The good thing about the vertical EFHW is that as you only need a small piece of the coax as radial/counterpoise, you can more easily place it higher on the mast. Try putting the half wave up a 12m mast and you gain 3dB. Not much, but it is an improvement over the vertical at ground level
During the Dxww contest a few months ago I made a 10 meter contact to reunion island from northern Illinois which is approximately 10000 miles. My setup was and still is a 5/8 gainmaster roughly 2 meters above average ground at the base, 250 watts, 50 feet of lmr 240 coax and a yaesu ftdx 1200. Couldn’t be happier. What an amazing antenna.
I did an experiment with circular radials on VHF. Effectively a spiral. Came out straight and then formed a circle. Really did work. No maths to back it up though.
That's a timely video for me Cal. Co-incidently built M0MSN Mike's GainMaster today but slightly altered for 28.5 MHz. I will be testing on a 12 metre pole tomorrow so have the option of raising the antenna to half a wave length off the ground. This video suggests that that is a good idea. Thanks. Thanks also for the QSO on 40m today.
I have been playing with a 3/4 wavelength 20 meter inverted-L, 41 feet is vertical and the remainder horizontal. I have four 16 ft. radials and four 33 ft. radials. The VSWR is good at 20 meters and since there is no matching networks, I use it on 17, 30 and 40 with a tuner. I am quite happy with the performance on 20 and it actually peforms decently on 30 an 40. My plan is to make this a pernament antenna with a better ground plane under it.
Love these type of videos Cal, I learn a lot from them, also your pondering on things too. Hoping to do some more experimenting with my set up again sometime fairly soon.
Really useful. Downloaded this software and another a while back but till a little intimidated by it, but your explanations here were helpful. Just waiting on the heatwave here abating (Brummies who lived in Scotland do not like 40 C) to start experimenting with my new DX Commander Classic. Going to try a Rybacov first. Excited!
In the early 1980s we ran a 5/8 vertical on 20m (41ft) with 16 radials. Ran 25w SSB. Worked really well, even a few New Zealand - UK contacts. However recall sunspots were in our favour way back then. We then had children, grandkids. All left home now. Might get back into it again.
Thanks Calum! Always great stuff. I'm getting ready to build a ½-wave (actually, .47-wave) tubing vertical for 20m, using a 49:1 unun and a relay box. With unun in circuit: ½-wave for 20m. With unun out of circuit: ¼-wave for 40m. Yes, I will use radials for the ¼ wave, and they will improve th ½ wave a bit too. 73 from west Texas!
When I was a CB'er here in Tennessee in the 1980's; a couple of fellow CB's had Sigma 4 3/4 wave antennas. These antennas are about 26 feet tall. I had a Maco 5/8 which was about 21 feet tall. I actually did better at local communication but the guys with the Sigma 4's did better at DX (we called it "skip shootin') 😁
Yes, isn't that interesting.. I have tried to fully comprehend the Sigma 4.. It might be that the BEST gain was very slightly above the zero degrees mark and perhaps peaked with higher-gain, but at just the right angle.. Very interesting.
Calum, great video. I would be interested in seeing the numbers for raising the feed point 12", 18" and 3' above the ground. All to be compared to a ground mounted feed point height. These are practical heights for raising the feed point for improving radiation patterns and gain for both permanent installations at home and portable installations. I believe Rudy Sevrens has as part of his published articles that raising the feed point 12" above ground level has a significant positive impact on radiation performance. I think your 5 degrees off the horizon as a baseline is right on the money. Great videos. KZ4FF Steve
Yes.. Next year, I'm going to do my own experiments in this regards.. Rudy did say there were some caveats on the elevated radials.. For the life of me I can't remember what they were now but I think sometimes we worry too much about the "numbers". I think the "maths" works out but the quality of or radios and ears probably don't care too much about 1dB etc..
Thanks Callum. As always, something interesting and informative delivered with enthusiasm and energy! , P.s. re your comment about the spreadsheet language l once changed a hand held programming language accidentally to Chinese. That was fun!
Thanks for the demo! From one who has used EZNEC exclusively MMANA is a lot more refined IMO. More demos would be appreciated. Trying to figure out how to add and space wires.
Hallo Calllum speaking about long antennas you never mentioned and extended double Zepp. 6.25 meters is 5/8 on 10 meters but 6.25 meters x2 is an extended double Zepp for 10 meters with about 3db of gain. It also happen that a 6.25x2meters antenna is a 5/8 antenna center fed on 20 meters. Feeding this antenna with ladder line and in a vertical fashion should give an advantage as a multiband antenna . Since this is not a resonant antenna a 6.25 metersx2 through a 6.5 meters x2 vertical antenna should be a great vertical antenna. To make it single band and using coax a 1/8 parallel line could be connected to a 50 ohm coax and make it a simple collinear 10 meters antenna.
