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HAM RADIO: Flower Pot Antenna, Perfect Stealth Antenna for 2m/70cm
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- čas přidán 6. 07. 2020
- HAM Radio, Antenna, the Flower Pot Antenna, a Stealth Antenna that you can hide in a plant pot and cover with plastic flowers and leaves, No one would ever know........Just 1.2 metres high and perfect for the patio or balcony ......
Credit to: John Bishop VK2ZOI
vk2zoi.com/art...
Hopefully Mike gets this _pinned_ to help Elmer others, as my other reply buried deep in the bowels of another old comment solved the riddle for a number of folks newer to radio, who didn't quite get how a _section of foil_ over the other antenna elements magically gives you 70cm use?!🤔
If you notice at 3:53 Mike measured and marked the dead center of the dipole elements on the outside of the PVC... then at 11:30 that mark ends up being used and I guess several people didn't catch the connection.
The coax portion of the antenna _inside the PVC_ is just like a simple "dipole", _until_ you wrap the foil around the outside with it perfectly centered in between those two 2m dipole elements, making a sort of Frankenstein combination of a collinear/Yagi parasitic antenna element.
The foil acts similar to the parasitic elements used in Yagi-Uda antennas, the unpowered/parasitic metal elements of a Yagi-Uda interact as either a reflector or director, a sort of "metal RF mirror" if you will to bounce, funnel _and amplify_ the RF as well, like an old school analog megaphone does with soundwaves, those are waves too right!
(like one of these...) media.yourobserver.com/img/photos/2022/10/18/403586_standard_t600x900.jpeg?3735229c1eac3ea66532f06aed1ba359424f7682
The foil in this case also acts as a quarter-wave matching stub/sleeve, it's blocking the RF coming from the center of the "2m" dipole elements which when you use a 70cm wavelength "stacks" them into opposing 70cm elements. Take two 70cm J-poles and "glue them together" at their bases where the coax normally connects, then make the short matching stub out of a tube of foil instead... Make sense now?!
Hi Måc! Wow, thanks for follow up and detailed explanation. I've done a screenshot and added to my "antenna" allbum. Wish there was a better way to capture and link key comments to the parent videos like a CZcams Wiki.
We lived in U.P. for 10-11 years and drove through Fircrest all the time (very slowly - your traffic police have no sense of humor!)
Kind regards,
John
@@johnbauman4005 glad I could shed even more light! I'm an extremely 'visual' kind of thinker and can imagine how things work or fit together in my head (that most people would need to put to paper or use 3D CAD to solve) which also tends to help me illustrate those ideas to others. And yeah no kidding... the fuzz around here are so bored out of their minds with nothing better to do than write traffic tickets for literally going "1" over the posted speed! (Not even joking, some friends of mine here got a couple tickets for 1mph over!)
73 John!
Thanks a Stack for a Brilliant Explanation ..... We here in ChCH, NZ use 477MHz and I am looking for some 'Pointers' as Just how to do this in this Great design .... ????? Strange, I was just thinking last night about just using to J-Poles ..... :-) :-) :-) Best to ALL from ChCH, New Zealand
@@kiweekeith and we just got a big bunch of Kiwis from the store?! 😋
What's confusing me, is that in the diagram the foil sleeve is not centered on that mid point. Have a look at the diagram again, and let me know if I'm losing my mind. To me it's showing more sleeve over the intact coax (lower) than the inner (upper). In the video the sleeve is just folded in half, which wouldn't adhere to the plan. That said, it seems to work, so I'm double confused.
Inventor of this antenna unfortunately passed away this year. RiP John Bishop
yes indeed
RIP Master John Bishop, thanks a lot for the masterpiece you shared
Hi Mike, just to let you know that I have constructed one of these flower pot antennas using Ultraflex 7 with Messi and Polaolini connectors. Made to 123 Mhz which is 54cm each leg with 87cm wrap as per Ray G4NSJ instructions and yours. I didn't use the foil because I don't transmit. The results are truly amazing! But not just on air band. I have a Uniden UBC125XLT for VHF and a Tecsun 501X for HF. I can receive all of the Amateur HF band with good signals and the scanner gives me a full 5 bars signal strength for the Tower and Approach frequencies and I am 11 miles from B'ham Airport. I also have a SDRplay RSPdx receiving on a Radio World HF discone and the flower pot far exceeds the discone performance and it's in the same place. I can't seem to get a definitive answer from anybody as to why this performs so well when it's supposed to be just for air band. Maybe you could shed some light on it please. Never the less thank you, thank you for posting your construction. It's a wonder the antenna makers don't go out of business with these flower pot antennas being so good and dirt cheap. Hope you can come up with some comments as I am really intrigued to get an answer. Thank you again.
