Very well done Ape. 👏. I went through this exercise myself for the adjustiwave choke. Just checked my results using DXW142 coax and the 240-43. Peak attenuation was almost 37db on 20m. 40m was 33db. This method is such a cheap way of making an effective choke. Thanks for sharing.
I will suggest that RG142 might give better results because of its double shield. This should reduce leakage between the inner surface of the shield and the outer surface. That is exactly why RG142 is used. That leakage can go either way, so RG142 should help prevent rf from leaking out, and noise from leaking in. I am getting ready to build a couple of these, and will probably try running them in series to increase their attenuation to see if they add together.
That was a very good informative video. Just a foot note: You can use 43 material for a choke and cover 160 meters as long as you put enough turns around the core. Yes, 31 material would be the better choice for 160 meters but so would 77 material. You gave a good pictorial of how much and where the attenuation occurs on the band. But one thing that is most important is not to exceed the minimum turning radius of the coax. You need much looser turns with the coax you are using. If the coax gets too warm, not abused, the center conductor can migrate through the dielectric and fail. RG 400, RG 142 and RG 303 are better choices for making the balun. Not only can you use a reasonably close turning radius, but it will handle legal limit with room to spare. Barry, KU3X
Mr. Ape. You motivated me to get some parts and build the choke. But I thought I would try something a little different. I bought a 140-43 toroid, and wound 12 turns of RG-174. At the end of the day, the center conductor of cheap RG-58 is about the same gauge, so I figured I would give it a try. Well match did not change. I am empirically seeing about a 1 to 3 S-Unit reduction in background noise, and no apparent reduction in signal strength. I am going to keep playing with it. I wish I could include a picture of it. With the RG-174, it looks super tidy. Again, thanks for the motivation and 73, Marc - N6UNX.
Try testing the 31 mix in series with the 43 mix to see their reactance adds. Quick and easy since you have them made up. Might be a way to help those who need even more noise attenuation.
I have a crazy idea to test... What happens if you stack 31 & 43 cores together? You'd double the wattage capability, but what would it do to the effective frequency coverage range?🤔
If you have some doubts abou tmix of a core, winding 10 turns through, measure low-frequncy L on a LC meter, and divide that L by 100 to get A_L value. Cross-check against spec sheets will narrow down what mix is what. 43 mix has 3 times the A_L of 31 mix so those are easily differentiated. Your VNA sweeps are also measuring the effect of turn-to-turn stray capacitance at higher frequencies which is probably more relevant for antenna chokes than what the DC characteridstics are.
I like end fed antennas and I use mix 43 to build the 49:1 transformers that enable 10-80m and they work very well. I use mix 31 ferrite beads and toroids to help reduce rfi since I have a very high noise floor. I used either beads or cores on almost all the electrical equipment in my house. They all work as advertised. Palomar is a great supplier. I've built chokes with mix 31 ferrite beads (from 5 beads to 8 beads) on jumpers of lmr 400 with mixed results at the antenna feed points but I do have chokes at the shack end of the coax. Thanks for another informative video. K5FIT
I bought a choke per another youtuber and now I have a means of testing it. If it's no good, I'm gonna do it myself. I have a funny feeling it will be fine but could use an improvement. Thanks for the very informative video. When is the point where I don't need to say I'm new to ham? I got all my licenses last year and never did anything like this in my life. Thank you for the video!
It would be interesting to see type 52 and type 61 mix compared as well since they are used in ham applications. In particular the type 240-61 is used with 13 turns as the Balun on the Spiderbeam antenna. It would also be interesting to see a side by side comparison of the return loss for a bifilar wound toroid using both magnet wire and PTFE wire vs coax wound and whether coax performed better. Just for one mix, not all.
@@TheSmokinApeI mention it because someone else did a video on magnet/PTFE/coax and all he did was compare SWR with a 50 ohm load which doesn’t say anything about performance.
Wow! I really wish the internet had been around when I started in Ham radio, these videos are gold. Just one observation, could the bend radius on the coaxial cable have anything at all to do with the results obtained? I don't know, I just pulled that straight out of "thin air". 😄
@@TheSmokinApe I just ordered the FT240-31 toroid after watching your video and looking at other specs. I was looking in my bag for a coax jumper. Found a 6' length of DXE-8X (RG-8X), which has a minimum bend radius of 2.4". If you do the math and want to make an 11 turn choke as yours, plus leads, then that's about a 15' piece of cable. Yikes! I also saw the LMR-240 has a 0.75" fixed/2.4" repeated bend radius. But it's pretty stiff to begin with. Any recommendations if I want to follow best practices? Thx John KM4FZP
You have to keep your test apparitus unchanged in order to maintain calibration of the VNA. If you move the clip leads closer or further apart as you did in this video, big changes, especially at higher frequencies will occur and invalidate your normalization effort.
