I'm surprised this antenna is not more widely used on the Ham bands. I built one at the weekend and I'm astounded by its performance on 20 meters compared with my doublet which is 12 meters high. Worked Caribbean, central Africa , Mid and south America with ease now. Seams the perfect solution for so many Hams as no need at all for radials and nice low angle radiation pattern. Thanks for the inspiration Tim.... Dave G1NNR
Thanks for this Tim, Just had a lovely afternoon playing radio. I now have a 20 meter qtr wave vertical. A medium Dulux paint tin as a former, TV co-ax feeder, choke and antenna. SWR (cheap Chinese inline digital box) is showing slightly less than my Nano VNA suggested at around 1.34 in a gentle curve away from 14.2 Mhz. So didn't have to trim this vertical. The rain held off, so even the dog enjoyed being out in the garden. Will have a play later as the greyline moves towards us. Pete M0WHT
Hi Tim, Tom KB0QIP here. I saw your podcast on QRZ this morning. I started to look for more info and found this gem of a video. I'm across the pond from you and we have our Field Day coming up in 2 weeks. I just happen to have some Mini 8 coax and will try to attempt to construct this antenna for 20 meters. If successful, I will have my radio club try it. Also just subscribed to your channel. I have you fellow Ham , M0MCX subscribed also. You both have a lot to offer the community and I look forward to more coming our way. Thank You for your work. Hope to see you on the radio soon. Tom
Hallo Tim, today i made this coax antenna. Only a little bit different. From the transceiver to the end of the coil i've used rg 58. After the coil i've used 75 ohm signal cable. The 7 mm one. And it works. For the coil its rg 58, 15 turns on pvc 75 mm. On the mfj analyser On 14.21 mhz 49 ohms ,near to 1:1 and x 2. So thanks for this video and this idea. Good luck and 73. Mvg. Hans
Managed a couple of contacts in the Russian competition - the surprise of getting through caused brain fog and I'm sure my response was gibberish lol. The 450D was set at 10 watts but the inline tuner (well known Chinese atu 100) said erp was about 6 so I was not expecting any success but got a 5&9 report. Your 20 meter antenna looks great for static mobile easy set up. Look forward to hearing more Tim. 73 M7BLC
Hi John. That just goes to show that it's the antenna that matters, not the amount of power that you are running. A little extra power can definitely help, especially when the conditions are marginal but ultimately it's the antenna which does the heavy lifting. As a side note, don't give too much credibility to signal reports received during contests. Contesters will nearly always give a 59 report irrelevant of how well they are copying you because it's quicker & easier for them to log. Most logging software automatically puts 59 in the signal report box. Giving them anything different means that they have to manually change it which slows them down in the contest. I'm not saying that's right..........I personally would rather have a genuine signal report. Then again, I'm not really into contesting. I'll occasionally call the odd contest station & give away a few points for fun but I have little interest in contesting. I've lost count of the number of times that I've had QSO's with contest stations where they have given me a 59 report.........then asked me to repeat my callsign several times as they were struggling to copy me!!! It's sometimes funny to see how giving them a genuine signal report (of 57 for example) can throw them. I've had a couple of contesters get really quite annoyed with me for giving a genuine signal report! Good to hear that you are making contacts. It's surprising what you can do with 10 watts.
Used a commercially built version of this antenna today. Worked well with contacts on Azores, Turkey, and Russia. Will be building a homebrew version soon.
Very nice video. I use an end fed half wave for 20 meters that is made from aluminium tubing. I match it with a home made 49:1 UNUN. It's a fantastic DX antenna that does not require any radials. The antenna uses the coax feeder as a counterpoise which is an old trick (no RF in the shack doing this). The same antenna can be made with 10 meters of wire. I used aluminium that is much thicker in order to maximize the bandwidth. The extremely low angle of radiation easily allows me to beat DX pile ups here in the USA while running only 100 Watts.
