The Truth About Optimising Take-Off Angles for Ham Radio DX
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- Опубликовано: 29 фев 2024
- In the main, DX signals will arrive at your station between 5 degrees and up to about 15 degrees. The absolute average is around 5 degrees. That's not to say SOME signals won't be arriving as low as 1 degree (eg long-haul DX on 40m) and up to 20 degrees for some 80m signals. Links to these papers follows:
www.arrl.org/files/file/antpl... - published by ARRL
on5au.be/Cebik-2/ThePseudo-bre... - Cebik's Brewster Angle discussed
en.wikipedia.org/wiki/Curtain... - Interesting observation about curtain arrays noting low angles
www.arrl.org/files/file/QEX_N... - Read the very last paragraph - page 20
The main arguments I debate and dispell are as follows:
1) the 5 degree “myth” has been around for 5-6 years and has been produced by newcomers who use modelling
2) the software “they” use is free so is unlikely to be accurate enough
3) the 5 degree angle, and I quote “does not appear to exist”
4) the reference angle should not be less than 10 degrees
5) the optimum angle from a QW is 26 degrees
6) buy the ARRL Antenna Handbook (agreed!)
After this video was filmed, an academic sent me a message (edited):
This 5 degree thing is actually a very technical issue. The papers on it are very interesting and complex. Firstly there is definitely the thing that [redacted] goes on about - the pseudo Brewster angle. Unfortunately for [redacted] it’s irrelevant in vertical 1/4 waves. In fact the very paper [redacted] quoted in his video states this fact. Secondly, there is no doubt that true DX does arrive at very low angles. This has been known for years. The fight to achieve low angles is well known. What he cannot deny is that 1) DX comes in at low angles. 2) comparing values of gain at any angle is just that - a comparison (a bit like dB). You can compare any number of things using the benchmark of your choice. In summary, do Brewster angles have any relevance to ground mounted verticals? NO. Does DX on long hops come in at low angles? YES. Regardless of where you chose to measure, it’s just a comparison.
An engineer had this opinion (edited):
Concerning modelling software, YES in the early days the free programs were a bit hit'n'miss and the commercial units were very expensive. The commercial units were also difficult to use and you needed a PhD to be able to run the darn things, so in the hands of an inexperienced operator you could torture the data to confess to anything....
However, technology has moved on and the likes of EZNEC and MMANA stared to become very competitive with some of the very expensive commercial gear and started producing results which were very favourable indeed. This all at a fraction of the price for full flung commercial stuff and just about any reasonably competent Tech could use them. The latest iterations of MMANA now are fully spec'd and DO take into consideration such things as wire diameters, end effects, brewster angles if applicable, etc.
In the main all these variables are configurable if you dig deep enough but normally assumed for general use. So, in the case of modelling a 1/4w ground mounted vertical for instance MMANA etc will know to ignore any brewster effect because it is not applicable. However, start changing the diameter of your wire antennas and the software kicks in a compensates.
A Broadcast Engineer sent me this:
The angle of radiation is definitely well known for DX and more so as we go lower in frequency. From a commercial point of view we design our AM towers to give a low angle of radiation so we get the widest audience possible. If we get this low angle then we are assured of the fill-in anyway. We are concerned about the ground conductivity and will build on a peat swamp if at all possible. But it is not the Brewster effect that worries us but the HUGE return currents we have to deal with.
Another opinion from an engineer (edited):
.. about the pseudo-Brewster angle showing an ELEVATED vertical with elevated radials - [redacted] falsely assumes that a ground mounted 1/4w vertical will act the same way. YES, there is a Brewster effect with an ELEVATED vertical but little to NONE with a 1/4w GROUND MOUNTED vertical.
Final note from me. I am not an expert at mathematics and can hardly understand this Brewster Angle anyway. I am only interested in ground-conductivity because I know that an excellent ground will give better results for a vertical. And for best effect, this ground needs to be for hundreds of wavelengths (eg sea water). But it'll still work regardless.
That's all on this subject. It's a huge topic and if I find some more decent quality information, maybe we can revisit this topic another day.
Thanks for watching. .See you on the next one! Callum. 
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I saw the original video questioning the use of 5 deg., and immediately realized you and that video were talking about two completely different aspects of rf transmission. The critical video was talking about where the most gain is, and you are referring to where the gain is at the best takeoff angle. I'm glad you responded. For me, free software is my world. DXKeeper for logging, WSJT-X/JTDX/FlDigi, wfview, etc.
Very fine!
It’s absolutely true. I tested this concept last summer. I raise my mast to a certain height and no higher. I maintain my angles and take off elevations as needed. Thank you for the video. 🤝
Excellent!