Interesting to see the measurements. I have a choke wound exactly like that on a 43 mix core which seems to work down as far as 80m. Never measured it, it is in a box outside my window and if it wasn't there I'd be getting nasty zaps from the metal clip on the back of my hand mic! That type of choke is a real problem solver in so many ways.
Does this not exceed the minimum bend radius of the coax? Would you get the same results with a loosely wrapped toroidal where the coax maintains the 1.5 inch minimum bend radius of an RG-58/U?
It sure does, my experience is coax bending is a problem when it’s repetitive. I have some like this that are 5 years old and just fine…. And if it does become a problem, I’ll simply replace it. 👍
Would be interesting to see how the type 31 toroid faired at 80M and 160M. For field day contesting I spend a bit of time on these bands. Also what would adding one or two more turns of coax achieve, please
Another well presented video. There is probably a very simple answer to this that I'm missing, but... If you get a certain RFI reduction by winding your coax through a type 31 toroid 5 times, do you get the same result using 5 type 31 ferrite beads on the coax? Is each single bead the equivalent of a single pass through the toroid and, therefore, 5 beads are the same as 5 wraps through a single toroid?
I live in an HOA and all the high voltage power lines run about 50 feet from by back fence. Who knows what else is buried there...Jimmy Hoffa. Anyway, just ordered some toroids to see if this helps. I'm not sure the CMC is the real problem, but I'll find out and let you know. Thanks for the video. Jeff, W0STO
Well, I tried the chokes today in my nasty noisy HOA. I used the 240-43 and 240-31 and they made a slight reduction in the noise. I also put a 240-31 on my power cord which didn't change the noise at all. I imagine that the buried power lines are overwhelming everything. I tried. It was a fun little experiment.
Here's an update. I wrapped as many turns (12) of Rg8X coax thru a 240-31. I tried this before but I didn't wrap the coax as tight as I should have. So I went back and tried again. I'm about 50% of where I would like to be but happy that I can use my radio at home. Thanks for the help.
You forget consider importance of restive part of CM impedance vs reactive impedance acc. to G3TXQ ? (PS. Take care also to measures setup and chokes self resonance. )
Great stuff for making RF chokes. But - when making impedance matching balun or unun, WHY is mix 31 bad? I'm sure the Palomar engineers are right, I just want to know what to look for if my toroids get mixed up in storage. I do QRP 10W, so warnings about power handling might not be relevant.
Hey Alan, it has to do with the way the mix reacts based off frequency. You will also see people use mix 52 and 71 (I think that’s them) based off frequency.
Spent the first half of the video stressing that you have the left side choke connector resting on the right hand side vna connector and wondering if they are connecting...... Even having them that close together might affect the readings.
For common mode choke I think Amidom K mix will do the best you can. We measure 4500 0hms of chocking ability. We replaced the balun on our palstar AT5K and bt 1500 tuners. I also made one for my atr15 The k mix puts all other mixes to shame. Only issue k mix is only made in 2.4” cores 😕 we stacked 4 core and wound it with 14 turns of rg 400
@@TheSmokinApe if you qrz my buddy John W2BYP he has a link on his qrz page story avenue > he has done sum balun testing on the oem palstar comparing it to the k mix also in there is extensive testing on the AT5K. Apparently the balance studs were outputting a unbalanced signal resulting in horrible rf emissions plus requiring three 00awg size ground connections. Now with the k cores in the AT5K he can run the dual 8877 to the wall 5kw no issues having ground connected or not. Mind you into a Dummy load for best practices 😉😉
@@TheSmokinApe i once tried not by stacking but connecting two 1:1 chokes together that increased the choking effect quite a lot, but i guess thats a different thing as compared to stacking..
Okay, I have a question. Suppose i want to use one of these chokes, (OR an ugly balun made of coiled coax), at the feed point of my antenna, and at the radio end for a mono band "resonate" (50 ohms) antenna (dipole, yagi, loop, vertical, whatever). Suppose I also want to have my coax cut to a halfwave multiple at that specific frequency so I can check my swr in the shack. Do I include the length of the windings as part of the "halfwave length"?
Good afternoon Ape, I am writing in inquiry to ask if an RG58 wound FT 240-43 common mode choke can be used with larger coax feed lines such as RG8U or DX400 of which I have both. Since there is a difference in diameter, does it matter when creating a common choke mode? I believe I know that answer but with the macro amount of information available, and everyone having their own opinion, it makes sense to me to ask someone that has knowledge. Lastly, to make a resistor load for testing transformers such as a 49:1, what size resistors are used to create a testing environment when you test the 49:1 balan? Thank you in advance for your assistance! Respectfully yours, Bill, KC3RMV, East Central PA.