Excellent video, I have made one of these for when I pass my exam. Thank you for showing us newbies how things are done properly
I bought a very similar collinear antenna for GMRS from Ed Fong. Great video, looking forward to building one!
I made this for the 1/3/22 for FMAC contest to go on the side of my bag out portable. Only use a 5 watts handheld got down to Cornwall 138 miles from the Malvern hills and gave me a 55 report. A fantastic antenna, also worked some SOTA stations in north Wales 🏴 Saturday morning . Great video Mike keep them coming.
73’s M7HFD
Rather than use fishing line to hold the top end in place, I soldered a small loop at the top, drilled a hole through the pipe, and passed a cable tie through. Well, I had cable ties on hand but no fishing line. Excellent antenna, sir.
Sounds great!
Mike, I have to make this myself with that grey tubing and some of that fancy heat-shrink.. Then give it away!
Thanks for the build so far I've built a 5/8 hy gain and a t2lt for 11 meters great reports now I'm going to build me a flower pot antenna hats off to you sir from Trinidad 73s.
Thank you Alvin. :)
Put one of these together this evening. Literally 25 minutes work. Didn't have any 25mm pipe so used 22m. Works perfectly first time, no tuning at all needed.
Thanks Mike.
2E0RSC
Great to hear!
Whatever Antenna Projects Im Looking For - Always Pops Up Mike With His Cool Videos :)
Cheers Kris
Fantastic video! I was licensed in February 2020, and really wanted to build this antenna. I was finally able to do so today, and opened a repeater 30km away with my UV-5R! 73 de VE3GKT!
Glad it helped! Congrats on your exam.
I build one for my Boafeng and tested it against the 2 other UV-5R antennas I had. It had the lowest SWR of any other antenna we tested.
I've made several flowerpots, for 2m/70cm and for 4metres - Great antennas, I tested the vhf/uhf one at 6feet off the floor and during testing managed a 40mile contact. Probably the same performance as some shop bought white sticks...
I made it toooo😇 And worke just super. Thanke you Mike
I'm a new ham from Texas. I've been looking for a way to get the most out of my HT as it's the only radio I have, so I followed your instructions and built this! I appreciate the detail and antenna analysis; I don't have the equipment to properly test mine, so I'm trusting your work. The signal reports I've received so far suggest that it works great. Thanks for the quality instruction.
Welcome aboard!
Superb video and explanation Mike. I now know how to hide/disguise an antenna from my neighbours. Hiding the feed line is the next problem.
That is the best videoed construction project I have seen. Thankyou so much.
James Goacher thank you.. 😁😁
That is a brilliant home brew antenna. Great work!
Thank you very much for making it seem so easy! It was enough to convince me to attempt and lo and behold, several hours later I could finally join the Essexham Monday night net @ the Danbury repeater! Should have seen me with one hand out of the window holding it and the HT in the other. I wonder whether I might get a better perf with a dipole though, guess only way is to build one. :)
You got it... :)
It IS a dipole.
Nice idea with the tape measure as a helping hand. Thanks for the video.
Great antenna Mike took the one i made the other night out on a SOTA trip and worked my mate over a path of 70km. I had the flower pot about 3 m up my sqid pole vx8 at 5w and vk5is was using his handy rig with its own antenna. Half scale sigs on both rigs. vk5cz ..
This cleared up many things for me...thanks!
Fantastic Chris/ Natalie thank you very much for the video look forward to the next one best 73 stay safe de.M1DHA..
hi mike just finished my flowerpot 2m 70cm and it works a treat mate im getting into gb3pt in liverpool and im 20 miles away in skelmersdale west lancishire and it was just on the floor against a bush lol works well 73 M7BYF ILL be trying the 6m one next because realy enjoyed that
Brilliant glade it was helpful Steve. :)
Brilliant thorough build demonstration.
I will be sharing your video around as it's one of the best I have come across.
73 Ray G7TQT
I didn't know Liem Nissan was a ham! Great work Mike.
😂 lol
Thanks for posting .... Nice relaxed presentation.... Looking forward to making one ☘️
You’re welcome 😊
What a great tutorial, I've seen plans for this antenna for a few years now and always thought I will have a go at that. Your video inspired me to build one too, it's turned out great, I am looking for a bottle cap to seal up the top end, so I can mount it on a pole outside. Cheers 73's. Idris Mw1abz
Thanks for the flowers, upside down coke bottle top works
Great job. Like your multiuse workbench
Thanks, worked a treat. Swr was super low and both bands.