Going to have a go at this Tim, I have some 40ft trees at the bottom of the garden, ideal for a stealthy operation, so the Mrs won't see them ha ha , great video's Paul M0BSW
There is a variation on this design Tim that uses a variable capacitor across the choke. That turns the choke into a simple parallel tuned circuit. Effectively it acts as a bandstop filter that blocks the reflected power for passing the choke so you achieve pretty much 1:1 SWR at the null point. To do this, you need to bare a small section of coax on both the first and last turns of the choke and solder the capacitor across those points. A small broadcast band variable does the job nicely. It's very effective and a useful variation on the theme. John EI5JS
I was just thinking about building one of these not 3 days ago for static mobile dx, although the wife decided i need to decorate 😢, great vid bob on for me and reference when i put the paint brush down
Nice one Tim. I presume that there's no reason why you couldn't wind your choke on a ferrite ring, which (although more expensive) would make it smaller and a bit more portable? I have one of the 22 meter Spiderbeam masts, so I'm thinking about giving this a go on 40m once the lockdown restrictions are lifted and I can go to my field. It might also be fun to try on 80m if I can find a way of getting it 40m into the air (which I readily admit is an extraordinarily ambitious challenge). Alternatively it could be configured as an inverted V, the same as you would a dipole. Might make a good portable NVIS antenna (maybe for SOTA).
Great vid Tim, love my T2LT on 11/10m. I think I’ll have a go at this. My pole is only 10m mind so I’ll take a look at Spiderbeam too. Stay safe yourself buddy, 73.
Excellent Tim. If my experiment goes as planned I would like to build a pair of something like this for QRO. any idea of the power handling? I'm thinking a beefed up version using RG142.
So quiet comparing to an EFHW... talking about the noise level. Love it... and thank you for sharing. I didn't think of this at all. I was really wondering how could I have a vertical next to my house for DX for 20m. One question. If I was to use it for portable... instead of the big choke... I guess it should be ok if I use a regular one using a toroid ? Is a 1:1 right ? 73 DE YO6DXE.
You say 10m was 5 turns. But I saw your video "T2LT - Half Wave Vertical Coaxial Antenna For CB Radio & 10 Metres" and it was 16 turns I made mine with 16 turns
Wonderful!!!! Thank you for prototyping this and making the video. Has anyone tried a design like this where you make a 90 bend at the dipole center in order to follow a horizontal attic space??? 2nd question: has anyone simply laid the antenna horizontal in an attic crawl space?
Thanks for the video Tim, I'm now a new subscriber!. I'm an SWL, and looking at a few antenna designs at the moment. I have some trees at the back of my house and I'll where a few verticals would work well. Sorry if this is an obvious question, but is the entire antenna including feed line one piece of coax ie no need to attach a connector after the choke?
Thanks for subscribing! Yes that’s right it’s one piece of rg58. You could also make it so that you can pigtail a thicker less lossy run of coax after the choke but unless this is a long run then rg58 will do just fine 73
Pretty cool. Would it be the same thing to just use a type 31 ferrite choke at the appropriate point on the coax, as opposed to the air choke? (even though I recognize the appeal and simplicity of an antenna that’s basically all built from the same coax that you’re feeding it with). I don’t think I’ve seen this one before-is there a name for it? Somebody in the comments made reference to a Bazooka, but it looks a little different than the bazooka dipoles I saw (for example RadioWavez)
HI Tim. Sorry slightly off subject but with the possability of lockdown restriction being eased over the next few months are there any plans to bring back the 145 alive events. Thanks... Richard
Thanks Tim, great video. Think I'll give this a go! Question (it may be a silly one): I have a Spiderbeam 12.5m mast but it's the aluminium telescopic. Being aluminimum, is that going to cause problems running this antenna up it? If so, maybe I could run it sloping away?
I’d avoid anything conductive to be near anything near the choke or above. This antenna is used either strung up a tree or better still attached to a fibreglass mast 73 and thanks for stopping by and commenting 👍
i've been procrastinating for ages about the best vertical antenna for me to get on 20 m. i've thought about an end fed half wave but was concerned about the "RF back down the braid" problem. i haven't seen a 20 meter "plant pot" till today. i think i'm sorted now.