Hey Bill, I do think you might have some trouble with larger diameter coax. Here is a guide that most hams use that shows positive results with RG58: www.karinya.net/g3txq/chokes/ I have tested a few different types and seem to have positive and consistent results with RG58 and mix 31 ferrites. To test a 49:1 you need ~2,450 Ohms, 49 * 50 = 2,450. Try to use 1/2 - 1w 1% resistors, here is a video I did: th-cam.com/video/vfmCpzBOuMc/w-d-xo.html
I have watched several different winding procedures for baluns. You have wound 6 turns of Coax and then cross over and wind another 6 turns. Another site wound 12 turns of coax around the toroid, NOT crossing over. Any reason for the difference ?. I can see your way the toroid fits better in the box. Also any advantage or disadvantages of using RG316 instead of RG58. Your thoughts. Thank you
I've seen people use 316 with success but I've mostly used 58 or something like magnet wire. Once you get to 10-12 wraps each additional wrap makes less and less of a difference. I've done both crossover and non-crossover, as long as my attenuation looks good I really don't care much 👍
Thank you for reply. My balun, (140/43 wound 10 turns (5x5) with RG316) I have on my 80M inverted V at the moment, works fine on TX but rig seems a bit more deaf than before ON receive .The rig also seems to run a bit hotter than normal. Had a good look at your sites, probably should have used one or maybe two, 240/43 toroids, Working on that soon as two arrive. I will see if the other Toroids 61 or 72 are readily available, and have a play. I am only running 100 Watts, assumed the smaller toroid would have been ok. Inverted V tunes & works ok low SWR mid 30s dB return loss. Now work in progress. John
ever considered mixing mixes? stacking say a 43 with a 31 and a 52 was curious if it makes a difference. Also have you tried different mixes in series with each other? i.e turns through a 43 straight into turns through a 31 straight into a 52. Again curious to see if it makes a difference led me to ask great video's by the way keep 'em coming
RG-58C is much more flexible than RG-58. It's available from The Wireman. I bought 25 feet of it for test leads. RG-58C is also 50 ohms, as opposed to some of the other RG-58 types that are 52 ohms. My smaller test leads are RG-316, which is also 50 ohms.
Why is there loss of 14v from hand wound toroid transformer output with separate winds on core not overlapping. The frequency of primary was matched to source AC, the primary and secondary windings are in same direction and entire ring core is covered with wire , but 2 separate sides. I thought the core under Primary caused induction into separate secondary windings. Desparate.
I have built a 71 foot "random" wire antenna using the 9:1 unun you instructed to build. It works great after I enhanced the RF ground a bit. The transmission line of RG58 from the shack to the unun is less than 6ft. I'm not using the coax as any kind of RF ground. Where should I place the choke - on the antenna tuner input in the shack? Or on the 9:1 unun antenna feedpoint? de KE7LOY
I would place it at an odd multiple of a quarter wavelength from the far end of the antenna. Consider the velocity factor of the antenna wire, and the shield of the coax, and not the VF of the coax. So for example, with a half wave antenna, a quarter wave down from the feedpoint, at 98% VF for the shied if you want to be that precise.
This is for the transmission line to the antenna, while 12v DC powers the radio it is converted in to AC / RF by the time it hits the coax. For 27Mhz I would make it the exact same way.
It depends on what you are measuring, I f the s21 is for insertion loss you want SWR. If you are measuring isolated choke impedance it’s not necessary 👍
Hi there Ape, There are times when we Ll like to use a little more power from the TxRx via a linear amplifier,, & so from various other videos ppl add another toroidal core, , , generally of the Same type. However, I've been thinking about mixing for example a 43 type with a 31 type core. What are your options & feelings about doing this please. Also, if you have a Discord Channel, would you please be kind enough to let me know how to join it please. Many Thanks,, Kind Regards, Ray. Location ~ JO01ii.
Howdy Ray. I hang out on the TOADS discord that I run with some other YT buddies: discord.gg/ttfyDBBJaR hope to see you there. I wouldn't stack the core but build two and use them inline, if power was an issue I would stack them but using the same mix. Hope that helps!
Yes. See Steve Ellington's choke video on YT. He uses up to 3 240-31s in series, reportedly to excellent effect. He recommends placing them 1 - 6" apart at the shack end of the feedline, but also notes that placement near the unun may be necessary in some cases and recommends experimentation. However he doesn't do the nice VNA measurements to demonstrate the cumulative effects as Ape shows here. He states RG-8x is fine up to 500 watts or so but recommends RG-400 for higher power or high SWR. It seems toroid mix, number of turns per toroid and number of toroids in series all can affect choke attenuation/frequency. For some EFHW antennas, placement of the choke at least 0.05 wavelengths back from the unun is recommended to allow the coax feedline segment between the unun and choke to function as a counterpoise. The wavelength in question is the longest to be worked with the antenna (e.g. for 80m, 0.05 x 80 = 4m). If you wind up needing a choke near the feedpoint also, you may need a counterpoise separate from the feedline. I understand wrapping 2 or more toroids together results in little to no increase in choke function but does increase power tolerance. Others describe placement of the proximal portion of the feedline through a 10' galvanized conduit which acts a large choke. I am not an expert and am working through these questions right now myself. 73, John - KK7JBZ
it's about the number of turns combined with the ferrite material. More turns does not necessarily equate to a higher choking impedance. In fact, a poorly designed choke can increase common mode interference. For 10/11, I use 5 Fair-Rite FT240-43 ferrites, stacked, with 4 turns of RG213 for a high choking impedance. So pass through four times to form three loops, and depending on the type of 213, watch the minimum bend radius (large loops spread out evenly for stray capacitance).