Very interesting Callum, thanks 🙂 I guess that a disadvantage of long verticals is on receive; I suppose the big high-angle lobes will pick up a lot more natural (cosmic) noise on HF.... especially considering that it is arriving through much less of the absorbtive D-layer, than at low angles. Would be interesting to evaluate! On the other hand, perhaps most peoples' noise is dominated by man-made, unless they are out in the lovely country like yourself! 😀
@@DXCommanderHQ Yes, I guess for most people, man-made noise will dominate. Although interesting to note that, in the reference below, Fig.10 shows cosmic noise (field-strength) being several dB above quiet rural noise at around 28 MHz: www.earth-prints.org/bitstream/2122/3674/1/11bianchi.pdf
hey callum another great video please keep up the great work ...i have a question unrelated to this video ???? what does a faraday cage REALY do is it worth all the trouble to make one maybe you can make a short video about it there is to much information about it on the net ...what should we believe seems like they all say something different about there usefullness lol
The only reason you would need a Faraday cage is to put something inside to stop it radiating, like a microwave. Maybe I got the wrong end of the stick..
Love your enthusiasm for antennas. I have seriously thought about getting a 5/8th wave CB antenna for the 10 meter band . Looks like it could provide some useful gain . Rob 2E0GQL
Good argument for 5/8 - at least on 10 meters where it is practical. But .. what did happen to the SWR ? I see the same crazy numbers when attempting to model an elevated vertical.
Good video Cal. I came across a video of a guy building a 5/8 over 5/8 for I think 140 od MHz. He used a 1/4 wave spacing between the two and wound a 1/2 wave length of copper to join the two elements together so it was 180 deg. Out of phase. By all reports it works very well. Couldn’t understand a bloody word he said. ( Asian ). Mite be worth a go on ya computer. Cheers cock. 👍🇦🇺🥃
Commercial repeater antenna do this, think partial inflated tire intertube squished flatter from the top , narrower vertical beam width in all directions
Complicated subject. Most large contest stations do not use verticals above 40 meters. They always can do better with horizontal antennas. The exception is if you can’t get that horizontal antenna “high”. All contest stations (good ones) do use verticals or some form of vertical on 160 meters. Almost no one can get “high” on 160 meters because we are talking 270 feet for only a half-wave! 80 meters is the lowest band where it is possible to get “high” but it’s expensive and labor intensive. So some form of vertical as in conventional half square or 4 square. With the 4 square you change directions with the flip of a switch whereas you need maybe two half square antennas for good coverage. 40 meters is where good contest stations with moderate towers go to Yagis and guys like me ( tired of working on towers) go with phased verticals or dipoles at 65 feet. Being on salt water tips the scale to phased verticals! Your videos always make me think and I enjoy them!
I've messed with MMANA before, but figured I'd follow along just for practice. Your elevation in the far field screen is 27.6, but mine is 23.9, and I can't seem to change it in a way the calculator actually uses it. I get the same SWR, but different dB at 5°.
@@DXCommanderHQ Any screen with inputs that you captured to show in the video, I made those inputs match. There's gotta be a setting buried somewhere, but I can't find one.
@m0mcx what email am i sending to? I was most interested in the radiation pattern from a vertical dipole vs horizontal configuration and the heights. I downloaded MMNA GAL the other day but need to practice with it more. I am in the process of attempting to make a 40, 20, 10 meter "fan" dipole... was going to do 40 flat and 20 and 10 inverted off the same feed point. I am looking at a 66 ish foot feed point for 40 meters so my legs on the other 2 bands will still be quite high... if a vertical will do about the same i am unsure on how this would perform in its radiation pattern. I like the DX commander antenna design and am unsure if it would be better to just do a vertical. A tiny bit more explanation on the x(1,2) and y(1,2) and z(1,2) would help a tad too if u think about it in your next few videos? (If you have videos about vertical vs regular dipole in similar configurations please link?)
Why don't you fly over to Oregon to see Rudy Severns N6LF? Take a couple of cameras and a DX commander for him. Set up a patreon or gofundme and I'm sure many of use would chuck in a few quid to go towards the costs. Would be a perfect way to archive the views on his science for future budding amateurs. Would be a shame to lose his wisdom over a few emails rather than get his thoughts down on tape (or SD card!) :-)
Hey Mate, You aren't writing with a drum stick there. lol And by the way Did you try a 7/8 wave to see what would happen? I run 2 verticals here with a co-phasing harness made from RG-11 and a T connector into a run of LMR-600 to the shack. The verticals are the original Avanti Sigma 4's at 75 feet. And they deem to beat the 3 element beams pointed to Australia by at least 1db when I switch them. de W4DRA
I know I'm a little late to this game, but, how would you stack two or three verticals? Is coax mandatory for the hire up ones? Very curious. Thinking about stacked vertical kite antenna. Thanks very much.
Great video, interested in the phased pair, but side by side. Or is that classed as out of phase, I can't remember now. I've seen a guy on YT years ago down under on CW next to a beach. I can't remember his name and I'm certain he said it was directional. Just wondering what it would be like for 10/11m for a out and about antenna? Regards
Callum, Have you experimented with a random length (nonresonant) vertical configuration? Popular in a horizontal configuration, there are nonresonant values that would make a vertical arrangement practical but necessitate a matching circuit.
Yes I used to have an SG450 (I think that was the model) which matched anything. Never noticed a difference really.. Not scientific but lots of hassle for no real-world gain in my opinion.
@@tphilpin i tend to agree with the 43ft suggested by Pete above, at least for 60m through to 20m (even 80m at a pinch with pretty thick wire)... and 20 feet for the 17m to 10m bands. Only two elements (you would need to switch them) and an ATU at the bottom, with comprehensive radials, and presto! For non high-power stations, I wonder whether that is a more cost-effective configuration.
