won't be a remotely controlled thing, but this simple trick may help pulling out some more DX signals :) !

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13dka
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Re: LoG antenna trick

Post by 13dka »

Excellent tip! :)

I use stakes with short ropes attached to them for that:

Stake.jpg
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LOG_29-June-21_sml.jpg
LOG_29-June-21_sml.jpg (53.78 KiB) Viewed 924 times

(Sorry, bad pics, didn't mean to picture the stakes that morning and quickly realized that trying to take pics of a LOG is kind of ...ummm... difficult. :mrgreen: )
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Andrew (grayhat)
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Re: LoG antenna trick

Post by Andrew (grayhat) »

13dka wrote: Tue May 31, 2022 1:35 pm I use stakes with short ropes attached to them for that:
Yes, ropes will work, although they may tend to "wrap/garble" while nylon tiers will remain a bit more rigid
13dka wrote: Tue May 31, 2022 1:35 pm (Sorry, bad pics, didn't mean to picture the stakes that morning and quickly realized that trying to take pics of a LOG is kind of ...ummm... difficult. :mrgreen: )
Oooh, c'mon, I don't think someone will pretend that all the pics here should be ready for some gallery exposition :D

And since we're at "LoG" and "tricks", another trick if the LoG is installed in a garden/yard is to use a length of garden hose and slide the LoG antenna wire inside the hose and seal the hose ends to avoid that water may accumulate inside it, that way, when mowing the lawn there won't be problems with the antenna wire laying on the ground ;)
B2B2
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Re: LoG antenna trick

Post by B2B2 »

Simple yet effective ideas. I have the needed materials and I am getting ready to assemble this LOG soon, so timely post.
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Andrew (grayhat)
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Re: LoG antenna trick

Post by Andrew (grayhat) »

B2B2 wrote: Mon Jun 06, 2022 3:26 pm Simple yet effective ideas. I have the needed materials and I am getting ready to assemble this LOG soon, so timely post.
If you don't have a 9:1 balun with galvanic isolation, you may pick one of those

https://www.nooelec.com/store/balun-one ... bones.html

they'll work just fine, by the way you'll need an enclosure, also, a cheap and good cable for the LoG is the "RG6" (sat/tv) coax, it will work much better than a run of RG-58 and will cost less
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AL850
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Re: LoG antenna trick

Post by AL850 »

Not to over-think anything.. but 'ground level' really means - what? 2-inches, 4-inches, or ?? above ground?

Looks like something fun to try.

Thanks!
EM64rp
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Andrew (grayhat)
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Re: LoG antenna trick

Post by Andrew (grayhat) »

AL850 wrote: Mon Jun 06, 2022 6:22 pm Not to over-think anything.. but 'ground level' really means - what? 2-inches, 4-inches, or ?? above ground?

Looks like something fun to try.

Thanks!
on the ground means on the ground, and... yes, the first time I saw that I thought it was some other "magic antenna", it isn't, mind me, just set it up... errr lay it down properly and you'll see... hear, I mean, just ensure to lay it down on grass/dirt and keep it away from buried pipes, wires and other buried conductive objects and ensure the feedpoint transformer is "by design" since those are the main issues with such antenna

check this for an idea

https://youtu.be/wMb8i5QajW0
13dka
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Re: LoG antenna trick

Post by 13dka »

Testing YT embedding BBCode here (having a rough start on this, 'youtu.be' URLs will not work)... :)

Here's a video I shot last year using the passive 20m LoG antenna before I shot the pics above:



That's 16,000km away from my secret LOG testing ground, on a day with no particularly elevated condx. OK, I know I don't have to tell just of all you how great these things are! :D
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Andrew (grayhat)
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Re: LoG antenna trick

Post by Andrew (grayhat) »

13dka wrote: Fri Jun 10, 2022 1:13 pm Here's a video I shot last year using the passive 20m LoG antenna before I shot the pics above:
[...]
That's 16,000km away from my secret LOG testing ground, on a day with no particularly elevated condx.
The link seems to be working, and the video shows what an antenna laying on ground can do; then... if you're going to shot some more of those, it would be a good idea having the ability to switch in a second antenna (even a miniwhip or whatever) to show the kind of difference the LoG makes :D
13dka
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Joined: Sat May 28, 2022 4:27 am
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Re: LoG antenna trick

Post by 13dka »

That's exactly what I bought this switch for. :)
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