Nice video...I have built numerous verticals since 1952...My mentor taught me that the radials must be y made of the same material as the vertical element and to mount the base of the vertical element approximately 0.5 wave length above ground ( ie 8.5 feet for 20M)...You will only need 4 elevated radials as each radial overlaps covering approximately 100 degrees closing any dips in the lobes...Usually a 45 degree angle on the radials will get you close on SWR and impedance...Make your final adjustments with radial lengths and angles...It takes a lot of time but well worth the effort...HP4RWE/Ron
Nice video and good craftsmanship on the antenna build, Derek. If you enjoyed the lower recieve noise, just wait until you throw a 20 meter mono band yagi on top of a 40 foot tower! I was blown away at how quiet it was compared to my ground mounted hustler 5BTV. Speaking of the 5BTV, I recently relocated it to 16 foot above ground and following manufacturers installation recommendations, ran several tuned "raised" radials for each band of interest. It worked fine, and was quieter than when on the ground, but not much. I then moved it to 12 foot above ground and attached the 10 foot rigid steel mast to my RV's bumper and a unistrut bracket at the roofline, mast not touching the earth. I then bonded my radial plate to the metal skin of the RV and completely removed the raised wire radials. This is working extremely well and dare I say BETTER than any combination previously used. SWR is < 1.5 on all bands except for 40 meters, which is at 1.7. The takeoff angle must be better for DX than before, due to the locations of contacts I have made now compared to being ground mounted. I haven't tried to model it due to not having the program yet, but I will try to download the modeling software you gave the link to in the description, although, Im not sure if it's possible to model a 30' RV as a radial field. 😅 Anyway, thanks again for taking the time to document and explain things! Experimenting is truly the best part of the hobby, or at least it is for me. 73 DE KN6UIZ
Good video. It is refreshing to see someone, on TH-cam, that knows what He's talking about and shows, how to build an antenna properly, instead of going to the shop. I'm into this hobby for 46 years now. There are several people that make TH-cam video's and pretend to be elmers, but give the wrong or incomplete info. What They don't understand is, that if You don''t use a Common Mode Choke, the outside of the coax shield, becomes a radial.
Thank you very much. There's a lot of great information out there, but also a lot of fluff not backed by sound theory and test. Which is why I think it's important to show the result as well as any source of information that I'm unable to demonstrate. There's really something to be said for making your own equipment, antennas or otherwise. I may continue adding ham related content into the channel and hopefully folks are inspired to make and test their own equipment. True that without the CM choke, the feedline becomes part of the antenna system. Its on the list to make a video about chokes... now to find the time! Thanks again and 73
Run at least two or three extra coax runs to the same location. I see trees back there. Setup a dipole. All the labor for one coax is the same and you will want it later. Trust me. Also use 1 1/2" or 2" PVC water pipe (super cheap) and while running your cables pull some rope as well. Then later you can pull a new line or replace if needed. Great results by the way and looks like a stout antenna.
First one of your videos that I have caught and your monopole sounds like an interesting build and the performance comparison to your attic antenna was informative.
Lightning in Central Florida is kind of bonkers, and I've always wondered what HAMs did about that. Even without a direct lightning strike, I bet there are non-trivial electrostatic dangers for an outdoor antenna. FWIW, I turned it up when Beethoven started (though I prefer the 2nd movement from the 9th :)
Yes! I knew I forgot to cover something. I installed ground rods and have lightning arrestors on order. Maybe I'm paranoid, but I always unplug my gear. At least since we moved here 5 years ago. I've seen 3 trees with the bark blasted off in that time, and a very tall tree blown to half its height! Thunderstorms are a daily occurrence, so my coax connectors get a workout.
As you raise the base above ground, less current flows through lossy soil and more through radials. Droop the radials about 30 degrees and the feedpoint will be closer to 50 ohms. If you must ground mount, obstructions can be troublesome, and you need many more radials to achieve decent efficiency. It can be a good DX antenna. I've also used a 4:3 unun to get closer to 50 ohms.
Good job! Sadly many people don't read these scary paper things and just buy "a high efficient DX antenna" with a loading coil and single radial for only 200$. Happy to see another approach for a change. Hope to meet you on the bands!
