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Delta loop antenna on higher HF bands

I’m looking for feedback / reports from anybody who is using / has used a Delta Loop antenna on the higher HF bands such as 15/12/10m especially if they have used other antennas on the same bands.

What I’m looking for is comments such performance compared with other antennas you have used either as a chaser or activator. From any activators, how easy / difficult did you find deploying them on summits and whether the antenna was directional or omni in its pattern.

And the killer question, having made and used one would you still use it assuming the bands were open or do you have something you would now use in preference?

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Hi Andy,
I have a 6m and 10m version I use on beaches mainly, and have used a 40m delta from home as a chaser antenna.
I find loops whilst portable catch the wind more than other aerials, and do appear to exhibit some directional properties, though this is not scientific data, more observation.
Verticals are easier to deploy, catch the wind less, and dont need so many guy lines, so I tend to use them more these days.
73
Tim
G4YTD

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While not a Delta-loop per-se, I built a 40 metre portable full wavelength sky-loop (which works on 40, 20, 15, 10m) of very thin and light wire and used tripod supported fibreglass poles on Mount Elliot (VK2/HU-098) 6.5 years ago. It would never have been possible without help from other CCARC club members.
Did it perform? yes.
Was it directional? not that I could tell.
Was the effort worth it and did I ever try it again? no (the thin wire managed to tangle itself up so badly when I packed it away that it was junked).

Whenever considering a portable antenna, one major factor for me is - can I carry it to the summit and put it up and take it down with little effort, repeatedly. For a long time my “go to” antenna has been a SOTABeams “band-hopper” linked dipole antenna (which could be modified for 10/12/15m in answer to your original request) but on my most recent activations, I have switched to the Komunica HF-PRO-2-PLUS-T loaded vertical (there are similar antennas from non-European distributors and manufacturers but they are more expensive). It gives me a compact size (especially with the change to a telescopic radiating element from the fixed one in the previous (non -PLUS-T) model) and using it with my own modified photo-tripod, it performs reasonably well, needs little space and no on-site support for a fibreglass mast to be able to set-up and best of all it’s quick to set-up and take down.

I hope to compare this antenna against the linked-dipole tomorrow morning on 40 & 20m. Both of my summits tomorrow are within forests so this will make it hard for the vertical but we’ll see how it performs against the dipole.

Here’s my report on my three easy activations last Wednesday, where I only used the loaded vertical.

DD5LP/P – November 18th 2020 – DM/BM-374 Wülzburg, DM/BM-226 Dürrenberg & DM/BM-135 Hesselberg. | DD5LP / G8GLM / VK2JI blog

Oh yes the loaded vertical covers from 80 metres through 2 metres, so another advantage of not needing multiple antennas but on VHF, I suspect it wont perform as well as a “proper” VHF antenna.

I’ll be interested to hear how the Delta-Loop performs if you decide to build one Andy, especially if it is directional.

73 Ed.

1 Like

Hi Andy,
I have used my Delta loop antenna during Trans-Atlantic S2S QSO party in November 2019. You can see how it looks like in the picture of the thread Trans-Atlantic S2S QSO Party Autumn 2019 (Nov. 2nd)..
It is easy to deploy, but not so easy to transport, it is mostly suitable for drive-on or near drive-on summits. My antenna was app. 21 m long wire, now I have made a shorter one (18 m) which has better directivity on bands 20m and up. 4nec2 simulations show some directivity on 20 m, and good directivity on higher bands. In practice, there was a clear peak on LU activator signal on 17 m band. My antenna was only 2m agl, at say 4 m agl would be much better directivity.
Experience on TA S2S event was good, although my setup was not optimal. I made contacts on 40/20/17 m band with this antenna. I will use such antenna again in next TA event.
I made some changes in the setup:

  • shorter loop (18 m)
  • manual tuner (Zmatch) at antenna feed point to minimise losses in cable.
  • will try to put it higher (3 -4 m agl)
  • solved problem of changing direction in windy conditions (have to check this in real life)

I like this antenna for it’s high efficiency compared to vertical or A shape delta loop antenna.
How it performs compared to a vertical? I don’t know. 4nec2 simulations show that Delta Loop should perform better. My plan is to do a comparison test on my next SOTA activation, where I will install both antennas and try to figure out which one is better.

