K7RAW-The Antenna Whisperer and designer of the NoodleTenna here to help you SUCCEED with your 20m NoodleTenna. First off, nice job in construction. You showed a pretty decent SWR at timestamp 7:13, just a bit high (14.88 MHz) in frequency so you know it can resonate. You just need to realize that this is simply a physically-shortened but electrically identical antenna to a classic wire dipole (like the well-known "Slinky Dipole") which is technically called a "continuously-loaded dipole". A couple of suggestions: 1) Add a "common-mode choke" (in this case a 1:1 BalUn) located at the antenna to isolate your feedline from the antenna. Evidence for needing this is any effects on SWR from nearby metal. A "coax-wound" CMC on an FT-240-31 toroid is ideal; 2) Run the feedline 90 degrees from the NoodleTenna to minimize interaction. Mounting the NoodleTenna horizontally makes this easy (like down the vertical mast tubing); 3) Set up your NanoVNA properly (frequency range first, THEN calibrate). Then you can easily see whether you have an open, a short or something close to 50 ohms ; 4) Make the legs EXACTLY the SAME LENGTHS (and fold-back the extra wire under the last turns) so you can adjust the turns to get a VERY GOOD SWR match, otherwise you will never get a good SWR (high SWR minimum means unequal turns); 5) You DO NOT NEED A TUNER because this is a resonant antenna with close to 50 ohm impedance (no ground, no radials, no impedance transformer). This design is nearly identical to the classic "Slinky dipole" which many people have had lots of success with (only I use good-conducting wire instead of the Slinky's poorly-conducting spring steel). The stiff noodle and PVC backbone does not seem to degrade performance over an air-core Slinky. The shortened design makes it somewhat less sensitive on the receive side but does not affect the transmit efficiency. Avoiding noise-generators nearby like high tension power lines will lower your background noise. So PLEASE, BEFORE you "bad-mouth" someone's design, maybe you should seek out a little help from a knowledgable antenna builder to show you how to implement my suggestions above to succeed. I've had lots of people build my NoodleTenna and make lots of QRP QSOs. If you want some help getting good results with this antenna I can walk you thru the simple process. Just email me at rudi@wiedemann.cc. I'm THAT CONFIDENT I can show you success with this antenna. You are SO CLOSE to the finish line. 73....Rudi the Antenna Whisperer.
The antenna is a helically wound linearly loaded dipole. There will be interactions with the enviroment. Trying to tune it to resonance indoors may not predict its performance outside. Hight above ground might be playing a factor. The idea of adding telescoping whips to either end and tuning the antenna using them may be a good suggetion. Just a few inches of straight wire or some wires in a fan configuration might improve its performance. The role of the coax feeder has to be considered. A current choke close to the feed point might make the performance more reproducible. Antennas of similar design are going to be be sharply tuned and you may have to decide what portion of 20m you intend to operate.
I love this video - simply because it shows a true amateur experiment that failed. Together with the comments this is a great learning experience. More of that!
Your feedline may be coupling with your radiator. Make sure your feedline is perpendicular to radiating element. I use a vertical 20m OCFD antenna and had high swr when my feedline was was not at a 90 degree angle from the feedpoint. Good Luck Ross, K8RLB
@@mysteryham4065 the description on K7RAW's noodletenna video mentions using a Mix 31 ferrite choke (which is sometimes called a balun; when he says "no balun" he is sort of using the narrow definition of a balun). Years ago I played around with slinky dipoles and frequently had issues getting it to tune. I suspect this was largely because I didn't discover the importance of chokes. You can do an air-core choke (no ferrites required) if you have some extra coax. Somewhere in my junk drawer I have an air-core balun that I made wrapping coax around a plastic water bottle. For lower bands you'll want to use a larger form. For higher bands, probably fewer turns are needed. Ferrites just make the job easier because it means having to coil fewer feet of coax (which can get lossy, btw, when you have non-trivial SWR).
Partner, what you made was a large loading coil. Add a stinger to each end and the performance will increase. Adjust the coil count for better tuning. A loading coil is only one part of the antenna system. Experimenting is the fun part of the hobby. Good luck.
This is NOT just a big HamStick dipole (which isn't that efficient). I've tried your suggestion with little success. Please read my comments for more details of how this design works.
Love your little mcHF transceiver! I really like mine. Bought it 2nd hand but won’t sell it. I’ve tried the slinky dipoles. They work, not great but it was fun (to me) trying.
Thanks. Sometimes I like the RS-978 and sometimes not so much. But most recently I like it again. Some guy was selling it out of the back of his pickup truck at Hamvention 2023 and I went for it. Thanks for stopping by.
