Hi! Ich arbeite gerade an was sehr Ähnlichem. Leider habe ich keinen Zugang zu Gerätschaften, die mir erlauben würden, sowas selbst anzufertigen. Aber nach mehreren Aufenthalten / mehreren Stunden bei Obi, hab ich eine 20m vertical mit elevated radials die recht gut funktioniert. Vielen Dank für die vielen tollen Videos. Ich hoffe Du wirst bald mit vielen, vielen Subscribern belohnt. 73 aus KG
When something does not make sense, there's a reason. How far are you from home? You say this is NVIS but you need to be many miles away for NVIS. If you are just a few miles away then you are dealing with ground waves, especially on 40 meters. Ground wave transmission has a short local coverage and this is similar to what an AM broadcast station does. They use vertical antennas. Now it your dipole has NO balun the the coax is radiating vertically which will provide the needed low angle ground wave to reach your home. I suspect the balun is actually doing its job and preventing this vertical signal from the coax. Your signal measurements are better because the coax is radiating. The only way to do this is to use Reverse Beacon Network and get reports world wide.
As you pointed out, the isn't a lot of difference between the two... The elevated is a little stronger on transmission, ground radials a little better on receive. While the elevated has less to carry, there is one BIG advantage to the ground radial system.... Chaning bands. The elevated requires an entirely new tuned radial to change bands... Meaning a different length, with a separate attachment point. That is, unless you make a linked radial, staked out at it's farthest position, at which time you always have 16ft worth of line constantly elevated, just waiting for someone to trip into 😂... And that is only if you are limiting yourself to the high bands. 40M and 80M, if you have a loading coil, would require considerably longer, meaning higher elevation to account for sag. Ground radials, on the other hand, you just adjust the whip/coil. As the radials couple to the ground, their exact length isn't much of a factor. Changing bands can be done in a matter of seconds. My portable setup runs 18 3M long radials and I've been able to tune it from 80-6M using my 5.6M telescopic and my Wolf River Coil Mini. I'm sure I lost some gain on the lower bands, but I also didn't have to have a ~20M wire elevated at least 3ft off the ground either. Also, because the radials are short, light, and don't easily tangle (26g silicone insulated wire), they pack fairly small (using a 6" kite string winder) and can be deployed just as quickly, if not faster, than an elevated system, being that nothing is needed to suspend them in the air. That also means placement is easier, as my footprint is less than 6M in diameter *and* can be walked over, this less likely to be walked into by sometime stray pedestrian.... 73
@@CrazyChekov Yeppers. When I go to pack them, I just unhook them from the tripod mount, then pull them all up simultaneously, and wind them on the winder.... Takes all of 30 seconds, if that. I then secure them via a Velcro strap. Deploy them almost as easily.... Unwind, separate the bundles, toss them in each direction, attach them to the mount, and finally spread them out over their respective section by running them between my fingers (6/bundle, 3 radials in each hand) to individually separate them.... Takes maybe a couple of minutes and they're ready to go. No need to touch them again till I'm ready to pack.
Don't know how I got here but your DIY projects look like mine! You can tell a lot about an engineer by looking at his handy work. +1 sub, I'll definitely watch more off work. Hello from a semiconductor plant in AZ USA 👋 🌵
After watching your video I constructed a 20 meter version of the antenna & counterpoise using wire, and fed with coax. The wire was hung from a tree and counterpoise elevated about 3 feet off the ground in a westerly direction. I have operated from this park quite a few times (US10650) and have had very limited success contacting stations west of the Mississippi River using a variety of antennas. With very challenging conditions this weekend I worked about 20 stations, and half were west of the Mississippi, and even into CA which in recent weeks has not happened for me. So in this test the antenna definitely favored the direction of the counterpoise, and the other contacts were about evenly spaced around the continental US. Even getting 20 contacts was pretty good for conditions lately (I run QRP CW) ... I would definitely suggest others try a raised counterpoise/radials, as even a simple wire construction of the antenna proved to be quite effective. Thanks for the video! Paul NA9M
Man...I've been around a long time but I have no idea what you are saying. It appears you are comparing your field with your home station somehow and getting huge differences of -12 vs + 12db. Where are you getting these numbers? How are you comparing anything? Maybe it's a language barrier. What is a wein and a Nope LTg? Must be German or something.
Im sorry I guess its my bad english. Im making digital signal reports where in the end I average the results and compare with that two things, or set ups. My home station is automatically replying to a received message and sending me back the signal to noise ratio. its in the end the same what we are doing when we ask someone for a signal report, just digital and more precise.