Callum or Peter - need a Harry Hill style FIGHT😂
🤣🤣
There'll be no fighting. Everyone has a respectful view, I am sure.
You don’t seem to like it when its different to your opinion.
@@justmejonboy He does tend to throw his dummy out of his pram.
Peter's
I have learned a lot from Peter and respect him very highly. I’ll continue to look to him for deeper understanding of the hobby.
Excellent.
Nice response Callum. I like the fact that you responded to the criticisms in a respectful way & kept to the facts.
The other person (I think we all know who we are talking about) came across as quite dismissive & used slurs like "newcomers to the hobby" in an attempt to discredit others. As soon as someone does that they lose a lot of credibility in my opinion. I also noted some inaccuracies in the information presented on the other channel.
Pointless getting into a war of words or any kind of argument. Just put the facts out there quoting your sources (exactly as you did) & let people make up their own minds.
I'm very glad you noticed I was respectful. We are all allowed an opinion, of course.
Callum does a great job at keeping positive through this video. He is a class act.
As a great woman once said. If that start attacking you personally they have no argument left.
I watched and listened to the entire video. I'm new to HF so most of this went way over my head. But, I'm catching more and more information watching your videos. Thank you, Cam.
Welcome Tommy!
Hi again, Cal. Thanks for the takeoff angle discussion. In continuation of our prior dual 10-meter wires discussion, my SWR is 1.5 or better from 28.300 and 28.620, then again at the 29.500 and 29.600 AM/FM frequencies. Totally fascinating. Back to the takeoff angle discussion, I've been working the SSB contest this weekend and I'm consistently making contacts in New Zealand and Japan from here in Florida with 100w on my DX Commander Classic, even in pileups. Last night I made a New Zealand contact on 40m at 100w. I'm always impressed with that gear.
Heck, that's good work!
Absolutely love, the video fantastic information that you shared as always Callum enhancing the understanding and development of others that want to learn more.
Thanks Billy!
A genuinely well presented and researched video, Sir.
Thank you kindly!
Thanks for this Callum. You make some great points that answer some questions and ask many more.
Sadly, there are SO MANY variables that when it comes to antennas and radiation patterns that it is impossible to have ANY hard and fast rules.
As you have said yourself "Everything affects everything" - and it DOES.
I think that the best one can do is to try to "stack the odds" in their favour as best they can, and hope for the best. - Cheers!
Stacking the odds.. Yes.
I am just in the middle of setting up a higher mast for my folded dipole (without enraging the neighbours or the YL). Thanks to Your older "howto" videos, I used mmana-gal to simulate my antenna and realised why I struggle making proper DXs with my current setup. By raising my antenna a bit, I will have 2-3dB extra gain for 5-10 degrees takeoff angle.
Lovely.
Thanks a Stack Callum, Yet Another Brilliant Vidclip, So well presented and Chocka FULL of Information .... Best to ALL from ChCH, NZ
Many thanks!
Thanks for bringing so much clarity with this video. I don’t have much experience with vertical antennas but will definitely try them out after this video. I leave about 20km from the beach then perhaps my soil can be help.
Yes maybe.. The one mistake I used in my early career was only using them to compare RECEIVE signals.. That can put a downer on it, particularly with the advent of low-to-ground dipoles and loops-on-ground (search Loop On Ground) since our radios have HUGE pre-amps built in so getting a really pleasant signal out of a radio is lovely. I made a video here, from about 7 mins, particualy on 40m band: ruclips.net/video/z5MhYu2LUrY/видео.html
Fascinating stuff RF works in mysterious ways ❤
Indeed!
Very informative and well presented. Factual too, which is always good. Thanks Callum 👍🏻
Much appreciated Ian!
I've worked beside saltwater numerous times and the difference from being inland is incredible. Think about stacked yagis the megastations run. They can independently select which antenna to use. Why is is that? It's because each antenna can receive at a slightly different angle where the incoming signal can be stronger, weaker or non existant. If none of it mattered, people simply wouldnt bother.
Good point.
Wow Cal - this is great, am gonna watch this again and again, there is a lot of good stuff covered here 👍👍👍
Awesome, thank you!
Thanks for the extra info Callum, very interesting and useful for my QTH plans.🍻🤠
No problem 👍
much better quality through new lights. and great input. btw: science is always discussion, simulation, testing, measurement, thinking, proofing. tnx es 73
Great point!
Well put across Cal as others have said, I look at it if you have a benchmark you have something to compare other products against, which you have. Keep up the good work 👌
Indeed. Nothing like a good benchmark - then testing it out.