Brilliant!!!!! Jolly good show!
Might try that at the weekend Mike. Many thanks
Gracias muchos videos dan vueltas y vueltas tratando de explicar, es genial tu video tanto para los nuevos como para los que tenemos varios años en la Radio, un abrazo desde México, XE1YO ;)
Gracias 73´s
Gracias 73
Nice project and one for me to do in the spring.
Could you do a video for a 6m version please Mike?
yes will do.. :)
Great project Mike, stealthy too.
Great job Mike! Thank you for your clear tutorial very well done! I will do it soon, I'm just testing the new Popovic dual band antenna realized with poor material but now, I will realize your Flower Pot Antenna! Great, I just have a couple of doubts on the measure you show between the tail and the end of the mass of the coax...I will see again the tutorial doing the job! Thank you again, BRGDS 73 IZ0AIO - Angelo
This may help.. vk2zoi.com/articles/half-wave-flower-pot/
@@mike-M0MSN Thank you so much! Now Everything is clear to me! I will proceed as soon as I have a bit of time...just another question, I have a 20mm PVC conduit, can I use it of is necessary a 25mm because of spires? Thank you for your kind help! Ciao
What kind of wire stripper do you use? I've never seen a stripper that strips wires and coax with no adjustment. Please guide me to purchasing one for myself!
Nice project Mike, thanks, regards,Carl.
Good project Mike, keep em coming 👍
Parabéns aqui Robson do Brasil bem explicado a construção da antena
Muito Obrigado
Great little project & they work very well. Loving the new intro graphics also. 👍👍
Thank you for the build such a great antenna and very budget friendly 73s from 9Z4APA .
Very welcome
Good project for people to try and excellent results 👍🏻
I just found out the hard way that Australian 2m and 70cm bands are different by using the instructions from the source (now sadly silent key) seems mine is hmm, okay but resonant frequencies on both bands a little high. SWR is great just OOB. Oops! 😂
Very nice! The part I don't understand Mike is how you get away with using the kitchen counter for your workbench :)
Me neither
Nice video again Mike..... cheers
I have a loft antenna , my intention is to run the coax down the wall inside the plasterboard (trying to keep the Mrs happy by not having surface mounted cable or trunking) is there a so239 mounted on a blanking plate available or will I need do make up my own?
Made one, works great.
Great to hear!
Well done!
I like this. I made a 2 meter ground-plane but it measures out between 1.3 and 1.4 swr, I think your project might be a better
solution. I need it to run reliable winlink messaging.
I think this is the first antenna build video that I watched that is not about some form of dipole. Weird not to see the coax braid connected to it. Good one though!
This is basically a dipole antenna. One leg is the bare wire on the end, the other leg is the unstripped portion of coax which will radiate from the end of the braid down to the balun.
I'm assuming a non-rigid version where the pipe is only used to form the coil, is possible. The whole thing would be suspended from the top of a kite-pole, with the pipe possibly sliding over the pole. I'll know soon enough anyway.
3:12 Genius ;]
Thank you
Great job Mike 73
Really enjoyed your build of this antenna. Just past my foundation exam and only allowed 10 watts. Is there an antenna that I could build that would satisfy 10 watts?
Only able to pick up GB3HN from my handheld at my location.
Thank you for sharing 👍🏻
The red cable that you used, I could not see any detail on the gauge. Is it critical to get that matched?
Ellerbe Strawberry Festival It is 1mm stranded flex, BTW, it was not UV safe so is now orange. :)
What a brilliant idea Mike. 73 Mike M1KEY
I want to make a wire aerial for walking up high ground. Would this do for 446? Or would it need to be a little shorter?
Thanks, Craig
yep
it's cool, but why would you need one?
Excellent table top project Mike, thanks for your time.
Alan G0SMD
Question: In the video, your coil has 9 turns. On your website, in the photo of the final version, the coil has 13 turns. Why did you increase the number of turns in the final version?
To reduce the RF going back to the shack, not needed but .....
Hi Mike, Thanks for the video.
Just made my first antenna ;-)
Question, Can the tinfoil section be wrapped with tape to save it from peeling?
Another project! Can’t keep up 👍🏻👍🏻👍🏻 73 de M0AZE Mike
What size is the red cable . Thanks
1mm
Nice one Mike! I was intrigued by the phasing sleeve and must give it a go. Is the sticky back foil a building /DIY item?