Hey man, thanks for posting and sharing your experiences. I have build and tested many of both and some have performed better than others. I've found that this particular choke works well.
If the only negative effect of more windings is after a certain point each wind has less of an effect, than why not wind the toroid till it's full, say with 17 winds? Seems a no brainer to me. I'm going to try the ft400-31 with the Messi and Paolini hyperflex 10 cable. That will be a beast hopefully.
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Very well done Ape. 👏. I went through this exercise myself for the adjustiwave choke. Just checked my results using DXW142 coax and the 240-43. Peak attenuation was almost 37db on 20m. 40m was 33db. This method is such a cheap way of making an effective choke. Thanks for sharing.
Glad you liked the video Collin!
I will suggest that RG142 might give better results because of its double shield. This should reduce leakage between the inner surface of the shield and the outer surface. That is exactly why RG142 is used. That leakage can go either way, so RG142 should help prevent rf from leaking out, and noise from leaking in. I am getting ready to build a couple of these, and will probably try running them in series to increase their attenuation to see if they add together.
That was a very good informative video. Just a foot note: You can use 43 material for a choke and cover 160 meters as long as you put enough turns around the core. Yes, 31 material would be the better choice for 160 meters but so would 77 material.
You gave a good pictorial of how much and where the attenuation occurs on the band.
But one thing that is most important is not to exceed the minimum turning radius of the coax. You need much looser turns with the coax you are using. If the coax gets too warm, not abused, the center conductor can migrate through the dielectric and fail.
RG 400, RG 142 and RG 303 are better choices for making the balun. Not only can you use a reasonably close turning radius, but it will handle legal limit with room to spare.
Barry, KU3X
good points about the coax, thanks for checking it out Barry
you can put two toroids together, one next to the other, side by side, and the turns pass through both toroids as if it were a single thicker toroid
Mr. Ape. You motivated me to get some parts and build the choke. But I thought I would try something a little different. I bought a 140-43 toroid, and wound 12 turns of RG-174. At the end of the day, the center conductor of cheap RG-58 is about the same gauge, so I figured I would give it a try. Well match did not change. I am empirically seeing about a 1 to 3 S-Unit reduction in background noise, and no apparent reduction in signal strength. I am going to keep playing with it. I wish I could include a picture of it. With the RG-174, it looks super tidy. Again, thanks for the motivation and 73, Marc - N6UNX.
Thanks awesome, glad to hear that it's working out for you.
Try testing the 31 mix in series with the 43 mix to see their reactance adds. Quick and easy since you have them made up. Might be a way to help those who need even more noise attenuation.
I will see if I still have them, thanks for the suggestion 👍
This answered (indirectly) a couple of questions, it also hi-lited the usefulness of the Nano.
Glad it was helpful 👍
Thank you. I’m tackling some interference in my truck install and researching how to clean it up.
Good luck with it 👍
Thanks for this vid and the analysis! 240-43 toroids ordered. Once arrived, I will make one of these chokes. Cheers and 73 from VK
Good luck with it 👍
I have a crazy idea to test... What happens if you stack 31 & 43 cores together? You'd double the wattage capability, but what would it do to the effective frequency coverage range?🤔
If you have some doubts abou tmix of a core, winding 10 turns through, measure low-frequncy L on a LC meter, and divide that L by 100 to get A_L value. Cross-check against spec sheets will narrow down what mix is what. 43 mix has 3 times the A_L of 31 mix so those are easily differentiated. Your VNA sweeps are also measuring the effect of turn-to-turn stray capacitance at higher frequencies which is probably more relevant for antenna chokes than what the DC characteridstics are.
Yeah, that works. Thanks for the comment 👍
The 31 core has an Al 3 times that of the 43 core.
I’m trying to make an RFI choke and was clueless. This vid and a few others really helped. Thank you. (I coiled some coax.)
Glad it helped 👍
I like end fed antennas and I use mix 43 to build the 49:1 transformers that enable 10-80m and they work very well. I use mix 31 ferrite beads and toroids to help reduce rfi since I have a very high noise floor. I used either beads or cores on almost all the electrical equipment in my house. They all work as advertised. Palomar is a great supplier. I've built chokes with mix 31 ferrite beads (from 5 beads to 8 beads) on jumpers of lmr 400 with mixed results at the antenna feed points but I do have chokes at the shack end of the coax. Thanks for another informative video. K5FIT
Thanks for the additional info and thanks for watching Jack!
