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Building a Balcony Vertical Dipole VHF Antenna.

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Sometimes things don't work as planned. This antenna was supposed to work for the 6m FM band on 51.5MHz. It is actually a vertical dipole as a quarter wave antenna would have radials on the ground or at a 45deg angle for a 50 Ohm impedance. Disappointing results due in my opinion to the metal rail assembly in close proximity. What do you think?
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Опубликовано:

22 авг 2024

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Комментарии : 122

@la6yja 4 года назад

A falure is NEVER a failure! It is a learning experience. 73s de la6yja..

@kckoellein 3 года назад

Print the clamp with two tube holders, one up and one down, and the bnc in the center. Then solder each tube to the bnc as a TRUE dipole. Your results were due to a imbalance between the two elements. Technically a dipole balun would be required because one element is going to see a capacitance effect from the railing metal and the other element is in "free-er space". I used a PVC pipe T from the rail... Used a stub of 12" to extend the dipole away from my tower, and then another PVC pipe T to hold the vertical elements. The other options to make what you have useable is to make the wire "counterpoise" massively capacitant. Think of how a ground plane works. It sees 1/2 of a dipole element in good length/tune... And radiates half of the signal on that element... And it "sinks" the other half of the signal "cleanly" into the ground plane. Your current setup counterpoise does not "sink" it "cleanly". It is close enough to greatly distort your overall signal. Try adding material to the counterpoise (aka, the second half of the electrical dipole) to see if you get some values that do not interfere with the success of the measured element?

@JT-py9lv 4 года назад

Great video. You never know if you never try. Like the great hockey player Wayne Gretzky said "You miss 100% of the shots that you don't take". Thanks again !

@DonzLockz Год назад

I think you are right, the steel handrail must be interfering with it. Print a new plastic 3D handrail!😆👍

@RWisGoad 4 года назад

Love the fact you shared this video. You only learn from failures, successes are simply replicated. If you have never failed you have never tried anything new !

@RadioPrepper 4 года назад

Yep, failures are teachers.

@rlcsystems4061 4 года назад

I am just new to the hobby of antenna building. Already built 1/4th wavelength groundplanes, Moxon, hentenna, J-Poles, Biquads.. flowerpot antennas... and it sure helps that all elements, especially the radiator, of antennas be mounted far from metals that sure can affect the swr readings.

@RadioPrepper 4 года назад

You're not a newbie anymore ;-)

@migalito1955 4 года назад

Hi Gil, I have been busy doing other things so radio stuff has been on the back burner but don't trash the vertical dipole yet. I used the verticle dipole often in the past and here are a few observations that might help. 1: The orientation of the coax to the antenna can make a big difference. I find the vertical dipole behaves as expected if the coax juts out from the feedpoint at a right angle for roughly at least a foot. I had a horrible SWR reading on a 10 meter verticle dipole where the coax dangled along the antenna that became a perfect reading when the coax was allowed to extend at right angles to the antenna for roughly 2 feet. 2: Regardless of all else you should be able to make it usable by lengthening or shortening the 2 elements. I would just clip on an alligator clip to each component of the dipole with perhaps an inch of wire attached to see if longer was better. If not I'd trim 1/8 inch at a time So as to equally shorten each radiator. Either longer or shorter should do it if coax adjustment fails. Mile Kc2wvb

@RadioPrepper 4 года назад

Thanks. I will test further.

@buzhug35 Год назад

Parfois on échoue, parfois on réussit, mais toujours on essaie! Merci pour vos vidéos sur un élément qui est méconnu du plus grand nombre. Et pourtant, « tant vaut l’antenne vaut le système » dit-on. 73’s de f4jwq

@leventeboda9138 4 года назад

Although this antenna project was a fail as you said I really enjoyed watching it! Looking forward for next videos!

@RadioPrepper 4 года назад

Thanks, coming right up!

@MrJones-uq5cg 4 года назад

Thanks for bringing us along on the build, Gil. 73s.

@m.p.6330 4 года назад

Gil, your channel is my favorite HAM channel. If you aren't failing, you aren't trying hard enough. We appreciate you showing the success and failure of experimentation. Looking forward to your next video.

@RadioPrepper 4 года назад

Thanks. There will be other failures, no worries, LOL.

@markharrison1160 4 года назад

One tip for 3d printer is the plastic typically shrinks and depending on how accurate your measurements are you might need to oversize things by say 3%. Look at the manufacture for shrinkage amounts.