Yes it is!
@@mike-M0MSN Thanks, I've found it now.
That looks so cool. I have no idea how you know these measurements or really what your doing. Been studying to get licence but really have no clues what half this stuff is. Anyway great job. Lots of folks commenting great job. So will I .
Measurements, just remember in radio, everything is a % 300......when it comes to antennas example. 300 /145mHz = 2.xx / 4 for a quarter wave
@@mike-M0MSN 300/145=2.068/4=0.517 is what
VISWANATHAN R ELAYIDOM 51cm is the length of the top(driven) element.. :)
What is posible happen if we made flowerpot antenna without coil?
Now that impressed me, but I think I missed something along the way. The coax from the coil went back through the pipe to the radio, yes? How did you use the foil to get the 70cms. Sometimes you speed up your video just a bit to much and it is easy to miss something. If you were new to this and just got your licence it might be hard to follow. The only bit I didn't quite get was the 70cms bit Mike. Have you a Website it is on? Or can you explain it here or the next time you are on Discord? That is an excellent aerial for someone that is in a flat with a balcony. I like it and might have to result to it myself. Now can you build one for 80 meters? Only joking!
bob fourjs foil acts like a co-linear not sure how but it works, and yes the coax goes back inside the pipe and out at the bottom.
@@mike-M0MSN I am going to have to look this one up. It is a new one to me, but it shouldn't be as Ham Radio Concepts did one and put plastic flowers over it and put it on his mothers porch. I can't remember if it did 70cms, This is good, I need to get my head round this one. Thanks for the reply.
vk2zoi.com/articles/dual-band-half-wave-flower-pot/
@@mike-M0MSN Thanks Mike, just what I need :-))
@@BoB4jjjjs The coax portion of the antenna inside the PVC is like a dipole, the foil goes around the outside perfectly centered in the exact middle of the dipole elements and makes more of a collinear; if you notice he measured and marked the dead center of the dipole elements on the outside of the PVC at 3:53 but you have to wait until 11:30 where that mark ends up being used.
It’s actually a centre fed dipole…….skin effect.
Very cool build. I just ordered a cheap 2m radio off of Amazon, and I thought a better antenna would greatly improve the performance. There is just one thing I don't understand. At about 11:45, where you're putting the metal foil around, centered at the center point of the PVC, the metal foil is not connected to anything? It just wraps on the outside of the PVC? The antenna can work with 2m and 70cm without any kind of switching? Forgive my questions, I've been studying antenna theory for about 2 hours now ! Very little experience of knowledge.
the antenna will work without the foil however the foil is there as a parasitic 70cm element
Whats the size of the red cable!! 73!!
Cheers Mike, another lockdown project to tinker with. Anything to stop this one being made "suitcase packable"? I.e. without the conduit? Foil tape wrap direct on the cable & the same "air core" choke position & dimensions?
Cut the conduit in half and use a straight connector, foil rap needs to be spaced 10mm off the coax...
What are the measurements in inches
How many watts have you pushed through it?
Up to around 100watts
Hi love the video just starting out on sdr radio can you tell me the best coax to use 50 ohm or 75 ohm thanks
Arthur
Hey Arthur, you should alway check the radio but I bet it uses 50 ohm coax. :)
if the paralon pipe reaches a length of three meters, can it or not? thank you
Hello Mike,
Im delighted to report that using the "Real Baco foil" and not the tape after a few tries with a cheaper brand baco foil?then with some of that tape you used! afellow ham friend came up with a better idea! that actually works? for the would be makers of the flower pot, ask the wife for the "Branded Baco Foil ,measure the amount needed has per video! rap it around in the suggested position! and secure with elastic ands at each end?this is to allow for adjustment of SWR on both bands from 144.500 and thru to far end of band,plus also on 70cms either end both with me @ 1.3, im very pleased with the advise given to me by2E0PAF phil in Bromley Kent for that suggestion, ive also made a Square aerial with the driven element made into a Quad Aerial from Antenna Workshops and a little modification by phil again! his antennas are in his roof space the square one is on a rotator and the performance is better than any white stick i know of. from 2E0GMD mick
good can you build me one good net on radio thanks all the best and phil
What kind of strippers do you use?
Mine only do standard wire and dont grip enough to do that well!
Hi. Nice video! I am not clear why you add 2cm on 45.7 to find the midpoint. Could you please explain? Thanks.
Yes, i am also not clear with this?