I bought a choke per another youtuber and now I have a means of testing it. If it's no good, I'm gonna do it myself. I have a funny feeling it will be fine but could use an improvement. Thanks for the very informative video. When is the point where I don't need to say I'm new to ham? I got all my licenses last year and never did anything like this in my life. Thank you for the video!
Glad the video was helpful Gaptastic, heck I have been licensed about 6 years or so and I am a new ham!
It would be interesting to see type 52 and type 61 mix compared as well since they are used in ham applications. In particular the type 240-61 is used with 13 turns as the Balun on the Spiderbeam antenna. It would also be interesting to see a side by side comparison of the return loss for a bifilar wound toroid using both magnet wire and PTFE wire vs coax wound and whether coax performed better. Just for one mix, not all.
I’ve tested so many core and so many windings I’m not sure if I have done those or not.
@@TheSmokinApeI mention it because someone else did a video on magnet/PTFE/coax and all he did was compare SWR with a 50 ohm load which doesn’t say anything about performance.
Agreed, I'd want to see insertion loss
Wow!
I really wish the internet had been around when I started in Ham radio, these videos are gold.
Just one observation, could the bend radius on the coaxial cable have anything at all to do with the results obtained?
I don't know, I just pulled that straight out of "thin air". 😄
So generally bending coax is bad but its really repeated bending that can cause the center conductor to move though the dielectric and short the coax.
@@TheSmokinApe I just ordered the FT240-31 toroid after watching your video and looking at other specs. I was looking in my bag for a coax jumper. Found a 6' length of DXE-8X (RG-8X), which has a minimum bend radius of 2.4". If you do the math and want to make an 11 turn choke as yours, plus leads, then that's about a 15' piece of cable. Yikes! I also saw the LMR-240 has a 0.75" fixed/2.4" repeated bend radius. But it's pretty stiff to begin with. Any recommendations if I want to follow best practices? Thx John KM4FZP
@@TheUtuber143 I use a 3’ piece of rg58. It’s cheap so if I have a problem I can replace it…. There are a few sellers on eBay.
I would have loved to see you put the two in series and test the combo of the two
Dang, wish you were here when I made the video. That’s a good idea 👍
I get lucky once every few years with a good idea 😁
@@TheSmokinApe Would you consider doing two 240-43's? Ty
@@TheSmokinApe and set the sweep from 3.5 Mhz :-)
I had some specific questions and this video nailed it for me. Thanks.
Glad it was helpful MM 👍
You have to keep your test apparitus unchanged in order to maintain calibration of the VNA. If you move the clip leads closer or further apart as you did in this video, big changes, especially at higher frequencies will occur and invalidate your normalization effort.
Hey Richard, thanks for the info 👍
I use the M-F coax myself. Reduces 2 points of failure, the two connections to thw barrel. You can have them custom done by companies like ABR.
Thanks for the info and for watching!
Ive been looking at building my own choke recently. This was really helpful!
Just built one with a mix31 toroid I had. My 40m noise went from a S10 to a S5.... Ill take it!
Thats awesome 👍
It's good you are able to accurately test each choke. Did you end up putting one at each end of your feed line?
I do have a choke at each end of the feed line 👍
Interesting to see the measurements. I have a choke wound exactly like that on a 43 mix core which seems to work down as far as 80m. Never measured it, it is in a box outside my window and if it wasn't there I'd be getting nasty zaps from the metal clip on the back of my hand mic! That type of choke is a real problem solver in so many ways.
Yeah, I use these all the time. Thanks for watching Stuart.
THANK YOU. Just the video I needed, before using an unmarked Toroid. You gotta love the NanoVNA !!
Hey Patrick, the NanoVNA is the best 👍
Does this not exceed the minimum bend radius of the coax? Would you get the same results with a loosely wrapped toroidal where the coax maintains the 1.5 inch minimum bend radius of an RG-58/U?
It sure does, my experience is coax bending is a problem when it’s repetitive. I have some like this that are 5 years old and just fine…. And if it does become a problem, I’ll simply replace it. 👍
Would be interesting to see how the type 31 toroid faired at 80M and 160M. For field day contesting I spend a bit of time on these bands. Also what would adding one or two more turns of coax achieve, please
I'd probably look at 61 or 72 mixes for the lower bands as they are better for heat.
Another well presented video. There is probably a very simple answer to this that I'm missing, but...
If you get a certain RFI reduction by winding your coax through a type 31 toroid 5 times, do you get the same result using 5 type 31 ferrite beads on the coax? Is each single bead the equivalent of a single pass through the toroid and, therefore, 5 beads are the same as 5 wraps through a single toroid?
the relationship between the beads and the toroids is close but not exact.
Can you upload a video with explanation how to do such measurements on NanoVNA?
Hey Mr D, check out my NanoVNA Playlist: NanoVNA Playlist: th-cam.com/play/PLm8ROkpFeqornjIRLKS0RJqSrUl_lr5lv.html
@@TheSmokinApe thanks! Will check...