It might be worth building an EFHW transformer and trying it, a bit of wire is lighter and easier to manage up the pole than coax. It would be nice to see a comparison of the two to see if there are any significant differences when using a transformer. If you're worried about RF back down the braid, you just use a choke, exactly the same way as for the flowerpot antenna (air coiled coax or ferrite, both should work) (but maybe put the choke closer to the transceiver in the case of the EFHW).
Hi, Tim. Do you recommend using that antenna with an earth? Would it improve reception? In fact is grounding essential for any HF aerial when running a maximum of 10 watts? 73, Rob.
Tim thanks for the video. Please can you elaborate a little more on your choice of choke. Why 15 T on a 110 former? I looked at the G2TXQ chart and its not clear to me what criteria I would use to pick 15T out of all the possibilities for 20 meters. Some of the other choices have much higher Xs @ 14 mHz, like 20 T on 110 mm, so why not any of those? Any further info much appreciated. 73 de k1jbd
Great info. Opinion, would a 40 m ham stick work as a EFHW 20 m dipole? Compromised yes, but for a second floor apartment balcony , it would solve issues.
No it wouldn’t. You would be better off using 2x 20m Hamsticks as a dipole maybe? Or… look up my latest video on the Slidewinder coil.. lots use this type for apartments and it’s multiband
I wonder how one of these might work if tossed out of a high rise window pointing down. If so it could be an apartment or condo dweller's solution. We have a local retirement tower that is 13 stories up. A family member lived there and I remember thinking a tossed out the window HF antenna might work there, well these single band resonate with a choke antannas could be a value as a Ham aproaches that time in thier life. Spread out some wire with a atrificial ground tuner and toss it out and go for it?
@@timg5tm941 Probably be wise to use a as long as you could pole to get it away from the building. If one researches a antenna can be found to fit any situation. 13 floors up it ought to see something even ground wave. Your simple to build solutions will help folks get on air Thanks for the effort making all your videos !!!
Tim, I like your ideas regarding a half wave vertical with a 64:1 balun. Is it possible to wind the antenna on a fiberglass rod that I can mount on a bicycle? I'm interested in running mobile CW with a QRP 20 meter radio without using antenna radials. Any ideas would be greatly appreciated. James - KW5CW
Great! A good smear of silicone grease or liquid insulation tape at the point where the braid is visible and sealed with a few inches of heat shrink over that point would make it very suitable for permanent outdoor use. Nice video.
Useful insight. The impedance changes the lower the antenna to ground. It could be that electrically your antenna became shorter as it was closer to ground so resonance shifted upwards in frequency.
Would another choke, at the rig, improve the noise issue, or is it inherently a vertical antenna issue? Try it and see I suppose is the obvious naswer to my own question. Grahame G6MZK
estou usando o google trabslate, então peço desculpas pela linguagem pobre: a bobina é um estrangulamento que impede qualquer rf viajar de volta pelo cabo coaxial. então a própria antenba está acima da bobina. 73 bom dx.
I drill the pipes at each end of the coax and secure the last windings with cable ties. I can’t countenance any antenna built without any cable ties. It’s unnatural.
@@timg5tm941 As a newish ham to the HF world, the home base antenna that doesn’t look like crap and doesn’t piss off the wife and neighbors is my struggle. Have you ever used ham sticks?
Tim can you put the measurements in American measurement please. I am not familiar with metric system. Thank you so much for the help.73 AE4OY William Peacock EM-81UF SOUTH EAST GEORGIA USA
I'm surprised this antenna is not more widely used on the Ham bands. I built one at the weekend and I'm astounded by its performance on 20 meters compared with my doublet which is 12 meters high. Worked Caribbean, central Africa , Mid and south America with ease now. Seams the perfect solution for so many Hams as no need at all for radials and nice low angle radiation pattern. Thanks for the inspiration Tim.... Dave G1NNR
That's great to hear Dave - Ill be trying another version of this soon but with hopefully a lighter choke - stay tuned!