Callum, there are times like this I would just like to sit down with you, one on one and pick your brain for all the questions my brain sometimes has. This was actually very captivating to me from begining to end. Thanks and 73. Vic de KE8JWE
Deal!
Vic, you'll be buying the stout at the pub, right?
Well explained tutorial. I learned some cool new stuff tonight 🙂
Awesome, thank you!
Good to know that the software takes the “Brewster Angle” into consideration.
Great stuff Calum. All this confirms my real world experience of using verticals by saltwater using very low power…
Yes, amazing isn't it..
Fantastic info Cal! Keep it coming…
More to come!
Really enjoyed this one cal n your video is so crisp n clear 👌
Crisp and Clear.. Sounds like a product!
Great information and content as always from the DX Commander “Video Channel”
Much appreciated!
I’m new. I just got my license, KO6DEV. I like what you said and you are right. I made my first DX to Japan with a GPA-80 on the ground with 8 ground wires on 20 meters. Yesterday it was Chile, and Hawaii. I ‘ve got an 891 with a yaesu tuner. It works great.
I had no idea an antenna sitting on the ground was better than elevated one 10 or 20 meters above ground for DX. I am gladly surprised. I no longer need to worry about getting a 20 meter yagi on top of the roof, which would be a an impossible dream in a residential area.
I am still learning and I wonder why an antenna right on the ground is so good for 5 to 10 degrees. The antenna was supposed to be mounted on a mast, but I modified it as per your advice and mounted the eight wires on the ground. I did have to get in to the box to get a wire to be able to ground the wires, because the antenna was not meant for it, but it worked quite nicely.
The antenna is no good for 40 meters, but I am making one as we speak based on the same principle, right on the grown. It’s going to be a 20 meter monopole right on the ground with tons of wires laying beneath it. I bought the aluminum rods used for camping gear, which were very cheap. It’s 10 meters long. Very basic and I hope it works. Hurray for vertical antennas mounted on the ground! Thank you for the advice
It'll work great!
I just put a parasitic vertical 3.4m behind my 20m vertical long path ant another 2 points.
I am glad to hear your side of the story.
It's not so much "my side" but a case of getting the right information out because with great reach comes great responsibility :)
Great Video Callum. The explanation is spot on. The lower the angle the better for DX. Why in the heck do all these guys build these big towers to get their antennas up high... to lower the radiation angle. If you look at a dipole at good height 1/2wl+ you will see the TO angle lowers and more RF is squeezed into those lower angles vs the middle or high angles. If you want the good numbers for long haul depending on the band, it is lower than 10degrees. Yes, in some areas of the world 20 degrees will work for short haul DX, but to use a turn of phrase, IN the main for long haul 5 degrees is the sweet spot. If you look at the big DX'ers and look at old antenna books, which you know I have a library of now... it is a LOW angle radiation game. Just great work.
Low angle. Yep, true.
As long as my coffee is above 50 degrees then I'm happy. I hate cold coffee 🤣🤣🤣🤣🤣🤣🤣 I am having great success with your antenna and truly appreciate the effort you have put into it's design. Have a great evening Cal
Have a great weekend!
Thanks for your energy to keep us on track 😊 PD5RV
Always!
Top banana Callum. I remember on my foundation course it being drilled into us that for DX, you want low angles. It’s just obvious!
Good point mate.
Never doubted you for one minute. 😁Nice to have it explained with some good reasons why 5% makes a valid baseline/benchmark. 👍
Glad it was helpful!
I don't consider myself a mathematician, nor do I consider myself an idiot. The longest distance will be achieved by the most obtuse angle bounced off the ionosphere. Thus the lowest take off angle that can be achieved as well. What you've said made perfect sense the first time I heard you say it. Pretty simple mental picture. I can't really wrap my head around it being argued...
Yes.. if it's 20 degrees one day - then 5 degrees the next. You are right.
That's not necessarily the case. Start reading the proper research that is done for OTHR, and you will learn that higher angles can propagate further than lower angles. The ionosphere is so much more than a mirror.
Cool stuff, Very useful info. Thank You!!
Very welcome!
But... But... But... PW was so convincing with his avuncular presentation style! 🙂
I'm sure he was. We all have an opinion.
PS - "avuncular".. That's a new word for me.. I see what you mean.
