Great illustration on toroids. Been a ham for little over 2 years now and there is a lot to learn. I find your channel very helpful regarding many technical topics. Thank you!
I accidentally ordered some 140-61 cores for my 80m EFHW antenna. The 61 cores are no goers on the lower bands, they start to work good above 24MHz. The transformer was wound as any 49:1 unun. The 61 cores are also good for transformers in 50MHz push-pull PA-s. :) This is my experience. 73's de YO6PNQ
Excellent introduction to toroids, materials and use cases. As a QRP operator, the 1/2 inch size is about as big as I go -- and I can confirm that in my experience, 'size doesn't matter.' Its the 'mix' that's important. I've also stacked 1/2 inch toroids for 'QRO' (50 watts!) and that works well too -- Its just even more of a challenge to wind the little beasts! 73 Bruce G4ABX
@@TheSmokinApe I'm currently building a 49:1 EFHW, and your toroid/unun video, and 49:1 transformer kit are fabulous resources. I didn't buy a kit, so I've been cobbling together as much reference material as I can.
I got a little lost on this but that is because I’m just not there yet. In a few months this will make more sense. Still studying for the general test. Ape you are a good teacher, sometimes the students aren’t ready. One comment you made I would like to see a short video about. That is when you said you mostly stay on 40-10 meter HF. What are the reasons for that? Thanks. Keep them coming
There are THREE big questions when it comes to toroids: 1. How big should I get? (100W needs more than 10W QRP) 2. What material should I get? (Impacts frequency etc) 3. What I get this wrong? (broken core from heat, or just over priced under performing)
Are there examples of series coax chokes wound on different cores? Such as a coax choke wound on a 43 mix toroid followed by a coax choke wound on a 52 mix toroid to get better broad band choking.
I was thinking of using my oscilloscope clip probes (wt 10x switch) since they are made for carrying frequency (though I wanna get some with higher rating) & bnc to sma adapter
SO GOOD to find these videos. I just drop a comment on a guy who was more interested in letting you know just how smart he is but was not very helpful. If you have your EE degree, you'll be right there with him. the rest of us, not so much. Not sure who his target audience was exactly. If you were able to follow him... you didn't need him. Lol!
Love the videos! I'm still unclear how to calibrate the test leads for testing a choke using the setup you've posted? I'm unclear how to do it. My understanding is that I would need to place the open, short, and load at the end of the leads? Thanks!!
Question, your tests are of a single wire wrapped on half the toroid. At 3:06 of your video, you show a double wire wrapped full toroid. How would that be tested? Would you solder the yellow then white pair together and test them separately? Or test all four wires separately and and the results together?.
Hey Carl, thanks for watching. The single wire test was just testing each of the toroid mixes to see which would do a better job of attenuation, we want to "choke out" common mode current. If I was going to test the yellow and white wrap you could solder the two yellow or two white together and test that way.
NOTE: I’ve bought two different versions of this power supply. One just needed pin 33 & 36 jumped (no resistor). The second, w/o resistor would only produce the voltage for
The best way would be to perform comparative tests against known cores, if that's not possible you could compare test results against factory specs. I'd suggest not worrying about the mix and test it for the use case you have planned.
Gday Ape, If you were using the same mix with your test setup but with differing sized toroids (eg 240-43 & 140-43) would you expect the same attenuation curve? Meaning toroid size only affects power handling capacity and the toroid mix determines freq verse attenuation performance? Thanks
Thanks for the helpful video. I want to make some common mode chokes to use in conjunction with an active mini-whip and SDRplay for listening to VLF and SW. How can I determine the best size/rating of toroid core to make the common mode choke?
Excellent stuff. Thank you for making these very informative videos. Just one question. You mentioned that the T140-43 is good for 100W SSB. If I wanted to go for higher power, do I need to stack 2 or 3 cores of 43 mix (or 31 mix)? Or would you recommend going for another mix instead? 73 de 4G1FBL from the Philippines.
The mix is about how the toroid works, size would be what we use for more power. You can use a larger mix43, like a T240 for example or even stacked 240's. Thanks for watching Elmore.