Another thing you might consider doing is building a 49:1 balun and then using a noodletenna as an end-fed half-wave. That means you can feed it from the bottom, and also will work on some frequency multiples. I've seen some videos of people making end-fed slinky antennas that work well on 40 meters and 15 meters. You will need some short counterpoise wires but should be a lot easier to deal with than a traditional 1/4 wave vertical (which requires a bunch of 1/8 or a few 1/4 wave radials). Here's an example of a slinky in EFHW mode: ua-cam.com/video/RejzmpjhTwU/v-deo.html You can build a 49:1 balun cheaper than you can buy, fwiw. Basically you need some wire and a toroid ferrite.
The z of a heavily loaded dipole is less than 10ohms. Maybe 5 ohms. You could make it work but the z is one of 2 problems. The other is that, unless its on a tall mast, it needs to be horizontal so both sides are balanced to ground. Apart from that , it's perfect 😂
If you touch the outside of your coax connector and the SWR changes your getting RF on your coax (Common Mode Currents), and therefore false SWR readings. Your coax needs to be decoupled with a 1:1 balun or ferrite chokes, AKA Common Mode Choke, before your radio to stop this. Any loaded shortened antenna like this will be less efficient than a stretched out wire. Antennas are sensitive to their environments, especially metal in their environment, especially indoors, as your finding out. Antennas prefer wide open spaces, ABOVE things in their environment. The further away from your living area, the less QRM / man made noise from digital devices within your home will affect your reception. The odds were stacked against your setup working well. ALWAYS make wire antennas longer than you think you need (lower frequency) them trim them to increase resonance to your desired center frequency. Too high a resonant frequency, too short the antenna. 73 -mike
Your down too low in the 20 meter band. You were down below the frequencies they were using, unless you were shooting for the CW stations. You might try this on 10 meters. This might work better with your SWR
K7RAW-The Antenna Whisperer and designer of the NoodleTenna here to help you SUCCEED with your 20m NoodleTenna. First off, nice job in construction. You showed a pretty decent SWR at timestamp 7:13, just a bit high (14.88 MHz) in frequency so you know it can resonate. You just need to realize that this is simply a physically-shortened but electrically identical antenna to a classic wire dipole (like the well-known "Slinky Dipole") which is technically called a "continuously-loaded dipole".
A couple of suggestions: 1) Add a "common-mode choke" (in this case a 1:1 BalUn) located at the antenna to isolate your feedline from the antenna. Evidence for needing this is any effects on SWR from nearby metal. A "coax-wound" CMC on an FT-240-31 toroid is ideal; 2) Run the feedline 90 degrees from the NoodleTenna to minimize interaction. Mounting the NoodleTenna horizontally makes this easy (like down the vertical mast tubing); 3) Set up your NanoVNA properly (frequency range first, THEN calibrate). Then you can easily see whether you have an open, a short or something close to 50 ohms ; 4) Make the legs EXACTLY the SAME LENGTHS (and fold-back the extra wire under the last turns) so you can adjust the turns to get a VERY GOOD SWR match, otherwise you will never get a good SWR (high SWR minimum means unequal turns); 5) You DO NOT NEED A TUNER because this is a resonant antenna with close to 50 ohm impedance (no ground, no radials, no impedance transformer). This design is nearly identical to the classic "Slinky dipole" which many people have had lots of success with (only I use good-conducting wire instead of the Slinky's poorly-conducting spring steel). The stiff noodle and PVC backbone does not seem to degrade performance over an air-core Slinky. The shortened design makes it somewhat less sensitive on the receive side but does not affect the transmit efficiency. Avoiding noise-generators nearby like high tension power lines will lower your background noise.
So PLEASE, BEFORE you "bad-mouth" someone's design, maybe you should seek out a little help from a knowledgable antenna builder to show you how to implement my suggestions above to succeed. I've had lots of people build my NoodleTenna and make lots of QRP QSOs. If you want some help getting good results with this antenna I can walk you thru the simple process. Just email me at rudi@wiedemann.cc. I'm THAT CONFIDENT I can show you success with this antenna. You are SO CLOSE to the finish line. 73....Rudi the Antenna Whisperer.
I'm curios now as to what you whisper to these antenna's.....should we be concerned 😜😜😜
@@bitemykrank1970 I whisper "sweet nothings" in their ear (or feed point), HA HA
Thanks those are very good points
@@rudiwiedemann8173 can't wait to try to build this.