Thanks for the video. would it matter if I used 1.5mm solid single core instead of the 1mm and could you tell me what type of coax did you use? Thank you.
Yep you can use that, the Co-ax was RG58..
Hi ! What gauge is the red cabled wire please sir ?
1.5mm.
Hi ! I've finished it , I've put heat shrink on the conduit it's a little on the heavy side now but it's waterproof
I see the red wire is 1mm “18 gauge”. Could I use 16 gauge instead or would it change too much
you can use that yes
@@mike-M0MSN thanks. Already made and it turned out great
hi mike great video mate im ready to build one but my pipe is only 21mm wide that won,t matter will it
No worries 21mm will work well
Hi Mike. Sorry for being noob, but i like to know how the alu tape for the 70cm works. Its not attached to the coax in any way.
parasitic element, but the antenna would work without it as it is an harmonic of 430MHz
Hello. I saw your antenna project and i would like to make a antenna for a fm stereo reciever, from 89 to 104,8 Mhz. Could you please calculate the measurments for my aplication. Tnx
300 / Freq /4 = 1/4 WAVE. so 300/95= 3.1578 / 4 = 79cm each leg. top 79cm, coax 79cm, coil 79cm,
Nice job, Mike! Can You tell me, please, - how many turns I have to wind for balun if I will use rg-8 or rg -213?
Should be the same, it equals a 1/4 wave in length
Thank You, Sir
What is that bright yellow and green striped tape that you use to wrap and mark with? Is it available in the U.S.?
No idea, it is PVC tape from a DIY store
Hi Mike,another very informative video, can this antenna be made out of RG mini8 coax without having any effects on the antenna. Thanks in advance Paul.
Yes you can!
@@mike-M0MSN Thanks Mike I put my flowerpot antenna up at 30ft today and its working very well. 👍👍
Hi, comparing flowerpot dual band, flowerpot dual band high gain and the ground plane dual band you built, which one perfomed the best?
They was not a lot in it, I would say it was between high gain and the ground plane simply because I could get it higher the Ground Plane....
Thank you Mike, 7X2CX
Thank you Mohamed. :)
Is this considered a half wave antenna on both bands?
Make me one please 😂
Intrigued, some say 5 turns, yours is 9, what’s the theory here please?
Incredible SWR 👍
I base all of the air chokes on 1/4 or 5/8 wave lengths
@@mike-M0MSN thanks Mike 👍
If I made this from 75 ohm RG6 coax, is there anything special I would need to know? Or is it just a bad idea all around?
Give it a go, should be fine..
@@mike-M0MSN RG6 has a different (much higher) V factor than RG58, and using the web calculator from the start of the video, you get very different dimensions
Does the diameter of the pipe matters?
yes the bigger the less turns required.
HI,
I've had a go at the 2/70 flower pot this morning. I enjoyed the vid and building along. However, on completion my SWR on 2M is high. It tunes in great at 150Mhz?? Also, I get no reading at all on 70cm.... CAn you think what I may have done wrong?
Rich
Sounds like the elements are a little short, not a problem, just add 3cm of wire to the top element and re-SWR. :)
@@mike-M0MSN Hi, I've sorted the problem on 2m but I still get nothing on 70cm. I'm testing with a n MJF269 and it shows nothing at all on 70CM. Working great now on 2Mtr
@@richtaylor6773 so if I am reading this right, you have no SWR reading on 70cm at all? What is the reading just outside the band? 446mHz? 438mHz? Is the transmitter working? No reading or very high reading? Cheers
@@mike-M0MSN I test my mfj269 on my house 2/70 antenna and get the same reading of nothing. I may have a problem with my analyser I didn’t know I have. Looking on bright side that’s Something else to research and buy lol... thanks for all your help
Hi. Nice video. Please have a question. What is the purpose of the aluminum foil around the perimeter of the pipe? Need if I want to listen to radio traffic on Air Frequency?
It is for 70cm, phasing,
@@mike-M0MSN I'm sorry. I'm not educated in this area. Does aluminum foil have a positive effect on listening to the air zone? The frequency range of the air band is 108-136 MHz thanks
No, it would be better without for the air bands, but I would suggest you will not see any difference if you leave in on.
@@mike-M0MSN thanks you ;-)
Nice video and nice antenna :D 73 de SP7ELO!
Thanks a lot!
Hi Mike ... Do you have a link or details of your coax / cable stripper ... looks to be a nice one ... Tnx ... Gerry
RS Componants
@@mike-M0MSN Thabks Mike ... Appreciate your reply .... Enjoy the rest of your day 🇮🇪