I live in an HOA and all the high voltage power lines run about 50 feet from by back fence. Who knows what else is buried there...Jimmy Hoffa. Anyway, just ordered some toroids to see if this helps. I'm not sure the CMC is the real problem, but I'll find out and let you know.
Thanks for the video. Jeff, W0STO
Good luck with it Jeff!
Well, I tried the chokes today in my nasty noisy HOA. I used the 240-43 and 240-31 and they made a slight reduction in the noise. I also put a 240-31 on my power cord which didn't change the noise at all. I imagine that the buried power lines are overwhelming everything. I tried. It was a fun little experiment.
@@Bridgestreetnursery sorry to hear that, here is a resource that might be helpful www.arrl.org/radio-frequency-interference-rfi
Here's an update. I wrapped as many turns (12) of Rg8X coax thru a 240-31. I tried this before but I didn't wrap the coax as tight as I should have. So I went back and tried again. I'm about 50% of where I would like to be but happy that I can use my radio at home. Thanks for the help.
@@jeffstover9579 glad to hear the positive results, good luck in the future Jeff 👍
You forget consider importance of restive part of CM impedance vs reactive impedance acc. to G3TXQ ? (PS. Take care also to measures setup and chokes self resonance. )
fair point
Great stuff for making RF chokes. But - when making impedance matching balun or unun, WHY is mix 31 bad?
I'm sure the Palomar engineers are right, I just want to know what to look for if my toroids get mixed up in storage. I do QRP 10W, so warnings about power handling might not be relevant.
Hey Alan, it has to do with the way the mix reacts based off frequency. You will also see people use mix 52 and 71 (I think that’s them) based off frequency.
Very helpful video. Thanks!
Glad you liked it 👍
like your video the coax with the connectors where can i buy that and what il the lenght do i need for making those choke
I got everything off ebay, they are 3' RG-58 cables
Spent the first half of the video stressing that you have the left side choke connector resting on the right hand side vna connector and wondering if they are connecting......
Even having them that close together might affect the readings.
Great review on testing suppression using VNA. Thanks. Can you share your source for the 3' coax you show in this video?
I got it from wifi_expert on ebay
@@TheSmokinApe thanks!!
For common mode choke I think Amidom K mix will do the best you can. We measure 4500 0hms of chocking ability. We replaced the balun on our palstar AT5K and bt 1500 tuners. I also made one for my atr15 The k mix puts all other mixes to shame. Only issue k mix is only made in 2.4” cores 😕 we stacked 4 core and wound it with 14 turns of rg 400
I am going to have to get me hands on some K mix, as always thanks for watching Kevin!
@@TheSmokinApe if you qrz my buddy John W2BYP he has a link on his qrz page story avenue > he has done sum balun testing on the oem palstar comparing it to the k mix also in there is extensive testing on the AT5K. Apparently the balance studs were outputting a unbalanced signal resulting in horrible rf emissions plus requiring three 00awg size ground connections. Now with the k cores in the AT5K he can run the dual 8877 to the wall 5kw no issues having ground connected or not. Mind you into a Dummy load for best practices 😉😉
G8jnj wrote an article on k mix chokes with technical data years ago, his website is a good read.
Nice comparison Video...what if we stack two toroids, would it increase the effect ?
It's my understanding that it wouldn't.
@@TheSmokinApe i once tried not by stacking but connecting two 1:1 chokes together that increased the choking effect quite a lot, but i guess thats a different thing as compared to stacking..
Did you ever figure out why the mix 31 didn't work well?
The cause of the dip? I didn’t
Okay, I have a question.
Suppose i want to use one of these chokes, (OR an ugly balun made of coiled coax), at the feed point of my antenna, and at the radio end for a mono band "resonate" (50 ohms) antenna (dipole, yagi, loop, vertical, whatever).
Suppose I also want to have my coax cut to a halfwave multiple at that specific frequency so I can check my swr in the shack.
Do I include the length of the windings as part of the "halfwave length"?
That is a good question, I’m going to say “no” but I have never tried it 😕
Good afternoon Ape, I am writing in inquiry to ask if an RG58 wound FT 240-43 common mode choke can be used with larger coax feed lines such as RG8U or DX400 of which I have both. Since there is a difference in diameter, does it matter when creating a common choke mode? I believe I know that answer but with the macro amount of information available, and everyone having their own opinion, it makes sense to me to ask someone that has knowledge. Lastly, to make a resistor load for testing transformers such as a 49:1, what size resistors are used to create a testing environment when you test the 49:1 balan? Thank you in advance for your assistance! Respectfully yours, Bill, KC3RMV, East Central PA.
Hey Bill, I do think you might have some trouble with larger diameter coax. Here is a guide that most hams use that shows positive results with RG58: www.karinya.net/g3txq/chokes/
I have tested a few different types and seem to have positive and consistent results with RG58 and mix 31 ferrites.
