That sounds very intriguing, thank you for the video link, I am watching it now.
Probably Fraser, but maybe not all across each of the bands⊠so I have the tuner in place.
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The delta loop has an advantage that you can put the feedpoint right at the radio, and not need any coax or tuner. By adjusting the dimensions you can get a 50 ohm feedpoint on a mast about 1/4 wavelength.
Traditionally a vertically polarized delta would be fed part way up one side, but they still work pretty well if fed in a bottom corner (assuming the point is up). I have dimensions at the end of this article: Dimensions for Vertical Full Wave Loops â Practical Antennas and a video here: https://www.youtube.com/watch?v=h-Di9yH9Qqg (although that isnât exactly a SOTA installation). The loop will probably be a bit shorter than the dimensions given when the bottom wire is less than 3m off the ground.
Some of the horizontally polarized delta loops can be set up with the feedpoint at ground level if you have suitable trees, again connecting them directly to the radio with no feedline. But the dimensions can get awkward on 20m unless you have some trees available, as the required heights are a bit much for small telescoping poles.
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The EFHW clearly outperformed the random wire, showing a 6â12dB improvement, with more stations picking me up on the RBN.
How was the pattern of the stations picking you up? Were it the same stations? Different ones? Both antenna will undoubtly have a different radiation pattern with their lobes given their different length which (obviously) will affect how strong youâre received.
73, Martin
My YL Carine, HB9FZC and I were searching for such a solution as well a few months ago and launched HB9NBGs Clever-Whip Kit. The first version was only working on 10/6/4m, but worked well. In the meantime weâve officially launched the Multiband-Version for 20 - 4m, and soon some tests for a 40/30m-extension-Kit will follow. The Kit, as we offer it today, is a very lightweight Full-Size Vertical for 20m - 4m, that will be installed on a Carbon-Tripod, which is also included in the package, and which is built with the sections of my hiking-sticks. Carine and I used HB9NBGs Clever-Whip kit on nearly all of our SOTA-activations 2024 - also in the Swiss High-Alps, and: IT WORKS 
On the link above you can find more information and also some pictures, weâve took. Please see also our Report of HB9NBG+HB9FZCs SOTA-Summer 2024.
vy 73 de René, HB9NBG
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If both antennas are installed in the same way⊠then I think that this big difference may have other reasonsâŠ
Of course the radiation pattern is important. When I was in Cyprus recently, my vertical 5.80m wire on the 1:9 Unun on 10m worked significantly better than the 40/20/15/10m endfed as Inv V at a height of 5m⊠towards the EU.
Unfortunately, neither system is an option here because (as I have read) you canât get toroidal cores in NepalâŠ
That leaves only one antenna that doesnât need to be transformed⊠and already has its 50 ohms⊠or can at least be easily adjusted using a tuner.
73 Armin
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@hb9nbg could it be that you were at Ham Radio Friedrichshafen with the Clever-Whip Kit?
Operating at 4500m+ doesnât just mean a lack of convenient trees, it also comes with very high winds. Have you thought about testing and, if necessary, strengthening the design to withstand such conditions?
@dl6gca My experience is that an EFHW should never be used as an inverted-V, where the ends of the antenna are at or near the ground.
An EFHW is a voltage-fed antenna. The endpoints have a very high impedance, which makes them very sensitive to parasitic capacitances â such as proximity to the ground. Setting up an EFHW with either or both ends near the ground, in my experience, results in a shift in antenna resonance that moves it off-band.
I have cut my EFHW a little bit long (extra inductance) to compensate for the extra capacitance when it is hung too low. When hung âproperlyâ I roll up the tip of the antenna, up to a mark on the antenna wire.
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Yes, we know that conditions from our activations in the swiss Alps. We havenât used HB9NBGs Clever-Whip Kit on summits above 4â000m yet, but we used it several times above 3â200m (the highst summit in Switzerland is 4â634m) and also when it was very, very windy like here on the âPointe dâOrnyâ, HB/VS-139 on 3â272mâŠ
There is a guying-kit included in the package, which - according to our own experiences - can be installed in nearly every environment. Beside of that, thereâs also a new and very rugged adapter included:
Have you had a look at our website to HB9NBGs Clever-Whip-Kit? Weâve worked a little bit on it and have added a slide-show with some pictures from some activations in the Swiss mountains.
BTW: Yes, we presented the antenna-package for the first time on our Booth at the HAM RADIO 2024, but that was the old version with the old adapter - the new version is much more robust
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Thatâs fantastic. Wish I had one with me! Does it work with any trekking poles, or do you need to carry specific ones?
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The hiking-poles are very special, and the adapter fits only to this ones - the Telescopic fits to the adapter, and the guying-kit is made especially for the Telescopic-Whip, which is included in the package. Itâs really a complete-solution with the hiking-sticks included
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The answer(s) depend on how much you want to trade improving performance against other factors like speed/ease of set-up/pull-down, robustness, weight, packed volume.