True, I think it’s worthwhile to understand the theory enough to not sink your money into a $200 dummy load. As far as building antennas, I suppose it’s not for everyone. I have a hard time buying antennas, because physics is the same for the little guy as it is for company X. Why not use my scrap pile to make my own?! Give me a shout if you hear me on the air! 73
Thanks for making this video and presenting the facts and explantation in such a clear way. I'm in a similar situation regarding building a "stealth" antenna amongst trees and the information here will be very useful. Best 73s.
Very nice build quality! I'm a passionate POTA activator and designed the ideal portable antenna via 4NEC2 based upon portability, performance and efficiency. I went through many different antenna variations and settled on the elevated vertical (3-4' up) with two tuned elevated radials (90 degrees apart for some directionality). I call it my POTA PREDator = Portable, Resonant, Elevated, Directional. Not only can I get
Great video I also did some modeling on mmana and found that the antenna would work on 6 meters with a 3.18 swr and 15 meters with a swr of 1.94 so really its multiband for a mono band antenna good job....
Great to see another video from you. You're always working on some interesting stuff. I got a magloop in my apartment that covers 40m and 30m pretty nicely, mostly made out of 3d printed parts and pvc.
Thanks Angel. Loops are good fun. How are you feeding yours? I got best results with a #43 core. Currently working on a remote stepper controller for it, so I'll probably do an update soon.
Good build, reminded me of an antenna built by Crush Craft years ago that had a motorized remote tuning ability. It was an R3, if you search TH-cam for an R3 their is a video of the tuning unit. If you added something simular this vertical could then tune 17, 15, 12, 11, and 10 or even 6. I aquired the control box for the R3 but so far no luck with the box to mount at the antena. If you desired to build you remote unit, Icould make that little control box available. I live up in Panama City.
Just checked the R3 video on TH-cam.. looks to be the exact same capacitor that I have sitting in a box here. I’ll have to do a video on using that cap and see what kind of performance I can get. Thanks for the tip! And I’ll give you a shout if I end up doing it.
Enjoyed the video even though it doesn't apply to my situation. Can never learn too much! (I'm trying to do 80m on a city lot with no place at all for ground radials. Entire lot is buildings and concrete.)
Thanks! That sounds like a difficult situation. Have you considered a magloop antenna? I’ll have a video out in the next month or so on one for 40m.. maybe see if I can get it working on 80 as well.
@@AmRadPodcast I've looked at mag loops. The low Q, and extreme directionality have me looking elsewhere. Good to talk, lousy to listen! Also, the Huge variable capacitor needed is not something easily obtained anymore. It is a lot of systems to make the antenna useable. I'm building a redesigned TTFD at 124' and 20" spacing. Sloping from 14' to 36' AGL. Testing will determine the final termination resistance and the ratio of the balun.
Yep. Pretty much my experience too. ‘Course, a directional antoona will outreach your two, but that requires more, shall we say, real estate ;-). 73 de W8IJN
You answered some of my questions so now I have some work to do. I too have an indoor dipole and a TS440S and the background noise is horrendous, S+9 with antenna attached and nothing with antenna disconnected. Because of all this noise I don't listen very often and for only a short time. I'm going to give your vertical design a try and see what happens. Maybe I'll wait till the snow melts and the ground thaws though.
The 440 is a great radio (as long as you know how to fix the "Dreaded Dots"). Yeah, I'm back up to S7/9 for noise on the attic antenna. Really need to isolate where that's coming from. I hope to lay the coax next weekend for a permanent installation. Good luck and keep us posted on the results!
I also have the TS-440S with a 10 meter horizontal dipole in my attic and found most of my noise was coming from my high efficiency furnace and condensing unit. They use unshielded stat wire for communication between stat, furnace, and condensing unit rather than hard wired relay control. The indoor fan has an ECM motor and the outdoor unit has a variable frequency drive that converts my 240 single phase power into 3 phase power to drive the compressor. All very noisy. Chokes on each end of the comm cables and AC power inputs made a big difference in my noise levels. Thanks for the great video. 73. W3LOU
Great video! I was watching thinking to myself how cool it would be to use a 2" EMT with a reducer to 1.5" on top. Can you imagine the bandwidth of that set up? Great job tinkering with antennas. Thanks for your video!