To test a 49:1 you need ~2,450 Ohms, 49 * 50 = 2,450. Try to use 1/2 - 1w 1% resistors, here is a video I did: th-cam.com/video/vfmCpzBOuMc/w-d-xo.html
I have watched several different winding procedures for baluns. You have wound 6 turns of Coax and then cross over and wind another 6 turns. Another site wound 12 turns of coax around the toroid, NOT crossing over. Any reason for the difference ?. I can see your way the toroid fits better in the box. Also any advantage or disadvantages of using RG316 instead of RG58. Your thoughts. Thank you
I've seen people use 316 with success but I've mostly used 58 or something like magnet wire. Once you get to 10-12 wraps each additional wrap makes less and less of a difference. I've done both crossover and non-crossover, as long as my attenuation looks good I really don't care much 👍
Thank you for reply. My balun, (140/43 wound 10 turns (5x5) with RG316) I have on my 80M inverted V at the moment, works fine on TX but rig seems a bit more deaf than before ON receive .The rig also seems to run a bit hotter than normal. Had a good look at your sites, probably should have used one or maybe two, 240/43 toroids, Working on that soon as two arrive. I will see if the other Toroids 61 or 72 are readily available, and have a play. I am only running 100 Watts, assumed the smaller toroid would have been ok. Inverted V tunes & works ok low SWR mid 30s dB return loss. Now work in progress. John
It's always a work in progress, lol! The lower frequencies can get them hotter so bigger is better. Good luck 👍
ever considered mixing mixes? stacking say a 43 with a 31 and a 52 was curious if it makes a difference. Also have you tried different mixes in series with each other? i.e turns through a 43 straight into turns through a 31 straight into a 52. Again curious to see if it makes a difference led me to ask great video's by the way keep 'em coming
Hey Gary. I haven’t for chokes but I have used a mix 43 for a 49:1 UnUn and then in series had a mix 31 Balun.
You can use RG316 to get a few more turns. RG316 can handle 400W at 100 MHz. WJ3U
Yes, you can but it’s a good idea to measure impedance just to make sure 👍
Mr Ape, are these really required on UHF/VHF?
Like all stuff in HR, it depends. If you are not having a problem I wouldn’t worry about it…
Thanks
👍
Where can we find that piece of coax. And if you made it yourself Where can I find that style of SO-239 connector
I grabbed it off eBay, sorry man I no longer have the link
@TheSmokinApe Thanks found them. Also how long should I get to make a choke
RG-58C is much more flexible than RG-58. It's available from The Wireman. I bought 25 feet of it for test leads. RG-58C is also 50 ohms, as opposed to some of the other RG-58 types that are 52 ohms. My smaller test leads are RG-316, which is also 50 ohms.
Why is there loss of 14v from hand wound toroid transformer output with
separate winds on core not overlapping. The frequency of primary was
matched to source AC, the primary and secondary windings are in same
direction and entire ring core is covered with wire , but 2 separate
sides. I thought the core under Primary caused induction into separate
secondary windings. Desparate.
I’m sorry but I am not sure I am following the question?
What’s the effect on six metres?
It would choke out any CMC on your transmission line, use mix 31. palomar-engineers.com/ferrite-products/ferrite-cores/ferrite-mix-selection
I have built a 71 foot "random" wire antenna using the 9:1 unun you instructed to build. It works great after I enhanced the RF ground a bit. The transmission line of RG58 from the shack to the unun is less than 6ft. I'm not using the coax as any kind of RF ground. Where should I place the choke - on the antenna tuner input in the shack? Or on the 9:1 unun antenna feedpoint? de KE7LOY
I typically put one on each end of the coax but seeing how you only have six feet, I would put it at the tuner. Best of luck with it!
I would place it at an odd multiple of a quarter wavelength from the far end of the antenna. Consider the velocity factor of the antenna wire, and the shield of the coax, and not the VF of the coax. So for example, with a half wave antenna, a quarter wave down from the feedpoint, at 98% VF for the shied if you want to be that precise.
Put the 2 chokes in series and you should get some good numbers.
I put them at each end of the coax. Thanks for checking out the video Rick 👍
Really helpfull video thankyou
Thanks for watching Paul, glad you liked it 👍
If i use this on 27mhz 12V INPUT POWER WIRES how many turns should i use. thanks
This is for the transmission line to the antenna, while 12v DC powers the radio it is converted in to AC / RF by the time it hits the coax. For 27Mhz I would make it the exact same way.
@@TheSmokinApe Can i use this toroide choke on 12v radio power wires to reduce LED lights noise
@@johnwestgarth2830 yes
@@TheSmokinApe Thanks Mate
Ahhh so, VSWR readings can be ignored in a s21 measurement?
It depends on what you are measuring, I f the s21 is for insertion loss you want SWR. If you are measuring isolated choke impedance it’s not necessary 👍
What happens when you stack a 31 and 43 for a dual toroid?
Hey Paul, I never tried but get asked this question often. Maybe I will do a follow up video. Thanks for the comment!