Thanks for this Tim, Just had a lovely afternoon playing radio. I now have a 20 meter qtr wave vertical. A medium Dulux paint tin as a former, TV co-ax feeder, choke and antenna. SWR (cheap Chinese inline digital box) is showing slightly less than my Nano VNA suggested at around 1.34 in a gentle curve away from 14.2 Mhz. So didn't have to trim this vertical. The rain held off, so even the dog enjoyed being out in the garden. Will have a play later as the greyline moves towards us. Pete M0WHT
Fantastic!! Hope you enjoyed!
really nice ! like that spiderpole and that it doesnt need any radials, looking forward to your results on contest.
Thanks! Can’t wait to try it out
great video tim mate👍 never seen a 20m bazooka made before! top job👍👍
Thanks Joe!
Hi Tim, Tom KB0QIP here. I saw your podcast on QRZ this morning. I started to look for more info and found this gem of a video. I'm across the pond from you and we have our Field Day coming up in 2 weeks. I just happen to have some Mini 8 coax and will try to attempt to construct this antenna for 20 meters. If successful, I will have my radio club try it. Also just subscribed to your channel. I have you fellow Ham , M0MCX subscribed also. You both have a lot to offer the community and I look forward to more coming our way. Thank You for your work. Hope to see you on the radio soon. Tom
That’s very kind of you Tom! Please keep me updated how you get on with the antenna. I really appreciate your support 73
Another great vid showing the simplicity of homebrew antenna making.
Thank you Gary! 73
Hallo Tim, today i made this coax antenna. Only a little bit different. From the transceiver to the end of the coil i've used rg 58. After the coil i've used 75 ohm signal cable. The 7 mm one. And it works. For the coil its rg 58, 15 turns on pvc 75 mm. On the mfj analyser On 14.21 mhz 49 ohms ,near to 1:1 and x 2. So thanks for this video and this idea. Good luck and 73. Mvg. Hans
Brilliant Hans congratulations and enjoy the antenna!
Good antenna Tim, I have been using 1 a few years when Tom told me the dimensions worked 6 new dxcc on its first outing. Keep the videos coming. 73 👍👍
Brilliant !! Thanks for stopping by and commenting 73
I also have made one of these but I use a slightly different choke but it works very well and I’ve worked the world on mine.
Great vid Tim
Hard to beat for simplicity of build and ease of deployment aren’t they?
Nice new call sign Stu👌
Managed a couple of contacts in the Russian competition - the surprise of getting through caused brain fog and I'm sure my response was gibberish lol. The 450D was set at 10 watts but the inline tuner (well known Chinese atu 100) said erp was about 6 so I was not expecting any success but got a 5&9 report. Your 20 meter antenna looks great for static mobile easy set up. Look forward to hearing more Tim. 73 M7BLC
Hi John. That just goes to show that it's the antenna that matters, not the amount of power that you are running. A little extra power can definitely help, especially when the conditions are marginal but ultimately it's the antenna which does the heavy lifting.
As a side note, don't give too much credibility to signal reports received during contests. Contesters will nearly always give a 59 report irrelevant of how well they are copying you because it's quicker & easier for them to log. Most logging software automatically puts 59 in the signal report box. Giving them anything different means that they have to manually change it which slows them down in the contest.
I'm not saying that's right..........I personally would rather have a genuine signal report. Then again, I'm not really into contesting. I'll occasionally call the odd contest station & give away a few points for fun but I have little interest in contesting.
I've lost count of the number of times that I've had QSO's with contest stations where they have given me a 59 report.........then asked me to repeat my callsign several times as they were struggling to copy me!!!
It's sometimes funny to see how giving them a genuine signal report (of 57 for example) can throw them. I've had a couple of contesters get really quite annoyed with me for giving a genuine signal report!