@@DXCommanderHQ I love discovering new words. Glad I could help 🙂 DE 2E0PTY
that was great . love the ARRL books . super great reading. love the free software for ham radio . some apps for smart phone as well. having fun with coax antenna lately. The T2LT running up a 10 meter DX commander pole. gets NY to England in the AM, NY time. 10/11/12 meters. I got Derbyshire on SSB CB 11 meters from NY last weak. even did MMSSTV free program for SSTV and it works on CB . I even herd the DX commander antenna on 11 meters CB. just cut the wire put it on and it works. the little numbers on square beads is great. can use letters also. TEN or 10 . love how antenna companies (some) claim all this DB gain. and they leave out at what angel . and numbers they give is if antenna is in free space. numbers mean nothing if you don't use the point of reference. And state the reference. 73's
Well said.. PS - Good work on your experiments!
Good analysis! One thing which may have been mentioned is that the information Callum analysed about the average elevation angle of received signals in a variety of paths such as USA to Europe and Japan, was from a study undertaken 24 hours a day over a whole 11 year sunspot cycle and endorsed by the ARRL. I’m happy to use and trust MMANA, despite being a “newcomer” 73
Ah.. Hiya Tim!
Those Arrl plots of skip angles are fixed, I would say the propagation angles are at least general and really out of date at worse, as the angle will change in real time .a layer can be miles wide vertically and temp, other forms of prop will interact on the second ,third on fifth bounce or all of them I agree its all you can do to get your take off as good as you can..but prop will always be "king" and unpredictable. Thats why I could hear Japan or Italy or both at the same time and the guy down the road 20 miles might not..Antenna science is a facinating thing,but prop is of a different magnitude of complexity.. Even more so at this time, keep the videos coming love em
You can hear Japan and Italy at the same time because your RF is going "everywhere".. But thanks for the comment and understanding of the complexity. I had to cut it short at 20 minutes else it would have been a 2-hour video which nobody wants to watch - and I certainly don't want to edit!
Well said, Callum. All the while we argue this, we are using amtenna matchers to keep the SWR in range, but show no concern for the efficiency (I should say lack thereof) of an antenna that is nowhere near resonant. Sure... The signal leaves the feedline, goes into the antenna, but how much ends up being radiated electromagnetic H & V waves, and how much ends up as heat for the neighborhood? LoL... I have seen far to many willing to criticize with formulae and engineering resolution in the numbers, but in so doing, lose all common sense. Your video on radials illustrates that quite well... SURE... The BEST radial field is probably 128 quarter wave radials, but oh man... look at the resulting gains, is it worth all that copper and labor? Thank you for the education , you are one of my goto Elmers, Sir!
I try! But we're all learning...
Thanks, very informative!
Glad you enjoyed it!
Callum, thanks for your help.👍
No worries!
Hi Callum, I've heard about the 5° thing for years. I note what you said about 7 MHz and houses.
Since putting 5 dipoles, 20m to 10m in my attic I looked for attenuation of brick, slate, wood and other materials and all I could find are figures for high u.h.f. and up.
I came to the conclusion that h.f. signals going through a house must not be a problem. The problem is likely to be copper pipes and wiring coupling r.f. into them, and a row of houses makes quite a barrier.
G4GHB.
Yes, I would agree with that.. Fairly convinced that the copper pipes and wiring will skew a pattern.. Good be for the best.. might be worse (in that direction) but you and I have similar thinking there.. Too many experiments in my back garden / yard convinced me just next to the house.
Nice words for a nice video about explaining why another nice video may have been mistaken 😂
No name calling.. That's not the true purpose of this video. We are all respectful, I am sure.
I like Roly’s approach … put it up… see if it works. And I saw this discussion ? ? ? would develop a few weeks ago and hoped it wouldn’t start
up any animus because we all have different experiences and opinions, something that works in one back garden or mobile location will be different from others… we are in this for whatever interests us… I’m very much into antennas but what Cal, Roly, and Mike does is
w a y beyond me as it is with a few of us… my biggest investment in the future will be an antenna analyser… for my antenna interests and I’m going to be putting up my wires and “see if it works” I hope this discussion doesn’t start anything off in the Ham Radio Community… 73 💙
@Rubedo Yep, at the end of the day put your antenna up and see what happens :0
Then change it a bit and see what happens.
However, be careful.......this can become VERY addictive :)
Cheers
What Roly said :) PS - nothing is "started" - just good information.. See end of video. No name calling please, no back-chatter. I think you know that. It won't develop from here.
@@DXCommanderHQ Cal,,, I always watch to the end of your videos… and I watch them all three or four times because I enjoy your presentations, I felt when the other channel posted, because of what was said, there would be a response, and I know what you are getting at with your antenna R&D,,, sometimes it’s a little beyond me but I still watch them several times. As I do with Roly and Mike’s videos.
Some are expecting arguments, I don’t want that, and I don’t expect it to “develop from you” or be “started” by you.
