Toroids, Chokes and Baluns for Ham Radio - Part 2 

Found this video series very informative and confirmed what I thought I already knew. The information is presented in a professional manner and was easy to follow. Great job, thanks.

Again, really good explanation of the terminology and the choke use-case. You certainly have a talent for getting your message across -- with just the right balance of theory, experimentation and 'cutting to the results' without making the viewer watch a complete test, 'soup to nuts' (as we Brits say.) Your 'disappointing' home made choke with parallel wires in your 'choke box' would probably be improved if you twisted the wires together as I suspect at least part of the problem is stray capacitive coupling at the higher frequencies that are messing up the 'balance' between 'inner' and 'outer' conductors and hence the SWR, -- a problem that does not occur when you use coax and either ferrite 'sleeve' or ferrite 'core.' You might also try 'crossing over' on the toroid at the 50% turns point winding half the toroid in the opposite direction. This also has the advantage of separating your 'input' from your 'output' as each will be at opposite side of the completed toroid. 73 Bruce G4ABX

This. Well done. Nice setup before the demo. Good explanation of terms and a real experiment. Thanks!

I bought a choke that performed worse than the one you made. I found that tying the pair of wires together at each loop around the toroid with dental floss kept the impedance constant and made the plot flat. One could tie the wires or tape them prior to winding, too.

Good info

Hi Ape - Thanks for sharing your experimental results. Since the focus of this video is on chokes, it seems (as I think another reader mentioned) that an attenuation measurement (S21) would be more revealing than a reflection (S11),or SWR, measurement. In fact I’m not sure how to interpret the reflection measurement results as I think they say more about impedance mismatches than they do about attenuation (i.e., choking). I guess some of the results leave me wondering as to the source(s) of impedance mismatch suggested in some of your plots. Interestingly, the commercial product ( short piece of coax wrapped in ferrite beads) showed essentially no variation in SWR versus frequency, which is kind of what I expect. Anyway, I’m not being critical of your results. Rather I’m trying to make sense of them. - Cheers! - Jim

Loving this series on roids. Good stuff, Ape!

good

Would have liked to see the CMC attenuation on the last three chokes that you showed. Thanks for showing the disappointing results of your home brew core VSWR, I’ll be sure to test for that now.

Remark at 3:45 in the video "I" is not L .... "I" is the symbol for current like in Ohm's law or Kirchoff's law. It's confusing. It's not L1 coming in but I1 ... pronounced lke "eye 1" You guys in america happen to write "I" a lot meaning the letter L. That's why you probably say L in the video. Where talking about currents here .... not something else. In europe we make a clear difference between the two. "L" is voor coils .. meaning inductance. "I" is for current ... Ampère or Amps. Keep up this nice work. 73

Yinz are doing a good job.

More good info. Thanks!

Good video, as always. What is the length of the RG8 cable that you wrapped around the toroid at 1:44 in the video? I think that looks like an easy first choke project.

In other words, think of it as Tor - Oid...these two syllables.

Can you just add the beads to your coax and just shrink-wrap them in place?

how much power one ft240-43 can withstand in this configuration with rg8 or with wire

Hi Ape, I know this video was posted 2 years ago but was hoping you could offer some advice on this topic. I have LED overhead lights in my home and I cannot replace them as I am renting the place. These LEDs are causing interference. Diagonal lines show up on the waterfall display of my FT-991A as soon as I turn on the LED lights. The interference is visible on the VHF 2m / 144-166 MHz band but not on UHF 70cm / 430-440 MHz. It looks like the coax cable is picking this up and sending it into my radio. If I unplug the antenna, the waterfall turns black so the radio itself is not picking up the interference. I want to operate on VHF. What sort of choke/toroid mix could I use to suppress this interference going into my radio but allow my desired VHF signals to be transmitted ?

What was the core material (and ring size that you used for the choke you compare to the Chameleon. I must have missed it.

5:57 "What Ape Chokes" 😂😂😂 Are you using snap on ferrite cores for the other choke points? Or are you using the same choke you're demonstrating in all of those places as well?

SK G3TXQ published a lot of his test results on different mixes as well as air core chokes. www.karinya.net/g3txq/chokes/ His recommendation was that you want to have as much of the impedance to be resistive at the frequencies of interest because inductive components can actually increase common mode current under some circumstances. I'm hoping to set up a fixture to use a NanoVNA for testing homebrew chokes. Thanks for the great videos!

Is it Toe-Roid or Tow-Roid?! Good info as always, man!

Awesome #2, ohhhh that didn't sound good! Lamo 😂

Would a choke be appropriate on VHF where I have a certain frequency interference on receivng only from one repeater?

Hi Ape. An equally informative video as part 1. I just bought my first HF radio and is planning on putting up a homebrew EFHW antenna with a 49:1 balun to connect to my radio. In my understanding the 49:1 balun will also act as a choke to eliminate CMC, since the connecting wires goes through a ferrite core (planning to buy 2 pcs of T240-43 for my balun). Am I correct in this assumption? Or am I missing something? Thank you for the help. 73 de 4G1FBL from the Philippines.

That's not Skin Effect!

Nice 'roids man

be careful of 'roid rage. :-D

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