@RadioPrepper 4 года назад

Good to know thanks.

@charlieb.4273 4 года назад

Gil, Great video and a valid attempt. I have two ideas, what if you used the railing as your ground and tried a wire for your radiating element suspended from the roof over your balcony. See what happens when you shorten the wire, the SWR curve will either get better or worse. It is worth a try. Idea number two, I have had great success with a “Jungle Antenna.” Which is just a quarter wave ground plane with three sloping radials. The antenna is made from wire and the structure is a bamboo pyramid. It was popular in Vietnam and works very well with my PRC-77s. There are pictures of mine on my QRZ page. I keep the wires an frame collapsed and hang it up only when in use. It takes only a couple of minutes to assemble and dissemble and from what I see, it will fit on your balcony. 73 and good luck Charlie KM4ZZ

@RadioPrepper 4 года назад

Thanks Charlie. I thought about that... The jungle antenna will be for another video.

@grantmcduling9760 4 года назад

Gil, what this experiment shows is that every silver lining has a cloud. But all part of the learning process as you say. Enjoyed the video; showed me that I am not the only one who suffers failures! Grant VK4JAZ

@RadioPrepper 4 года назад

Indeed!

@JohnTarbox 4 года назад

It would be interesting to see you take this antenna out to the field and try it where there would be no interaction with the metal of the building. A plus for this antenna is the wire counterpose so it is easy to adjust the length of the counterpose as well as try multiple wires at various angles to see what would work best. It may not be right for the balcony but it might be great for portable operation.

@RadioPrepper 4 года назад

I will definitely try!

@donaldsmith3048 4 года назад

Can you print another mount that puts the antana higher so the antenna isn't next to the rail, maybe use small coax in the mount to shield the RF from the railing. Also is there a way to make the railing part of a ground plain. You may need to shorten the length of the antenna with a small coil in it. I think you have a good idea just need to work on it some. There is steal up at the top of the antenna, made into part of the building. Just a fast thought is to put a small coil just above where it is mounted. This will shorten the antenna and keep it from the steal in the building above. A peace of plastic pipe to wind a coil on. Maybe someone will have other ideas to help. Here in the US there is all sizes of plastic pipe, I don't know what you have there.

@RadioPrepper 4 года назад

Unfortunately the ceiling above prevents doing so. I definitely need to investigate this further though...

@donaldsmith3048 4 года назад

Good Luck! I thought putting a coil in would make it shorter becouse part of the lenth would be in the coil.

@PBenetton 4 года назад

You should try, with a PVC tube or wood piece, just to get the antenna about 1m or more away from the balcony rails and measure swr again.

@pd1rwk825 4 года назад

Thanks for sharing your failure. Most projects end up different than they suppost to.

@sauroiu5asa696 4 года назад

Ciao Gil, Some times happen.... I would try to make It All in copper tube and with One or two radial at 45° out in the clear. Impedance should be closer to 50 ohm and resonance may be better, because in far away from the handrail... Other try could be to use the complete handrail as grownd... And trim the radiator for resonance... Have a try. Best 73 Gil

@RadioPrepper 4 года назад

Thanks. I thought about that, might try...

@jordan390a 4 года назад

The first thing I would have done is to use the metal hand-railing as your ground plane. Actually, technically speaking, your antenna is not a dipole but a monopole.... A dipole would have worked too, and could simply be hung from something higher. Lastly, i you're finding that you can't get a low R/L or SWR reading at any frequency, something is wrong.... If you're finding the SWR low at a lower frequency. your elements are too long....for a 1/4w at 51 mhz, your elements should be about 51-52 inches long....You could easily adopt plans for a 6 meter band antenna which would very well at 51 mhz.....! Keep at it...!!

@RadioPrepper 4 года назад

It wouldn't be so far off... The size is right, and it is a dipole? Two opposed quarter waves makes a dipole. I thought about using the rail but it is painted and isn't mine. I will definitely tinker with it more...

@jordan390a 4 года назад

@@RadioPrepper Sorry..I couldn't see the lower element wire...That will couple to that hand rail and any other metal objects around or above the antenna will have effects on performance....It might work better leaned up against a wall indoors away from metal, if possible....You could also try to add another wire element to the lower one and spread them evenly along the handrail in opposite directions...The more radials like that the better....