Can we have some parameters that define "better" please? Easier to match? Higher gain? Less current at the base? Do you want those nasty high lobes that appear past 1/2 wave? Is it wider Q you want? Etc etc....
question. For example, I make a vertical antenna for 40 and 20. like the antenna you offer, and I make I instead of 8 (radials 4 for 40 and 4 for 20). 8 radials with, for example, a tap on them all, so that one length of the radial is suitable for 40 and the tapped part is made suitable for 20 meters. So basically a combined radian. (the antenna sizes are randomly chosen). in fact, this also happens with youre radiators, right? PS. Informatief channel. 73 Marcel pd1mm.
Good evening everyone, quick question. Watching Cal's videos, when he models various antennas, several of them have negative gain, such as -5db. If someone was to feed 100W into a -5db gain antenna, what would effective power be? I assume 0db gain would be 100W effective, and +3db would be 200, so what would -5db be? Thanks
OK.. Honestly.. this is just a number. The "minus" bit is comparable to another. And frankly MOST antennas measure MINUS something at 5 degrees off the horizon. It's a fine number. The ERP would be around 30W. Sounds shit right? It's not.
The gains that Callum are showing are dBi. The i is important. That tells you what it is referencing it to. In this case, it is -5dB down from a theoretical isotropic radiator - one that radiates equally in all directions and elevations. Apart from the Sun, isotropic radiators don't really exist. Keep in mind that of the 100W you're putting into your antenna, the effective power making it to the person you're talking to is generally only nanowatts or picowatts. The rest of the power is zooming off in other directions or heating up your coax, antenna or the ground. Even an S9 signal is less than 100 picowatts at the other end. So what that -5 tells you is at that particular elevation, the antenna is putting out 5dB less power in that direction from what an isotropic antenna would be doing.
Another thought: Those highish-angle lobes, on 10 metres, could offer an interesting experiment for short-skip meteor-scatter? I tried MS once on 10m with a modestly-equipped Belgian station, and we completed in about 2 minutes! I guess that it would probably need a major shower for the high-angle stuff to show up in any useful quantity. If anyone is interested in doing a test, during one of the showers, let me know! Could be fun actually seeing the meteors which are pinging for us! 😀I'm in south Oxfordshire; anyone, in the range of about 100 to 300 miles from me, could be in with a ping!
Interesting. I have a question...perhaps you know the answer (?). A center-fed dipole is said to be 75 ohms impedance. Can it be fed off-center...or modified somehow... and match to 50 ohms?
A center fed dipole is only 72 ohms impedance (1.44 SWR) in free space (many wavelengths above ground). As it gets closer to the ground, impedance varies between 50 and 100 ohms in a diminishing sine wave pattern (see chart in link 1. Beware, that chart mislabels X graph, 3/2wl should be 3/4wl). Off-center feeding dipoles will only raise impedance, as the center point of a half wave dipole is highest current (and therefore lowest impedance). You can however take a center fed dipole and lower the ends to reduce impedance. A 90 degree inverted V dipole in free space will have around 50 ohms impedance naturally. See graphs in link 2. There is no simple answer, because actual impedance will differ from theoretical impedance depending on height above ground and proximity of other objects nearby. But fortunately, trimming dipole length to achieve close to 1.0 SWR is all we have to do to ensure a good impedance match! www.electronics-notes.com/articles/antennas-propagation/dipole-antenna/dipole-feed-matching.php www.hamuniverse.com/w5altinvertedvdipole.html
A resonant center fed dipole is usually around 70 ohms, so it is already not far off. If the ends are angled down, the impedence is reduced. At 70 ohms, the SWR would only be 1.4:1. 1.5:1 is a 3% loss and 2:1 is an 11% loss, so at 1.4:1 it's not bad.
That's the purpose of an inverted V. If you lower the ends of the dipole towards the ground, it lowers the feed impedance. At the right angle/height, it'll be 50 ohms.
Impedance varies with height above ground. It finally settles down at around 70 ohms (apparently) but I've never seen 70 ohms myself. ANd you can move the feedpoint slightly but the impedance would normally rise. Frankly you would never notice so we don't need to worry about it too much.
That isn't dB, that dBd. dBi is dB compared to an isotropic radiator (a theoretical antenna that radiates equally well in all directions - they don't exist). dBd is compared to a 1/2 wave dipole. A dipole has 2.15 dB gain over a theoretical isotropic radiator.
Some recent testing revealed that increasing the number radials, up to 16 radials can increase gain significantly, more than 16 radials does not. 1/4 wave and 5/8 wave antennas respond to radials, while 1/2 wave antennas don't respond much to radials. Besides not gaining much low angle gain with a 1/2 wave antenna, a 1/2 wave can suffer the most from ground loss, compared to 1/4 wave and 5/8 wave antennas. The ideal height of elevated 1/4 wave and 5/8 wave antennas is at least one antenna above the ground to the bottom of the antenna. To minimize ground loss with a 1/2 wave vertical, it needs to be at least one full wavelength above the ground to the bottom of the antenna. Antennas longer than 0.65 wavelength long begin to increase their radiation angle and lose their low angle radiation. Elevated 1/4 wave antennas can increase gain with sloping radials, but 5/8 wave antennas have best gain with 90 degree, flat radials. A 10m 1/4 wave, when elevated should be at least 8 feet above the ground. A 10m 5/8 wave when elevated should be at least 20 feet above the ground. A 10m 1/2 wave should be at least 16 feet above the ground. Radials don't help the half wave's gain much, but might help with frequency range.
