Induction Coils for Ham Radio Antennas - TheSmokinApe
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- Опубліковано 1 січ 2025
- Induction Coils for Ham Radio - TheSmokinApe
Just a short video where I discuss Induction Coils, how they are used in Ham Radio and show of one that I recently built.
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TheSmokinApe
Hello SmokinApe
I am a Ham radio operator from the Netherlands, PD5FS.
With interest I follow your videos on all matters concerning this hobby.
And I just want to say that all your lessons on antenna building are much appreciated by me.
I enjoy following all new instruction videos.
Greetings from the Netherlands
That’s awesome Frans, glad they are helpful 👍
Even though I have very little experience in ham at all I was able to understand and follow along and can see this info benefiting me soon enough. I like how you talked about where you went wrong in making the first one and now we shouldn’t make the same error and also liked how you just shrugged it off as we should. Thanks!
Thanks Randy, I have to admit I had a hard time figuring out how the message the content. I'm glad it came across In a way that was consumable 👍
Hello, I Am The Guy Who Made That 80 To 10 Meters Diagram, Im Glad That It Is Used.. 73
That is awesome, thanks for putting it together!!!
@@TheSmokinApe Thanks For The Great Video
@@krisraps Glad you liked it 👍
@KrisRaps fine job on the diagram.
Hi Kris!
Where is your diagram and article published? I think I saw it online in an edition of the "Radio Communications Handbook," by the Radio Society of Great Britain, but haven't been able to track down the specific edition.
Thanks!
73,
John - KK7JBZ
Thank you.. most enlightening and now I am 81 with short term memory problems is simple enough for me to follow HI
Glad you liked it Trig!
Your clear obviously student-oriented presentations help and inspire me. I’m 75 and have been a ham since the 80s and had an Elmer who was detailed, gentlemanly, soft spoken, and encyclopedic beyond what Google could put up as competition. He spoke to me hours a day for about 8 years, and I was really unworthy of such great beneficence. I think you are that kind of teacher and you are needed in this culture-a solid staid measured scientifically wise teacher. God bless you man. -Glenn N5MCH
Wow, thank you and thanks for watching Glenn!
Clear and informative Ape! I especially like the idea of having follow-on videos as the project progresses!
Thanks Phil, working on the antenna video now. It's turning out to be a promising antenna 👍
Great explanation. Thanks Ape! Looking forward to the antenna build.
Thanks Jason! Hope you are doing well 👍
Keep doing these....very good!! Looking forward to the antenna build.
Thanks Bill, glad you liked it 👍
Only comments I have are good video and keep it up.
Awesome, thanks Lindsay 👍
Very nice presentation. The theory and real world results were very well explained. Thank you.
Thanks John, glad you liked it 👍
Dude that looks beautiful! Nice work!
Great topic too!
Thanks Michael, now I need to get working on the actual antenna.
@@TheSmokinApe You got so this!
Fingers crossed 🤞
Just to let you know, if the coils uH value is slightly out all you have to do is adjust the length of the tail and the position of the coil within the antenna. cheers
True and fair point, I didn't want to start doing all that and wanted to work from the "instructions." Thanks for wanting and for the comment Mike.
Thanks for the build, sir. I am going to try this build on my RV in a vertical mode and with my 40ft Sotabeams mast. I will report back my findings. 73,WG7D
Good luck with the build WG7D.
Nice video explaining how to. very very understandable video for guys like me without experience.
Thanks Peter, glad you liked it 👍
Good stuff, Ape! Keep 'em coming!
Thanks Richard, that’s the plan 👍
good explanation and good video.
Glad you liked it!
This is a great video...you have inspired me to give this a try!
Awesome, thanks For watching David 👍
Thanks a lot. I now have basic understanding of the coil.
Glad you liked it KC
Thanks for the video!
Glad you liked it 👍
I need to do this, been using a 60 ft wire on a G90, can hear great but not getting out. I think my nanovna h4 with the experimenter board should be able to help tune a coil.
Hoping to have a video out in a few days on the whole antenna, just finished tuning and mounting the antenna today. So far it seems promising.
Great Video Ape!
Thanks Rob!
Great video. Made me a subscriber. Please add an Amazon link for the electronic calipers.
Hey Ralph, glad you liked the video! Here is the link: amz.run/5m8Z now I am going to be upfront and say these ain't the best calipers out there...
You are right, it did make me happy 😁
Awesome, thanks for checking it out Charles 👍
Very well explained ,thank you
Thanks Jason, glad you liked it 👍
You will find that the 34.40 uH coil will work just fine for you... you will compensate for the 0.40 uH by the length of the shorter wire to finish out the 40m antenna. You will find that the given length to operate on 7.255 might be a little shorter than you originally had thought to get the SWR back down to 1.2:1. But I really don’t think .40 is going to hurt you at all.