73,
Mirko

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Thanks Mirko. I was considering a single band 10m A shape loop fed in the corner with with 1/4wave 75 ohm matching line. I have a 0.64wave 10m vertical but it needs an 8m pole which is very heavy. I also have a 12m 1/4wave vertical and was going to make a new top section for that so it covered 12/10m with a link. They will both fit on my normal 5m pole. I have a 6m and 7m pole so I may modify mountings so a longer pole can be used with the 1/4 wave and delta loop.

The nice point of you having a tuner means it’s easy to cover all of 10m. My 0.64wave needs the tap adjusting on the base loading coil when you move from CW/SSB to the FM portion. Not hard but it’s just another thing to do.

More examples of loops need to be considered…

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Yes. Used delta loops, dipoles and groundplane antennas for those bands. Groundplanes win in every respect for me. Easier to make, faster to deploy, faster to pack away, hear more on RX, makes the most contacts.

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Mirko,

The EZNEC simulation (below) for your 18m Loop antenna confirms the expected difference in the data for 2m hag and 4m hag.
Eeryone can decide for themselves whether the additional effort for the construction of a portable antenna is worthwhile …

73 gl, Heinz

18m 3side Loop – 2m vs 4m hag comparison (gain [dBi]/elevation [deg])

14.1 MHz 5.58/45 vs 6.23/35
18.08 MHz 6.27/35 vs 7.39/30
21.1 MHz 6.82/30 vs 7.98/25
24.9 MHz 7.39/25 vs 7.83/20
28.1 MHz 7.29/25 vs 6.78/20

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Thanks Heinz for your excellent analysis. My 4nec2 simulation showed similar results.
V shape Delta loop radiation efficiency is quite higher compared to quarter wave vertical antenna and gain at lower angles is somehow comparable (?!). So I would like to check in practice how do they perform for DX and medium distances.
73,
Mirko

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Yes, that makes sense, because both 4NEC2 and EZNEC use NEC2 for their calculations, hi.

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During the 10m/6m challenge I built and used a single element diamond quad for 10m. Fed at the lowest corner, with the sides guyed and the apex was at about 6.5m on a 7m HD pole. It heard well, I got good reports and made contacts in the ARRL 10m contest. But I didn’t have a standard antenna to compare it with. I did turn it around by 60 degrees, by walking the side guys around to new points, to try for more JA contacts once the US signals faded out, I think it was slightly directional.

I am so used to subtracting the 5% allowance for end effect that I cut the full wave loop too short and had to add the 5% back to the top of it to get it to resonate. Bandwidth was good, it worked well at 28.06 and 28.5, I didn’t try the 29 mhz section of the band.

Loops don’t have any open ends, so the wire length required for resonance is very close to 100% of the free space length.

3 Likes

If your target is DX, I would always go for the delta loop. I used it on summits for all bands from 20 metres to 10 metres. It works great with moderate effort in building and set up.
Rx is really quiet on the loop. Take off angle is low and with our design fairly independent of ground properties.
Here is a short manual for the 20 m version. If you need the dimensions for higher bands, just let me know:

If you want to spend more effort, a VDA could be interesting:


It is more complicated to build and set up but performs excellent - again with the focus on DX. I didn’t publish a detailed description yet but dimensions are available for all bands if you’re interested.

73, Roman

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Really a landing on the point, congratulations to the designer Uwe@DL4AAE.

Although on 20 m the gain at an elevation of 20 degrees appears to be only about 0.5 dB better than the 18 m / 2 m agl multi-band loop from Mirko@S52CU, the difference in terms of “portability” is considerable .

BTW, Ken@K6HPX noted that, for portable use, the C-Pole antenna could be a very good compromise between a delta loop and a simple ground plane antenna.
Thanks Ken for the hint.

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Hi Andy,
An inverted Vee link dipole will give good low angle performance without the visitor tripping radials for a vertical or the big winder full of wire for a loop.

A 40 m dipole can be converted to a 20 m loop with the aid of a short shorting link and a couple of nylon guys. Not worth it IMO. Tried it and not impressed.

Back to the tuned doublet.

73
Ron
VK3AFW

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Hi all,
Yes, portability of V shape Delta loop antenna is a drawback, so it is suitable mostly for drive on summits. But once on the summit, it is very easy to deploy. It is directional on higher bands, and can easily be rotated, which is not the case with A shape delta loop.
Of course, my usual activator antennas are EF, doublet or vertical, hi.
73,
Mirko S52CU

1 Like

Thanks for the comments and suggestions.

The reason for wanting an antenna with some “oomph” for the higher HF bands is two fold. Firstly there is a strong possibility that a future challenge will include 10m amongst other things although the MT have not actually finally agreed what will be and when but we have taken on board comments from those who commented. The second reason is the rather obvious fact that the Sun is waking up from her slumbers and early indications bode well for a more active maximum than last time.