Hey Donald. Thanks for the comment. I’ve heard of folks using conduit, but wonder about the losses. Lately I’ve been playing with EFHW and they’re much easier to deal with than a monopole.. I plan on doing an A/B comparison just for fun.
Have a look at the DX Commander (Antenna and TH-cam channel). I've a couple of those and they work very well indeed. I have about 25 radials around 2.5m long. The main difference is that you have multiple elements - kind of like a vertical fan dipole. I have 160m-2m on one antenna using inverted L configuration for 80m and 160m.
Ground conductivity is measured in millimhos/m. Low values are not ideal, higher the number, the better. Not sure if you’re in the US, but the FCC has a detailed map here: www.fcc.gov/media/radio/m3-ground-conductivity-map
@@AmRadPodcast i am not a ham but i am interested to get start, i think the video is understandable, some concept and therminology like swr has been covered also by other electronic channels
Greetings from Colombia. I am new in ham radio, I want to make and install my own antenna for 20 meters band, and I don't see all the real dimensions of your antenna and others details. Why two holes? What is the diameter of your antenna? What material is using for that? Exactly how meters tall? Why 3 radials instead of 1 radial? If you offer this details in a blog, please tell me the link. 73!
I ended up using #16AWG on a FT-240-43 core, but the SWR starts to rise up at the 17m band and above to uncomfortable levels. A few days later I tried "crossover winding" 17 turns of RG-58 on the same type core and it performed better than the magnet wire. Ok for a couple hundred watts, but not much above that. Soooo, I have more experimenting to do - probably with the camera on.
Im not lic. amateur radio operator but honestly, your explainations was too interesting for me...and im on MF and HF trying hard...cheeRs from PHILIPPINE ISLAND.
If one were to use galvanized steel pipe for the radiator, (TV antenna mast free in my case) how would that compare to copper wire on your modeling program. Same dimensions or longer/shorter ones? Thanks
That’s a tough one. Traditionally, for best performance we’re always told go with non-ferrous materials only. That makes sense to me at upper HF and certainly at VHF and above. I’ve heard of old timers using galvanized pipe or fence posts as HF antenna elements with no problem.. You’ll incur losses in the steel to some degree as it is ferrous, but on the other hand galvanized pipe is zinc coated and because of the skin effect the RF would flow mostly through that. I have no idea what the zinc thickness would be, nor would it be process controlled to a high standard.. I don’t think a “simple” program like mmana allows tweaking of parameters like that. Maybe someone with one of the pro simulators could chime in. High power AM stations use galvanized towers to transmit, so it wouldn’t be a total no-no. My advice would be, if it’s free, give it a shot! And definitely let me know if it works out for you. I want to look into this further. Regarding your question about length, the standard formulas apply, but I couldn’t tell you what the velocity factor is for galvanized pipe. So... if you want to go barefoot you’d need to go long and trim it back, or load it with a coil or a cap hat. I like to run without a tuner, so I’d take the ol angle grinder to it!
@@AmRadPodcast thanks, it was free from neighbor and exactly 33'-2". Seems like it was meant to me tried,lol. Later this summer, I lol have to try it. Maybe if it's not resonant, I can feed it as an end fed.
Hello, why a balun on a vertical monopole? It's a unbalanced antenna! Also I saw you tested the SWR of the balun... In that way you know the power reflected back, but not the most important thing: its insertion losses! How did you calculate that balun and how did you choose the mix for the toroid? 73s
It’s not a balun, it’s a common mode choke. You watched the entire video? Insertion loss is negligible with this choke. Type 31 vs type 43 core depends on frequency of interest. To learn more, google G3TXQ or see this article: gm3sek.files.wordpress.com/2019/01/G3TXQ-RC.pdf
@@AmRadPodcast The output of that thing is balanced: so it is a balun! It is written also at the beginning of the article you linked. Did you read it? The same article explains to you how to test a balun (the insertion losses first of all). In any case you haven't wound the coaxial cable on the toroid as in that article (losses practically equal to zero) but I can only see that you have wrapped many enamel copper turns (it is a real balun scheme) perhaps too many compared to the frequency, and for no reason because if all this is to fight RF currents on the outside of the cable, they come from a completely poor antenna ground plane. Instead of trying to fight them with a choke, increase your ground plane and you'll improve your antenna efficiency. Don't rely on the SWR to do this because when it reaches unity you will still have about 15 ohms of leakage resistance in the ground plane. This is because a perfectly efficient quarter-wave vertical exhibits a radiation resistance of about 36 ohms. However, this small mismatch is better than wasting almost a third of the power in the leakage resistance just to read an SWR equal to one!