I am running the Short 80m HWEF antenna with great results a crossed all the bands (-60m I am not sure why I can’t use my tuner to get a decent match on 60m, but I’m building an antenna dedicated to 60m for those instances that I want/need to work 60m).
Great video again 🦧 I wish I could catch the premiers and live streams, but my wife just started night shift, so my UA-cam and radio time slots have changed.
Thanks for the info Overland, I'm hoping to get the elements cut and attached to the coil today.
#ThNHR
#TeamReplay
Great video Ape. Now I understand. Thanks.
Glad it was helpful No Code 👍
Nice explaination. Its always nice to look and admire your newly made induction coil, I think we are all like it.
It doesn't hurt to be 5to10uH out with the coil after the effort of making a coil just add a meter length of wire onto the radiator after the coil and tune it (if you have the room). Subbed
All the best
Thanks for that info, and thanks for watching Norty 👍
The internet instructions for those said to use 19mm tubing, does that correspond to let's say 3/4" or 1/2" PVC pipe that you would buy at Home Depot. I need to spend some time re-doing mine.over again. The calculator I Saw showed measuring the wire and pipe at the outside diameter of the pipe and the equivalent of half the additional diameter of the double diameter of the wire or 1 mm. But I figured I would do what you did and over wind it. I need to do a re-do. Thought about making a short and fat one.
Yeah, what I found out a that the diagram was close but not exact and the same with the calculator. Good luck with it 👍
SmokinApe GREAT video, thanx. I also built your efhw... works great... thanx again. Now BOSS I need a 40 meter coil for my 17' ss whip... WRC is always out of stock... so how about a build video man. 73 NS9T ... P.S. 100 WATTS
Hey Radioman, glad you liked the video. I am actually working on a 40m coil for my 17' whip, I have to hit up the HW store tomorrow for some parts.
@@TheSmokinApe thats awesome... looking forward to it 73 NS9T
In some calculator,length of coil required, can we take exactly dia.of wire×turns.90 turns of 1 mm dia wire means length of coil would be 90mm
Correct
Thanks Ape! Watched this earlier, learned a lot, watching it again!! Keep up the great work!! Can't wait to see you put it to work! PS Do you have a length to the magnet wire and a link to your L/C meter?
Thanks Randy, hoping to put the antenna up tomorrow and start testing 👍
I'll post links in the antenna video
Thanks for god information. I understand the efhw 110uH version is a bit longer and goes for 80 40 20 15 and 10. The short part of the wire goes for 80. The lognest part goes for 40 20 15 and 10. If the longer part is optimized and cut for 20 m, will the remaining bands 40 15 10 follow optimization on the 20 m band?
You won’t get 15 on the shorter one 👍
Wow, thanks for showing me the buttons.
Buttons are the best part 👍
nice video Brother
Thanks Larry, glad you liked it 👍
Love This
Cheers.
Thanks Vince 👍
Awesome
Thanks Sean 👍
smokin ape would love to see how you build that loading coil and two would love to see you build one for whip antennas kind of like the wolf river coils as well @TheSmokinApe
Thanks for the suggestion Andrew, I'll see what I can do.
hi .. 40m coil is designed here .but why 34micro henri How did you get it .can you explain
Is from the design I used 👍
@@TheSmokinApe yes
Can I make use 110 mh coil for 40-20-10 my band as it could be used for 80mt band too.second question , why length of coil and wire diameter both required ,if it is closed wounded, as length equals turns x dia.third question regarding on second question is ,whether coil wound closely or 1 or half mm spacy?
If you use 110 you will need to tune the wire lengths differently. The length and diameter of the coil wire effect the inductance of the coil which changes the resonate frequency 👍
Newby here is this wire insulated or bare. Thanks.
It’s called enameled magnet wire, it has a thin coating of enamel
Sir please please Philips 15rb708/00s radio m/w antenna coil data .
I have a 20 meter ham stick and use a MFJ tuner to get it to match. Will a loading coil help me do better on 20 meters? Or help me tune to other bands and still use my 20 meter ham stick...?
New to loading coils and thank you for the help.
Hey Walter, we’re all new when we start. You wouldn’t use a coil to use a 20m ham stick on 20m, but you would to use it on a lower hand like 40m. Thanks for watching 👍
Nice video. I'll be waiting for the antenna video. But in the mean time, will you need a balun or unun for that antenna build?