Now the morbid bit… if you work on getting “three score years and ten” roaming the Earth and the Solar cycle averages 11years you get to see 6 maxima in your brief period here. Most people don’t start playing on HF till they are late teens etc. and that brings the number down to 4. The first 2 maxima when I was licenced I was less interested in HF and didn’t experience them and the last one was a serious blast at times. It also was a pretty rubbish maximum as well. So realistically I have 1 more maximum when I will hopefully be able to play SOTA on 10m etc. I very much hope there will be more than 1 but… See it’s being so cheerful that keeps me going! :slight_smile: So I don’t want to waste the next maximum.

A delta loop and 1/4wave GP for 10m are my immediate designs to build. My 1/4wave GP for 12m weighs about 170g and adding an alternative radiating section or adding a link will only add 50g or so and gives me a twin band antenna that can stay in the bag now. I’m also considering seeing at how lightweight I can make a Christman phasing unit so I can drive 2x 1/4wave GP to give a steerable antenna. I’m not sure if the weight and trouble setting up 2 antennas will “weigh less” than a small PA instead and I want to compare this against a delta loop that is steerable by moving the guy ropes and letting it rotate about its mast.

Anyway things to make now and things to try when the lovely Nicola lets us out of lockdown.

Once more, thanks for the comments.

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For the previous 12/10/6 flavour, I made a new GP. I cut the radials to be quarterwave on 12 and the driven element to be roughly halfway between quarterwave on 12 and on 10. Sounds a very sloppy approach, but I remembered from years ago that the VSWR was reasonable and usable for 12m on the 10m GP and vice versa. It worked well, and DX contacts were made on both bands!

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A long time ago I had a Delta-loop for 20m, which I had installed on the pole with fiberglass tubes. I had fed it with a smartuner sg-230. With it I could work all bands from 10 - 40m.
It was rotatable and inside the triangle were the yagis for 2m and 70cm.
I remember that it was a quite calm antenna. It worked quite well until a storm disinstalled it.

Last summer, inspired by Ignacio, I built a Delta-loop with plastic pipes for the electrical installation. The idea was, to get the possibility to change the direction. It was a fragile wind-prone thing and I discarded it.

I prefer quick and dirty at SOTA and I am quite happy with my vertical. I don’t see any advantage here compared to the effort.

73 Armin

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Yes, if raised high enough this can be a handy and satisfactory solution for dx.
I also experimented with a similar version years ago for 15-12-10m (dimension and vertical radiation diagrams below). Initially, the intention was to trim the antenna to 12m for resonance, but the highly praised fiberglass masts required a shortening of the vertical radiator lengths by approx. 12% …
Therefore a variant was implemented that could be matched by a simple ATU on all 3 bands. The ATU at the feed point (or with a 1m of RG58) was a L-network (series L), switchable between Hi-Z (12 and 10m) and Lo-Z (15m).
Ambitious operators who like to work in S&P could alternatively attach a remote ATU on the mast.

For comparison, the 15-12-10m vertical radiation diagrams of a 6 and 9m long vertical antenna with 2 radials of 4.20m each (below):
The 6m Vertical looks not bad, while the 9m Vertical looks not very exhilarating, both are no longer easy to match. But how do you say "When a band is open, almost any piece of wire is sufficient also for dx …).

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Maybe also take a look at rectangular loops if you can handle monoband usage. 2:1 proportioned upright loops have 50 ohm feedpoint, so no need for tuner. Been using ones for 6,10, and 15 meter bands here at home. Needs some support out at the corners to keep them fairly square, but there’s no reason why 6 and 10 couldn’t be portable…and maybe 15m too. Hard to make a complete assessment, but I’d always go for a loop versus a dipole. Hopefully know more about a 10m comparison when the ARRL 10m contest happens in a couple weeks. I’ll have both a vertical and the loop working…and looking forward to it.

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As these antennas (loops) have only minor gain unless they have a reflector or director added, a simpler way to get a few db of gain is a DEZ. For 20m the DEZ is about 88 ft long, ie. it is two 5/8 wave elements fed as a doublet. The feed impedance is reactive, with judicious choice of feedline length the reactance can be compensated.

The simplest way of doing all that is the ZS6BKW which is slightly longer than a DEZ but still does have a few db of gain on 20m. Better if it is horizontal and high, like all antennas.

73 Andrew VK1DA/VK2UH

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