Maybe how I said it gave the wrong impression, it wouldn’t be the first time… or the last.
Roly is exactly right. I can see the results, my DXC is much better at DX, while my EFHW is much better for local.
You the antenna goat.
Just hit a repeater Abt 30 miles away tonight. And its in-between a mountain that's Abt 2000 higher respective of the 2 locations. Yes!!
Wow
Always laugh when people say that free software isn't any good - what do they think runs the entire Internet!?
Good point!
Absolutely the best video I’ve watched in a long time. Great explanation Callum. As for operating by saltwater, I know a guy…… 73, Walt K4OGO
HAHA - I know a guy too Walt!! LOL
Over to Peter now 😁
😝
Game over
I do enjoy your videos Callum. Question, with a 40-10 EFHW what is the linear distance from the mast to the feed point if the mast is 29feet high? Assuming a 5 degree take-off angle. Thanks for any insight for this.
SO for a 40m End Fed, that's 20m long.. So if you feed at ground level and go Inverted L? That's the way I see it. Then get as much of it as vertical as you can (say half) for best DX / Low Angle.
@@DXCommanderHQ Many thanks Callum
The fun thing, of course, is when all the theory is absorbed - and all the options for your perfect antenna are considered. The only way to guarantee results is to build, experiment and build again!!! That’s what the hobby is all about!!
Yes. Let the results talk.
I saw the other chaps videos and the response. I would suggest reading a good book, for instance HF Antennas for all Locations. Its an absolute classic. The mathematics is reduced for clarity. Interestingly no bananas mentioned, although imaginary numbers are in the same realm I guess 😅 I think the other chap was making some good points. I think his arguments weren't really centred around what should be a bench mark. Rather, he was making the point that very far from the antenna there are effects to consider. Additionally, when considering the myriad of possible propagation mechanisms, maybe low angle may not be so important. In particular chordal hop propagation provides hope to all regardless. I thinks it fairly academic to reason that near resonant lengths of earthed wiring in household electrical systems will have effects in the near and far field. 1:38
Nothing like an imaginary number to light your bulb!
I find it intersting when looking at You Tube channels, the commercial nature of the crearot is obvious, sometimes! Take ML&S, unashamedly an outlet for sales, but also full of good sound information, always respecrful of products they do not stock and generally informative. Then there is DX Commander, again a business related site, or is it? Most of the time you cram your channel with interesting science based practical information and and on air streams. When you have a new product you will do a bit oif a "sales pitch", and like ML&S you show respect for other Ham related concerns. Now to the "detractor" in this case. Information in his video seems to be based around books written some 50 years ago, and does not acknowledge that science has moved on!One point I would also make is that the channel concerned always heavily plugs the store he is conncected with, as if it is the only Ham outlet in the UK. That is fine, but please, Mr Expert, do not use you company platform to attack another Ham outlet, particularly on sketchy information! As a point of reference, I remember back when I first passed my ticket, I found your channel, Callum and there is one thing I recall vividly and that was you saying that you chose 5 degress purely as a baseline to compare results, and you did not know if it was an accurate representation, rather like the use of bannannas as a unit! Ours is a scientific hobby, and as such you have backed up your methods with science, well referenced by respected up to date sources. To critisise without up to date science based references is simply just wrong and an attempt to belittle a man who does good work based on the science and engineering that he loves. Keep up the great work mate, and ignore that tatty, out of date parrot!!! Sorry this is a bit long but a certain person annoyed me with his "indepth examination" of a subject he obviously had not researched enough! 73 Jim M7BXT
Hello Jim.. I appreciate your comment (I know you are a regular) but as I said at the end of the video, no name calling, we're all respectful. Bless you and have a great weekend.
Well played Callum. I still stand by my comment that was BTW deleted from the first contradictory video, seems to me that there's some sour grapes due to the ML&S deal.
Yes, there are some folks that delete comments. We have also noted that too.
Callum Keep up the Great work 😁There's always one who knows best 🙄
Legend!
Brilliant. Brilliant. Brilliant. I do like watching the videos on [redacted]'s channel, but [redacted] does seem to have become obsessed with 5 degrees recently. I wasn't sure that I agreed, but couldn't prove it. So, thank you for this invaluable information !!! 73, Mike. M0MTJ
It's nothing to do with him, however the end of the video summed it up by divilging the right data for anyone to go and check them selves.. I appreciate folks have an opinion.
@@DXCommanderHQ Thanks Callum. I did not want to disrespect the other channel, but I didn't disagree or comment negatively. I really like their work and the many contributions so much. But it's all clearer now! Thanks again.
Great video and I always enjoy watching your videos ,
The question that comes to my mind is: How can I adjust the antenna so that the signal takes off at 5 degrees or close to that?