MMANA-GAL is free and is the program I used in the video. It'll give you a rough idea about feedpoint impedance and elevation angle of propagation, help you optimize the length for resonance. BUT in my opinion, the best tools are an antenna analyzer, wire cutters and a spool of wire. Simulations can only go so far.
Stackclimber: I purchased the entire contents of a defunct radio/tv repair service. Too many thousands of components fro me to ever use. I will view the public comments section of this video for any interest. Not trying to make big $$, maybe no $$ at all. Sharing with others would be a good idea in this situation. Located in NW Florida/ Florabama.
@@AmRadPodcast I realize now from your question that I may be hammering the S/N ratio on your channel, which I did not realize or intend to do. My post was off-topic. My intent is not to sell parts, but to give them away. Most antenna builders are not just antenna purists, they dabble in electronics and other technologies. I bought maybe a quarter million components for $250.00. A real bargain, but I cannot store them for long. If I made my $250 back that would be great, but is not my main goal. In this situation, sharing with other hobbyists and fabricators is the right thing to do. Not trying to draft you into my effort. Again sorry if I intruded. Joe
I beg you to look into open feed line vs coax even 30$ a foot coax has .03% loss the lmr400 is .23 % down. Check out the The Toad Harbor Facebook page. With a balance tuner you’ll save 1/5 of your signal from loss. KC3ONO
For antennas with feedpoint near the earth, in a back yard, open wire line simply is not practical. If he had 100 ft of RG213 and 1.5 swr he only has 0.8 db loss at 14 mhz. Then you have to deal with matching at both ends. The Toad Harbor guys run OWL on 160 meters, to minimize loss? Look at the real numbers. Current Source is 100% right in his practices. Congrats to him. 73 de K2XT
Low loss, yes, but you would have to use a transformer at the base to convert to balanced, high impedance (open wire runs 200-600 ohms). True that you can run OWL with mismatch and into a tuner, but you must keep it balanced. Unless you're running a long way, probably not worth it. If you are interested in OWL, search for my call. 73 W4NEQ.
Nice video...I have built numerous verticals since 1952...My mentor taught me that the radials must be y made of the same material as the vertical element and to mount the base of the vertical element approximately 0.5 wave length above ground ( ie 8.5 feet for 20M)...You will only need 4 elevated radials as each radial overlaps covering approximately 100 degrees closing any dips in the lobes...Usually a 45 degree angle on the radials will get you close on SWR and impedance...Make your final adjustments with radial lengths and angles...It takes a lot of time but well worth the effort...HP4RWE/Ron
Nice video and good craftsmanship on the antenna build, Derek. If you enjoyed the lower recieve noise, just wait until you throw a 20 meter mono band yagi on top of a 40 foot tower! I was blown away at how quiet it was compared to my ground mounted hustler 5BTV. Speaking of the 5BTV, I recently relocated it to 16 foot above ground and following manufacturers installation recommendations, ran several tuned "raised" radials for each band of interest. It worked fine, and was quieter than when on the ground, but not much. I then moved it to 12 foot above ground and attached the 10 foot rigid steel mast to my RV's bumper and a unistrut bracket at the roofline, mast not touching the earth. I then bonded my radial plate to the metal skin of the RV and completely removed the raised wire radials. This is working extremely well and dare I say BETTER than any combination previously used. SWR is < 1.5 on all bands except for 40 meters, which is at 1.7. The takeoff angle must be better for DX than before, due to the locations of contacts I have made now compared to being ground mounted. I haven't tried to model it due to not having the program yet, but I will try to download the modeling software you gave the link to in the description, although, Im not sure if it's possible to model a 30' RV as a radial field. 😅 Anyway, thanks again for taking the time to document and explain things! Experimenting is truly the best part of the hobby, or at least it is for me.