@dl8cy 4 года назад

@@RadioPrepper please please do a follow up on your investigation - this project is not at its end :-) vy 73 de dl8cy

@dalegirard8453 2 года назад

Your wife must be very understanding all your projects

@RadioPrepper 2 года назад

That's why I'm single ;-)

@YZFoFittie 4 года назад

Try testing the antenna by mounting it to something nonconductive like a wood chair. You should be a minimum of 1/2 wavelength away from anything conductive.

@timkeene2717 4 года назад

May I suggest building a magnetic loop for 6 meters. Mine has worked very well. Even from INSIDE my apartment. It is very small at approximately 45cm in circumference.

@RadioPrepper 4 года назад

I did a while ago. See on radiopreppers.com. Good idea thanks.

@USXPOP 4 года назад

Always good to see your videos. Maybe it didn't work as expected, but it was not a fail. Learn by doing. Learning is never a failure. Concept seems good, just trim a little. You can always convert it to a different frequency. Keep the videos coming.

@RadioPrepper 4 года назад

Thanks, will do!

@jamescoffey5225 4 года назад

What would happen if you shortened your vertical ends a bit at a time? E.g., I mounted a horizontal 6 m dipole using 2 each buddistick 5.5-ft whips mounted on an isolated dipole mount on 10-ft of 1/4-inch copper pipe and "adjusted" by the standard formula but, the SWR was too high on 6m. The copper pipe was duct-taped to a 10-ft 2.25-in OD vertically mounted PVC pipe that was sunk into the ground in my backyard. It is a temporary set-up. I had to reduce the whip lengths, bit by bit, using my antenna analyzer (the now discontinued, wonderful Rigexpert AA-54) to achieve eventually a SWR=1.3 or so. The overall length of the whips was about 10% less than the formula length. The lesson of this exercise (yours and mine): antenna performance is dependent upon "location, location, location." BTW, I like your 3-D printer and CAD/CAM software! 73 de AE5ZX

@RadioPrepper 4 года назад

I tried, by 3cm.. I should test it in a different environment first...

@jamescoffey5225 4 года назад

@@RadioPrepper Correction. I used 0.5-inch copper pipe. Also, could you try your new antenna as a 1/4 wave vertical and use the other half (1/4 wave) of the dipole or a shortened wire segment connected to the metal railing as a counterpoise?

@Motor_Cackle 4 года назад

You might want to try this: Remove the counterpoise and add a matching 1/4 wave to the "ground" side of the bnc connector to form a complete dipole. Run 8 or 9 turns of your coax on a Fair-Rite Part # 2631803802 torroidal core to form a balun. The downside is, I'm afraid the railing might be a bigger problem with this setup unless you can get further away from the railing. On second thought, try just adding the balun first... that should reduce any interaction with the coax acting as a parasitic element.

@RadioPrepper 4 года назад

Thanks. Good idea. I will try the choke. It is a quarter wave already.

@nlo114 4 года назад

Talk (google) to an industrial electrician/supplier about '50mm SWA cleats' for attaching to the balcony handrail. They are strong and fit for purpose and cheap.

@gudrutis 4 года назад

Hello, I suppose you should try HALO LOOP antenna, it is very convenient to mount to balcony rails, and also have horizontal polarisation. 73.

@RadioPrepper 4 года назад

Yes, but that's for VHF. It would be huge on HF..

@gudrutis 4 года назад

@@RadioPrepper yeah, but in this video you did antenna for 2 meters :) Still, if you have lack of ideas - just try, in your location is not bad, especially if raised with some mast from balcony, if it is not possible, just move like 70-100 cm from railing and use it. Have a nice day.

@theoldhobbit3640 4 года назад

Not radio related, but I have just bought myself a very cheap 3D printer (Ender3) and am really enjoying playing with the free stuff you can get on Thingiverse. I have also downloaded Tinkercad and boy am I confused LOL. Already printed different stands and VFO knob for the 817, so finding it very useful.

@RadioPrepper 4 года назад

Absolutely. I used RU-vid to learn Tinkercad and will get the Ender3 myself soon.

@theoldhobbit3640 4 года назад

@@RadioPrepper There are self print upgrades for the Ender 3 which really do make a difference. RU-vid Tomb of 3D printer horrors is a very good point of reference. I replaced the Bowden tube and puch connectors as these are really low quality as delivered. You will really enjoy it and get lots of use from it.

@Aussat 4 года назад

Gil great video don't give up. I'm amazed also how you use the 3D printer to print useful things to use, great idea well done. Love the video's it looked very well made, just some fine tuning for the future!

