Posted: 7/14/2026 9:50:49 PM EDT
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I have had a borrowed Wolf River Coils (WRC), and a 1/4 wave vertical wire (40M) with above grade radials at my QTH for a couple of months. The WRC is on loan from @Canoeguy. Here are my observations on them, for my specific setup, my QTH, your mileage *will* vary. The EFHW is 40M with a TennTennas 49:1 balun, probably 35' up, erected flattop, over ground sloping up towards the end. The 1/4 wave vertical is on a fiberglass pole with 2 above grade tuned radials. the WRC is a 25' whip, normally over a 4'x10'(?) "magic carpet". Tonight I added the three radials that came with the WRC setup. The additional radials did not seem to make a difference. I have not tried shorter antennas with the WRC on 40M, because, why? All antennas measure an SWR of less than 1.4 on 40M SSB. Tonight the bands were "long" so generally folks within close distances were not able to hear each other. I suspect that part of this is due to vertical antennas not doing NVIS nearly as well as horizontal, particularly since I could hear Canoeguy at 50 miles or so. The 1/4 wave seems to work better only beyond 600 miles. Under 600 miles, the EFHW is better. The WRC follows the 1/4 wave, but is little lower, probably 1/2 S unit, or less than the 1/4 wave. Both are normally lower by about an S-unit than the EFHW. Tonight on the 40M SSB net, the WRC was 1-2 S-Units lower than the EFHW. For folks within 100 miles of me or so, it was almost unusable. Canoeguy, who is ~50 miles from me, was deep in the noise on the WRC, but a very readable 58 on the EFHW. None of these observations are surprising based on generally available information or modeling. While the EFHW receives a TON of hate, when erected as a flat top, it performs almost as well as a dipole, but also handles multiple bands. I have not compared the WRC to DX work, where it would likely beat the EFHW due to lower take off angles. In my opinion, unless you are serious about DX, the WRC is a pain to setup for QTH work, compared to other alternatives like a DX Commander style multiband vertical or a 43' multiband vertical with lots of radials. Summary: The WRC is a fine setup for portable work. It will cover every band, but requires adjustment for each band. I'm not sure radials are any better than the "magic carpet". The WRC has limitations on closer contacts, probably under 200 miles or so. You could easily convert a WRC to a NVIS antenna just by clipping a horizontal wire onto a shortened whip, but I have not done this. To improve my access to the Tuesday SSB net, I plan on getting my EFHW higher. It is erected over sloping ground, and I plan on raising both ends, with a goal of at least 45' average height. Yes, I know, if I get it too high, NVIS coverage will suffer. I have an alternate EFRW 80M antenna at 25' or so for NVIS if I need to fall back on that. |
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I will chime in since I was mentioned with no data whatsoever except to say TVille helped me set up my embed fed half wave which is ridiculously simple and I hear everyone in the net wonderfully. It’s not even in the best set up. I hear all of the east coast and as far west as Texas any day of the week. Such a stupid simple set up and man, it works. |
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Originally Posted By TVille: The WRC follows the 1/4 wave, but is little lower, probably 1/2 S unit, or less than the 1/4 wave. Both are normally lower by about an S-unit than the EFHW. Tonight on the 40M SSB net, the WRC was 1-2 S-Units lower than the EFHW. For folks within 100 miles of me or so, it was almost unusable. Canoeguy, who is ~50 miles from me, was deep in the noise on the WRC, but a very readable 58 on the EFHW. ... To improve my access to the Tuesday SSB net, I plan on getting my EFHW higher. It is erected over sloping ground, and I plan on raising both ends, with a goal of at least 45' average height. Yes, I know, if I get it too high, NVIS coverage will suffer. I have an alternate EFRW 80M antenna at 25' or so for NVIS if I need to fall back on that. For example, here is the foF2 map at last night's net time which shows NVIS conditions on 80, and perhaps 60, but not on 40 (from https://www.sws.bom.gov.au/HF_Systems/6/5 ): Attached File You will gain a lot of performance with a higher antenna, and exceeding 1/4 wave above the ground on 40M will not strongly diminish your NVIS performance. If you are really worried, use the 80M antenna as you have already mentioned. Also, if any of the propagation paths were surface (ground) wave, the vertical antennas should do better. That they didn't may have to do with the propagation paths in play, or it may have to do with cross-polarization losses on a surface wave path. Cross-pol losses generally don't affect skywave paths because reflection and refractions by the ionosphere create elliptically polarized waves. And, as you point out, the antenna pattern for a vertical drops off quite a bit at higher elevation angles. I would encourage you to not only raise your EHFW as high as you can get it, but also to experiment with a 40M doublet in its place (dipole + 450 window line). You will probably be pleasantly surprised at the gain in performance across all bands using the doublet. This assumes you have a decent, wide-range antenna tuner to use with the doublet. |
"Cogito, ergo armatum sum."