Is it by adjusting the height of the antenna from the ground? Or in another way?
I'm trying to understand this matter .
By the way, the antenna that i used spiderbeam 5 bands at a height of 13 meters from the ground.
The place where the antenna was installed is relatively high. The ground is dry and mountainous.
apologize if you explained this in the video and I could not understand it and asked about it again
Thank you very much. Best regards, HZ1MW 73
Unless you are into VHF *or* have massive towers, you won't get the main lobe down to 5 degrees.. Just beware of all the techniques to guide your main lobe lower (which impacts DX). All we can hope to achieve is get as much as we can between say 3 and 8. I have another video coming out shortly which also discusses slopes, tilting and near the end, some added value on this topic.
@@DXCommanderHQ I always work with Dx and enjoy it, and that is why I make sure to get the best position for the antenna. I hope to talk to you on the radio. Thank you and I am waiting for your video 73
I am not very technical which it comes to my choice of antenna. I find for 20m and up during the daytime, I use a vertical for dx, whereas, an efhw or efrw as a sloper seems to work better for working the continental USA. For my qth antenna, I chose an inverted L efhw. Definitely interesting video and models Cal. 73, friend.
I was convinced Calum was pulling out chain at 12:24 🤣
Great video.
Thanks!
Slightly related: I have been working on contacting a friend in Minnesota on FT8. Because the software displays stations state locations i can watch the propagation move around like a searchlight. It can move from north to south USA in a minute. Usually its a south west to north east strip. The surprising thing is tgat although the bands have been open to USA its taken weeks to make contact between our two stations. GM4SVM
Amazing!
When I go pota-ing with an EFHW is there a shape of antenna wire I should shoot for that’s best DX? I worked you on your last live stream, it was awesome! Thanks. WY7WL
Have you tried to use the free software out there? Test it, inv v, inv l, sloper or vertic. See what far field plots it comes up with. Then test it out. Make it fun, make it work for you. 😊
@@garyh8315 your right, I need to learn that software. It’s just above my head at the moment
WY7WL.. Probably get most of it as vertical as you can and less inverted V.
I think I know the person you are on about and I have to say I’d believe you far more Callum than a doddery old man who shares my surname. Personally I’ve stopped watching his videos as they are now painful to watch.
At the end of the day he is just an amateur. An amateur who sells (but doesn’t sell DX commander) but an amateur all the same. You however clearly understand the science behind it because you can explain it in such simple terms. Keep doing what you’re doing Callum. I really enjoy these videos. 73.
Interesting.. and thank you for being respectful..
5 Degree up works on vhf uhf as well.
Radio waves are like, a laser, a torch, a flat rock, a bullet, but not like a bomb.
Bullet ricochets at a shallow angle, lasers reflect at a shallow angle, flashlight reflects at a shallow angle, skip a flat rock on a lake at a shallow angle. Bombs just go up and fall back down.
Pretty simple.
I did over 9,800 miles, SC to Tasmania on 40m with my 12.4 DX Comander.
Top banana!
Hey the Bill... Good to see YCARS represented!
You mean the person in Tasmania heard you with a 5 element beam 100ft above the ground, it wasn't the DXCommander doing all the work
@@Andydigital80 he was got his signal there correct? Yes heavy lifting from Tasmania but still got is signal there
@@FromthehamshackwithNJ4ZI got Tasmania with an EFHW and 50 watts i.e. not a vertical, it’s the propagation that makes the biggest difference. Same antenna got me into New Caledonia with 100 watts just a week or so ago when Intermediates got the power increase.
What he said was good reading, but your antennae work great!
Sorry about that!
@@DXCommanderHQ keep being Cal and The DXCommander!! Love it!
Dear Callum! I have a 5w transceiver and I can raise the center of my dipole around 12 meters high and tie the ends to nearest trees with long ropes. The three options I have is almost straight dipole, inverted V and a vertical with extending the wire from the top to the side. I am not able to make any kind of yagi, nor frame antenna. Is there any way to concentrate the beam for DX by adding some amount of wire on the ground to use as a reflector/director, or to make the ground more reflective just like the salty water/soil? What area of salty water/soil under the antenna is playing the role in such reflecting effect?
OK.. make another element and fit it 6-10 feet BEHIND your driven element.. In effect, make a 2 element vertical Yagi. It will be in a fixed position though.
