Common Mode Current Baluns and Chokes for Ham Radio Antennas

[@HamRadioCrusader]

I laughed WAY TOO HARD at the video thumbnail 😂😂😂😂😂

[@Lancedsanders]

Same here. That cracked me up.

[@bdinnocenzo]

Yup! Me too…

[@TheSmokinApe]

Haha, even I cracked up about it 👍

[@brad1725]

Guilty of laughing, too… 😂

[@PARTner91]

Freakin hilarious 😆

[@acestudioscouk-Ace-G0ACE]

Interesting and informative information well delivered by you both.I like your individual channels as you both present information clearly in a laid back and non-gimmicky way. You also work well together and convey the information well. Too often multi presenter videos forget the viewer whilst the presenters try to out-joke each other, trying to become the dominant personality and party at the viewer's expense. You and Chuck don't fall into this trap and compliment each other. I look forward to more videos from you both. 👍👍👍👍👍😃😃

[@TheSmokinApe]

Thanks Ace, glad to hear you like the videos!

[@RandallRash]

Deep dive on a technical subject would be great!

[@TheSmokinApe]

Well do it 👍

[@bill-2018]

I've been experimenting with h/b h.f. dipoles lately, a 60m inverted vee and a 2m 2 element collinear and trying ferrite chokes. I decided my best place was at the tx end as it kept the SWR happy unlike at the aerial end where my hand on the coax in the shack affected the SWR. My theory is that r.f. surrounds the coax and it was picking r.f. up after the choke. Perhaps a few snap on ferrites spaced out along the coax near the aerial will do the job. I'm going to try it. G4GHB.

[@TheSmokinApe]

Yeah, I do choke at both ends. Good luck with it Bill 👍

[@bill-2018]

@@TheSmokinApe It does seem it's going to be best. 73, G4GHB.

[@ornithopterindia]

👍Thank you sir.

[@TheSmokinApe]

Thanks for watching 👍

[@kevinkc3onohelijeepworld953]

Ape would love to see you on every Tuesday. Maybe you can get that Amidom Kmix balun tested on the 1st episode going with the cmc theme 😉☺️anxiously waiting ☺️

[@TheSmokinApe]

I was looking at that core today 👀

[@Ezzell_]

It would be interesting to see what effects clam chokes (clamp-ons) may have on swr of the antenna. If you were to tune an antennae to your sweet spot then place several chokes on the line.... would the SWR change at all if re-measured?

[@VE9ASN]

If it does, it proves you had common mode current on the exterior of your feedline .

[@Ezzell_]

@@VE9ASN hard to argue with that...

[@TheSmokinApe]

Yeah, it would only change if there was CMC.

[@bob_mosavo]

Thanks, Ape 👍

[@TheSmokinApe]

Thanks for watching Bob 👍

[@AndyAAzeroAM]

Definitely 1. Any opportunity to learn some stuff is cool with me

[@TheSmokinApe]

Thanks for watching Other Andy 👍

[@paulm0hpd319]

Good video on how to suppress cmc ,perhaps more should be mentioned on what actually causes cmc ,ive noticed some believe its from an impedance mismatch

[@TheSmokinApe]

Thanks Paul, I appreciate the feedback 👍

[@DaytonaJim78]

Funny thing is I am only Gmrs licensed but a choke and swr and cable loss seems to be more important in the higher frequencies because it already struggles with distance. So most people are running crap setups with Gmrs and the potential to make it way better is there with just a little bit of research!

[@TheSmokinApe]

Hey Jim, I think part of it is that the GMRS radios come with little information so they probably just don’t know any better.

[@DonzLockz]

Awesome, I "gobbled" up all the info today. 🐓 I like power point presentations but you need pretty pictures too. 👍🤠

[@TheSmokinApe]

Thanks Don 👍

[@DonDegidio]

Hi Ape, I saw Don's questions about remote coax switch and remote tuner. I have both and put a CMC at the input to the remote tuner and have both the tuner and switch box connected to a ground rod. Never had any stray currents come into the shack. 73 WJ3U

[@TheSmokinApe]

Thanks for the info Don 👍

[@blugoose86]

I missed this live Ape, sorry. Did you say that a carbon fiber pole is NOT good to hang a wire from?