73 DE KN6UIZ
I came here to subscribe to your channel after watching the interview on DX Commander. Great Job, Looking forward to browsing your content. 73/ NQ0A
Thanks Mark! It is much appreciated
I'm here because I saw your interview on DX Commander's channel
Good video. It is refreshing to see someone, on TH-cam, that knows what He's talking about and shows, how to build an antenna properly, instead of going to the shop. I'm into this hobby for 46 years now. There are several people that make TH-cam video's and pretend to be elmers, but give the wrong or incomplete info. What They don't understand is, that if You don''t use a Common Mode Choke, the outside of the coax shield, becomes a radial.
Thank you very much. There's a lot of great information out there, but also a lot of fluff not backed by sound theory and test. Which is why I think it's important to show the result as well as any source of information that I'm unable to demonstrate.
There's really something to be said for making your own equipment, antennas or otherwise. I may continue adding ham related content into the channel and hopefully folks are inspired to make and test their own equipment.
True that without the CM choke, the feedline becomes part of the antenna system. Its on the list to make a video about chokes... now to find the time! Thanks again and 73
Very informative. Thanks!
Run at least two or three extra coax runs to the same location. I see trees back there. Setup a dipole. All the labor for one coax is the same and you will want it later. Trust me. Also use 1 1/2" or 2" PVC water pipe (super cheap) and while running your cables pull some rope as well. Then later you can pull a new line or replace if needed. Great results by the way and looks like a stout antenna.
Excellent job, dear OM.
Many thanks for sharing!
FJ OM! TNX for sharing! My TS-440AT have dots in display! 73
Dots are an easy fix if you have tweezers and a bucket load of patience.
I’m a ham who works in broadcasting. Love seeing your speech processor behind you. Your aUdio is nice, even and smooth! Keep up the great work.
Thanks Rick. Good to get feedback from a professional!
First one of your videos that I have caught and your monopole sounds like an interesting build and the performance comparison to your attic antenna was informative.
Great Video. Fantastic antenna also.
Nice one, the explanation at 11.55 minutes in is really helpful.
Lightning in Central Florida is kind of bonkers, and I've always wondered what HAMs did about that. Even without a direct lightning strike, I bet there are non-trivial electrostatic dangers for an outdoor antenna.
FWIW, I turned it up when Beethoven started (though I prefer the 2nd movement from the 9th :)
Yes! I knew I forgot to cover something. I installed ground rods and have lightning arrestors on order. Maybe I'm paranoid, but I always unplug my gear. At least since we moved here 5 years ago. I've seen 3 trees with the bark blasted off in that time, and a very tall tree blown to half its height! Thunderstorms are a daily occurrence, so my coax connectors get a workout.
As you raise the base above ground, less current flows through lossy soil and more through radials. Droop the radials about 30 degrees and the feedpoint will be closer to 50 ohms. If you must ground mount, obstructions can be troublesome, and you need many more radials to achieve decent efficiency. It can be a good DX antenna. I've also used a 4:3 unun to get closer to 50 ohms.
Good job! Sadly many people don't read these scary paper things and just buy "a high efficient DX antenna" with a loading coil and single radial for only 200$. Happy to see another approach for a change. Hope to meet you on the bands!
True, I think it’s worthwhile to understand the theory enough to not sink your money into a $200 dummy load. As far as building antennas, I suppose it’s not for everyone. I have a hard time buying antennas, because physics is the same for the little guy as it is for company X. Why not use my scrap pile to make my own?! Give me a shout if you hear me on the air! 73
Thanks for making this video and presenting the facts and explantation in such a clear way. I'm in a similar situation regarding building a "stealth" antenna amongst trees and the information here will be very useful. Best 73s.