@@BrandonLeeBrown It depends. I get what Callum is trying to do here. When you're talking to your buddies at 20 over 9, none of this matters in the slightest. You can take a horrendous 20 dB loss and you're still talking to them just fine. So don't worry about it. But when you're working that weak DX, or a mobile, or a QRP station who is just above the minimum discernible signal level, a couple of dB is the difference between making the contact and not. There are instances where these small changes make all the difference. I work weak signal modes and in that realm none of the signals make the meter move at all. Half an S unit is HUGE at those times.
@@stargazer7644 A change of one S unit of signal require a change in gain of 6 db. There was a study conducted not long ago, that found little difference after 16 radials, including doubling that to 32 radials. if contact can't be made with 16 radials, it's not going to happen with 32 radials. There just isn't change to make any difference on the air.
@@BrandonLeeBrown Oh, well then how many dB do you think is necessary to make a difference? 1dB? 3dB? 6dB? 20dB? The answer is, if the signal you're trying to copy is 1dB below the S/N needed to make the contact then any change that gets you even a single dB WILL ABSOLUTELY make the difference. This is what you don't seem to be grasping. You're right, small changes make no difference with big signals. But they make a huge difference with weak ones. In weak signal work people spend THOUSANDS of dollars just for a dB or two more. Your world view is not the only one. Look at the money people spend to put up a tower with a tribander. That only gets you about 6-7dB over a dipole. One lousy S unit. That can easily be a $10,000 investment. Why do people do it? Because even that one S unit makes a lot more contacts possible. All else being equal, one S unit DOUBLES the distance you can work stations.
The good thing about the vertical EFHW is that as you only need a small piece of the coax as radial/counterpoise, you can more easily place it higher on the mast.
Try putting the half wave up a 12m mast and you gain 3dB. Not much, but it is an improvement over the vertical at ground level
There’s a bit of a dead spot from 0.85-1.15 wl long for low angle gain. But it just shows what can be done with longer verticals.
Yes.. Agreed. As you and I say in the UK Tim, "Horses for Courses". See how fast it takes for Peter to copy it :)
@@DXCommanderHQ 👍🤣🤣🤣
During the Dxww contest a few months ago I made a 10 meter contact to reunion island from northern Illinois which is approximately 10000 miles. My setup was and still is a 5/8 gainmaster roughly 2 meters above average ground at the base, 250 watts, 50 feet of lmr 240 coax and a yaesu ftdx 1200. Couldn’t be happier. What an amazing antenna.
Please do more tutorials on mmana. Enjoy your videos
Will do!
I did an experiment with circular radials on VHF. Effectively a spiral. Came out straight and then formed a circle. Really did work. No maths to back it up though.
Interesting..
Her indoors calum always says longer is better and she does'nt ever touch my radio equipment 😉😉😉 have a good weekend sir
That's a timely video for me Cal. Co-incidently built M0MSN Mike's GainMaster today but slightly altered for 28.5 MHz. I will be testing on a 12 metre pole tomorrow so have the option of raising the antenna to half a wave length off the ground. This video suggests that that is a good idea. Thanks.
Thanks also for the QSO on 40m today.
Excellent!
Awesome stuff Callum... The vertical phasing is quite interesting. I have a sirio M400 10meter vertical at about 6meters. it does a good job.
Very cool John.. Need to book a Live with you sometime.. You are in the book..!
I have been playing with a 3/4 wavelength 20 meter inverted-L, 41 feet is vertical and the remainder horizontal. I have four 16 ft. radials and four 33 ft. radials. The VSWR is good at 20 meters and since there is no matching networks, I use it on 17, 30 and 40 with a tuner. I am quite happy with the performance on 20 and it actually peforms decently on 30 an 40. My plan is to make this a pernament antenna with a better ground plane under it.
Love these type of videos Cal, I learn a lot from them, also your pondering on things too. Hoping to do some more experimenting with my set up again sometime fairly soon.
Please do!
Great episode! I love that I had seen the ep on radials so really understood that part.
I’d love to see more about stacked verticals and phasing.
Noted!
Excellent video. I'm starting to experiment with a monoband 3/4 wave vertical for sporadic E working just need the E's now
Good luck!
Really useful. Downloaded this software and another a while back but till a little intimidated by it, but your explanations here were helpful. Just waiting on the heatwave here abating (Brummies who lived in Scotland do not like 40 C) to start experimenting with my new DX Commander Classic. Going to try a Rybacov first. Excited!
In the early 1980s we ran a 5/8 vertical on 20m (41ft) with 16 radials. Ran 25w SSB. Worked really well, even a few New Zealand - UK contacts. However recall sunspots were in our favour way back then. We then had children, grandkids. All left home now. Might get back into it again.
