Intro to Baluns 

@ 10:02 I'm not sure what sort of explanation that is, but a balun is basically an RF choke that eliminates, or chokes via the toroid element, stray signals and RF from traveling down the feedline back to the transceiver. This RF can be produced from an unbalanced antenna. Strangely enough, an inverted vee is a balanced antenna if properly cut, so no balun is actually needed. Also, their saying you get 500 to 2000 miles from a balun is kind of hyping it as a magic box. You get the distance from your antenna and transceiver and feed line, the balun simply allows you to use an unbalanced antenna and/or feed line.

The title of this didn't live up to the video name. Nothing about wire gauge, insulation, bifilar, core permeability, impedance matching the list goes on. This was the equivalent to I bought a toroid core used a chart to wrap wire around the core I bought and used Teflon wire but further explanation.. How often is your balun going to be on fire? Anyway, really enjoy the geek sphere around radio - good work guys!

bravo..good job..my friends

Thanks for posting an interesting and informative video on a choke balun. M6APJ 73's.

Thanks.

This was an excellent presentation with good teaching material! Thanks!

can you all do a video/class on using an icom ah4 on yaesu and kenwood radios, such as the yaesu ft.450d and the yaesu 857d..... making a unit to start the tuning process.

Great Video, I am just getting into Radio (not even a HAM yet, just planing around with some SDR's). Thinking of building one of these for a 15M Dipole using strands of solid copper Ethernet cable. As a network tech it's something I have in ready supply. I'll let you know how it work.

9:30 where might I find this Balun Chart (that Bruce references) on the internet ???

The ferrite ring (toroid) catalog data gives the inductance foe each. BUT it is a little confusing, because they can vary their units. Some give it per 10 wire turns, or per 100 turns and so on. The important thing to learn is that the inductance increases by the SQUARE of the number of turns. And then you naturally want to use the frequency dependence to get the impedance at your desired frequency. Here is just one arbitrary example. Assume you see a listing of 4 nH/ turn squared. So, with two turns you get 4 * 4 nH = 16 nH. 3 turns makes 9 * 4 nH = 36 nH. 5 turns produces 25 * 4 nH = 100 nH. Ten turns then is 100 * 4 nH = 400 nH or 0.4 uH.. That last one at 14 MHz represents 35.2 ohms impedance (not resistance). That is the core of the required knowledge. Beyond that, you are going to pay attention to the frequency range that the selected ferrite is specified. And for the kilowatt implementations also thermal issues. Different ferrite materials have different maximum temperatures. But that is enough for the basics.

YOU ARE Awesome !

I used a FT240-31 ferrite toroidal as described with 12 AWG PTFE stranded wire and wound it according to the instructions on the video. The Balun didn’t work. I got what appeared to be infinite SWR on all bands and could not tune with my antenna tuner. First thinking that my coax was shorted, I used my DMM and eliminated that thought. Next, thinking I wound it incorrectly, I double checked and everything was wound correctly. Next, I shorted the winding on the Balun to bypass the toroid and my SWR dropped to under 1:3. I rewound the toroidal using the Guanella current 1:1 style and everything worked fine. I am wondering if the design is incorrect.

Hi guys from the UK. Great video. Look forward to seeing more... many thanks 🙏 just out of curiosity could you substitute 16swg enamelled copper wire instead Of Teflon coated?

Excellent all your video ,only one question.For 20 and 40 meter a can use ft240-43 or ft240-31 wish one work better thanks in advance Eddy

W5ESH Darrell what size wire is used to make the Baluns

Another excellent video...👍

i really love HF over in america, after listening to a few online SDR setups.. Americans seem to stop and chat a lot more compared to here in Europe, we just seem to CQ wait for a response, take call sign and then move on :(. i really like the 40m band too, i've spent a few evenings listening to some really interesting conversations between people in america

I got a 9:1 UNUN, then started with 124.5' but 160, 80, and 40, were too high for internal tuner. Cut to 121' and working great with external tuner. Now, with internal, as high as 2:7. but at 5 watts. If power is increased, even to 15 watts or 10, it will go very high. Will the chart I used work better with a 47:1 UNUN instead? It is an end fed with a 30' counterpoise, but planning to use a ground rod to see differences. Now, 20, 15, 12, 10 and 6 are working great with internal or external tuner. Thanks.

If I'm doing a field construction of a balun to operate a manpack HF radio, how crucial would the ferrite core be?

Excellent presentation on baluns. Thx,

very good video from 9w2asf from west malaysia

can it be for RIG Alinco DR135 MK II radios?

Can this be used for 2 meter if so how would I build it

Will baluns in general make RX improvements as well?