I believe the radiation pattern difference is the key to understanding. With the ground radials you have nothing but very low take-off angle while with elevated radial you actually have an L antenna which has both low and high angle radiation providing a more universal pattern. Really, the only situation where a 1/4 wave vertical using ground radials is superior is for local coverage on the AM BC band. Thank you for doing this hard work.
Experimentation is a great feature of ham radio. In this case I think you might find that the one elevated radial signal was helped by the ground radials even though they were not connected to the system. There has been some experimentation that shows that a ground screen formed by radials that are not connected to the antenna system still improve the signal for a vertical with am elevated system. Nice video!
@@CrazyChekov Check Out ON4UN's Low Band DXing Section 2.2.13 Elevated Radials combined with Radial Screen On the Ground. The book is out of print but it shouldn't be too hard to find a copy perhaps online. Larry
The radials don't radiate far field owing to symmetry. So they're a pure loss into the ground, not storing unradiated energy and offering it again the next cycle. The point of multiple radials is to reduce the current in each, which after I squared losses results in 1/N less radiation into the ground with N radials. Elevated radials avoid loss into the ground instead just by not being near the ground. Hence you need lots of radials on the ground vs much fewer if they're elevated.
yes the more the better. but for a portable operation I wouldn't carry a lot...so thats why I dont want to make the comparison with more than 12 (alread a lot). for a stationary antenna I would for sure go with more.
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Why one radial? if you add a second one you will cancel/reduce radial radiation and probably get different results. And, it would help if you had a common mode choke on both antennas to eliminate the coaxial cable impact on final results. 73 Danny E73M
Thank you for sharing your test results. Enough samples were taken to make your data and conclusions reliable and conclusive. In addition... the elevated counterpoise will provide a small amount of gain in the direction of the wire. A vertical with a raised counterpoise is essentially a bent vertical dipole. The best results for this type of antenna is with the vertical high enough to drop the radials at a 45 degree to the vertical. It should be kept in mind, that this type of antenna is susceptible to common mode currents on the coax, which in deed will and can affect performance and SWR. So it is recommended that some kind of coax choke be installed at the feed point of the antenna to keep the coax from radiating. In essense, the coax without a choke or 1:1 balun is just another counterpoise whose length can affect tuning. A choke (hopefully) takes the coax out of the equation. Best 73s Dan K1YPB - On the air since 1962
What ratio transformer and for what do you usually use this one? Asymmetrical multiband dipole, end fed random wire? Or in the case that it’s a 1:1, do you have two of the four wires connected together on each side, to effectively have 2 conductors in a bifilar winding pattern (creating a 1:1 balun without any expected impedence transformation)? The number of colored wires is throwing me off :)
Hey Cc. Sorry if I missed it but curious as to which way your radial was pointing relative to the stations you were receiving at? There’s asymmetry from 1 radial, but not huge. Greg from CA (a big POTA guy-forgetting his call rn unfortunately) has a lot of success running 2 elevated radials at 90° from each other to get additional gain between the span of those 2 radials. If they’re 180° from each other it is supposed to tame the asymmetry quite a bit. … overall I think your conclusion is a good one, that the single radial is a nice contender. There are potentially additional benefits from raising the radiator, since you’re able to clear obstacles in the near field better like cars and things. I got a clamp for camera equipment which I attach to the roof rails on my SUV vehicle and screw the whip that way and attach a tuned radial since my sunroof is massive and there isn’t much metal up there. That is of course when I have the car, which is not always. But it can forego the extra support structure, and becomes just as easy as the ground stake. … btw your machining skills look cool. Nice homemade base unit
thank you for the comment! the radial is pointing to the receiving station. i think that should generate the maximum gain for the targeted station from what I know.
hi love then content i have one too ptefere it to my 705 now ive looked everywhare for the screen protector with no luck could you provide a link for them please Dylan m0dsy
Hi, nice vids! I was wondering if you had any tests with ground on the transceiver and not on the ant. ground element on a balanced dipole coaxal feed? I have done better results with ground on the transceiver but with ground dependent systems, unlike a dipole which does not require a ground. though keep in note that your ground in this vid might of been with a higher flux on the results if you had added a 1.5l bottle of water to the ground at the ground rods. we must take into consideration the actual ground soil levels of conductance (moisture, rain, dryness of soil, etc.) to myself, out of experience the ground looks somewhat arid and poor for good ground conductance in your video. Most importantly, on a balanced system like a dipole ground is not much an issue, but a system using UNUNS like end-fed random wires such as a 9:1 unun or 4:1 system you will see great differences with the ground, unlike with end-fed half waves and 1;1BALUN fed dipole system. the subterrain type of soil, bedrock, etc. where antenna is placed also plays a great factor in antennas in the field , not surprisingly, is never the same value even in the same location during different seasons. lastly, on a non-ground dependent antenna system like a dipole, grounding the braid of the coaxial feed right after the 50Ω exit of the transceiver will result in signal degradation. Your choice of transceiver being a Russian made SDR holds superior technology in reception of signals and its extremely low voltage power requirement for both rx and tx to generate signal and rf is so advanced that its hard to tell with such a superior piece of kit, such kind of tests, unlike let's say a xeigu x-6100 or an ic-705 or even a FT-891(qrp levels) so take that into strong consideration as well. Nevertheless, awaiting your next vids. and results, 73s
One of my favorite backpacking antennas is a upright V Terminated at the radio, no feed line. Worked very well lite wight. I used the radios internal antenna tuner two 42 foot wires
Missing infos... The shown values are SNR measured by Js8Call. Blue columns --> received SNR in the field. Red columns --> received SNR from my "data package" at target station. Power about 7W based on what the TX500 showes me.
