HF Vertical Antenna Experiments
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- เผยแพร่เมื่อ 12 ต.ค. 2024
- HF vertical antennas are used throughout the world and are particularly notable for their low angle radiation. This makes them a popular choice for DX operation.But they also have a reputation for picking up noise. Many ham radio operators place their verticals on the ground with lotsa of radials. Is this the best way of installing a vertical? Peter G3OJV gives his views and details of experiments he has carries out.
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Really good video Peter! I got my first vertical in 1977 and always put my verticals on 10-12 ft poles with raised radials. Today I hang them up high in trees, and I dig down my coax in the ground and noise is never an issue.
very interesting comments. Thanks.
N2UGO, mostly 2mtrs and 70cm for now, Amateur Radio joins Us in a single community 😁 I prefer Tea ☕
Hi Peter, thanks for your wonderful video, which is very thought provoking. Always appreciate your nice words. Go well my friend.
Thanks, you too!
One of the best antennas I ever used was a homemade one. Just a 1/4 wave vertical for 20m made of wire with 2 elevated radials. Worked all continents except Antarctica in just 1 day with my FT817 5 Watt SSB. It helped CQWW was on that weekend but the antenna performed great with just 5 Watt. 73 de OO4M
Yes a great antenna and easy to build. Thanks for sharing.
This man is spot on correct. DX propagation is somewhat analogous to golf. Sometimes you need a driver. Sometimes you need a iron while other times a wedge. It all depends on how far you are from the hole. You can put a ton of power into a wedge and pop that ball sky high but not go very far (like NVIS). Other times, you want to dominate groundwave and so you use a driver (5/8 wave vertical). It's not JUST the power from the transmitter or the "gain" of the antenna but also the takeoff angle that is part of the "where does my signal go" equation.
Example:
VHF mobiles know that there are many times where a 5/8 vertical is NOT the best antenna because it puts too much signal at the horizon and if you are in the city, the repeater antenna is on top of that 50 story building away from where you're pointing your signal. 👍
Interesting observations. There are a lot of variables!
Modeling shows that elevated radials radiate quiet well and at a high angle. Radiation is then shared with between the vertical mast and horizontal radials. Ground mounted verticals excel for local, very local, contacts. Their low take off radiation is quickly absorbed by both earth and surrounding objects way before reaching the ionosphere. This is why AM broadcasters use verticals.
An elevated vertical with horizontal radials is NOT purely a vertical at all. We used to call them "ground plane antennas". These always have 2 major lobes. One lobe at low angles and one at medium angles. It makes a wonderful combination...
AM broadcast stations use ground wave and NOT low angle for reaching their audience. Ground wave is very strong up to around 2MHz. Radiation from am elevated vertical is much the same due to interaction between Vertical and ground plane.
Dear Mr. Waters -- I have enjoyed many of your videos, especially antenna videos. You have a practical, "do-able" nature evident in all your presentations. I think you must be a remarkable man. I was especially grateful that you mentioned Brian, ZL3XDJ in this video. Of course I went to have a look. Another well-grounded, practical man with quite a surprising story. I'm in the Philippines, now, and have a bit of land with the next-best-thing to seawater as a ground -- a rice paddy. With input from you and Brian and some lengths of bamboo, I hope to get something vertical in the air early next year. Thank you again, sir -- 73 from the Philippines, Stef, DU3/NN3M
Peter, I would really love to sit down with you and talk about antennas and propagation theories over a cup of coffee. You are a valuable resource of wisdom and experience. Thank you for the videos. 73
Many thanks.
U.K. has always been in the forefront of Amateur Radio 🎉 and Radio development in general, N2UGO
I think tubes will last longer in Radio, at least a little while longer.
Hello Peter. I really enjoy your videos - especially your videos on antennas. They are so informative and helpful! Thanks for this latest one which provides us with some rather interesting experimental results highlighting the DX performance of vertical versus horizontal antennas. 73 to you sir!
Glad you like them!
Very good information keep the videos coming
Thank you Peter a wonderful thought provoking video and based on your considerable practical knowledge of amateur radio experimentation. A wonderful must watch for beginners and OT's like me and certainly exercised my remaining little grey cells. It really is still great fun and its all magic still.