I just put up the antenna to work on the video, I am using a 49:1 unun 👍
Cool video!
Thanks James, glad you liked it 👍
7.3cm long? Am I missing something? I am assuming that 7.3 is supposed to be the length of the form/winding? I am getting a CM conversion length of roughly 2-7/8 inches... 73
Would be cool to see how to measure this with a nanovna. I don't have a lc meter.
GOOD JOB
Thanks CC 👍
I've built a couple of them and they work really good however for 80 you will have to determine where you want to use it and you will get about 50 khz that is resonant so you will have to tune it. I love my EFHW's what I have are 2 antennas and orient them appropiatly
Yeah, playing with 80 ain’t easy! That is for the comment James 👍
@@TheSmokinApe I had to raise and lower the coil end and just trim and trim and trim but got it centered on the frequency of interest and it works pretty good. I like your how to videos. 73 ki0ad
Glad to hear it worked out for you James!
I just bought a comet ca2x4 nmo antenna. Im getting no ohms reading across phasing coils when i touch the meter leads to the antenna. Is that normal? Im getting better performance from a much cheaper mag mount .
It’s not normal, I’d use a multimeter to check the continuity of the coil 👍
I'm new to using a VNA I have a new SV4401A. Can this serve the function of the L/C meter you used in this video?
Yeah it can 👍
What size was the PVC? Looks like about 1/2 inch. I don't need one, but good information 👌 to know if or when I need it. Our club has a place for address to handy websites and I will see if I can get that in the list. Thank You for the information! 73 W4DES
Hey Donald, the OD is .83"
@@TheSmokinApe Home Depto website said 1/2 PVC is 0.84. But I don't think the difference between 0.83 and 0.84 is going to be a problem. I don't think they are that close on the PVC pipe anyway. That is only about a RCH.
@@donaldsmith3048 yeah, I’m sure it’s the same. It’s from HD 👍
good work APE..but what about the unun that are we goıng to use for this antenna..is it 49.1 .because of half wave lenght of wıre used here...thenk you.. de TA3LE....73....
Hey Ziya, I did use a 49:1 with it. Thanks for checking out the video!
Tried this with a 240-43 toroid near the match box, with 10 feet of radiator wire. Only took 7 thru 17 windings from 20-80m. Very low Q. Efficiency was very low. About .1% on 40m. Thinking of trying this air inductor, with taps. Hoping for higher Q, and higher efficiency.
Yeah, higher q is good. Sorry to hear you didn't get the results you were looking for...
Toroid may be useful for a quick empirical estimate of needed inductance.
Yeah, I've seen videos where folks have used them for testing
Sir iwant fm radio antena coil wirng
The charts originated from the Waters and Stanton UA-cam channel - British ham operators and proprietor
Thanks for the info Pat 👍
Cool video. I want to make the coil for getting 40 on a 20m half wave end fed antenna. Where did you find the plans for it? I’m curious on how they calculated the value of 34uH for the coil to get 40m.
I found them on the internet somewhere, sorry Bill, I do not have the link.
Should the short wire be first, then the longest one, or will it not matter? Question comes as I have seen a mod in a wire antenna, where the coil on short run came in first.
The short end is the end of the antenna the long end will connect to my 49:1 transformer 👍
@@TheSmokinApe That is what I got, a 49:1 transformer and a 134' wire #14. Great from 80-6 with Palstar AT2K tuner. Now, with a relay, 12 volts and a switch, will remove transformer from the circuit, so due to that the same wire will do 160, better 80 and better 6. Off, it is normal from 80-6, and on, will remove transformer. Ground will be at the relay box, not at the 49:1 transformer. In short words, a grounded wire of same length above, will do great in a set up like that. See this link for a better explanation. I am not pretending to teach you anything, instead I am telling you what I got now, and what I am working on to get the 160 there. See this as why I asked you the question, and also covers what I am also doing: ua-cam.com/video/BpdpkUEW39o/v-deo.html Thanks a lot for your great videos. 73
@@k2icc remember the antenna is first a 20m 1/2 wave... the coil acts as a trap for frequencies below 14.000MHz. Then @ 7.999 MHz and below the coil loads the short end of the antenna to make the whole antenna resonate or the desired portion of the 40m band.
By going the other way so short wire first, the coil acts as a trap on the high frequencies and as a loading coil for lower frequencies: getting a match would problematic.
@@Gravel_Rat78 Thanks a lot for your time for us out here on the way over a better us. This great UA-cam work you guys do really means a lot to a lot of people in the ham radio venture. The 49:1 wire is up and running and the 160 side parts are here, so will be on it soon. Also some Arduino and Teensy programming as well as the STM32F103 series chips. Again, thanks a lot.