Good to hear that you are making contacts. It's surprising what you can do with 10 watts.
Nice job John. Good on you for getting in there
"You are 59....again again?"
I do like these simple antennas, great if your garden is tiny! Ive just built a dipole for 15 Meters, unfortunately the band is open at the moment.
Next weekend it will magically open for the contest 😉
Used a commercially built version of this antenna today. Worked well with contacts on Azores, Turkey, and Russia. Will be building a homebrew version soon.
Great idea. They cost little to make. Glad you had success today 👍 73
Very nice video. I use an end fed half wave for 20 meters that is made from aluminium tubing. I match it with a home made 49:1 UNUN. It's a fantastic DX antenna that does not require any radials. The antenna uses the coax feeder as a counterpoise which is an old trick (no RF in the shack doing this). The same antenna can be made with 10 meters of wire. I used aluminium that is much thicker in order to maximize the bandwidth. The extremely low angle of radiation easily allows me to beat DX pile ups here in the USA while running only 100 Watts.
They are excellent antennas
Flower Pot Antenna - well done keep up the great work
Indeed! And thank you 73
Great video Tim, giving me ideas for antennas to use in my tiny garden when I get my HF set, thanks.
No problem Steve I’m glad to help and I hope you enjoy Hf
Think I have a couple of half rolls of cheap RG58 in the shed. Might try making one of these up for the /P we discussed. Nothing to loose :-)
Absolutely, go for it
Going to have a go at this Tim, I have some 40ft trees at the bottom of the garden, ideal for a stealthy operation, so the Mrs won't see them ha ha , great video's Paul M0BSW
Nice one Paul good luck
Hi,good informative video, 👌 you explained it in simple English, I don't need one yet, but you never know, thanks from Rotterdam 👍
Thank you and if you make one I hope you enjoy 73
Nice informative video, Tim! Cheers from Holland, 73! Alexander PD0ALX
Thanks! 73
Good luck in the contest and thanks for the video Tim 👍👏👏
Good one Tim! Easy to make and portable too 👍🏻 Might bump into you in WPX 😀
Thanks Ian I hope so
There is a variation on this design Tim that uses a variable capacitor across the choke. That turns the choke into a simple parallel tuned circuit. Effectively it acts as a bandstop filter that blocks the reflected power for passing the choke so you achieve pretty much 1:1 SWR at the null point. To do this, you need to bare a small section of coax on both the first and last turns of the choke and solder the capacitor across those points. A small broadcast band variable does the job nicely. It's very effective and a useful variation on the theme. John EI5JS
Thanks John 👍
@johnc3403 John do you now how many pf, wood be nice to make this with coax if it is noth to much??
Hi Tim one of your other videos l have ask how to make one of this antenna but l just watched this video now lovely ....
Keep up the good work mate...
Thanks!!
I was just thinking about building one of these not 3 days ago for static mobile dx, although the wife decided i need to decorate 😢, great vid bob on for me and reference when i put the paint brush down
Brilliant Tony. Hope you enjoy it
Nice one Tim.
I presume that there's no reason why you couldn't wind your choke on a ferrite ring, which (although more expensive) would make it smaller and a bit more portable?
I have one of the 22 meter Spiderbeam masts, so I'm thinking about giving this a go on 40m once the lockdown restrictions are lifted and I can go to my field.
It might also be fun to try on 80m if I can find a way of getting it 40m into the air (which I readily admit is an extraordinarily ambitious challenge).
Alternatively it could be configured as an inverted V, the same as you would a dipole. Might make a good portable NVIS antenna (maybe for SOTA).
Hi James. Yes G3TXQ in his choke chart has given that info for toroids. Worth a go
6 metres of RG58 about £3. FT240-43 from Mouser about £6-£8. So not that much more expensive. :-)
@@paulsengupta971 Fair enough, I thought that the ferrite rings were more expensive than that .
Great vid Tim, love my T2LT on 11/10m. I think I’ll have a go at this. My pole is only 10m mind so I’ll take a look at Spiderbeam too. Stay safe yourself buddy, 73.