Hi there Ape,
There are times when we Ll like to use a little more power from the TxRx via a linear amplifier,, & so from various other videos ppl add another toroidal core, , , generally of the Same type. However, I've been thinking about mixing for example a 43 type with a 31 type core. What are your options & feelings about doing this please.
Also, if you have a Discord Channel, would you please be kind enough to let me know how to join it please.
Many Thanks,,
Kind Regards,
Ray.
Location ~ JO01ii.
Howdy Ray. I hang out on the TOADS discord that I run with some other YT buddies: discord.gg/ttfyDBBJaR hope to see you there. I wouldn't stack the core but build two and use them inline, if power was an issue I would stack them but using the same mix. Hope that helps!
Hi Ape,
Could one glean similar info using a Rigexpert analyzer in place of the VNA?
Thanks!
73,
John - KK7JBZ
Nope, you can’t do the 2 port test (s21 gain) on the RE.
any benefit to run 2 chokes in series?
I would put them at either end of the cable, in fact that's how I have my shack configured.
Yes. See Steve Ellington's choke video on YT. He uses up to 3 240-31s in series, reportedly to excellent effect. He recommends placing them 1 - 6" apart at the shack end of the feedline, but also notes that placement near the unun may be necessary in some cases and recommends experimentation. However he doesn't do the nice VNA measurements to demonstrate the cumulative effects as Ape shows here. He states RG-8x is fine up to 500 watts or so but recommends RG-400 for higher power or high SWR.
It seems toroid mix, number of turns per toroid and number of toroids in series all can affect choke attenuation/frequency.
For some EFHW antennas, placement of the choke at least 0.05 wavelengths back from the unun is recommended to allow the coax feedline segment between the unun and choke to function as a counterpoise. The wavelength in question is the longest to be worked with the antenna (e.g. for 80m, 0.05 x 80 = 4m). If you wind up needing a choke near the feedpoint also, you may need a counterpoise separate from the feedline.
I understand wrapping 2 or more toroids together results in little to no increase in choke function but does increase power tolerance.
Others describe placement of the proximal portion of the feedline through a 10' galvanized conduit which acts a large choke.
I am not an expert and am working through these questions right now myself.
73,
John - KK7JBZ
I wish I’d seen this before taking the advice on the Palomar site and buying $300.00 worth of 31’s for HF RFI 🤬
Yeah, it can be done cheaper 👍
@@TheSmokinApe Great videos….. love how you’ve demonstrated the Tiny/Nano’s… helped me end up getting. An H4, Tiny and Tiny Ultra, thanks again.
Awesome Jennifer, glad it was helpful 👍
How much power can be handled by rg58?
I am not exactly sure, I run 100w all the time with no issues.
When you don't the numbers of turns it trail and Error
73 KQ4CD Paul ⚓
Correct, thanks Paul!
Where did you find the female SO-239 connector you show on the balun at 1:28 in this video?
I think it was ebay, I'm sorry I don't have the link.
@@TheSmokinApe That's okay. Your videos have been very helpful.
is rg400-m17/128 good for making common mode choke
I haven’t tested those, I typically use rf-58 or 318 👍
Thanks for the technical information! 73. K7NFO
Thanks for watching Mike, glad you liked it 👍
I don't think you tested the common mode insertion loss incorrectly. You must inject equal currents on the center conductor and sherld.😢
No, it was done correctly.
Why don't you test 80 meters and 160 meters?
This was built to use on 40-10 👍
@@TheSmokinApe @TheSmokinApe what mix for 80-10?
What happens if you were to use RG213 to wind the choke ?
You could use it but I think it bigger and diameter and you would get less turns. The rg58 works pretty well…
it's about the number of turns combined with the ferrite material. More turns does not necessarily equate to a higher choking impedance. In fact, a poorly designed choke can increase common mode interference. For 10/11, I use 5 Fair-Rite FT240-43 ferrites, stacked, with 4 turns of RG213 for a high choking impedance. So pass through four times to form three loops, and depending on the type of 213, watch the minimum bend radius (large loops spread out evenly for stray capacitance).
'TOE-ROID' again. Try 'TORE-ROID'.
Son, let me 'splain it to you... the word is Toroid, your don't double down on the R by splitting it with an E... 😐
Is a toe-roid lower in the band than a hem-roid? :D 73's
These coax baluns are not very good, not flat at all with both mixes. Wire baluns are much better.
Hey man, thanks for posting and sharing your experiences. I have build and tested many of both and some have performed better than others. I've found that this particular choke works well.
Sorry I used your thumbnail - Andeas M0FXB
If the only negative effect of more windings is after a certain point each wind has less of an effect, than why not wind the toroid till it's full, say with 17 winds? Seems a no brainer to me.
I'm going to try the ft400-31 with the Messi and Paolini hyperflex 10 cable. That will be a beast hopefully.
Good luck with the build 👍
Nice video mate!! Easy video ranking = P r o m o S M !!!
Thanks for checking it out Curt!