The Alex Loop for SOTA

Hilarious video; cheered me up on a gloomy Sunday morning. “makes a huge difference” “well not a huge difference”. “makes a big difference” “well not a huge difference overall but a small difference”. Ham radio at its best! Sounds like the rat-tail vs no rat-tail HT discussions.

Edit: a coupling loop is only one of several ways to feed a small transmitting loop. Direct feeding is possible as well.

ISTR making a loop that had a feed that looked like a type of Gamma match. It matched but I wasn’t impressed with the loop overall. Maybe it was fine as loops go and I needed to compare against something like an Alexloop to get some kind of baseline.

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I have such a loop, an ASL110 designed and produced by a leading German ham, Elmu, DL4KCJ who has been giving lectures on such loops for many years at Friedrichshafen. The loop can be set to operate on any band from 80m through 10m by where that “gamma-match-like” Omega-feed connects on the loop. Fine-tuning is done using capacitors in the base unit where the coax also feeds into it. Unlike other loops, it is relatively widebanded and I currently have mine located in the (wooden) roof of my garage as my 17m antenna.
image

Antennen - DL4KCJ-Antennen (in German)

Is this better than an Alex Loop - I have no idea as I don’t have an Alex loop. It works, needs relatively little space, hears well, can be used portable or fixed (but not really designed to be put on a mast and be up in all weathers). The quality of manufacture is good and as Helmut was packing up his stall at the time - I got the display model for a good price.

73 Ed.

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That doesn’t bode well.

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Wideband in this context being 28-37 kHz as explained on the website. I think the coupled loop mag loops (like the Alex loop) are narrower.

At the end of the day, if either type of mag loop designs fits your requirements, that’s the main thing. This one works for me in the role I use it for (when I want to chase on 17m, although I have used it once on an activation where it proved a little cumbersome).

Ed.

I love my linked dipole and I use it in the 90% of my activations but at summits with little room I have used Diamond RHM-8B or Comet MHJ-350, both saved me many times. Now instead these antennas (Comet-Diamond) I use a 5m long nonbranded telescopic antenna with 10x5m radials. Marking the antenna you can use it as a 1/4 vertical from 14mhz onward. For 7mhz I add a coil at the base.
Just examples how this works with 5 watts and CW (To be honest on 7mhz I run 20 watts)

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I’ve enjoyed using my AlexLoop and happy to have it as a part of my options package.

My go to antenna is the LNR End Fed which goes up quickly and works well enough.

Most of my experience with the AlexLoop was during 2015/2016 when the last cycle had some legs and agree that as 25 picks up the AlexLoop will be more viable.

I think it’s two biggest limitations are a) bulky to carry with a viable stand and b) as Elliott (@K6EL) shared the inherent limitation of a loop on 40m.

Here’s a link to my AlexLoop write up.

AlexLoop

Paul
M0SNA/W6PNG

Hi,
I use the HF-PRO-2-PLUS-T - Multi-Band PL-Antenne - 80m bis 2m-Band for most of my activations or an homebrew Endfeed for 10 to 40m band.
For the vertical I use an photo tripod and 4 counterpoise 3.5m long.
I have an magloops too, but it is difficult to adjust in outdoor situation…
73’s de Stefan DG4RBS

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https://qsl.net/aa5ck/mag.html

AA5CK - your loop is very similar to the one I have been trying to perfect for a while now, originally inspired by K6ARK’s “folding rule” portable MLA. I’ve abandoned the thin aluminum bar stock and gone to lightweight but stiff coax (5C-FB) for the 1.2-meter diameter loop, motor drive for the tuning cap so I don’t have to be poking at it constantly, and remote relay-switched parallel fixed caps. Now finally working, but whew, good thing I’m retired. All of my other SOTA antennas work as well or better but take up more space, but I am grimly determined to make this loop into a good SOTA antenna as well. Steve JS6TMW

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Your right: OM0ET loop is very odd design but… it’s working :grin: I used Alex loop and OM0ET loop and I can’t see the difference. Both antennas have got too weight for me (~2 kg with tripod). So, I prefer 4 meters SOTA beam with EFT LNR Trial Friendly 40/20/10m (InVee configuration) - weight 0,5kg only :+1:

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