Very nice build quality! I'm a passionate POTA activator and designed the ideal portable antenna via 4NEC2 based upon portability, performance and efficiency. I went through many different antenna variations and settled on the elevated vertical (3-4' up) with two tuned elevated radials (90 degrees apart for some directionality). I call it my POTA PREDator = Portable, Resonant, Elevated, Directional. Not only can I get
Great video I also did some modeling on mmana and found that the antenna would work on 6 meters with a 3.18 swr and 15 meters with a swr of 1.94 so really its multiband for a mono band antenna good job....
Great to see another video from you. You're always working on some interesting stuff. I got a magloop in my apartment that covers 40m and 30m pretty nicely, mostly made out of 3d printed parts and pvc.
Thanks Angel. Loops are good fun. How are you feeding yours? I got best results with a #43 core. Currently working on a remote stepper controller for it, so I'll probably do an update soon.
I also use an attic dipole with great results as long as my wife isn't running the dryer
Funny, I can’t use my attic dipole at more than 10 watts because it makes our dryer front panel go berserk.
Good build, reminded me of an antenna built by Crush Craft years ago that had a motorized remote tuning ability. It was an R3, if you search TH-cam for an R3 their is a video of the tuning unit. If you added something simular this vertical could then tune 17, 15, 12, 11, and 10 or even 6. I aquired the control box for the R3 but so far no luck with the box to mount at the antena. If you desired to build you remote unit, Icould make that little control box available. I live up in Panama City.
Just checked the R3 video on TH-cam.. looks to be the exact same capacitor that I have sitting in a box here. I’ll have to do a video on using that cap and see what kind of performance I can get. Thanks for the tip! And I’ll give you a shout if I end up doing it.
Excellent
Enjoyed the video even though it doesn't apply to my situation. Can never learn too much! (I'm trying to do 80m on a city lot with no place at all for ground radials. Entire lot is buildings and concrete.)
Thanks! That sounds like a difficult situation. Have you considered a magloop antenna? I’ll have a video out in the next month or so on one for 40m.. maybe see if I can get it working on 80 as well.
@@AmRadPodcast I've looked at mag loops. The low Q, and extreme directionality have me looking elsewhere. Good to talk, lousy to listen! Also, the Huge variable capacitor needed is not something easily obtained anymore. It is a lot of systems to make the antenna useable. I'm building a redesigned TTFD at 124' and 20" spacing. Sloping from 14' to 36' AGL. Testing will determine the final termination resistance and the ratio of the balun.
Yep. Pretty much my experience too. ‘Course, a directional antoona will outreach your two, but that requires more, shall we say, real estate ;-). 73 de W8IJN
Haha.. I just watched this again Derek! Giood work as always :)
Thanks Callum. Hope you’re having a good holiday (and you didn’t bring too much gear with you)!
@@AmRadPodcast Hahaha not too much!!!
You answered some of my questions so now I have some work to do.
I too have an indoor dipole and a TS440S and the background noise is horrendous, S+9 with antenna attached and nothing with antenna disconnected.
Because of all this noise I don't listen very often and for only a short time.
I'm going to give your vertical design a try and see what happens.
Maybe I'll wait till the snow melts and the ground thaws though.
The 440 is a great radio (as long as you know how to fix the "Dreaded Dots"). Yeah, I'm back up to S7/9 for noise on the attic antenna. Really need to isolate where that's coming from. I hope to lay the coax next weekend for a permanent installation. Good luck and keep us posted on the results!
I also have the TS-440S with a 10 meter horizontal dipole in my attic and found most of my noise was coming from my high efficiency furnace and condensing unit. They use unshielded stat wire for communication between stat, furnace, and condensing unit rather than hard wired relay control. The indoor fan has an ECM motor and the outdoor unit has a variable frequency drive that converts my 240 single phase power into 3 phase power to drive the compressor. All very noisy. Chokes on each end of the comm cables and AC power inputs made a big difference in my noise levels.
Thanks for the great video. 73. W3LOU
Great video! I was watching thinking to myself how cool it would be to use a 2" EMT with a reducer to 1.5" on top. Can you imagine the bandwidth of that set up? Great job tinkering with antennas. Thanks for your video!
Hey Donald. Thanks for the comment. I’ve heard of folks using conduit, but wonder about the losses. Lately I’ve been playing with EFHW and they’re much easier to deal with than a monopole.. I plan on doing an A/B comparison just for fun.
