Small, Cheap, Efficient Vertical Antenna for 40m
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- čas přidán 18. 11. 2023
- #hamradio #hamr #antenna #radio
Demonstration of a linear loaded 1/4 wave vertical amtenna that shows (at least) in modeling that it is as efficient as a full size 1/4 wave.
What do you think?
Let me know in the comments below. - Věda a technologie
That's great! I haven't tried a linear loaded antenna yet, but I love how you can get 40m with a smaller mast.
Thanks Mike. Probably be good for those in an HOA too.
Good Morning Master Colin! What a nice Video again. And everything you build looks so clean and proper. And of course because of your precisely Work the Final Product works as best possible. To me you are one of the greatest Antenna Builders without a Doubt. Keep up your fantastic Work as I am looking forward for your next Video Episode to come. Have a good new Week & 73 de Your Friend Uncle Günter, DK5ONV 💯🙋♂
Your comments always appreciated UG 🙏
I always enjoy watching your videos, seeing how enthusiastic you are about making new antennas and what a great job you do making antennas that have your signature touch. This is a great all-around design for those who are limited in space, especially if they’ve already got a 20m multi-band hex beam already sitting in the yard - it complements that setup perfectly. My only gripe with vertical, omni-directional antennas is the fact that they need so many ground radials and also that they are as good at picking up noise as they are at picking up signals, and ivy their very nature pick up a lot more noise than signal. It’s also a shame to be using so many wires and only have one band. You should do a video where you turn it into a fanned vertical. May as well since you’ve already got all those ground radials laid out.
I’ve got a home brew 40m EFHW strung diagonally across my not-so-large property up at 30ft and it does a very respectable job on 40, 20, 15 and 10 meters without a tuner, all bands with SWRs below 1.5. It would be interesting to compare it to this one 40.
Thanks for sharing your thoughts. Normally I use a couple of raised radials but used ground radials as I thought more would use those. I have run this as a 20/40 version so could make a video on that.
Excellent presentation. I've used a few linear-loaded verticals in the past with great results.
Thanks. Yes, they punch will above their weight IMO.
Great experiment Colin! In the past I have done the same sort of thing for a 40m vertical, but I used 450 ohm ladderline, shorted together at the top of a 7m pole and running back almost to the bottom. I also used ground radials and found a good match. Two suggestions if I may: 1) you can use a linear loaded raised radial or two at the same sort of length and this would probably equal or beat ground radials for efficiency ( even tack them to a fence). 2) Efficiency wise, having read up on W8JI's study on this, I think the linear loaded shorter version is likely to be a little down on the full sized 1/4 wave, but hey.. it works and when the band is singing we will all make some great contacts. 73 mate - great presentation.
Thanks mate, agree fully on your points. Normally I would use raised radials but used ground radials as thought more folks would use these, expecially for permanent installs. I dont beleive it will be "full" performance either but its a good compromise for the size 👍
Great work as usual Colin!
Thanks Chuck. Nice to be back making a video of what I enjoy most.
Good video Colin, linear loaded antennas as you demonstrate work very well on short masts, good up the good work mate.
Thanks, for a time I only ran 40m like this with good results.
Well done Sir, love the cleverness of the "T" top .. Thanks -N2QFK
Just some simple cheap components I managed to repurpose that work well like this.
I’m a great fan of linear loading as I am EFHW. Colin. Are to my rescue a few ago as my experiments with linear loaded whilst good lacked the sophistication of components Colin used. So I’m eternally grateful for the work he had completed which helped me on my linear loaded antenna journey. Great source of technical information who practices what he preaches. Thank you Colin 👍🏻 73 M0AZE Mike
Thanks Mike. I'm just glad I could help you in some way. I enjoyed getting this up and going again.
Hello Colin a more challenging version cloud be to make the antenna with elevated radials for Hams that do not have a garden to reduce their numbers. A more challenging version would be to use only two sets or radials in a plane, these radial could be connected in parallel and separated at the ends. Personally I only have a 6 feet wall to hang on my poles and antennas. Vince
Your spot on Vince. I have done this many times with a single elevated radial which has always worked well for me.
Cracking Video Colin - looking forward to your next one! M7MNP.