I have the nanovna saa2 using nanovna-qt software but there is no (s21 gain) as your nanovna to test the chokes. Do you know if (mag 21) could be the same just different name? Thank you!
This is something I’ve been curious about. Do you have a video that explains the difference between a choke, an unun and a balun? I have an OCF dipole for 80-10 meters and I’m trying to decide what I need in that respect and I’m trying to decide coax vs ladder line vs window line. Any thoughts??
Hey Todd. Part 2 in the video series may be helpful... A choke, sometimes called a Balun or a Choke-Balun is generally used to suppress Common Mode Current (CMC) that can be present on the feedline, CMC can cause havoc in the shack (I do have a video on CMC). An UnUn is a transmission line transformer that is used to match the impedance of the antenna feedpoint to the feedline, or get it close enough that a tuner can match the antenna system to the radio impedance. I'm reasonably confident that your OCF already has a 4:1 transformer and may have a 1:1 choke as part of the design. What OCFD are you using? I have a video one the MFJ OCF Dipole that might be helpful. Best of luck!
I’ve got some FT400-31 and FT240-31 toroids. Would the FT400’s give me better RF noise filtering when used on DC power line feeds to my mobile or HF rigs?
@@TheSmokinApe , you know your content is great when the other popular UA-cam HAM channels frequently mention your channel for reference on various HAM related topics!
Nice video. Question - I am wondering what effect stacking several toroids on your antenna feedline. In your table one toroid provides some amount of attenuation. By adding additional toroids do you expect to get additive attenuation? i.e. if one toroid attenuates 27 dB, does adding a second toroid give you 52 dB, no additional or some mathematical summation?
@@TheSmokinApeThanks for your response, still a little perplexed. On the bigger toroids that you presented there are 10 or so wraps, this would be similar to adding 10 snap on ferrites no? So the 10 wrap example you would get the same attenuation if you only had one wrap? The extra 9 provide extra heat dissapation? Just trying to understand.
Very cool!! I made a choke with a type 61 and it works very well on 11m. I have a nanovna but wanted to know once calibrated what trace do I use? At the moment I have only 2 (SWR and smith chart) Hope I am making sense . Thank you!!
Hey RP, most hams are concerned with SWR first and then the Smith Chart to see why the SWR reading is what it is... SWR Measures the power reflected back from your antenna system to your radio when there is an impedance mismatch between the two. The Smith Chart allows you to view the actual impedance characteristics of the match / mismatch. Check out my NanoVNA playlist for more info. ua-cam.com/video/ay58sp8VaNM/v-deo.html
@@TheSmokinApe Thanks for getting back! Ya both SWR and Smith chart look good. I failed to ask how measure the choke I made. Not sure if I measured correctly but it seems to choke around 87db. I have it plugged into the nano with the 50ohm load at the end.
Just got a new FT-991A and seems I need some Toroids for 2m and 70cm. It is feeding back in to smoke alarm system. 240-52 on Power connection? How many wraps?
You say that powdered iron is a lower performer than the ferrite toroids. This really isn't a fair (rite?) comment. Your tests I have seen really haven't shown any at-power results. Ferrite gives you a lot more inductance per turn than the similar sized iron core, but the ferrite will saturate before the iron core saturates. Air core inductors will not saturate but you need a lot of turns to make up for not having a metal core. But someone wanting to use some of these ferrites using a lot of power will be saturating the cores and the harmonics will come way up as the signals will be distorted.
Thanks for the comment BD, I tend to agree with everything you posted, I did want to point out that I was talking about chokes and the broadband characteristics of ferrite seem to be a better option IMO.
@@TheSmokinApe when you make videos, can you test over power? I'm not sure how much power you can put out but if you could test to see about saturation in your designs, that would be nice. It could be tested by looking at harmonics at say 5 watts and compare that to 100 or 250w. It would be nice to know how close we're getting to where the core will saturate, but I'm not seeing that data here.
Sorry to be a stickler, but 'TOE-ROID' sounds like some foot growth. 'TORE-ROID' is the common pronunciation. I know it's prob your regional accent, so shhhhhh...I won't tell anybody. As an old radio broadcaster we used to chide each other daily about pronouncing stuff. Just a latent habit...