And are there other coils than induction?
Hey JW, all coils are inductors 👍
If we take longer wire, will induction increase or decrease?if we take higher diameter pipe,induction increase or decrease? If we take higher diameter wire,induction increase or decrease? These question is just to know so that if we don't get desired value of induction, we we should do.
How much power can a coil handle without sparking. What thickness , sort wire should I use for 1kw max.
I haven't pushed more than 100w through this
Good antena 73
Thanks 👍
This is a super video showing how to work with variables, Excellent video APE❗️❗️👍❗️❗️ 73. KV5P
Thanks Mike, glad you liked it!
Team Replay- Nice explanation!
Thanks Don!
Sorry for the dumb question, I’m brand new to ham just passing my Tech.
Would you still have the need for lets say a 49:1 or 64:1 UnUn with this set up? I’m assembling one when my parts arrive (still deciding on which one).
Hope to take my general this week, lots to learn on my new 7300!
EDIT: Never mind, just watched the follow up 🤣👍
Hey BS66, if you saw the follow up you know... the 49:1 is to match the feedpoint impedance and the coil is to shorten the element, you do need both. Thanks for watching!
@5:52 you say, "A Henry is zero dot five zeros of a Henry. " Please fix.
(The following inductance formula requires units in inches.)
Does the wire need to be bare or can it have coating on it?
So the wire I used here does have a very thin enamel coating, you need to scrape it off where you want to make a connection, I believe you could use totally bare wire as well. If you are asking about wire with a PC or Teflon type insulation I believe you could use that as well but would need to account for that when using the calculator.
It needs to have insulation of some kind... a bare wire will case one giant short with very very very low inductance... remember what induction is...Induction is the process by which electricity or magnetism is passed between two objects or circuits without them touching each other.... so in other words if you wanted to use a loose wound coil without insulation, then it would work, but it would become heavy and long to get the same results as with magnet wire.
For my coils I use scrap magnet wire from junk appliance motors (washing machines, dryers, or any other appliances that use an electric motor).
What if one makes a coil only antenna, long enough for the required inductance and without a whip. Would it work? :)
I am not sure it would be a good radiator
@@TheSmokinApe I suppose maybe it would have a slim bandwidth? Thanks for the videos, they make it easier to understand these concepts.
How do I know what inductance I need? I want to build a coil but I’m lost on what values I need. I can follow instructions all day lol but I’m still confused lol
This was a known antenna design, so the value was published. If you are going to do a different antenna I would look to see if there are any plans out there.
Even better than measuring the wire and the tube then adding would have been just get an inch or so of wraps then measure the diameter of the whole thing.
Thanks for the idea Slick.
Just now studying for general license. I am puzzled; why do I want to build an inductor? Can I not buy one? Usually I can buy better and for less than I can make in most areas. So do hams build inductors because they can't buy it or maybe because it is fun to build. Puzzled.
Good questions. I'm not sure you can buy one fit for use and purpose, maybe? This was probably 5$ to build and part of ham radio is the rewarding experience of building and experimentation. But that comes with humbling setbacks. When you build an antenna from scratch that works you learn and have a sense of accomplishment if that makes sense 👍
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Calculator is wrong, because the approximation in the formula didn't change when switching from bananas to metric
Makes sense because I had to do more windings too.
That antenna diagram is bogus. If you want to use a wire like the one depicted in the bogus diagram on 40, 20 and 10 meters, do the following. String out 12 meters of wire. At a point along this wire equal to 1/2-wavelength on 14 MHz, insert a parallel tuned circuit (a coil shunted by a capacitor) tuned to 14 MHz. At 14 MHz, this "trap" will act as if a break in the wire, causing the wire to be 1/2-wve on 14 MHz. On 40 meters, the trap acts like a piece of wire, causing the wire to be 12 meters long on 7 MHz. On 10 meters, the "trap" will also act as a piece of wire, causing the wire to be 12 meters long, or about 1.2 wavelengths on 10 meters.
The diagram is fine and makes a great antenna: ua-cam.com/video/v6U8jBEtWs0/v-deo.html
@@TheSmokinApe With a 30 foot support pole, you have enough space for the 40 meter 1/2-wave end fed. I won't tell you how. You have to figure it out for yourself. ;)
Bro, I use this antenna all the time. I've used it w/o a 30' pole... Maybe, just maybe you the one who needs to do some figuring.
@@TheSmokinApe Well, I guess I'll have to hit the books, Son.
--W1ZY