@@DXCommanderHQ Thanks, I will try that. I really want to reach USA someday
Callum can i ask, could you optimise recieve through a yagi by tilting it up 5 degrees rather than mounting horizontal to the ground to get maximum gain along the elements? Rather than the signal hitting the antenna top down it would travel in from the end cleaner/more effectively. This would be a good experiment. Thank you regards Steve M6WVV aka Enthusiast Steve
Wow.. I am JUST about to do a vid on this Steve. Stay there!
Great minds think alike 😁👍
Tnx Callum.. Cheers and 73 de SM3TEK
Any time!
Is there a way to measure or lookup the actual soil conductivity for your location, or is it mostly guesswork?
Very good question.. You *can* buy a soil conductivity meter. The problem is that some are HUNDREDS and some are cheap.. I might buy a cheap one and do some experiments.. I did also ask ChatGPT if I could home-brew one.. That was an interesting discussion too!
There are charts and maps online here for the US, but it is not specific to any one area. It is more of a generalization. Soil in one area can be good and 30 meters away can be crappy. .
@@DXCommanderHQ - As an electrician we often have to use earth stakes out in the sticks where I live for earth continuity back to the transformer. When measuring this you can guarantee when we have had a load of rain you get much lower resistance readings.
Do you think that the take off angle can be disregarded if you wind the power up to a 1000W or more? Just asking for a friend in GB. 🙂
In all seriousness, the lower the better (in the main!)
In fairness to him. He did to a very good video about air fryers.
Oh fine.
Well, just to add my opinion to the debate.
Undoubtedly low angle signals do exist, there is a multitude of research into transmission and reception of signals at very low angles, However, the more observant among you will have noticed that that the argument put forward by PW regarding attenuation/cancellation of low angle signals was in relation to ground mounted verical antennas over average ground, again, much research has been conducted on this matter, and appears in both ARRL and RSGB publications; the response came in the form of comparing apples and oranges; a yagi at 1/2 wavelength and above has a completely different interaction with the surrounding environment than a ground mounted vertical.
The way I am thinking after seeing both vids and reading publications on the matter is that both arguments are correct for the type of antenna being referenced.
Your opinion is valued.
what happens to the radiation of the antenna if i orientate the antenna at an angle to the ground? how does the radiation angle to the sides change?
BRILLIANT question.. Please look out for a video next week!
I had a QSO from Buffalo to Fiji tonight on FT8, 10w, ocf dipole 20' in the air. Almost 8,000 miles. Am I to assume my radiation angle was around 5*? 10m band
No, not really.. SOME of your energy will have been at the appropriate angle to reach Fiji. COuld have been 2 degrees or 9 degrees.. Approximately 99.99% of your signal would have been comopletely wasted. Actually, more like 99.999% :)
Linux.... thats my free software of choice... along with some Apache lol :D
I hope to get my new expedition together this weekend... (just have to drag it out of my shack and down to my garage, and its been cold and wet in Seattle) 73's
Yes, I was goijng to mention some Unix variants but having no experience in that field, I left it up to you.
Still wanting 5 degrees and having a maximum of 15 degrees means the most effect is still at 15 degrees wherever you want or desire.
Incorrect.. The most GAIN might be 15 degrees - but your signal might be actually be best at 2 degrees, 8 degrees, 17 degrees etc.. Your antenna will still radiate.
That is what I say, most power where the lobe is.
But the DX signal is not at that angle of arrival - meaning that when you have a DX contact it is not at the highest gain angle of your antenna - it still works though but as you say at a lower "power". Hence we want to get the lobe down low if we can for DX. That's all we are talking about. @@haraldlonn898
6:12 How did they work out the angle at which the skip was occurring? It is on this assumption that the whole experiment depends.
I'll find the link.. It's complicated!
Free software Cal you put me onto station master and it's an excellent logger and all in one HF toy for digital/SSTV
1) A good majority of long-haul DX arrives at a low angle (as Callum says)
2) There is an advantage if your antenna is able to hear/transmit at these low angles. This is why stacked Yagi's are designed to enable selection of the correct angle according to targeted DX.
3) Also why having a high conductivity ground plane (e.g. by the sea) results in an increase in gain at the lower angles desired (and it is spectacular and great fun).
4) The Pseudo Brewster angle is irrelevant for ground-mounted verticals of 1/4 wave length - that's just trigonometry, not RF science. www.arrl.org/files/file/QEX_Next_Issue/2016/March-April2016/Zavrel.pdf
5) Measuring and comparing gain numbers at a particular angle is just that - a comparison.
6) Modern (free!) software has the ability to calculate and incorporate these variables.
7) Most ham radio enthusiasts have an average ground, some wire in the air, vertical or horizontal at relatively low heights and it still works for them. The nuances of granular RF science are interesting but ultimately irrelevant for daily usage.