[@LeeMcc_KI5YPR]

[DISCLAIMER: I am not @TheSmokinApe] Carbon fiber is strong for the weight, but it conducts electricity some. Not as much as a metal, but much more than fiberglass. I use carbon fiber to hoist a hamstick dipole, or one end of an EFHW. Using it to raise a wire vertical is problematic. It might work, but if it does not, that is the first thing to check.

[@TheSmokinApe]

Lee is correct, CF is conductive and will almost certainly have an effect on radiation pattern and tuning. I don't use it...

[@MrMudsHamRadioRadioTime]

Great delivery and focus on the subject Ape! Started to search your channel instead of Google when I’m looking for an answer or help on radio related content. 🤙🏻

[@TheSmokinApe]

Hey Mr Muds, glad you are finding the videos helpful 👍

[@PARTner91]

The video thumbnail LOL 😂

[@TheSmokinApe]

Haha

[@bdinnocenzo]

CMC is real. All current needs to flow and will ALWAYS seek the path of least resistance. The best solution is to eliminate or minimize the current at the source. Knowing that the current most likely won’t be eliminated you should give it a path to ground that protects people and equipment.

[@TheSmokinApe]

Totally agree and thanks for the comment!

[@mjy]

Love the thumbnail image. LOL

[@TheSmokinApe]

Haha, it made me laugh when I dd it...

[@K3JRZOnTheAir]

Fantastic info! Thanks for sharing! 73!

[@TheSmokinApe]

Thanks for watching!

[@Rusted_Link]

Welcome to the Smokin' Ape Adult Toy Store !!

[@TheSmokinApe]

lol Rusty 👍

[@Cliff-KI5OPP]

QUESTION! Wouldnt your coax be grounded at the entry point into your shack, via the lightning protector that has potential to ground, help eleviate the cmc getting into the shack? The current should look for the easiest path to ground. I would think the coac grounded at your tower or pole help with the same thing?

[@Cliff-KI5OPP]

Coax sorry my fingers are too fat to type on a phone

[@TheSmokinApe]

Yes, that is correct. That said, it's best to keep the current off the shield.

[@norrinradd8952]

A good RFI Choke can redirect enough CMC to cook a chicken. The trick is to get it from the shack to the kitchen. The solution is to have the shack IN the kitchen.

[@TheSmokinApe]

Hey Norrin you are correct but I prefer my chicken fried!

[@bierbarrel]

I sure wish you would do another Q/A on this topic...Im tired of my radio losing USB connection on certain freqs

[@TheSmokinApe]

It's something we cover often on the channel so I am sure it will come up again 👍

[@bierbarrel]

Thx...I have already started looking at your videos on the topic. Funny how it all started with FT8@@TheSmokinApe

[@TheSmokinApe]

👍

[@bassangler73]

The thumbnail still has me laughing

[@TheSmokinApe]

It’s one of my better creations 🐔

[@bassangler73]

Lol....Happy New Year bro!​@TheSmokinApe

[@TheSmokinApe]

@@bassangler73 same to you BA 🍻

[@enginedave]

What is better? A coax choke on a 31/43 mix toroid or a bilfillar wound toroid of 31/43 mix?

[@TheSmokinApe]

It's a pretty hot debate and its going to depend on core size / type / wire gauge and type / number of turns and pattern. Here is a good discussion to check out to get started: ham.stackexchange.com/questions/13005/coax-or-bifilar-windings-for-a-choke

[@richysradioroom]

A picture of a choke and chicken? What could it mean? Oh I get it. They both use inductance to create resistance at a specific frequency.

[@TheSmokinApe]

Exactly Richy 👍

[@user-tl5tt5yw3c]

So if one has no interference to other equipment in the house or shack does that mean one has no issues ?

[@TheSmokinApe]

CMC can be a problem even though you are not hearing "interference" I'd recommend that you use a choke. Thanks for the comment!

[@Zavestang]

Ape, based on what you said, would love to see your setup in regards to connecting to your radio via wifi, I have a 710, wondering if I can do that same. Be nice to isolate the radio from my computer. Or is that just a feature your radio supports out of the box?