I clicked the like button... and I've already clicked the subscribe button. It did indeed make me happy. Nice work Ape
Glad you liked it Hayden, thank for the support brother!
Great illustration on toroids. Been a ham for little over 2 years now and there is a lot to learn. I find your channel very helpful regarding many technical topics. Thank you!
Thanks Rumsin, glad to hear you like the videos 👍
I accidentally ordered some 140-61 cores for my 80m EFHW antenna. The 61 cores are no goers on the lower bands, they start to work good above 24MHz. The transformer was wound as any 49:1 unun. The 61 cores are also good for transformers in 50MHz push-pull PA-s. :) This is my experience. 73's de YO6PNQ
Hey Pityu, thanks for watching!
Excellent introduction to toroids, materials and use cases.
As a QRP operator, the 1/2 inch size is about as big as I go -- and I can confirm that in my experience, 'size doesn't matter.' Its the 'mix' that's important. I've also stacked 1/2 inch toroids for 'QRO' (50 watts!) and that works well too -- Its just even more of a challenge to wind the little beasts! 73 Bruce G4ABX
Thanks Bruce! I've seen people crazy glue them together to make it easier to wrap.
thank you Ape- good info
Glad you liked it 👍
Good stuff, man! I'll be payin' close attention to this!
Glad you liked it 👍
Thank You. This is exactly what I needed to begin learning
Awesome, stay tuned there more coming 👍
@@TheSmokinApe WILCO
Thanks for the breakdown!
Glad you liked it 👍
@@TheSmokinApe I'm currently building a 49:1 EFHW, and your toroid/unun video, and 49:1 transformer kit are fabulous resources. I didn't buy a kit, so I've been cobbling together as much reference material as I can.
@@d3jake best of luck with the build, they are great antennas 👍
I got a little lost on this but that is because I’m just not there yet. In a few months this will make more sense. Still studying for the general test. Ape you are a good teacher, sometimes the students aren’t ready. One comment you made I would like to see a short video about. That is when you said you mostly stay on 40-10 meter HF. What are the reasons for that? Thanks. Keep them coming
Glad you liked it Randy. I mainly do those bands because I don’t have the space for a larger antenna, lol 👍
I feel so happy... I clicked a button... Good series man!
Awesome! Glad it's helpful.
There are THREE big questions when it comes to toroids:
1. How big should I get? (100W needs more than 10W QRP)
2. What material should I get? (Impacts frequency etc)
3. What I get this wrong? (broken core from heat, or just over priced under performing)
For 100w a t240 should be plenty. Chokes get 31 and ununs get 43 generally speaking. If you run them hot enough long enough they will crack.
Are there examples of series coax chokes wound on different cores? Such as a coax choke wound on a 43 mix toroid followed by a coax choke wound on a 52 mix toroid to get better broad band choking.
Hey Viron the part 2 of this video does just that 👍
Clicking the button DID make me happy!! ;)
🤜🏻👍🤛🏻♡♡♡
Awesome!
I was thinking of using my oscilloscope clip probes (wt 10x switch) since they are made for carrying frequency (though I wanna get some with higher rating) & bnc to sma adapter
I’d love to have a scope, oh and know how to use it 👍
SO GOOD to find these videos. I just drop a comment on a guy who was more interested in letting you know just how smart he is but was not very helpful. If you have your EE degree, you'll be right there with him. the rest of us, not so much. Not sure who his target audience was exactly. If you were able to follow him... you didn't need him. Lol!
Lol, thanks for watching Jack 👍
Love the videos! I'm still unclear how to calibrate the test leads for testing a choke using the setup you've posted? I'm unclear how to do it. My understanding is that I would need to place the open, short, and load at the end of the leads? Thanks!!
You could do that but we are mostly concerned with the through calibration, you could just do that part with the leads.
Just grabbed an FT-240-43, hoping it will help with my antenna setup, 73 Ape! Good video as always
It should help, check out part 2 in the series where we cover chokes in more detail. Thanks man!
Very timely. Thanks for the advice!