Sure, do it :)
If you interview with Ron Burgundy for a spot on the news team, remember to answer Yes to owning a trident. Great video!
Thanks Calum! Always great stuff.
I'm getting ready to build a ½-wave (actually, .47-wave) tubing vertical for 20m, using a 49:1 unun and a relay box. With unun in circuit: ½-wave for 20m. With unun out of circuit: ¼-wave for 40m.
Yes, I will use radials for the ¼ wave, and they will improve th ½ wave a bit too.
73 from west Texas!
When I was a CB'er here in Tennessee in the 1980's; a couple of fellow CB's had Sigma 4 3/4 wave antennas. These antennas are about 26 feet tall. I had a Maco 5/8 which was about 21 feet tall. I actually did better at local communication but the guys with the Sigma 4's did better at DX (we called it "skip shootin') 😁
Yes, isn't that interesting.. I have tried to fully comprehend the Sigma 4.. It might be that the BEST gain was very slightly above the zero degrees mark and perhaps peaked with higher-gain, but at just the right angle.. Very interesting.
Great stuff. So much easier to understand with the visuals of the software. Thank you.
Would like to see the same thing but with a horz wire antenna. Good job.
I love the guitars on the wall. I have two in my radio shack but i cant play them beyond three blind mice in jazz fusion style. They look good though.
Three Bliond Mice? I can do Mice and Blind but not in the right order!
Calum, great video. I would be interested in seeing the numbers for raising the feed point 12", 18" and 3' above the ground. All to be compared to a ground mounted feed point height. These are practical heights for raising the feed point for improving radiation patterns and gain for both permanent installations at home and portable installations. I believe Rudy Sevrens has as part of his published articles that raising the feed point 12" above ground level has a significant positive impact on radiation performance. I think your 5 degrees off the horizon as a baseline is right on the money. Great videos. KZ4FF Steve
Yes.. Next year, I'm going to do my own experiments in this regards.. Rudy did say there were some caveats on the elevated radials.. For the life of me I can't remember what they were now but I think sometimes we worry too much about the "numbers". I think the "maths" works out but the quality of or radios and ears probably don't care too much about 1dB etc..
Thanks Callum. As always, something interesting and informative delivered with enthusiasm and energy! ,
P.s. re your comment about the spreadsheet language l once changed a hand held programming language accidentally to Chinese. That was fun!
Oh heck!
Thanks for the demo! From one who has used EZNEC exclusively MMANA is a lot more refined IMO.
More demos would be appreciated. Trying to figure out how to add and space wires.
I've done a few vids on the subject.. Have a cruise around YT..
@@DXCommanderHQ Thanks! After a few hours of tinkering I figured out how to make it play.
Hallo Calllum speaking about long antennas you never mentioned and extended double Zepp. 6.25 meters is 5/8 on 10 meters but 6.25 meters x2 is an extended double Zepp for 10 meters with about 3db of gain. It also happen that a 6.25x2meters antenna is a 5/8 antenna center fed on 20 meters. Feeding this antenna with ladder line and in a vertical fashion should give an advantage as a multiband antenna . Since this is not a resonant antenna a 6.25 metersx2 through a 6.5 meters x2 vertical antenna should be a great vertical antenna. To make it single band and using coax a 1/8 parallel line could be connected to a 50 ohm coax and make it a simple collinear 10 meters antenna.
Gain.. Yeah but off the ends.
Very interesting Callum, thanks 🙂 I guess that a disadvantage of long verticals is on receive; I suppose the big high-angle lobes will pick up a lot more natural (cosmic) noise on HF.... especially considering that it is arriving through much less of the absorbtive D-layer, than at low angles. Would be interesting to evaluate! On the other hand, perhaps most peoples' noise is dominated by man-made, unless they are out in the lovely country like yourself! 😀
Interesting.. I don't think the basic cosmic noise we need to worry about much.
@@DXCommanderHQ Yes, I guess for most people, man-made noise will dominate. Although interesting to note that, in the reference below, Fig.10 shows cosmic noise (field-strength) being several dB above quiet rural noise at around 28 MHz: www.earth-prints.org/bitstream/2122/3674/1/11bianchi.pdf
Would be interesting to see a standard half wave dipole mounted vertically in the group for comparison. Thanks!
Oh yes.. SImilar to that moster I built.. But obviously lower down.. OK, later this year we can do that.
Contesters really dislike rotators. Prefer stacks on a switch. So much faster! Would be nice to have a 40m vertical up 20m high though😂
hey callum another great video please keep up the great work ...i have a question unrelated to this video ???? what does a faraday cage REALY do is it worth all the trouble to make one maybe you can make a short video about it there is to much information about it on the net ...what should we believe seems like they all say something different about there usefullness lol
The only reason you would need a Faraday cage is to put something inside to stop it radiating, like a microwave. Maybe I got the wrong end of the stick..
great stuff... all nmakes you think... thanks Cal...
Quite good OM, amazing teaching skills. Have you made a video of slowly raising the bottom of the vertical until it is horizontal? W1KRI~Keith
Not yet! Need a thumbnail and appropriate title - but it sounds like fun!
Very interesting stuff. Thanks for doing this !
Love your enthusiasm for antennas. I have seriously thought about getting a 5/8th wave CB antenna for the 10 meter band . Looks like it could provide some useful gain . Rob 2E0GQL
CB antennas on 10m band are excellent.