@RadioPrepper 4 года назад

Thank you! 3D printing changes everything...

@ericalbert6954 4 года назад

Belle leçon d'humilité, merci !

@RadioPrepper 4 года назад

Aux US un échec est une leçon... En France c'est un échec...

@ericalbert6954 4 года назад

@@RadioPrepper En effet : "learning by doing"!

@Anonopsmo 4 года назад

Oh yes, Gil the life is a learning process. the next one will be work great! i hope so for you! ;) best greets from damn cold bavaria, jan

@RadioPrepper 4 года назад

Thanks Jan :-)

@chuckkie9159 4 года назад

Hi Gil, I think your measurements needs to be checked. At 51.5mhz, a 1/2wave ant is 2.7meters long total length. So you need to cut 2.7meters to half for a 1.37meter long each element. Then it would be 1.37m for the upper tubing element and 1.37m for the lower element, making a total length 0f 2.7meter long dipole antenna. The lower element takes the place of the counter pose. I think what you did was a 3.5meter long vertical plus the counter pose which made it operate on a much lower frequency.

@RadioPrepper 4 года назад

That's what I did...

@lemd49 3 года назад

Deltaloop

@YihBrucebv2ki 4 года назад

Try to let the top tip of antenna offset away from calling edge and then adjust length both of antenna and radial.

@RadioPrepper 4 года назад

Yes I did that...

@steinshaw2490 4 года назад

Thanks for sharing Gill, I wonder if you have a better antenna than you expect. Isn't a center feed dipole about 200 ohms? Don't you need a 4 to 1 balun? Or 4 radials at about 45 degrees to get a 1/4 wave antenna to 50 ohms?

@steinshaw2490 4 года назад

I found this a really interesting read... Maybe 8 radials is a good thing. www.qsl.net/kk4obi/Elevated%20Radials.html

@RadioPrepper 4 года назад

A dipole is around 72 Ohms... Indeed radials at 45deg do make 50, but I think the railing is the culprit.

@sanebedlam 4 года назад

I've ordered a 3d printer and was wondering if you'd consider a video on 3d printed items for ham radio as the topic.

@RadioPrepper 4 года назад

Definitely. I will get myself one too for Christmas.

@sanebedlam 4 года назад

@@RadioPrepper birthday present for myself I'm getting an artillery sidewinder x1 and have already been working on micro iambic paddle design for portable ops and a few other items

@LevyCarneiro 2 года назад

Could it be that it has a high SWR because it’s so close to a metal structure? Maybe if you find a way to place it far away from the balcony it would work? Thanks!

@RadioPrepper 2 года назад

Certainly...

@LevyCarneiro 2 года назад

@@RadioPrepper I have the same limitation here, metal balcony. Thanks for your videos!

@LevyCarneiro 2 года назад

@@RadioPrepper on the plus side, I wonder if you could find the resonant frequency of your balcony and use it hehe

@RadioPrepper 2 года назад

With more fiddling I am sure I could tune it.. I do have other options though but if that was the only one I would dig deeper...

@LevyCarneiro 2 года назад

@@RadioPrepper would be funny to have a built in antenna that only works in a specific frequency hehe Merci

@tomjohannesen2223 4 года назад

hi old man, antenna brackets made of plastic are not sustainable in sun/weather. Rather use ALU/metal. GL!

@RadioPrepper 4 года назад

Sure, but this is only semi-permanent...

@willlaplusbelledesminiz996 4 года назад

Hello,bonne vidéo encore...je suis un passionné d 'écoute (aviation de 108 à 133 donc mhz) que me conseilles tu pour que je fabrique facilement une bonne antenne qui aurait un gros gain donc milieu de bande environ à 120mhz ? est il possible d envisager une vidéo intéressante sous forme de tuto j ai un peu de connaissances mais pas assez pour me lancer seul dans cette aventure et j essuie bcp de refus merci d avance cordialement l ami 73:)

@RadioPrepper 4 года назад

Le problem d'un gros gain c'est que c'est trop directionnel, surtout pour l'aviation. Je suggère une Moxon. Cherchez "Moxon online calculator."

@willlaplusbelledesminiz996 4 года назад

@@RadioPrepper merci bcp pourrais tu stp me montrer en video comment concevoir cette antenne ce serait sympa éhéhéhé si tu ne peux pas je comprends l ami merci pour tes vidéos et tes conseils ;) and take care ;)

@RadioPrepper 4 года назад

ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-vCcygBAOlWw.html

@willlaplusbelledesminiz996 4 года назад

@@RadioPrepper je vais essayer de me débrouiller avec ça merci quand même

@willian.direction6740 4 года назад

Gil could you make a 6m inverted V dipole out of tubing and elevate it a bit above the balcony.