Glad you liked it, thanks for the comment Jim 👍
Thanks for the information.
Thanks for watching Charles 👍
Great info! Thanks.
KM4ACK glad you liked it 👍
Question, your tests are of a single wire wrapped on half the toroid. At 3:06 of your video, you show a double wire wrapped full toroid. How would that be tested? Would you solder the yellow then white pair together and test them separately? Or test all four wires separately and and the results together?.
Hey Carl, thanks for watching. The single wire test was just testing each of the toroid mixes to see which would do a better job of attenuation, we want to "choke out" common mode current. If I was going to test the yellow and white wrap you could solder the two yellow or two white together and test that way.
NOTE: I’ve bought two different versions of this power supply. One just needed pin 33 & 36 jumped (no resistor). The second, w/o resistor would only produce the voltage for
a toe roid sounds painful. Great video Sir!
Haha, thanks man!
Excellent video comparing chokes. Is the FT240-31 better then the FT240-43 or they are similar in performance ? Thanks.
The 31 is a much better choke 👍
@@TheSmokinApe Thank you.
A question for you - If one has a toroid with an unknown mix, from the junk box for example, how does one determine what it is?
The best way would be to perform comparative tests against known cores, if that's not possible you could compare test results against factory specs. I'd suggest not worrying about the mix and test it for the use case you have planned.
Awesome video. Definitely gonna follow this series, KO4DNI
Glad you liked it, thanks for watching!
Thank you! Excellent info. 73, AA4EZ
Thanks Raymond, glad you liked it 👍
Gday Ape, If you were using the same mix with your test setup but with differing sized toroids (eg 240-43 & 140-43) would you expect the same attenuation curve? Meaning toroid size only affects power handling capacity and the toroid mix determines freq verse attenuation performance?
Thanks
The size will play a role but it’s not as impactful as the core mix 👍
Thanks for the helpful video. I want to make some common mode chokes to use in conjunction with an active mini-whip and SDRplay for listening to VLF and SW. How can I determine the best size/rating of toroid core to make the common mode choke?
Excellent stuff. Thank you for making these very informative videos.
Just one question. You mentioned that the T140-43 is good for 100W SSB. If I wanted to go for higher power, do I need to stack 2 or 3 cores of 43 mix (or 31 mix)? Or would you recommend going for another mix instead?
73 de 4G1FBL from the Philippines.
The mix is about how the toroid works, size would be what we use for more power. You can use a larger mix43, like a T240 for example or even stacked 240's. Thanks for watching Elmore.
Silly question, do toroids rust? What if I wanted to leave up an efhw permanently?
I haven’t seen one do that, but I guess it’s possible 🤔
Why do you use ferrite toroids rather than ferrite rods?
I just never messed with the rods, I do remember reading something that the can have losses at the ends 👍
I have the nanovna saa2 using nanovna-qt software but there is no (s21 gain)
as your nanovna to test the chokes. Do you know if (mag 21)
could be the same just different name? Thank you!
Could you mix them? What I mean is put a 43 and 31 together (or at least on the same feedline) to keep your attenuation low across the bands?
you can, check out my CMC video. I typically put a choke at each end of the feedline.
This is something I’ve been curious about. Do you have a video that explains the difference between a choke, an unun and a balun? I have an OCF dipole for 80-10 meters and I’m trying to decide what I need in that respect and I’m trying to decide coax vs ladder line vs window line. Any thoughts??
Hey Todd. Part 2 in the video series may be helpful... A choke, sometimes called a Balun or a Choke-Balun is generally used to suppress Common Mode Current (CMC) that can be present on the feedline, CMC can cause havoc in the shack (I do have a video on CMC). An UnUn is a transmission line transformer that is used to match the impedance of the antenna feedpoint to the feedline, or get it close enough that a tuner can match the antenna system to the radio impedance. I'm reasonably confident that your OCF already has a 4:1 transformer and may have a 1:1 choke as part of the design. What OCFD are you using? I have a video one the MFJ OCF Dipole that might be helpful. Best of luck!