Brilliant info as usual Professor Callum. 😁👍
Thanks 👍
Good argument for 5/8 - at least on 10 meters where it is practical. But .. what did happen to the SWR ? I see the same crazy numbers when attempting to model an elevated vertical.
Once you are about 1 wavelength over ground, raising the height doesn't affect the impedance.
I am so glad I found you again. I thought I was subscribed .... I am now!
Welcome back :)
Good info Callum. Thanks for you're time.👍🏽
Easy :)
Great stuff Callum!! How is Rolly? Havent seen a video from him for a bit. 👍
Roly and I will be doing a stream soon..
Good video Cal. I came across a video of a guy building a 5/8 over 5/8 for I think 140 od MHz. He used a 1/4 wave spacing between the two and wound a 1/2 wave length of copper to join the two elements together so it was 180 deg. Out of phase. By all reports it works very well. Couldn’t understand a bloody word he said. ( Asian ). Mite be worth a go on ya computer. Cheers cock. 👍🇦🇺🥃
Commercial repeater antenna do this, think partial inflated tire intertube squished flatter from the top , narrower vertical beam width in all directions
One thing I'd be interested in Cal, if MMANA is programmed to model magnetic loops and what it would make of them?
Mag Loops.. I don't know if it has the mathematics..
Complicated subject. Most large contest stations do not use verticals above 40 meters. They always can do better with horizontal antennas. The exception is if you can’t get that horizontal antenna “high”. All contest stations (good ones) do use verticals or some form of vertical on 160 meters. Almost no one can get “high” on 160 meters because we are talking 270 feet for only a half-wave! 80 meters is the lowest band where it is possible to get “high” but it’s expensive and labor intensive. So some form of vertical as in conventional half square or 4 square. With the 4 square you change directions with the flip of a switch whereas you need maybe two half square antennas for good coverage. 40 meters is where good contest stations with moderate towers go to Yagis and guys like me ( tired of working on towers) go with phased verticals or dipoles at 65 feet. Being on salt water tips the scale to phased verticals!
Your videos always make me think and I enjoy them!
I've messed with MMANA before, but figured I'd follow along just for practice. Your elevation in the far field screen is 27.6, but mine is 23.9, and I can't seem to change it in a way the calculator actually uses it. I get the same SWR, but different dB at 5°.
Oh.. How strange. Wait - check your ground..?
@@DXCommanderHQ Any screen with inputs that you captured to show in the video, I made those inputs match. There's gotta be a setting buried somewhere, but I can't find one.
Yes please more detail!
More detail.. OK.. Drop me an email to remind my in which direction I need to go with the more data.. No problem.
@m0mcx what email am i sending to?
I was most interested in the radiation pattern from a vertical dipole vs horizontal configuration and the heights. I downloaded MMNA GAL the other day but need to practice with it more. I am in the process of attempting to make a 40, 20, 10 meter "fan" dipole... was going to do 40 flat and 20 and 10 inverted off the same feed point. I am looking at a 66 ish foot feed point for 40 meters so my legs on the other 2 bands will still be quite high... if a vertical will do about the same i am unsure on how this would perform in its radiation pattern. I like the DX commander antenna design and am unsure if it would be better to just do a vertical. A tiny bit more explanation on the x(1,2) and y(1,2) and z(1,2) would help a tad too if u think about it in your next few videos? (If you have videos about vertical vs regular dipole in similar configurations please link?)
Id love a flat 24-32mhz version ,can we see 27mhz or 29mhz line of sight fm operation of antenna Callum?
That is in the plan.. We need to fit the TS590SG back at the house.. We can do some reliable line-of-sight experiments..
Another great video! Always a bit of fun and learning! All the best from Texas! 73 de KI5HXM
Glad you enjoyed it!
Why don't you fly over to Oregon to see Rudy Severns N6LF? Take a couple of cameras and a DX commander for him. Set up a patreon or gofundme and I'm sure many of use would chuck in a few quid to go towards the costs. Would be a perfect way to archive the views on his science for future budding amateurs. Would be a shame to lose his wisdom over a few emails rather than get his thoughts down on tape (or SD card!) :-)
I'm tlaking to Rudy now. He has a crappy inrernet connection so I'm trying to work out how to get his answers...
Hey Mate, You aren't writing with a drum stick there. lol And by the way Did you try a 7/8 wave to see what would happen?
I run 2 verticals here with a co-phasing harness made from RG-11 and a T connector into a run of LMR-600 to the shack. The verticals are the original Avanti Sigma 4's at 75 feet. And they deem to beat the 3 element beams pointed to Australia by at least 1db when I switch them.
de W4DRA
Well, I'll bet they work amazing at that height!
@@DXCommanderHQ The distance between them is 5/8 wave or 21 1/2 feet. if I remember right.
I know I'm a little late to this game, but, how would you stack two or three verticals? Is coax mandatory for the hire up ones? Very curious. Thinking about stacked vertical kite antenna. Thanks very much.
That's advanced stuff and beyond a reply I am afraid..
Thanks Cal, these musing always make good videos.
Hey DOn. Yes, I rather like the muse-factor! :)
Cool vid! Thanks bro
Any time!