8) To imply that there is "no" radiation below the Brewster angle of any antenna is wrong - just plain wrong - (and is irrelevant in the case of ground-mounted 1/4 wave antennas see point 4)
Wow. Beautiful comment Tom.
I all ways say 5 to 7 degrees is the best thanks 73
Yes, not a bad idea.. Indeed!
Great vid, learned lots as usual but... WHERE DO I GET THE BANANA RULER?!
One of the kids got it for a "throw-away" for Christmas!
I am sure most of us have an inkling as to the other participant in this "conflict". A younger me would have sought a resolution, but that does not serve the science of radio well. As I understand it MMANA-GAL uses the basic maths engine of MININEC, dismissing it because it in the basic form it is free I believe is unfair. However I do accept that MMANA-GAL does not offer the facility to model things like a rotten wooden shed containing 6 rusty hacksaws and a Suffolk Punch that last ran in 1987 in the near field. 73
Depends when the lawn mower was last serviced - or whether it's parked N/S or E/W.
@@DXCommanderHQ my Black and Decker must be a true wildcard then :-)
This is all fantastic information, but I must correct you on one thing: the Earth is, in fact, banana-shaped. (With apologies to Terry Jones.)
I thought it was flat on the back of a turtle and some elephants. Apologies T. P. 🤔
Good point.. And seeing that I am a banana expert, I should have known!
That hand drawn diagram of a vertical with rf lobes 😂
Yeah.. STu pointed that out too! LOL
At the end of the day, whats 5% between mates, its a great hobby anyway, and if you enjoy software or not, your time on the air is probably enjoyable.
Yes.. Just make it happen! :)
I visualize an explosion ,in the atmoshere and the atoms are like dominoes transfering the energy to its nieghbor and the propagation is like a hand grasping a baseball where there places the fingers reach and some places not effected at all depending on the path of least resistance ,hf is more like vhf ducting than it is hopping ,i dont believe in the double hop ,thanks callum
Beautiful!
I've seen this before, where good men who have some good things to say on the subject eventually run out of RUclips material, and either start making controversy to keep momentum, or start to just make things up. It is a sad thing to see, certainly more tragic than the RUclips channels that never knew a single thing to begin with. Better to correct them and try to correct the path....
As a side note on ground conductivity, I'm surprised to hear that 5 millisiemens/milliohms is considered "average". I suppose that can change place to place, and the big FCC map on ground conductivity in the US shows a vast difference in ground throughout the country. I suppose, like all due diligence, each operator should look up his own to be better informed.
I'm land locked, literal center of North America. However, we have 30 millisiemen/milliohm ground, and I credit this with some of the success I've had as a station. Beyond better return ground, it provides better far field, and ground wave is a well known thing here for 80 and 160. It is an interesting topic in and of itself.
I am considering buying a ground conductivity meter.. Fascinated by it.. PS - There's no fight, just different polite opinions.
Lord Callum knows the angle of his dangle.
Oh yes.
please explain the minus and positive issue.....please
There's no issue.. It's a reference-point. LKet me point you to another video and see if I can assist.. OK.. skip to about 3:05 of the following video: ruclips.net/video/ZZWzyypqqjM/видео.html
0dBi is equal in gain to an isotropic radiator at unity gain power,. +dBi is a gain over an isotropic radiator in a direction, -dBi is a loss of power in a direction compared to an isotropic radiator. dBd is comparison with the antenna in test over a dipole antenna at 1/2 wavelength in height.
So minus is bad and plus is good simply put, so how can a radiator with a minus figure be better, to be better is it the angle of take off ?@@FromthehamshackwithNJ4Z
thanks i watched that a while ago, its just the use of plus and minus. You are talking to someone who cannot understand 3.142 where does the remainder go ? into your "bananas". Cheers matey@@DXCommanderHQ
All my computers run on almost 100% free software. Also when someone produces a piece of software for free it is usually because they have a genuine interest in the software and what it does and usually use it for then own needs. We can all be paid to work on something we have little to no interest in.
Good point!
Told you 😂
I just run my center connector from the coax right to my ground rod. Works mint,,,,, at making the earth worms come to the surface.
HAHA! Actually, a customer reported to me that all his moles left the area after he installed his DXC antenna..!!
Cyprus 2200 miles from UK
Perfect!! Under that 2,500 mile hope then.. Haha!
We are ready to rumble
73´s DH1KJ
I have to deal with that many rules regs and BS during the week, sometimes it’s nice just to switch it on tune it up and talk. Hey, but that’s just me.
Do it...! Thank goodness for folks like you :)
Callum goes to Cornwall for his millisiemens 😉
My friend 😂