I’ve got some FT400-31 and FT240-31 toroids. Would the FT400’s give me better RF noise filtering when used on DC power line feeds to my mobile or HF rigs?
They might, but you should be able to get what you need from a 240 👍
@@TheSmokinApe , thanks, sounds good! And thanks for all the great HAM content on this channel!
@@rays9033 thanks Ray, glad you like the videos 👍
@@TheSmokinApe , you know your content is great when the other popular UA-cam HAM channels frequently mention your channel for reference on various HAM related topics!
@@rays9033 that does make me smile 😃
Nice video. Question - I am wondering what effect stacking several toroids on your antenna feedline. In your table one toroid provides some amount of attenuation. By adding additional toroids do you expect to get additive attenuation? i.e. if one toroid attenuates 27 dB, does adding a second toroid give you 52 dB, no additional or some mathematical summation?
The stacking is more about heat dissipation 👍
@@TheSmokinApeThanks for your response, still a little perplexed. On the bigger toroids that you presented there are 10 or so wraps, this would be similar to adding 10 snap on ferrites no? So the 10 wrap example you would get the same attenuation if you only had one wrap? The extra 9 provide extra heat dissapation? Just trying to understand.
Very cool!! I made a choke with a type 61 and it works very well on 11m.
I have a nanovna but wanted to know once calibrated what trace do I use? At the moment I have only 2 (SWR and smith chart) Hope I am making sense . Thank you!!
Hey RP, most hams are concerned with SWR first and then the Smith Chart to see why the SWR reading is what it is... SWR Measures the power reflected back from your antenna system to your radio when there is an impedance mismatch between the two. The Smith Chart allows you to view the actual impedance characteristics of the match / mismatch. Check out my NanoVNA playlist for more info. ua-cam.com/video/ay58sp8VaNM/v-deo.html
@@TheSmokinApe Thanks for getting back! Ya both SWR and Smith chart look good. I failed to ask how measure the choke I made. Not sure if I measured correctly but it seems to choke around 87db. I have it plugged
into the nano with the 50ohm load at the end.
👍
Looking to build a 49-1
My current antenna is a 49:1
Just got a new FT-991A and seems I need some Toroids for 2m and 70cm. It is feeding back in to smoke alarm system. 240-52 on Power connection? How many wraps?
I have a 240-43 with 12 wraps on my radio pier connection. Are you talking about the 110v into the UPS? I haven’t had to work on a problem like this.
@@TheSmokinApe I would say the power wires from the radio to the power supply.
You say that powdered iron is a lower performer than the ferrite toroids. This really isn't a fair (rite?) comment. Your tests I have seen really haven't shown any at-power results. Ferrite gives you a lot more inductance per turn than the similar sized iron core, but the ferrite will saturate before the iron core saturates. Air core inductors will not saturate but you need a lot of turns to make up for not having a metal core.
But someone wanting to use some of these ferrites using a lot of power will be saturating the cores and the harmonics will come way up as the signals will be distorted.
Thanks for the comment BD, I tend to agree with everything you posted, I did want to point out that I was talking about chokes and the broadband characteristics of ferrite seem to be a better option IMO.
@@TheSmokinApe when you make videos, can you test over power? I'm not sure how much power you can put out but if you could test to see about saturation in your designs, that would be nice. It could be tested by looking at harmonics at say 5 watts and compare that to 100 or 250w. It would be nice to know how close we're getting to where the core will saturate, but I'm not seeing that data here.
looks like jpmultiserve is gone ?
You can order direct here: www.jpmsupply.com/category-s/1840.htm
Is it possible to have too many turns of coax when making a choke with 31 mix?
You prolly would run out of room first.
Sorry to be a stickler, but 'TOE-ROID' sounds like some foot growth. 'TORE-ROID' is the common pronunciation. I know it's prob your regional accent, so shhhhhh...I won't tell anybody.
As an old radio broadcaster we used to chide each other daily about pronouncing stuff. Just a latent habit...
Everyone I know says Toe-Roid, I'm not sure where your hanging around that they double down in the R.
@@TheSmokinApe I had never heard "toe-roid" until watching this video.
@@gettingpast4391 that’s the proper pronunciation 🤣