@RadioPrepper 4 года назад

Yes but I already have my Delta Loop which works great... I was just hoping for something smaller...

@TheDgdimick 4 года назад

Have you found plans for a tape measure flexable 2 meter dipole for a handy talky? Amazon has them, but I think it would be fun to make one.

@RadioPrepper 4 года назад

Plenty of them online. I will make one :-)

@stewartrv 4 года назад

Don't throw it away yet! Just convert to Q-wave ground plane and use mobile. :)

@RadioPrepper 4 года назад

I will definitely experiment with it more!

@SubterranBayern 4 года назад

Did you try just the railing as counterpart? I mean without the radials. That would be interesting to see, if the SWR becomes bader or better. 73 Oliver DO1OH

@RadioPrepper 4 года назад

I thought about it but it is painted and I need to find a non-visible way to make a good contact.

@johndesmond9845 4 года назад

@@RadioPrepper Perhaps you could build a capacitor with tinfoil to couple to the balcony?

@alaanoor3679 3 года назад

a quarter-wave needs a ground plane ??

@RadioPrepper 3 года назад

It needs something extra to essentially make it a half-wave, if just a good ground...

@alaanoor3679 3 года назад

@@RadioPrepper true… do a half wave dipole or a quarter wave with a ground plane Thanks for the video though !

@RadioPrepper 3 года назад

Similar antennas, just the radiation pattern is different...

@daal1977 4 года назад

Peu importe le résultat "moyen", l'important est d'avoir mené l'idée au bout.Une antenne discrète sur un balcon? J'adhère! Salut Gilles et merci.

@RadioPrepper 4 года назад

Absolument!

@paolonervi2208 4 года назад

What is the Z (R+jX) vs. Frequency plot ?

@RadioPrepper 4 года назад

No idea!

@diverbon911 4 года назад

You did a good job Gil! My nephew and I built some 6m quarter wave verticals. At 52.500 the SWR is 1:1, up on an 8ft painter's pole. Thanks for sharing your experiences! 73, Bon- KX4EZ

@RadioPrepper 4 года назад

Thank you.

@tonycantrell9547 4 года назад

What is a good source for surplus radios?

@RadioPrepper 4 года назад

clansman-radio.co.uk and EBay.

@tonycantrell9547 4 года назад

@@RadioPrepper thank you sir.

@mikesmithg0rfd356 4 года назад

it looks like you were 15 cm too long on each leg.

@RadioPrepper 4 года назад

Not according to the formula... Something else is going on...

@mikesmithg0rfd356 4 года назад

@@RadioPrepper www.chem.hawaii.edu/uham/6.html

@Nicktgrief 4 года назад

I'd agree with Mike ... if its resonant on 40mhz then its too long.so try cutting some off and see how it looks. The balcony will be giving you some extra ground radials I guess but definitely too long

@Nicktgrief 4 года назад

I make it it should be 146 cm ( not accounting for the velocity factor of the copper)

@MoTown44240 4 года назад

Gil, take a looksee at KG0ZZ youtube video, ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-RcO5WAiksNI.html, from several years on the DIY 2m / 70 cm antenna. Your antenna might still work if your radiatimg element has greater separation from the railing, with an arm or halyard to extend it about 30.5 cm away from the railing. 72 KB8AMZ p.s. forgot the youtube link and had to edit my comment.

@RadioPrepper 4 года назад

Right, but it gets a bit more complicated... I will get back to it eventually...

@c00kie84 4 года назад

Hi Gil, thanks for very interesting experiment as usual. I would really recommend you download Autodesk Fudion 360 for your 3D designs. It is free to use for home users. There was a steep learning curve to start with but there are lots of RU-vid tutorials. Well worth the effort especially if you learn to design parametrically. 73 de Mark M0PVM

@RadioPrepper 4 года назад

I installed it already! But have not started using it yet....

@craigpalmer9196 4 года назад

I can not do that at all.apartment liver as well

@RadioPrepper 4 года назад

It's temporary...

@craigpalmer9196 4 года назад

@@RadioPrepper I have trees right outside, I live on 2nd floor, they would have a fit if I put a wire into one , so nothing outside like what you have