I will certainly do more reading on the subject. I just wish i could get rid of the YT ads ! Thanks so much and all done without autocue hi hi.
73 Martin GW3XJQ
You are very welcome Martin.
If you use Opera as a web browser it will get rid of the annoying adverts. 73's
I'd like to see a performance comparison between the Hustler and DX Commander verticals. At any rate, great video. Thanks as always for the information.
Thanks, Peter, for your thoughts. I guess that ionospheric-tilting might be part of the explanation; I think this happens most at the grey-line, which is often when UK and NZ stations are working each-other i.e. during the dawn-and-dusk enhancements. An experiment I would like to try is a space-diversity two-stack antenna system, and a true diversity RX, to measure the arrival-angle of ionospheric signals. 73! Tim
I think you are exactly right. There is one other factor that even amplifies what you say and that is the dipole has even 6 to 8 db more gain than the vertical at its best angle than the vertical does at its best angle. I have studied antennas and propagation since I took those classes in my EE course in college. The more we learn the more we realize what we still don’t know about propagation and the ionosphere!
Not sure where you get that figure from but remember ZL3XDJ is getting better performance from his vertical than he does with a dipole
@@watersstanton as you said the path is probably different and over seawater. He may be taking advantage of the vertical’s pattern ( fairly low angle) and seawater hops. The vertical over ground has much less gain ( maybe zero dBi) but over seawater it can rival the dipole gain. Typically the dipole has 6 to 8 dBi gain at its best elevation angle. That angle depends only on height above ground. Verticals will beat dipoles that are at modest heights at very low angles, as a dipole at half wave high has that 7 to 8 dBi of gain at about 30 degrees. While a dipole at one wave high has that 8 dBi at maybe 15 degrees. So if the optimum starting takeoff angle happens to be low for him and he bounces off seawater he has a great signal with the vertical. At the other end if the optimum takeoff angle is higher, then the additional gain of the dipole can be utilized but due to the ground conditions out in front of the vertical ( maybe Brewster angle) the vertical may not perform as good at that low angle and at the higher angle it has less gain than the dipole. It’s great to have both antennas and a switch! Another thing is the height of the F layer. It may not be the same, in fact it probably will be different at the two extremes of a long path. That adds another level of complexity and uncertainty. Then there is also the E layer that may bounce signals somewhere along the path. I spent one whole day comparing a vertical and horizontal antenna on 40 meters. I used CHU Canada as my test station. At different times CHU was strongest on first the vertical than the horizontal. Big differences throughout the day. So time of day made a huge difference in which antenna dominated. I can make generalizations about which antenna may be best but never can I be certain. Just too many variables as you well know!
Belle analyse de ta part, félicitations! . Merci encore pour cette vidéo et cette belle déduction. 73s. Joël/F8MGW.
Merci beaucoup Joe. Content d'avoir de tes nouvelles.
I think the position of the high current point is important with verticals. One reason why half wave verticals work so well. I have used a half wave for 20m. No radials and it worked incredibly well. Would be interesting to compare it to a quarter wave vertical.
Very interesting Peter. One consideration is Ionospheric tilt. Here on the West coast USA high angle antennas work better in the early morning hours on the path to Asia. The ionosphere is far from uniform and I suppose that adds to the fun...73, W6QR
Hi there. It’s a possibility but the anomaly is very consistent. If I had a telescopic tower it would be interesting to raise and lower the dipole.
I always enjoy your videos, Peter - many thanks. I love experimenting in my unique location on a salt water harbor facing NE in the Puget Sound south west of Seattle, WA. Perfect direction for Europe. Comparing a beach level vertical (the BB7V you reviewed), a beach level magnetic loop (Ciro Mazzoni baby loop) and a hill top horizontal wire, I too find varying differences depending on the day and the contact. Most often, the mag loop is the best performer. Ignoring ground interactions, my thought is that the mag loop gives all possible take-off angles towards Europe - and therefore can always "find" the ideal one for each contact. On rare days with excellent propagation, I have even made QRPp ssb contacts running less than 1 watt and then walked the power down to 100 milliwatts once I have made the contact. Most of the time I hear dx stations at equal signal strength on the mag loop and the vertical, but the other station often hears me better when I transmit on the mag loop. So much more yet to experiment with! 73, N7RLV
Sounds an ideal location with all that salt water. Great to hear from you.