Great video, interested in the phased pair, but side by side. Or is that classed as out of phase, I can't remember now.
I've seen a guy on YT years ago down under on CW next to a beach. I can't remember his name and I'm certain he said it was directional.
Just wondering what it would be like for 10/11m for a out and about antenna? Regards
Side by side would make it directional. VERTICAL stacking decreases vertical beamwidth. Increasing range, narrow beam. Think squished donut.
Yes you can phase a pair.. It seems to give about an S point of extra gain and good f/b.
Callum, Have you experimented with a random length (nonresonant) vertical configuration? Popular in a horizontal configuration, there are nonresonant values that would make a vertical arrangement practical but necessitate a matching circuit.
43ft
Yes I used to have an SG450 (I think that was the model) which matched anything. Never noticed a difference really.. Not scientific but lots of hassle for no real-world gain in my opinion.
@@DXCommanderHQ Thought maybe you modeled it for radiation characteristics as an alternative to your antenna with multiple elements.
@@tphilpin i tend to agree with the 43ft suggested by Pete above, at least for 60m through to 20m (even 80m at a pinch with pretty thick wire)... and 20 feet for the 17m to 10m bands. Only two elements (you would need to switch them) and an ATU at the bottom, with comprehensive radials, and presto! For non high-power stations, I wonder whether that is a more cost-effective configuration.
@@timdbl7804 I hope to analyze such a configuration and determine how the two elements might interact and the low angle radiation power.
Can we have some parameters that define "better" please?
Easier to match? Higher gain? Less current at the base? Do you want those nasty high lobes that appear past 1/2 wave? Is it wider Q you want? Etc etc....
Make your own mind up. I showed you how to model it. Surely you don't ned a spoon? :)
@@DXCommanderHQ no I don't.... thanks.
question. For example, I make a vertical antenna for 40 and 20. like the antenna you offer, and I make I instead of 8 (radials 4 for 40 and 4 for 20). 8 radials with, for example, a tap on them all, so that one length of the radial is suitable for 40 and the tapped part is made suitable for 20 meters. So basically a combined radian. (the antenna sizes are randomly chosen). in fact, this also happens with youre radiators, right? PS. Informatief channel. 73 Marcel pd1mm.
sorry for any translation errors. it is written with a little help from google translate.
For a GROUND vertical, you can make your radials any size you want, don't worry about that.
Good evening everyone, quick question. Watching Cal's videos, when he models various antennas, several of them have negative gain, such as -5db. If someone was to feed 100W into a -5db gain antenna, what would effective power be? I assume 0db gain would be 100W effective, and +3db would be 200, so what would -5db be?
Thanks
OK.. Honestly.. this is just a number. The "minus" bit is comparable to another. And frankly MOST antennas measure MINUS something at 5 degrees off the horizon. It's a fine number. The ERP would be around 30W. Sounds shit right? It's not.
The gains that Callum are showing are dBi. The i is important. That tells you what it is referencing it to. In this case, it is -5dB down from a theoretical isotropic radiator - one that radiates equally in all directions and elevations. Apart from the Sun, isotropic radiators don't really exist. Keep in mind that of the 100W you're putting into your antenna, the effective power making it to the person you're talking to is generally only nanowatts or picowatts. The rest of the power is zooming off in other directions or heating up your coax, antenna or the ground. Even an S9 signal is less than 100 picowatts at the other end. So what that -5 tells you is at that particular elevation, the antenna is putting out 5dB less power in that direction from what an isotropic antenna would be doing.
@@DXCommanderHQ Thank you for the explanation Cal. I appreciate your reply.
@@stargazer7644 Thanks for your explanation. I appreciate you responding
can i connect ham radio to marine band antenna at the top of a 15 meter aluminum sailboat mast?
Yes.. It will work quite well on the 2m band which isn't so very far away from marine.
@@DXCommanderHQ thank you for reply going to buy a president richard, thats my chiice right now
Stacking/phasing decreases the vertical beanwidth, think squished donut.
Is it possible to exchange 10M in classic or signature 9 to 30M ??? Just keeping 80invL
Try it. I don't see why not.
@@DXCommanderHQ how in your opinion should bands be placed looking from SO-239 Clockwise... 80/ 30 /17/40/12/20 ??
Another thought: Those highish-angle lobes, on 10 metres, could offer an interesting experiment for short-skip meteor-scatter? I tried MS once on 10m with a modestly-equipped Belgian station, and we completed in about 2 minutes! I guess that it would probably need a major shower for the high-angle stuff to show up in any useful quantity. If anyone is interested in doing a test, during one of the showers, let me know! Could be fun actually seeing the meteors which are pinging for us! 😀I'm in south Oxfordshire; anyone, in the range of about 100 to 300 miles from me, could be in with a ping!
Fascinating!!!
Should work. Long wires become end-fire at higher frequencies, so it's basically a verticle end-fire.
Interesting. I have a question...perhaps you know the answer (?). A center-fed dipole is said to be 75 ohms impedance. Can it be fed off-center...or modified somehow... and match to 50 ohms?
A center fed dipole is only 72 ohms impedance (1.44 SWR) in free space (many wavelengths above ground). As it gets closer to the ground, impedance varies between 50 and 100 ohms in a diminishing sine wave pattern (see chart in link 1. Beware, that chart mislabels X graph, 3/2wl should be 3/4wl).
