1:1 Common Mode Current Balun Explained

My simple explanation on how the common mode current choke works.
Let me know if it's useful or if I got anything wrong.

[@walteranderson7889]

Excellent presentation. Finally, someone using basic rules about magnetic fields respective of current flow. Best I’ve seen for explaining balun theory.

[@ChrisConner1]

Agreed, Thanks for making this.

[@dean5263]

Nice demonstration, it gives me the knowledge and confidence to construct one myself.

[@adventurelaus]

Thanks. Definitely go for it.

[@hubercats]

This is the best explanation of current baluns I’ve found to date. Thank you for making and sharing it. - Happy Holidays! - Jim

[@ianboard3555]

I had better luck winding it this way than using the 'crossover' winding style shown in some other videos.

[@ernieferguson6346]

i agree

[@ncooper8438]

He didn't explain how it was wound so only half useful.

[@oldbassist60]

Very well done. Thank you.

[@dmitriytimofeev5897]

I liked video. Good explanation and choking demonstration, but IMHO is not quite correct. We don't disconnect the other coil from the line. And if whole cable tries to be unbalanced on one coil, the other coil generates equal potential and return to balance of applied potentials. Thanks!

[@Viktorherenowhere]

Nice) Do you have same experiment with voltage balun ?

[@adventurelaus]

Not yet

[@abdula4699]

Thank you very simple. De a71br.

[@marcstrauven4697]

Dear Sir, I have build a magnetic loop antenna for 11 meter band. (tx ands rx) Do I need to ad 1:1 ballun between the magnetic loop and coax? And what would be the best core material for that band? Greethings from Belgium.

[@adventurelaus]

For 27MHz (11m) both 31 and 43 would work. Paalomar still suggests using 31. palomar-engineers.com/ferrite-products/ferrite-cores/ferrite-mix-selection I case you haven't seen it yet, I've made some measurements with the 43 mix as well. kzbin.info/www/bejne/rpLKiGypr7Vjm6s I'm not very knowledgeable if magnetic loops have causes of common mode current. Using a good common mode chocke shouldn't impact performance though.

[@marcstrauven4697]

@@adventurelaus Dear Sir, thank you very mutch for youre reply. So it is betther to use one instead of none. Best regards from Belgium.

[@rcampici]

You need to understand common mode and differential mode the two are not the same... The explanation has several erroneous assumptions Common mode currents exist when the matching from unbalanced to balance take place, any mismatch here creates common mode currents Its wrong to call a 1:1 current BALUN a common mode choke, the example in the video is wound as a choke and thus works as a common mode choke, however there is not conversion for differential mode, the transformer should be wound with differential matching structure. Showing the response in the spectrum analyser is also not correct, the test is done with unbalanced in and unbalanced out, thus the result does not show a lot aside the ferrite bandwidth. I understand that many use this kind of setup in the belief that its a 1:1 current BALUN and this propagates the myth into the wild, however its not providing the proper match as required adding to losses, note that any common mode currents generated are detracted from power intended for radiation thus its a loss, make a proper matching transformer and then the common mode currents will be negligible.

[@willharry6791]

What is the power handling capability?

[@adventurelaus]

The design of the current mode choke is from DG0SA www.dg0sa.de/balun1zu1gross.pdf . He rated the power handling up to 800 watts. Note that in Germany, where he's from the max power an amateur radio operator can use is 750 watts so I'm not sure if he had any interest to look into 1500 watts baluns and chokes. I have used this balun on 800 watts SSB without any issues yet.

[@nolyn78]

@@adventurelaus If I used 14 AWG with the same Ferite Core, this should e able to handle 1500 watts?

[@adventurelaus]

@@nolyn78 I'm not sure about that myself. Per instructions from www.dg0sa.de the 200 watt version uses 22AWG with a 40mm core and 12 windings, the 400 watt version uses 20AWG with a 40mm core and 10 windings, and the 800 watt version uses 18 AWG with a 60mm (FT240) core and 12 windings. As for buying the wires, I got them from ebay.

[@Thambiah-c3h]

ft140-43 ????? ft240-43 ????????

[@enginedave]

I use FT240-31. Good results

[@chublez]

Size depends on power needs. Mix depends on frequency. Edit: a 240 like shown in the video wrapped with 18awg PTFE should handle in the neighborhood of 600 watts just fine. Stepping down to a 140 and 22awg should cover you for 100 watts or most applications if you don't have an amp and want a smaller device. The costs are pretty similar unless yer making a bunch or em so the bigger one gives you head room for days and no worries of ever overheating it with a 100W radio. It's also easier to work with than the smaller one imho. 31 mix if you favor towards 160/80m, 43 mix if you favor 20/10m. Edit edit: cut them powers back and keep an eye for heat if yer gonna run some digital mode at 100% duty cycle nonstop. Really that's basic rule with anything I think particularly diy you need to verify what your device handles the way you use it. Most users with most materials will be okay around those levels in most operations. Also you can stack em if you need more power..napkin math says it'll about double it...real worl again is depends so verify.

[@RickGreenPhoto]

What core composition is best?

[@jimc5308]

Hi Rick, I'm using FT240-43 Toroid core for the 1:1 chokes I've made. I also have built some 4:1 Baluns using the same FT240-43 with great success. See TRXBENCH videos on building the baluns. I'm using 18 awg and 16 awg stranded silverplated copper wire with PTFE insulation. Best place to get the cores (for me anyway) has been MOUSER electronics. The 43 mix covers 160 through 6 meters very well. Hope this helps. 73 de Jim

[@adventurelaus]

Ferrite cores have a specific "Mix" that behaves differently depending on frequency. Mix 31 is good for low band HF and 43 is good for higher band HF. Wire type and winding will also have an affect on the performance. In short, there is no single best.

[@nolyn78]

@@jimc5308 HI Jim, If I use 14 AWG on the same Ferite Core, it ahould handle 1500 Watts? Where do you purchase the stranded silver plated copper wire with PTFE insulation?

[@jimc5308]

@@nolyn78 Hello Nomis, 14awg is not needed for 1.5 kw if you use PTFE silver plated, stranded wire and following "TRX Bench" you tube instructions. The heaviest I've used is 16 awg. Although I mainly use 18 awg, if I was going to wind a balun for high power use I would try the 16 AWG PTFE wire and use TWO ft240-43 cores. You can wind the balun the same number turns, etc but you will be using two cores instead of one. This helps with the heat build up from 2 kw. Stack the cores on top each other and use super glue to hold them together. Just a few drops. After they dry, wind them with the 16 awg stranded silver plated PTFE wire. I bought my wire at www.prowireandcable.com/ See below for 16 AWG ordering......... Item Description 106681 16(19ST)TFE-E MIL-16878/4 ORG 106679 16(19ST)TFE-E MIL-16878/4 BLU Hope this helps, 73 de Jim

[@harrybond007]

Explanation makes no sense

[@pratwurschtgulasch6662]

thumbs down for the way you drew the windings on the core. it would have been nice to understand how the green and red wires were wound and connected.