Cheers Paddy good to hear from you buddy 73
@@timg5tm941 cheers Tim, I’m always watching just been a bit Keyboard shy lately, lol. Keep up the great work
Fun video! Thanks for sharing! 73
Thanks!
When you calculated the length, did you use the center frequency of the band? Thanks.
Excellent Tim. If my experiment goes as planned I would like to build a pair of something like this for QRO. any idea of the power handling? I'm thinking a beefed up version using RG142.
Thanks Colin. I have a friend who has squirted 400w up the same antenna design with no issues so might be worth a go
@@timg5tm941 worst case is I would use RG142 then silicone wire for the vertical.
Hi Tim good video
Cheers Andy 👍👍
Good job Tim 👍
Thanks!
So quiet comparing to an EFHW... talking about the noise level. Love it... and thank you for sharing. I didn't think of this at all. I was really wondering how could I have a vertical next to my house for DX for 20m. One question. If I was to use it for portable... instead of the big choke... I guess it should be ok if I use a regular one using a toroid ? Is a 1:1 right ? 73 DE YO6DXE.
Hi there, yes certainly possible!
@@timg5tm941 Perfect... that is good to know. 73 DE YO6DXE.
Great video! I like the antenna design, it would be good for hoa environment!
Thanks for sharing, much appreciated!
73 de VE3QJ (Good Dx)
Thank you! 73
excellent idea to get rid of the pipe .
Thanks 👍
Great video! I am just getting into home brew antennas.
Thank you! Once you start it becomes addictive!
@@timg5tm941 I can see why... I work in electrical engineering, so it's all interesting stuff!
Very nice Tim 👍
Thanks!
You say 10m was 5 turns. But I saw your video "T2LT - Half Wave Vertical Coaxial Antenna For CB Radio & 10 Metres" and it was 16 turns
I made mine with 16 turns
It’s more turns around the alternative narrower diameter choke
Definitely going to give this a go
Go for it!
Wonderful!!!! Thank you for prototyping this and making the video. Has anyone tried a design like this where you make a 90 bend at the dipole center in order to follow a horizontal attic space??? 2nd question: has anyone simply laid the antenna horizontal in an attic crawl space?
It can be deployed as an inverted L or horizontal but with some changes to the swr and impedance but worth a try
Thanks for the video Tim, I'm now a new subscriber!. I'm an SWL, and looking at a few antenna designs at the moment. I have some trees at the back of my house and I'll where a few verticals would work well. Sorry if this is an obvious question, but is the entire antenna including feed line one piece of coax ie no need to attach a connector after the choke?
Thanks for subscribing! Yes that’s right it’s one piece of rg58. You could also make it so that you can pigtail a thicker less lossy run of coax after the choke but unless this is a long run then rg58 will do just fine 73
@@timg5tm941 Many thanks!
Good job 73
Pretty cool.
Would it be the same thing to just use a type 31 ferrite choke at the appropriate point on the coax, as opposed to the air choke? (even though I recognize the appeal and simplicity of an antenna that’s basically all built from the same coax that you’re feeding it with).
I don’t think I’ve seen this one before-is there a name for it? Somebody in the comments made reference to a Bazooka, but it looks a little different than the bazooka dipoles I saw (for example RadioWavez)
Yes I’m looking into a generic choke for 20-10m. Usually these antennas are known as flower-pot or the T2LT
Tim have you tried putting multiple bands of the T2TL on a single pole, like a DX Commander but no radials required??
Too much interaction Jim. Quarter waves are ok to do this owing to low feedpoint impedances but halfwaves are a different animal 73
Tim, I have built them for 20-6 meters and they work great. All mounted on my 8’ chain link fence. I switch antennas with remote coax switch.