Not sure how far you are from your receiving station in Wien and what type of antenna you have there…. But I think you can assume that you would get some type of vertical radiation (along with the dipole’s characteristic horizontal radiation) from the coax in the absence of a choke, and mostly horizontal only from a choked dipole. There are cases where the radiation from the coax could help your SNR, but not with high levels of reliability or predictability. When you’re relying more on ground-wave propagation, you probably would want more vertical polarization. And you’d want both antennas (transmitting and receiving) to be matched in terms of their polarization.
thx for your thoughts. distance wasnt far... about 20km but about 150m hill in between. the station at home has a vertical antenna. not sure about the vertical radiation from the cable...could be. I could test that theory by changing the coax cable from hanging down to going horizontal/perpendicular away from the feed point...or even better reduce the cable length to 1m or something like that.
afterthought...the SNR were higher with the choke at the feedpoint than without. that would contradict your theory imho. also keep in mind there was a second choke at the transceiver connected.
@@CrazyChekov maybe, but not necessarily. I think the point is that the radiation pattern will be modified from the textbook dipole pattern (even more than it already is by virtue of being in a low, real-world environment). The extent to which NVIS (on a low dipole) and ground wave are more effective will also vary by frequency and time of day. If your coax alters your radiation pattern by having the coax dangling from a horizontal dipole, it will almost certainly increase the proportion of vertical polarization. Whether that’s beneficial or not will vary based on the circumstances of both stations. You’ll get more radiation from the coax if your feed point is off-center. And if you’re going for NVIS, which sounds like maybe is your case given the hill/mountain between you and Wien, you’d probably rather want to keep as much of your radiation on the dipole elements as possible. Ultimately, you’d expect the same amount of total power radiated from either choked or unchoked, only with a modified pattern. But if your unchoked coax runs on the ground, you’d probably expect some ground loss. Having the chokes may also make the receiver quieter, in some cases. But perhaps less so when out in the field. You might be curious to look at the New Carolina Windom coax-fed off-center-fed OCFD antenna (which purposefully avoids choking at the feed point and rather chokes the coax a specific length away from the feedpoint). On its fundamental frequency, in particular, it adds that vertical radiation quite a bit. It’s not exactly your experiment, but it’s an interesting implementation.
will add a test to my list with nearly no feedline at all that should clarify it. we need more accurate real world tests to verify all these theories....systematically.
I didn’t realize that the feedpoint is low enough that you’re able to eliminate the coax completely. The length that’s dangling will make a difference, and will also be band dependent. There is a reason people like Dave Cassler (sp?) will say “with antennas, everything affects everything.” If you’ve got really consistent signal paths that you want to work reliably/consistently, then the systematic tests are quite viable. But I’m afraid you’d almost need an unviable number of empirical tests in order to generalize greatly beyond that, and would have to fall back on more of a ‘systematic review’ of many published results and/or modeling. But I think it’s great that you’re publishing your findings, and will be interesting to hear about where you think theory and practical measurements seem to differ. Nice chatting with you a bit and 73!
If you have a greater imbalance on your dipole (due to either environmental or design/execution factors), you’ll probably see more benefit. The benefit will probably arise from less than ideal/textbook setups for a horizontal dipole, but could be useful for a dipole in other orientations etc.
@@CrazyChekov possible. However the band going up and down ant a /b or in this case balun/ no balun is at best haphazard? Unless you conduct the experiment over a long period?
I prefer isolation transformers. Nothing will provide the kind of isolation a flux-coupled transformer provides at like 475 kHz ... baluns become ungainly at that frequency, and I use one on a 1/2 sized K9AY loop to keep computer noise from swamping real signals picked up by the antenna.