Off-center feeding dipoles will only raise impedance, as the center point of a half wave dipole is highest current (and therefore lowest impedance).
You can however take a center fed dipole and lower the ends to reduce impedance. A 90 degree inverted V dipole in free space will have around 50 ohms impedance naturally. See graphs in link 2.
There is no simple answer, because actual impedance will differ from theoretical impedance depending on height above ground and proximity of other objects nearby. But fortunately, trimming dipole length to achieve close to 1.0 SWR is all we have to do to ensure a good impedance match!
www.electronics-notes.com/articles/antennas-propagation/dipole-antenna/dipole-feed-matching.php
www.hamuniverse.com/w5altinvertedvdipole.html
A resonant center fed dipole is usually around 70 ohms, so it is already not far off. If the ends are angled down, the impedence is reduced. At 70 ohms, the SWR would only be 1.4:1. 1.5:1 is a 3% loss and 2:1 is an 11% loss, so at 1.4:1 it's not bad.
That's the purpose of an inverted V. If you lower the ends of the dipole towards the ground, it lowers the feed impedance. At the right angle/height, it'll be 50 ohms.
Impedance varies with height above ground. It finally settles down at around 70 ohms (apparently) but I've never seen 70 ohms myself. ANd you can move the feedpoint slightly but the impedance would normally rise. Frankly you would never notice so we don't need to worry about it too much.
@@BrandonLeeBrown Thanks...you're a wiz!
It's not how long your antenna is, it's how you use it. 😊
Is it dB of dBi? 0dbi is -2.15dB 😉 or is it a wrong conclusion?
That isn't dB, that dBd. dBi is dB compared to an isotropic radiator (a theoretical antenna that radiates equally well in all directions - they don't exist). dBd is compared to a 1/2 wave dipole. A dipole has 2.15 dB gain over a theoretical isotropic radiator.
It's irrelevant because we are comparinf one antenna in the same axium as another anyway. Bananas and Bananas.
Some recent testing revealed that increasing the number radials, up to 16 radials can increase gain significantly, more than 16 radials does not. 1/4 wave and 5/8 wave antennas respond to radials, while 1/2 wave antennas don't respond much to radials. Besides not gaining much low angle gain with a 1/2 wave antenna, a 1/2 wave can suffer the most from ground loss, compared to 1/4 wave and 5/8 wave antennas. The ideal height of elevated 1/4 wave and 5/8 wave antennas is at least one antenna above the ground to the bottom of the antenna. To minimize ground loss with a 1/2 wave vertical, it needs to be at least one full wavelength above the ground to the bottom of the antenna. Antennas longer than 0.65 wavelength long begin to increase their radiation angle and lose their low angle radiation. Elevated 1/4 wave antennas can increase gain with sloping radials, but 5/8 wave antennas have best gain with 90 degree, flat radials. A 10m 1/4 wave, when elevated should be at least 8 feet above the ground. A 10m 5/8 wave when elevated should be at least 20 feet above the ground. A 10m 1/2 wave should be at least 16 feet above the ground. Radials don't help the half wave's gain much, but might help with frequency range.
For some values of "significantly"
@@stargazer7644 Diminishing returns. Maybe able to measure, but not enough to tell a difference on the radio.
@@BrandonLeeBrown It depends. I get what Callum is trying to do here. When you're talking to your buddies at 20 over 9, none of this matters in the slightest. You can take a horrendous 20 dB loss and you're still talking to them just fine. So don't worry about it. But when you're working that weak DX, or a mobile, or a QRP station who is just above the minimum discernible signal level, a couple of dB is the difference between making the contact and not. There are instances where these small changes make all the difference. I work weak signal modes and in that realm none of the signals make the meter move at all. Half an S unit is HUGE at those times.
@@stargazer7644 A change of one S unit of signal require a change in gain of 6 db. There was a study conducted not long ago, that found little difference after 16 radials, including doubling that to 32 radials. if contact can't be made with 16 radials, it's not going to happen with 32 radials. There just isn't change to make any difference on the air.
@@BrandonLeeBrown Oh, well then how many dB do you think is necessary to make a difference? 1dB? 3dB? 6dB? 20dB? The answer is, if the signal you're trying to copy is 1dB below the S/N needed to make the contact then any change that gets you even a single dB WILL ABSOLUTELY make the difference. This is what you don't seem to be grasping. You're right, small changes make no difference with big signals. But they make a huge difference with weak ones. In weak signal work people spend THOUSANDS of dollars just for a dB or two more. Your world view is not the only one.
Look at the money people spend to put up a tower with a tribander. That only gets you about 6-7dB over a dipole. One lousy S unit. That can easily be a $10,000 investment. Why do people do it? Because even that one S unit makes a lot more contacts possible. All else being equal, one S unit DOUBLES the distance you can work stations.
Thought you was going to do a 80m or 160m antenna. 😂
We did the 12.4 and 18. They have 80m. Not got around to 160m yet. There's only one of me.
Tolles Video. Eine Software, die ich verwenden wollte. Danke DX-Commander 🤣
Google a "Franklin" antenna". 😎👍