HI Tim. Sorry slightly off subject but with the possability of lockdown restriction being eased over the next few months are there any plans to bring back the 145 alive events. Thanks... Richard
To be confirmed Richard. Hopefully very soon
Thanks Tim, great video. Think I'll give this a go! Question (it may be a silly one): I have a Spiderbeam 12.5m mast but it's the aluminium telescopic. Being aluminimum, is that going to cause problems running this antenna up it?
If so, maybe I could run it sloping away?
I’d avoid anything conductive to be near anything near the choke or above. This antenna is used either strung up a tree or better still attached to a fibreglass mast 73 and thanks for stopping by and commenting 👍
Great video Tim, MW3ASG.
Diolch! 73
Nice one Tim :-))
Thanks 👍
i've been procrastinating for ages about the best vertical antenna for me to get on 20 m. i've thought about an end fed half wave but was concerned about the "RF back down the braid" problem. i haven't seen a 20 meter "plant pot" till today. i think i'm sorted now.
Give it a try 👍
It might be worth building an EFHW transformer and trying it, a bit of wire is lighter and easier to manage up the pole than coax. It would be nice to see a comparison of the two to see if there are any significant differences when using a transformer.
If you're worried about RF back down the braid, you just use a choke, exactly the same way as for the flowerpot antenna (air coiled coax or ferrite, both should work) (but maybe put the choke closer to the transceiver in the case of the EFHW).
Hi Tim is there a calculator out there please 73
Hi Tony. For the choke search G3TXQ choke calculator online. The radiating part of the antenna is just the good old half wave formula.
Do you see any problem using RG8X instead of RG58?
Should be fine if slightly less flexible.
Hi, Tim.
Do you recommend using that antenna with an earth? Would it improve reception? In fact is grounding essential for any HF aerial when running a maximum of 10 watts?
73, Rob.
No need for earth and in my (controversial maybe) opinion grounding might be preferred but isn’t essential
RF is a strange thing isn't it! Half the frequency, triple the turns on the choke.
Its voodoo!!
Tim thanks for the video. Please can you elaborate a little more on your choice of choke. Why 15 T on a 110 former? I looked at the G2TXQ chart and its not clear to me what criteria I would use to pick 15T out of all the possibilities for 20 meters. Some of the other choices have much higher Xs @ 14 mHz, like 20 T on 110 mm, so why not any of those? Any further info much appreciated. 73 de k1jbd
Hi, that chart has a green shade to denote the best choking effect per frequency. The 15 turn does its best choking around 14 MHz 73
Great info. Opinion, would a 40 m ham stick work as a EFHW 20 m dipole? Compromised yes, but for a second floor apartment balcony , it would solve issues.
No it wouldn’t. You would be better off using 2x 20m Hamsticks as a dipole maybe? Or… look up my latest video on the Slidewinder coil.. lots use this type for apartments and it’s multiband
I wonder how one of these might work if tossed out of a high rise window pointing down. If so it could be an apartment or condo dweller's solution. We have a local retirement tower that is 13 stories up. A family member lived there and I remember thinking a tossed out the window HF antenna might work there, well these single band resonate with a choke antannas could be a value as a Ham aproaches that time in thier life. Spread out some wire with a atrificial ground tuner and toss it out and go for it?
Sure it’ll work as a horizontal or vertical as long as its away from any structures and in clear space I’d say go for it
@@timg5tm941 Probably be wise to use a as long as you could pole to get it away from the building. If one researches a antenna can be found to fit any situation. 13 floors up it ought to see something even ground wave. Your simple to build solutions will help folks get on air Thanks for the effort making all your videos !!!
@@americaswayout4489 thank you and I hope the antenna works for you 73
Tim, I like your ideas regarding a half wave vertical with a 64:1 balun. Is it possible to wind the antenna on a fiberglass rod that I can mount on a bicycle? I'm interested in running mobile CW with a QRP 20 meter radio without using antenna radials. Any ideas would be greatly appreciated. James - KW5CW
Hi James - yes as long as the support is non conductive that may well work
It would be great if you could explain how the antenna is made and what the red part is on the graphic.