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Originally Posted By aa777888-2: NVIS propagation has probably not been in play for you, at least not very often. See the NVIS FAQ tacked thread. For example, here is the foF2 map at last night's net time which shows NVIS conditions on 80, and perhaps 60, but not on 40 (from https://www.sws.bom.gov.au/HF_Systems/6/5 ): https://www.ar15.com/media/mediaFiles/16697/Capture_JPG-3795482.JPG You will gain a lot of performance with a higher antenna, and exceeding 1/4 wave above the ground on 40M will not strongly diminish your NVIS performance. If you are really worried, use the 80M antenna as you have already mentioned. Also, if any of the propagation paths were surface (ground) wave, the vertical antennas should do better. That they didn't may have to do with the propagation paths in play, or it may have to do with cross-polarization losses on a surface wave path. Cross-pol losses generally don't affect skywave paths because reflection and refractions by the ionosphere create elliptically polarized waves. And, as you point out, the antenna pattern for a vertical drops off quite a bit at higher elevation angles. I would encourage you to not only raise your EHFW as high as you can get it, but also to experiment with a 40M doublet in its place (dipole + 450 window line). You will probably be pleasantly surprised at the gain in performance across all bands using the doublet. This assumes you have a decent, wide-range antenna tuner to use with the doublet. I'll admit, I'm confused about NVIS vs groundwave. My understanding is that groundwave is attenuated by stuff in the way - buildings, trees, mountains. There are two stations within 50 miles of me that often appear on the Tuesday SSB net. One is rural and the route is populated with forests and rolling hills and mountains (at least what we call them in E. TN). I suspect this station is only NVIS. The other station route is populated by some trees and rolling hills, and a small/mid sized city. This station is also closer, so I suspect this *could* be groundwave. Both stations I can normally hear, although they do vary in quality week to week. I'll return the WRC setup to Canoeguy and we will try using it to talk. I have a 1/4 wave vertical, to offer the best chance for groundwave. I have followed the foF2 predictions and they sure don't seem to match my experience, unless I am missing something. I can hear the two guys on the net close to me almost Tuesday, regardless of the foF2. I often find POTA activators that are close to me, within 100 miles, that I cannot hear, but they are obviously getting out well due to folks I hear calling them. So I don't know if it is a tunneling or what is going on there. I have looked about raising the EFHW from a performance standpoint and until you get really high, in terms of wavelengths, I agree, it will only help, and not hurt NVIS. I put up the 80M at 25' because it was easy to do, and I have just left it there. I have heard all sorts of praise heaped on the doublet, but can't find anything to compare the performance on it's primary band. I believe it is basically a ladder line fed dipole, but works on multiple bands because of the ladder line eliminating any coax loss. I do have a wide range ATU with balanced outputs that I could use. But, since my shack is inside a metal sided barn, I'm not sure I want to fight with getting ladder line out. I also would have to find a way to put up a third support, in the middle of a field, which is a little more challenging than I can take on right now. |
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Originally Posted By TVille: Thanks for the detailed response. I have read the NVIS thread several times - thanks for taking the time to write that thread! Originally Posted By TVille: Thanks for the detailed response. I have read the NVIS thread several times - thanks for taking the time to write that thread!  I'll admit, I'm confused about NVIS vs groundwave. My understanding is that groundwave is attenuated by stuff in the way - buildings, trees, mountains. There are two stations within 50 miles of me that often appear on the Tuesday SSB net. One is rural and the route is populated with forests and rolling hills and mountains (at least what we call them in E. TN). I suspect this station is only NVIS. The other station route is populated by some trees and rolling hills, and a small/mid sized city. This station is also closer, so I suspect this *could* be groundwave. I have heard all sorts of praise heaped on the doublet, but can't find anything to compare the performance on it's primary band. I believe it is basically a ladder line fed dipole, but works on multiple bands because of the ladder line eliminating any coax loss. I do have a wide range ATU with balanced outputs that I could use. But, since my shack is inside a metal sided barn, I'm not sure I want to fight with getting ladder line out. I also would have to find a way to put up a third support, in the middle of a field, which is a little more challenging than I can take on right now. The trick with the doublet is to do a bit of tuning of the dipole length, and the ladder line length, in order to achieve a set of impedances that your tuner can handle gracefully. You don't need to fight with bringing the ladder line into the barn. Although, it is not difficult. A short piece of 2" PVC and bringing it through perpendicular to wall will work fine. However, unless your ATU is a truly balanced tuner, it's not worth bringing the ladder line into the shack anyways. More likely it is a tuner with a built in balun. In that case, simply put an appropriate balun on the outside of the barn, then run a short piece of low loss coax (LMR400 or equiv.) to the ATU. 25 ft of LMR400 is not going to add significant feedline losses. The choice of balun will either be a 4:1 or 1:1 current balun, depending on how your tuner feels about each set of impedances. I'm very partial to the DX Engineering baluns as they are available in high power ratings and the voltages can get quite sporty when tuning a doublet with the ATU. You'll also want some ferrite snap-on's on the coax immediately after the balun. You don't need a third support if you take down the EFHW 
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"Cogito, ergo armatum sum."
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Once again the EFHW rules. So much bias against them, yet my humble setup, 80m EFHW 35' AGL, has me talking to people 3 miles away, and Spain, Australia, Russia, Japan, etc... I often muse when I make contacts on 40m within 3 to 300 miles, whether it's groundwave or NVIS. It's academic, of course....the QSO happens no matter what. I do wish we could do an SSB net on some other night some time...I work Tuesdays, and it's impossible to get home early enough to get jiggy with it. |