Show

Everytime i hear someone say 3 to 1 swr is ok then use the atu. I have designed antennas professionally, and reject anything over 2:1. Even then i carry on to get 1:1 at the center of the required frequency and under 1.5:1 for at least 80% of the band in the case if ham hf bands. Teaching people that 3 to 1 is ok is not good. Everything has a ressonant frequency, so its down to the basics of making it resonate at the desired frequency, then design a feeder network to get the desired impedance. Do that and you have a happy antenna, with a 1:1 swr and some bandwidth. Even situations where there are physical restrictions to length, there are allways options available to get a smaller loaded antenna working at a low swr with a correctly designed feeder network... If you havent done that, then you havent finished designing the antenna... I have no room for an ATU in my shack. My radio runs straight through a swr meter, a low band pass filter, an antenna rorary sw, and to any one of my hf antennas, that comprise of a choice of 3 windoms, 3 verticals, and a 5el 6 meter beam with my own dual drive design. Please don't t teach people that 3:1 is ok.... Its a poor compromise at best...

Good one, the Ferrite Rings are magnetic ones ? Cable can we use 16 SWG Copper insulated ones ??

What's the wire gauge?

Very informative. May i ask how long for the wire do i need to tune for 145mhz and 460mhz? im using dual band. thanks

Can you give me the size of the core I heard the type 31 part?

How does this channel not have more subs

I built the Balun and is good at reducing received noise, but it acted like a loading coil and reduced the resonant frequency by 2 MHZ. I would have to trim maybe 6 feet of antenna on both sides of the dipole to get back to 40 meters. Did anyone else have this problem

Why not just put the toroid on the thin jumper wire between the tx and antenna tuner? Can easily get 10 turns in, and don't need a box assembly.

On a 1:1 current balun like the one you described, is the connections to the SO-239 critical ? Can they be wired either way as long as I have the right ends soldered to each other ? ( which I do )

I love your videos, but can you guys provide details in the description like suggest parts to buy? The presentation really didn't provide any detail at all. It was more along the lines of here is the magic device and kind of how it works, but you will have to guess on what materials you will need to buy it.

Great info

Awesome info thank you for the video

I wish there wasn't so much inconsistency on the construction of 1:1 baluns. Some have 5 wraps up to the top on one side, back down, and then 5 wraps the other way up the other side. Some say double wire, some say coax, some say 12 turns, some say 8...

Where did you get the electrical box for building the balun. I can't seem to find them. Henry

As far as power handling goes, you can figure about 500 watts per toroid, so if you want a balun that will handle 1KW, you need to stack 2 cores together. Also, you have your wires wrapped wrong ! They should be wrapped 2 wires side by side like: II Not wind one wire on one side of the core and one on the other. You are trying to created a transmission line balun and winding them separate like that is not the right way to do it ! In fact, for a 50 ohm 1:1 balun, it is best to twist the wires together and then wind them on the core !

4:57 again, how does he know the wire he did use to wind the core are of the right impedance ? How does he knows how much attenuation he gets on common mode current ? They say 8k ohm, how did they measure that ?

Cool share Bruce and Kevin on the dipole

Does it matter what side of the balun is going to coax and antenna?

What was the toroid the number went by so fast I didn't catch it? KI5ACA

I tried using #14 Thhn solid wire to wind that balun... NOT a good result! SWR 25MHZ to 30MHZ was well over 18:1 as measured on a VNA. I have some PTFE #18 stranded silver clad wire on the way and I'll give that a shot.

The first minute and a half of this video is commical 😂😂😂

Nice presentation.

what was the wire size bruce used on the balun

for some reason i would think a horizontal dipole would radiate straight up into the atmosphere.

Would have been useful to mention a 20/40/60m fan dipole

Wait.... 47:1 - not 49:1?

9:1 a balun? A 9:1 is a unun, transformer. Unun is unbalanced to unbalanced, a balun is balanced to unbalanced! A 1:49 or 1:64 is a transformer, can be used for multiband Half wave end fed antennas, resonant wire. A 9:1 unun needs a non-resonant wire, any wire length. For 80 m a wire of ± 84 feet will do! Keep in mind that this antenna needs a counterpois, and a very good common mode choke! I really don't know why everyone calls it a balun, when there is such a big difference!

This looks to me like a great Ham club! KN4UXO

TXS KQ4CDPaul

Can ham radio communication be encrypted?.

There is such a thing as a no antenna area ? that's just wrong . how do people watch tv or communicate with one another ? I am so glad I don't live in some screwed up area like that !

2023 thank you relevant still

Nobody ever charges "a hundred bucks" for a 1:1 balun. And a 1:1 balun does not prevent "goofy interference from your rig", it is to stop common mode rf from your antenna. Sorry, I couldn't stand to watch any more of this.

This "balun" is a complete bogus :-P

OMG. Have you guys ever heard of Powerpoint? Or even a simple flipchart? Sorry, great content, but the presentation style makes a lot of it useless.

Guy in the red shirt needs to learn some basic manners.