I did 73
I just made mine out of a half wavelength for 20 meters and fed it with a 49:1 unun and got a 1:1 swr across the entire band...ok 1:3 on the ends
Nice
Can you suggest a workaround for this antenna on a 10m fiberglass pole? Can I just run the bottom 2 meters horizontally to keep the SWR down?
Yes this can be done but may alter the impedance and very slightly the radiation pattern. I might model this to see.
Tim thanks you said this compares to a 1/2 wave dipole my question is with it mounted vertically is it vertically polarized?
Yes, but for HF, once it's bounced off the ionosphere, polarisation tends to be all over the shop anyway.
Yes John it is vertically polarised with the resultant lower angle of radiation suited to DX
Something didn't quite make sense Tim, can you edit the explaination for the braid? I comprehend it but some may be confused.
I’m a bit tied up to post edit if I’m honest. But it’s just a case of removing the braid and outer sleeve for the top 5.02m. 73
Great! A good smear of silicone grease or liquid insulation tape at the point where the braid is visible and sealed with a few inches of heat shrink over that point would make it very suitable for permanent outdoor use. Nice video.
@@mw0gbr1 good advice 👍👍
If you use air core coax, remember to seal the top bit too! :-)
Got the same on 11 meters. Very easy in portable, but have somme swr problems when the choke is under 3m from the ground.
Useful insight. The impedance changes the lower the antenna to ground. It could be that electrically your antenna became shorter as it was closer to ground so resonance shifted upwards in frequency.
Would another choke, at the rig, improve the noise issue, or is it inherently a vertical antenna issue? Try it and see I suppose is the obvious naswer to my own question. Grahame G6MZK
Indeed .. probably worth a go!
It's an inherent issue of the vertical antenna I think, due to the low angle of radiation picking up all the electrical noise from ground level.
Tim G5TM gostei da antena vertical 5.02 é só o mastro depois da bobina? serve para dx pw8br Amaral 73
estou usando o google trabslate, então peço desculpas pela linguagem pobre: a bobina é um estrangulamento que impede qualquer rf viajar de volta pelo cabo coaxial. então a própria antenba está acima da bobina. 73 bom dx.
I drill the pipes at each end of the coax and secure the last windings with cable ties. I can’t countenance any antenna built without any cable ties. It’s unnatural.
How much inductance does that choke have? Could I achieve the same result with torroid cores?
Yes. Look up G3TXQ's choke chart.
what about looking up W5JGV and see if you can get a Tree-Tenna onto 20 mtrs just altered it slightly sorry.
I’ll check that out
Jetsons? Showing your age Tim ! :)
I know lol
Hi Tim! Have you made a 40M 1/4 wave antenna with the coax? Do you have a video or dimensions?
No not a 1/4 wave. The design acts as a halfwave. So a halfwave on 40 is possible
@@timg5tm941 thnaks Tim
What kind of mast did you use? A link would be appreciated.
Any fibreglass telescopic mass is fine for this
@@timg5tm941 As a newish ham to the HF world, the home base antenna that doesn’t look like crap and doesn’t piss off the wife and neighbors is my struggle. Have you ever used ham sticks?
What cable should i use ,hyperflex 5 or ultraflex 7?
Rg58 is flexible enough
How do you enter that Contest Tim?
Just take part you don’t have to submit a log just use the correct exchange. Search for Hf 8 day contest calendar on google
can it also be done for 40m?
Yes - but with a toroid choke - see G3TXQ choke chart on that one.
Tim can you put the measurements in American measurement please. I am not familiar with metric system. Thank you so much for the help.73 AE4OY William Peacock EM-81UF SOUTH EAST GEORGIA USA
No problem.. about 16’ 3” per leg is all good. The choke diameter I think is just over 4 inches
Sorry T2LT!!
I like this a lot but you realise I am now going to have to spend a hundred quid on a pole 😭
You’ll get over it! I’m just seeing if spirit of the air has their 12m pole in stock it’s a bit cheaper