Making a Simple DIY 1:1 Common Mode Choke | How to make a Common Mode Choke

Рет қаралды 7,822

Darren N4VFR

Күн бұрын

Пікірлер: 33

@nhojcam 3 ай бұрын

do you have a materials list and source for each component? thanks for your videos.

@DarrenN4VFR 2 ай бұрын

I've updated my my descriptions to add links to the products I used. Here are the links: Affiliated Amazon Product links: 4" x 4" Plastic Conduit Junction Box: amzn.to/4enuI02 SO239 Bulkhead Connectors: amzn.to/3zGM0WN RG400 20 feet: amzn.to/4dwHHv4 Zip Tie Mounts: amzn.to/3N44B1Z Torroid FT240-31 31Mix: amzn.to/3BAN5zS

@nhojcam 16 күн бұрын

@@DarrenN4VFR thank you! i am circling back on this project. i need to get a couple of these built for some delta loops i'm building. are you satisfied with the results of the choke you built? i know it's difficult to get tight wraps on the RG400 to the toroid. any issues?

@DarrenN4VFR 16 күн бұрын

@nhojcam I'm happy with it and still using it at my S. TEXAS QTH.

@g0fvt 9 ай бұрын

These work very well, and of course if you have spare RG400 left over it makes great patch leads. 73

@jarmstrong2843 9 ай бұрын

Great Info. I've been looking for a video like this!

@jackhayward4605 6 ай бұрын

Thank you Darren! I am making one now and I came upon this video. I was going to use RG58 until I saw this, so I have changed my plans and am going with RG400 after watching your build. Thanks so much! Jack K1JW

@DK5ONV 9 ай бұрын

Looks really good 💯👌

@allswoop2 Ай бұрын

How much did it cost you to build this??? and would this help with my mobile Cb 11 meters with reducing background noise from my Tri axle truck??? also you don't have to worry about too much heat soldering the RG400. it won't melt the center, like other foam center s

@DarrenN4VFR Ай бұрын

I dont know about reducing noise from your truck. It will reduce Common Mode Currents traveling back down the coax. My guess, it should also work on 11 meters.

@dougcox835 9 ай бұрын

An easy way to do the braid cleanly is to use an awl at the end of the insulation and work a hole in the braid until it's big enough for the center conductor to go through. Then do a hard bend and you can fish the center out through the hole and use the awl to work it out. After the center is out you can work the braid and it looks like it was made that way. And the end of the braid will be pristine for soldering to your ground lug.

@corradoQC 4 ай бұрын

What you said made sense to me until I had to do it, is this demonstrated anywhere ? Let's say I've removed the outer jacket on a 1 inch section of the where would I start to make a hole in the shield ? 1/4 of the way near where the jacket is present ? Have you done this with rg400 ? the weave is tight.

@dougcox835 4 ай бұрын

@@corradoQC This is just something I've done many times at work. I actually don't use RG400 though but it won't matter because any braid will separate. All you need to do is push it a little bit to expand it some and then you can pierce it with an awl. I should make my own video on this. I figured this out myself and I don't know who else might do this method. When you hard bend the braid with the center conductor and dielectric the braid will separate at teh top all by itself and the reason for the awl is to poke in under the bend to give you leverage to pull the end through. Maybe try this with some smaller stuff like RG6, and unshielded. The foil complicates matters but it's only foil so it can be manipulated or removed as it's only the end anyway.

@DonDegidio 8 ай бұрын

Hi Darren, Great build. G3TXQ has very good common mode choke info on his website. RG400 uses a Teflon dielectric center insulator, so any soldering iron or gun wouldn't come close to affecting it. I've used a plumbing torch to install PL-259's on RG400. 73 WJ3U

@danazlin3409 2 ай бұрын

Nice video with one problem: You do not know what cores the commercial balun used. They may be a Mix 77, Mix 43, or something else entirely. When you abandoned the chart data showing actual measurements of chokes built on FT240-31 cores, the choke you built will have little resemblance to what your reference documentation specified. From the chart at 4:46, you choke will have Rs values somewhere between the values shown for 9 turns and 17 turns, i.e. less effective than 9 turns would have been. Will it still work? Yes. Will it be as effective? Probably not. You will only know when you put it on a VNA and test its performance. Dan KE6PO

@DarrenN4VFR 2 ай бұрын

Thank you Dan for the information.

@corradoQC 4 ай бұрын

Are you confident they used MIX 31 ferrites in the one you bought ?

@DarrenN4VFR 4 ай бұрын

Yes, I'm using it right now.

@dogsareloud 4 ай бұрын

Hey Darren. Saw your article in QST. Good job! Tom, N5ATR

@DarrenN4VFR 4 ай бұрын

Thanks Tom! heh heh heh.

@jackhayward4605 6 ай бұрын

Darren, I am thinking of combining this common mode choke with a 9:1 UNUN in the same project box. Do you think this will work, or could there be some interaction between the two if they are located in close proximity in the same project box? Thanks!

@DarrenN4VFR 6 ай бұрын

I don't see why not. I've connected my 4:1 to a 1:1 CMC but using a male to male PL249 connector to connect the two together.