The antenna is a helically wound linearly loaded dipole. There will be interactions with the enviroment. Trying to tune it to resonance indoors may not predict its performance outside. Hight above ground might be playing a factor. The idea of adding telescoping whips to either end and tuning the antenna using them may be a good suggetion. Just a few inches of straight wire or some wires in a fan configuration might improve its performance. The role of the coax feeder has to be considered. A current choke close to the feed point might make the performance more reproducible.
Antennas of similar design are going to be be sharply tuned and you may have to decide what portion of 20m you intend to operate.
Good advice. Thanks.
I love this video - simply because it shows a true amateur experiment that failed. Together with the comments this is a great learning experience. More of that!
I think you need a Balun at the feed point ?
I think it may play better horizontally ?
🤔.....?
I was thinkin g it might be good horizontal, and hung on my porch, on hooks It could be a horizontal POTA if needed
Your feedline may be coupling with your radiator. Make sure your feedline is perpendicular to radiating element. I use a vertical 20m OCFD antenna and had high swr when my feedline was was not at a 90 degree angle from the feedpoint.
Good Luck
Ross, K8RLB
That is an excellent point. I will try that!
@@mysteryham4065 the description on K7RAW's noodletenna video mentions using a Mix 31 ferrite choke (which is sometimes called a balun; when he says "no balun" he is sort of using the narrow definition of a balun).
Years ago I played around with slinky dipoles and frequently had issues getting it to tune. I suspect this was largely because I didn't discover the importance of chokes.
You can do an air-core choke (no ferrites required) if you have some extra coax. Somewhere in my junk drawer I have an air-core balun that I made wrapping coax around a plastic water bottle. For lower bands you'll want to use a larger form. For higher bands, probably fewer turns are needed.
Ferrites just make the job easier because it means having to coil fewer feet of coax (which can get lossy, btw, when you have non-trivial SWR).
Partner, what you made was a large loading coil. Add a stinger to each end and the performance will increase. Adjust the coil count for better tuning. A loading coil is only one part of the antenna system. Experimenting is the fun part of the hobby. Good luck.
Indeed. That makes sense. Thanks for stopping by!
This is NOT just a big HamStick dipole (which isn't that efficient). I've tried your suggestion with little success. Please read my comments for more details of how this design works.
Love your little mcHF transceiver! I really like mine. Bought it 2nd hand but won’t sell it. I’ve tried the slinky dipoles. They work, not great but it was fun (to me) trying.
Thanks. Sometimes I like the RS-978 and sometimes not so much. But most recently I like it again. Some guy was selling it out of the back of his pickup truck at Hamvention 2023 and I went for it. Thanks for stopping by.
Another thing you might consider doing is building a 49:1 balun and then using a noodletenna as an end-fed half-wave. That means you can feed it from the bottom, and also will work on some frequency multiples. I've seen some videos of people making end-fed slinky antennas that work well on 40 meters and 15 meters. You will need some short counterpoise wires but should be a lot easier to deal with than a traditional 1/4 wave vertical (which requires a bunch of 1/8 or a few 1/4 wave radials).
Here's an example of a slinky in EFHW mode: ua-cam.com/video/RejzmpjhTwU/v-deo.html
You can build a 49:1 balun cheaper than you can buy, fwiw. Basically you need some wire and a toroid ferrite.
The z of a heavily loaded dipole is less than 10ohms. Maybe 5 ohms. You could make it work but the z is one of 2 problems. The other is that, unless its on a tall mast, it needs to be horizontal so both sides are balanced to ground.
Apart from that , it's perfect 😂
If you touch the outside of your coax connector and the SWR changes your getting RF on your coax (Common Mode Currents), and therefore false SWR readings. Your coax needs to be decoupled with a 1:1 balun or ferrite chokes, AKA Common Mode Choke, before your radio to stop this.
Any loaded shortened antenna like this will be less efficient than a stretched out wire.
Antennas are sensitive to their environments, especially metal in their environment, especially indoors, as your finding out.
Antennas prefer wide open spaces, ABOVE things in their environment.
The further away from your living area, the less QRM / man made noise from digital devices within your home will affect your reception.
The odds were stacked against your setup working well.
ALWAYS make wire antennas longer than you think you need (lower frequency) them trim them to increase resonance to your desired center frequency. Too high a resonant frequency, too short the antenna.
73 -mike
Try it horizontal
Your down too low in the 20 meter band. You were down below the frequencies they were using, unless you were shooting for the CW stations. You might try this on 10 meters. This might work better with your SWR
take your time when building . looks rushed to me .
does not look ridiculous
need more round😅