For example, laying a counterpoise wire under the line of the EFHW theoretically improves performance but having tried it quite a few times, I no longer bother as I canât detect a significant improvement on the summit terrains where I activate, so Iâve concluded carrying and deploying a counterpoise wire is not worth the faff.
Hi Phil, youâve made this point before. You donât say why you favour a linked dipole over an EFHW. If itâs based on superior performance, I would argue your using an EFHW âonce or twiceâ is not statistically significant as you probably canât rule out confounding factors on the day(s).
I have two centre-fed halfwave linked dipoles [inverted-V], two EFHW [inverted-L or -7] and a vertical [Chameleon MPAS Lite]. With the mix of chasers at miscellaneous distances and RF paths, I canât detect an improvement of the linked dipoles over the EFHWs, so I mostly take the latter. However, if wx condx are poor and/or I need to be QRV very quickly, Iâll take the vertical. Itâs very robust and performance is close or as good [on average!] for 14MHz and above.
My experiment comparing LC-matched endfed for 15m and 8.8m random wire (fed with 9:1 unun and tuned with atu) was conducted as follows:
- Attached ~7.5m (15m half wave) to the vertical mast, sent a recorded CQ message
- Extended wire to 8.8m, replaced LC matching unit with 9:1 unun, added 4m counterpoise and sent again same message on the different frequency.
I extracted data from the RBN, and here are the results from the stations who copied me.
Yes, I know itâs not a scientific approach to compare antennas, but it was pretty convincing to me that EFHW worked better.
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Good comparison, but still the different radiation pattern with different take-off angels and different lobes, could also explain part of the difference. When at a specific location, I sometimes use a 50m random long-wire with a 9:1 unun and I plotted the patterns in EZNec and they look wildly different on each band.
But for your home-station you have now figured out which antenna works best in which direction. Itâs the stuff contesters do all the time.
73, Martin
Because of the theoretical known losses in a 49:1 balun Andy.
73 Phil
The EFHW vs dipole breaks down into one main source of loss.
On a centre fed coax fed dipole the loss for the length of coax in use, type of coax and frequency is well known and easily categorised.
For an EFHW there is the loss in the matching unit. This is harder to predict and really should be measured. There are lots of designs on line, some are better than others. There is also the quality of construction of this match.
If you make the match well and use the right design the losses should be comparable between coax loss and match unit loss.
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A proper 49:1 transformer will not lose that much, typically between 0.3 and 0.5 dB (7 to 28 MHz), based on my measurements. Plus, you can use very short coax since the feedpoint is located lower.
On the other hand, a dipole requires carrying a long coax, perhaps 10 meters, to achieve the same inverted V configuration. If itâs RG58, itâs incredibly heavy, at 45 g/m, which adds up to 450g just for the coax. Additionally, due to its length, there are losses as wellâaround 0.5 dB for 10 meters at 14 MHz. If you use lighter coax, such as RG316, the loss increases to about 1 dB.
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The proof of the pudding is in the eating - i.e. signal reports sent and received.
My ~7yo LNR-Precison EFHWs have high-quality, low-loss matching units and I use a short (2m or 3m) coax to feed the bottom of an inv-L config (or inv-7 if no far-end support is available). When in the mood (usually a warm day) Iâll take one of the linked dipoles [centred-fed with 5-7m of RG714], but it makes no difference.
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Yes, I agree. Look at my logs and my contact rate. That is always a good sign that things are working as they should be. The 49.1 half wave end fed remains in storage for now⊠I am favouring the OCFD with 4:1 balun made up for the 40m band and down now over the link dipole though. I can operate 40, 20, and 10m with that without needing an ATU or getting up from my seated position to change the dipole links, the same as the half wave end fed users do.
73 Phil
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Thereâs also some loss in the centre-fed dipoleâs 1:1 balun. But as others have said, itâs not hard to make low-loss baluns (1:1 or 49:1) or buy them.
All my âproperâ non-minimalist, full-size antennas work well on the bands they were designed for, and I like to mix up which one I take on the day just for the hell of it. A great ATU (e.g. KX2âs internal one) helps them work well when at the âwrongâ end of the band. More often than not, it isnât the choice of my antenna which affects the outcome but conditions on the day, propagation, summit topology (big objects in the near field, clear take-off, etc).
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I still prefer the linked dipole, it just seems that I have had more luck and perhaps had better propagation on the days I have used it. For me the other strange advantage is having to stand up and move to change the links, firstly it stops me seizing up completely, and secondly, particularly if I have put up a shelter it improves my situational awareness (Weather, Other people on the summit). If I wear headphones and Iâm in a shelter at the summit I find it very easy to rapidly lose track of time and the journey back downâŠ
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