[@TheSmokinApe]

I use a program called SDR Control, it's only for Icom 😜

[@rich4u1973]

Could you actually show choking the ham shack

[@phillyedhrj]

Can't show the ham shack. That's how they get ya. 😉

[@TheSmokinApe]

I did a video a while back that had some pics, I can show some of them plus updates 👍

[@rfburns3472]

Good info. CMC's have kept my bacon from burning in the shack! Can you produce a video, using the NANOVNA, measuring the feed point impedance of a specific length nonresonant EFHWA? I'm using a newly installed Balan Designs 9:1 with a 41 foot wire that is supposedly nonresonant at the 40 thru 10 meter bands. I have not found any videos measuring the impedance directly at the antenna feed point (ant/counterpoise). Also, the VNA H4 port impedance defaults to 50 ohms. Should this be changed to 450 ohms since the balun is 9:1?

[@TheSmokinApe]

I haven't done the measurement right at the feedpoint, I could the next time I have an 9:1 installed. The nanoVNA should be at 50ohms, which is the system impedance of the radio.

[@rfburns3472]

Agreed the impedance of the radio is 50 ohms but if your looking directly at the antenna "feed point" impedance I was thinking the NANOVNA port might be accurate when set to 450 ohms for a 9:1 balun. Does that make any sense at all?

[@TheSmokinApe]

@@rfburns3472 if you are testing without the transformer, the transformer effectively divides whatever the impedance is by 9.

[@rfburns3472]

Sounds correct. Looking forward to your video with a direct measurement at the antenna feed point. BTW, your videos are very well done. Thanks for putting forth the effort.

[@TheSmokinApe]

@@rfburns3472 thanks man, glad you like them

[@user-hb3dl3go9v]

1

[@DutchmanRadio]

The thumbnail was out of pocket 😂😂😂😂

[@TheSmokinApe]

😮

[@nortonics5745]

Is the chicken okay?

[@TheSmokinApe]

Yes

[@dickvercouteren1424]

Nice chicken 🤣

[@TheSmokinApe]

Thanks!

[@GlenMillard]

Why did you have a thumbnail of a chicken? On a video about choking. Chicken-choking? 😎

[@TheSmokinApe]

👀

[@kevingoshe4371]

RFI is bad, mmkayy?

[@TheSmokinApe]

Right

[@BusDriverRFI]

Hey now. Why am I bad?

[@phillyedhrj]

Look at you gettin' all fancy saying egress.

[@TheSmokinApe]

Every once in a while...

[@Lightning-bol]

MORE BS CLICKBAIT! DO NOT BOTHER WASTE OF TIME !!!!

[@TheSmokinApe]

Glad you liked the video 👍

[@Lightning-bol]

@@TheSmokinApe back to your bottle ya drunk

[@johngriswold]

Stopped watching when you said a choke was a balun.

[@TheSmokinApe]

Oh, that's a shame. If you watched longer I am sure you could have found something else to nitpick about....

[@johngriswold]

@@TheSmokinApe - Not terribly likely. I, along with many other hams, look to you for good information. Bad information hurts everyone. I'm sorry you don't feel the need to be accurate in your presentations.

[@TheSmokinApe]

@@johngriswolddon’t sell yourself short, we both know it’s very likely. It’s what you do…

[@BusDriverRFI]

All's we got is forward current, radiated current and reflected current. Then there's losses. Any other current that could possibly arise are above and beyond the generated currents. If they exist, they can be identified and isolated as free power. Nobel prize time. Common mode currents are an instantaneous measurement of a particular point along the feedline where the currents add up. Ideally, you have 1A in one direction at one point and -1A on the other side at the same point at the same time. Current flows in the coax shield. It's supposed to. It's balancing the current in the center conductor. RFI in the shack is real. It's the result of reflected current. It's the result of not having a matched load on each end of the transmission line. It's not a special current flowing along the outside of the coax. I know you like to chide the truth but the truth is still there. Facts don't lie.

[@TheSmokinApe]

Thanks for the info BDRFI, this is helpful 👍

[@paulm0hpd319]

@busdriver, No facts don't lie ,common mode current is not the result of a mismatch load its because of an antenna system imbalance, it most certainly is a separate current on the outside of the braid, nothing to do with differential or reflected currents which run on the outside of the centre conductor and the inside of the outer braid,look up skin effect

[@BusDriverRFI]

@@paulm0hpd319 Fortunately, I'm not imbalanced so I am not having the problems you are. My antennas have an impedance of R+j0. Never any imbalance with this style of antenna. I'm not sure which one you are using where you have so much angst. Don't be a sad ham.

[@billmcilwee566]

1

[@TheSmokinApe]

Thanks Bill 👍