I once received a commercial A.M. radio station in N.Y.C. in HI, Dominican Republic quite clearly on a car radio, with a bit of wire, on board a small ocean going vessel.
N2UGO
This is exactly what I have found, I can work South America fairly easily, whereas struggle with countries in the middle east, India, Korea etc. I think it must be as you're saying when traveling across sea the signals are attenuated much less than those across land. I find I can work VK and ZL also via long path much more reliably than by short path, which I assume is for the same reason.
My first thought on this phenomenon you’re experiencing is the fact that long path his signal is taking has it’s early hops on the Pacific and coming over the frozen Arctic Ocean late with some gain to give, your signal the other way has the higher amount of gain taken off the hop as you are hitting the Arctic earlier and losing more signal before getting over the Pacific. Just a guess but it’s my first thought. May even explain the dipole versus vertical difference you’re experiencing. 73, Walt K4OGO
Hi Walt. Nice to hear from you. Yes it is a puzzle with some complex possibilities.We may never know for sure! Well done on your channel.
I have the same vertical as you and it is at least S1 quieter than my 2 wire antennas. The vertical hears more but it doesnt hear better. I also follow several TH-camrs who really push the 5deg radiation patern BUT since we dont know (as you mentioned) what our antenna is actually hearing I expect we tend to fall back on pool skills where the incoming and take off angles of our signal will be equal. I think we would be surprised if we could actually observe them in real time. For now I switch between horizontal and vertical antennas so I dont miss something I would be interested in. I believe that no theory on DX communication is right all the time and neither are they wrong. Brian VE3GUE
Many thanks for sharing. The ultra low angle claims come from modelling programs. But it has long been established that this very low angle from verticals is cancelled out by “mirror” reflection.
Hello Peter - Great video and lots of food for thought. I wish I had a few extra footage to play with. What time of the morning Peter do you work into VK & ZL
It is very much keyed to the grey line. Currently BST ZL is around 7.30am and VK about an hour later. This is normally long path. There are openings in the evening on short path around 8pm but not as reliable as the mornings.
Thank you Peter for that information. Must try having a listen some mornings. Retired here so not up with the Lark any more.
Interesting video. KL7AJ in his now out of print book on propagation published by the ARRL suggests the path for a received signal may not the same as the the transmitted path to a distant station. He provides considerable physical insight. Full sized verticals are also more efficient. My StepIR works well but is reasonably well away from any structures. My property ,however, is much larger than a typical English garden.
I have plans to install a mono band vertical above ground level. Thanks for sharing.
Do your neighbors sometimes talk in low whispers about the odd duck 🦆 with all the ratty wires and strange radio kit ?
Great video! How long should raised radials be. full/half 5-8th wavelength?
They should be quarter wave.
Top Class Video ,,Very Interesting 👍
Many thanks
The Tx and Rx situations will be different. When you transmit then the angle of radiation, the number of hops and what the signal bounces off are all part of getting the signal to the area you want. The path in the other direction is different, it has to be, as it's a different antenna doing the transmission, but hopefully the end result will be more or less the same and the return signal will hit your antenna.
When the signal bounces of a reflective surface, another thing that can change is the polarization, that can be rather random. When you say you get a better signal on the dipole I suspect that this is what you are seeing. So what you now need is a dipole on a rotatable mount so that you can vary to polarization and find out what is happening. Maybe you need to find a windmill to operate from and install a crossed dipole on the sails 🙂
Interesting observations whatever is going on, nice video.
Andy
Hi Andy. Thanks for the comments. Polarisation on HF sky wave is continuously tumbling and is not related to the transmit antenna polarisation .
Very good
Excellent video
Thank you very much!
Yes, very good job 👍
N2UGO
Peter, I also value my time at Costa (OTHER COFFEE SHOPS MAY BE CHEAPER) Ha Ha!