@@AmRadPodcast Thanks for your reply. I have been using EFHW antennas in my HOA and have really good luck with them!
Good build!
cool video, nice job
Have a look at the DX Commander (Antenna and TH-cam channel). I've a couple of those and they work very well indeed. I have about 25 radials around 2.5m long. The main difference is that you have multiple elements - kind of like a vertical fan dipole. I have 160m-2m on one antenna using inverted L configuration for 80m and 160m.
Yeah Callum has a nice product. Great channel too. I just have a pile of DX Engineering fiberglass poles that I need to do something with!
@@AmRadPodcast well you can adapt his basic design to those I'm sure. If you have a few and enough space maybe make a vertical yagi :)
Very good video thank you
Outstanding being in Florida, go to the beach and add more rectals
Good stuff, I to have a mostly sandy ground, can you explain what ground is good, vs what is bad?
Ground conductivity is measured in millimhos/m. Low values are not ideal, higher the number, the better. Not sure if you’re in the US, but the FCC has a detailed map here: www.fcc.gov/media/radio/m3-ground-conductivity-map
This stuff is interesting
Thanks. I think most people that watch aren't hams, so I wasn't sure how it'd be received.
@@AmRadPodcast i am not a ham but i am interested to get start, i think the video is understandable, some concept and therminology like swr has been covered also by other electronic channels
Very interesting vid--tnx & 73 de WA4ELW in TN
Great project! Thanks for inspiration! 73 de LA6UOA!
Hi can you please do a video regarding the common mode choke you used in this video 2x12 turns ? And connections thanks
Excellent video and really informative. Thanks for putting this together. Liked and sub’ed! 73 de K2CJB
Greetings from Colombia. I am new in ham radio, I want to make and install my own antenna for 20 meters band, and I don't see all the real dimensions of your antenna and others details. Why two holes? What is the diameter of your antenna? What material is using for that? Exactly how meters tall? Why 3 radials instead of 1 radial? If you offer this details in a blog, please tell me the link. 73!
The WSPR test was interesting. How do you do it??
Love it
For that UHF/VHF radials, what if you just had a metal disc instead of radials?
Would 10awg solid core wire be good for 6/10m 1/4 radials?
What wire did you use for the common mode choke windings please ? Great looking project BTW
I ended up using #16AWG on a FT-240-43 core, but the SWR starts to rise up at the 17m band and above to uncomfortable levels. A few days later I tried "crossover winding" 17 turns of RG-58 on the same type core and it performed better than the magnet wire. Ok for a couple hundred watts, but not much above that. Soooo, I have more experimenting to do - probably with the camera on.
Im not lic. amateur radio operator but honestly, your explainations was too interesting for me...and im on MF and HF trying hard...cheeRs from PHILIPPINE ISLAND.
If one were to use galvanized steel pipe for the radiator, (TV antenna mast free in my case) how would that compare to copper wire on your modeling program. Same dimensions or longer/shorter ones? Thanks
That’s a tough one. Traditionally, for best performance we’re always told go with non-ferrous materials only. That makes sense to me at upper HF and certainly at VHF and above. I’ve heard of old timers using galvanized pipe or fence posts as HF antenna elements with no problem.. You’ll incur losses in the steel to some degree as it is ferrous, but on the other hand galvanized pipe is zinc coated and because of the skin effect the RF would flow mostly through that. I have no idea what the zinc thickness would be, nor would it be process controlled to a high standard.. I don’t think a “simple” program like mmana allows tweaking of parameters like that. Maybe someone with one of the pro simulators could chime in. High power AM stations use galvanized towers to transmit, so it wouldn’t be a total no-no. My advice would be, if it’s free, give it a shot! And definitely let me know if it works out for you. I want to look into this further.
Regarding your question about length, the standard formulas apply, but I couldn’t tell you what the velocity factor is for galvanized pipe. So... if you want to go barefoot you’d need to go long and trim it back, or load it with a coil or a cap hat. I like to run without a tuner, so I’d take the ol angle grinder to it!