Thanks Martin 👍
A fascinating video as always. The SWR is suspiciously low, the resistive part of the impedance as you go through resonance should be lower. Not pointing this out seeking to be a troll but I have been messing about with a LOT of radials on a ground mounted vertical. I suspect MMANA is in the right ballpark, that the feed impedance should be in the region of 25 ohms, the extra 17 ohms or so being ground impedance. I live in East Anglia in a region with high ground conductivity and with a similar number of radials I appeared to have about 20 ohms of ground impedance too. I like MMANA but it does not appear to factor in these losses. I increased the number of radials to about 150 trying to reduce the loss, (though I am sure many of them are now detached). From the ground loss estimates I suspect that your linear loaded vertical is losing about 1.5dB relative to a full height quarterwave. By no means a disaster, plus you have a much more robust antenna. 73
I agree with you. I do mention in the video that the jury is still out. Only way to really know is do a side by side WSPR comparison. But even that is fraught with issues. Being 1.5db down is something I'm happy to live with for the drastic reduction in height and rigidity as you say. Say you did this for 80m on a 12m spiderbeam pole (as I have). Could be a game changer for those in very small suburban plots.
Now you've got me thinking that I could get on 80m as just purchased a 12m spiderbeam pole... @@MM0OPXFieldRadio
Thank you!
Your welcome.
Novel Colin. It is nice and simple and not too tall. I bet it would work pretty well with fewer radials too.
Cheers, Fraser MM0EFI
I think so Fraser or even a couple of elevated radials.
Camping out in the CZcams lobby, waiting for this one!
Thanks 👍
Great video, I've done similar for 30m; now, I need one for 40, thank u & 73 de WA4ELW in TN 🇺🇸 dit dit 😃
Your welcome. More people need to try it.
Great production ehh
Thanks 😊
Really nice Video Colin, thanks !This compact setup looks almost as good as a full 1/4w vertical! I was wondering, in a enclosed space (houses, trees on low angles in most direction, etc) if this or a EFHW above the roof would perform better ?!
I think it will be slightly down on a full size but not my much. You hit the nail on the head. A dipole in the clear above roof height will outperform this (I've done the A/B comparison). If you could get this vertical above roof height with raised verticals it would be a winner.
Thanks ! that makes sense and appreciate the feedback of your tests. I think the initial QTH option is a wire strung just above the roof. Even though my neighbours love to put their TV Yagi's on 2.5m masts a 6m mast on the roof may create some issues LOL.... I really would like to try your vertical antenna for QRP sota, looks like a great option to try but need to figure out a better option for radials ? @@MM0OPXFieldRadio
Thanks for the video. Where did you get your mast from if I may ask?
Its a Lifes a Breeze 6m pro pole. Unfortunately not made anymore 😪
Nice job Colin. How does it compare with your efhw on 40m
Not a lot in it. Problem with the 40m EFHW is space.
on the 20m version that you built, did you also use a 1m cross section at the top, or was that decreased to a half meter
It was still 1m spacing
I wonder…if you wanted to add a reflector to get more gain in a given direction would it need to be linear loaded to?
My gut says no, as long as its electrically the right length. I've phased a pair of these and that definitely works.
I think if you raised the mast off the floor slightly say 1m you could use a linear loading radial ,no need for all the complicated ground radials if you add more than one you start creating useful gain also. Give it try 😊
Yes, this is how I typically do it but used ground radials for a change.
Could you make it shorter with an upside down ∆ kind of configuration?
Like a triangle?
@@MM0OPXFieldRadio Almost, but the end not coming closer to the feed point by 30cm or so.
How long did you cut your ground radials
Also would it be possible to get a 20 m antenna exactly half this size
These are 4m radials.
Yes and I have done it already 👍
Thanks again!
Do you need fiberglass? Or can you also use carbon fiber!? and what would happen if you would use an aluminium pipe!? 🤔 I am still a Noob 😅🤷🏻♂️
Ideally non conductive material if you can. I think you may get ot to work to an extent but the radiation pattern will be different.
@@MM0OPXFieldRadio thank you for your reply! 👍😉
I use a 24 foot fiberglass and aluminum painters pole, I make the painters pole part of the vertical, doesn't look crappy and for $40 or so for the pole it doesn't kill the wallet. 😂
They dont seem to be thay cheap here 😞
@@MM0OPXFieldRadio yeah some things are just cheaper in America. Land of consumerism. 🤣
Your shortened version is 9 meters tall, likely why the SWR is way off. It is suppose to be 6 meters tall. 4:23
Hmmmm no. Its 6 meters tall goes horizontal for 1 meter then back down the rest. This is normal for MMANA to show a high SWR for linear loading.
Thank you for the explanations, what software do you use for the analyses? Good luck, 73 QRO. CN8RED
Its MMANA, basic but easy to use.