A few weeks ago I made a 20 meter CW contact to India at 22:00 from IO81wk (Chippenham) with my FT818 / EFHW slopper at 5 watts, I'm sure he was doing all the heavy lifting! I directly connect the EFHW to an old KW EZ Match so part of the antenna is in the shack (kitchen). It has no radials just a good ground/earth. Sadly one of my neighbours has entered my garden and pull down or kick down the fishing poles that support the antenna, could be an element of hate involved. Bell wire, (telephone hook-up wire), is used for stealth and less air resistance so it wasn't blown down. In any case I was wondering what was the polarization of the transmitting antenna when you were checking your receiving strengths? Do you think that could have had an effect or do you think that skipping nullifies polarization? Regards es 73 de M0UET!
Sorry to hear about the damage. Sky wave signals have random polarisation that is continually changing, so the polarisation of the transmitted signal does not matter. It's the angle of radiation that is key.
I've just done some mods on a raised Hustler 5 BTV, raised to about 2.7 meters with a CNC'd aluminum disc, with 3 aluminum tubes, I have still yet to tune the antenna with my nanovna, but the signal difference between my untuned offset L composit and the hustler is substantial on various bands, but some signals are less. I have yet to add more wire radials for other bands, than the 3 tube radials that are cut for 10M. My TH-cam channel is Half Greek Geek - 73's G7UIV
Many thanks for sharing. Keep at it.
You may be working short path while the ZL station is working long path or visa versa. Also, your horizontal dipole is bi-directional and the vertical is omni. The orientation of the dipole will have alot of effect.
Both ideas have been written off with tests.
Many thanks. Neither of these explanations fit with the tests we have made.
Can you, please, show more detail drawings of your vertical antenna? "73"
Its a commercial Hustler 4BTV - there is a link below this video.
Great stuff. Thoughts and questions here… Firstly I love your occasional use of the flat earth term :). At the same time, it gets made clear even on FCC exams that lower angle is better for distance, although I’ve not seen anything saying how low except on your flat earth friend’s videos.
I like the concept of which type of surfaces reflect. To me, a land reflection first should hurt future hop success as opposed to seawater reflection first or first+second.
I’ve noticed on pskreporter that I can visually see my ft8 transmission hops, geographically, quite clearly. So I’d suggest you and the ZL try ft8 to see who is hoping where and how many
Yes low angle does get you further, but as soon a multi-hop takes place the optimum angle of radiation takes on a new concept.
have you tried using both antennas with one tx other rx, then reverse them? the old way! Not many radios are dual socket but I am sure you will have a switch
Oh yes many times!
Another great video, thanks! Robert K5TPC
My pleasure Robert.
It’s a right pan of stew… or as we say in the NW “lobbies” everyone’s is different. It all depends on your circumstances and how much garden you have.🤔 You just have to ‘lob’ up what you can and try it, sometimes it’s a good surprise🤩 other times although you’ve followed the recipe it’s only fit for the dog.🤮
It’s a part of the hobby that most of us can have input seeing we don’t have to build our transceivers anymore. It’s brill when a random idea, resonates.😜
Best wishes to everyone.73. 💙
G0uvl
As the radials in such a setup is said to also radiate the signal. Is it not so that you get a low radiation from the vertical wire and a medium radition from those elevated radials?
The radiation angle is predominantly the same, much like the more familiar VHF verticals.
8:00 Isn't it just because the polarization of that signal at that moment? Hang the dipole vertically and the signal changes one way, other signals change the other way.
I think you are confusing polarisation with arrival angle. Any HF signal arriving is randomly polarised, changing all the time. The arrival angle however is more constant.
Depends which way the dipole runs and what blockage the vertical has like buildings etc....
ZL3XDJ has his verticals in amongst trees and still they work better than a dipole.
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Blessings
Is receive angle and gain the same as transmit?
As regards receive angle, we just don't know. There is a suggestion that there could be a tilt in the ionosphere in which case the angle could change. I am no quite sure what you mean by gain. Clearly any change in transmitted power will be reflected at the receive end.
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Many thanks.