@@AmRadPodcast thanks, it was free from neighbor and exactly 33'-2". Seems like it was meant to me tried,lol. Later this summer, I lol have to try it. Maybe if it's not resonant, I can feed it as an end fed.
Hello, why a balun on a vertical monopole? It's a unbalanced antenna!
Also I saw you tested the SWR of the balun... In that way you know the power reflected back, but not the most important thing: its insertion losses!
How did you calculate that balun and how did you choose the mix for the toroid? 73s
It’s not a balun, it’s a common mode choke. You watched the entire video? Insertion loss is negligible with this choke. Type 31 vs type 43 core depends on frequency of interest. To learn more, google G3TXQ or see this article: gm3sek.files.wordpress.com/2019/01/G3TXQ-RC.pdf
@@AmRadPodcast The output of that thing is balanced: so it is a balun! It is written also at the beginning of the article you linked. Did you read it? The same article explains to you how to test a balun (the insertion losses first of all). In any case you haven't wound the coaxial cable on the toroid as in that article (losses practically equal to zero) but I can only see that you have wrapped many enamel copper turns (it is a real balun scheme) perhaps too many compared to the frequency, and for no reason because if all this is to fight RF currents on the outside of the cable, they come from a completely poor antenna ground plane. Instead of trying to fight them with a choke, increase your ground plane and you'll improve your antenna efficiency.
Don't rely on the SWR to do this because when it reaches unity you will still have about 15 ohms of leakage resistance in the ground plane. This is because a perfectly efficient quarter-wave vertical exhibits a radiation resistance of about 36 ohms. However, this small mismatch is better than wasting almost a third of the power in the leakage resistance just to read an SWR equal to one!
Excellent advice. Have a good day sir. 73
i intend to build a 11 meter 1/4 wave ground plane. i would like to know about antenna modeling . is there a free tool online ?
MMANA-GAL is free and is the program I used in the video. It'll give you a rough idea about feedpoint impedance and elevation angle of propagation, help you optimize the length for resonance. BUT in my opinion, the best tools are an antenna analyzer, wire cutters and a spool of wire. Simulations can only go so far.
Interesting 🤔
Thanks but all I can afford is a Tecsun PL 660!
Hey that looks like a neat radio... AND has an external antenna jack. Let me know if it works out.
Stackclimber: I purchased the entire contents of a defunct radio/tv repair service. Too many thousands of components fro me to ever use. I will view the public comments section of this video for any interest. Not trying to make big $$, maybe no $$ at all. Sharing with others would be a good idea in this situation. Located in NW Florida/ Florabama.
I’m not sure I understand what this has to do with an antenna. You want to sell components to people in the comments?
@@AmRadPodcast I realize now from your question that I may be hammering the S/N ratio on your channel, which I did not realize or intend to do. My post was off-topic. My intent is not to sell parts, but to give them away. Most antenna builders are not just antenna purists, they dabble in electronics and other technologies. I bought maybe a quarter million components for $250.00. A real bargain, but I cannot store them for long. If I made my $250 back that would be great, but is not my main goal. In this situation, sharing with other hobbyists and fabricators is the right thing to do. Not trying to draft you into my effort. Again sorry if I intruded. Joe
I beg you to look into open feed line vs coax even 30$ a foot coax has .03% loss the lmr400 is .23 % down. Check out the The Toad Harbor Facebook page. With a balance tuner you’ll save 1/5 of your signal from loss. KC3ONO
For antennas with feedpoint near the earth, in a back yard, open wire line simply is not practical. If he had 100 ft of RG213 and 1.5 swr he only has 0.8 db loss at 14 mhz. Then you have to deal with matching at both ends. The Toad Harbor guys run OWL on 160 meters, to minimize loss? Look at the real numbers. Current Source is 100% right in his practices. Congrats to him. 73 de K2XT
Low loss, yes, but you would have to use a transformer at the base to convert to balanced, high impedance (open wire runs 200-600 ohms). True that you can run OWL with mismatch and into a tuner, but you must keep it balanced. Unless you're running a long way, probably not worth it. If you are interested in OWL, search for my call. 73 W4NEQ.
Enjoyed your video. de K9BBQ