The effect of a 1:1 balun on a resonant dipole

[@barrykery1175]

That is the best demo I have ever seen for showing the effects of what happens when a balun is not used. GREAT VIDEO ! Barry, KU3X

[@markbruechert9967]

Count me as one of your subscribers. An excellent, easily followed demonstration. I am now certain installing 1:1 baluns on my dipoles was the right thing to do. VSWR is definitely NOT the only measurement you need to make on an antenna system. Best of all, this test may be easily replicated by anyone with a few simple pieces of test equipment. Thank you for making this video, and for thoughtfully using an English translation. Mark VK3PDG Rosebud, Australia.

[@harleytwincam2]

There seems to be much debate over whether a balun is necessary. I have heard many insisting that they are not needed and many saying that you should have one. You have put that debate to rest in my mind. From now on, I will always use a balun on any of my homebrew dipoles. Thanks for your clear demonstration of the benefits of a current balun.

[@wa9kzy326]

Thank you for this most "telling" presentation. Another advantage is a much cleaner radiation pattern. Because it is so easy to tie the coax directly to a dipole antenna, most hams just do it, not caring about the negative effects. Seeing is believing and you have done that.

[@pwnj0hn]

Very good demonstration! Thank you for putting this discussion to rest.

[@nmwilliam]

Very good explanation and demonstration. This makes clear that even with a resonant dipole a balun is a must to avoid common mode current on shield. 73s

[@nofxslc]

Fantastic! It’s so much easier to understand these kind of things when you see them in practice.

[@nonokodog622]

Agree 100 % I'm more into window line now, but when I do make a coax fed dipole I start by making a 1:1 Guanella choke and run the legs from that. I operate QRP and mobile a good part of the time, so I can never trust that my antenna will be tuned properly based on length only. Out in the field, you get coupling to trees and the soil makes a huge difference. It's easy for a dipole to become unbalanced and get common mode currents.

[@g0fvt]

An utterly superb demonstration, I probably started playing with common mode choke type baluns just before you uploaded the video, my experience has been very positive. I still suffer with high noise levels but it is good to be able to run QRO without issues. I suspect I will benefit if I use similar common mode chokes on our satellite LNB cables as I believe much of my QRM is the switchmode supply in it. The use of the correct type of ferrite and an adequate number of turns is of course vitally important for best results.

[@TheMariepi3]

perhaps certain balun-like assemblies can act as high-pass filters etc. that remove noise

[@g0fvt]

@@TheMariepi3 that is not the principle here, the onjective is to prevent the feeder from becoming part of the antenna.

[@wa9kzy326]

One more informative test: Measure the antennas field strength at 1/2 mile away. You will see a difference, as the feed-line that radiates causes wave cancellation with the antenna in the near-field.

[@Luachair]

Painstaking work there, many thanks for that and the clear commentary.

[@FrozenDoberman]

To widen the bandwidth of a aluminium rod dipole, a 4:1 balun is connected to the terminals. I use 75-Ohm coax cable. A 4 metre total length impedance mismatched horizontally polarised dipole covers about 25-70 MHz at my location.

[@radiofhi]

Great video! Thanks for conducting the experiment and sharing results.

[@richardwesterman5773]

Excellent video. Very simple, to the point, and easy to understand. TNX for sharing Davide. (DJ0IP)

[@WolfgangKMeister]

Perfect video with excellent audio. Yes, exactly, what I am preaching to our newcomers. Without an Balun, the RF does not make any difference between one leg of the dipole and the shield of the coax, even if the two look completely different ;-) The coax shield becomes a part of the radiating antenna and that should be avoided in any case. 73s OE1MWW

[@jfrphoto01]

I feed my dipoles with window line! I use a 4:1 Balun at the shack, aluminum storm window frames, and use coax from the Balun through an entrance panel to the tuner/transceiver. 450 ohm window line has a loss number of around 0.01 db per 100'.

[@jimaspinwall7814]

This is a good demonstration. I would add a few key points to enhance overall, including first noting this is a current balun vs a voltage balun. #1 critical element regardless is a station ground, having the feedline meet a grounded bulkhead outside the shack, having the station gear individually grounded to the same point, so no RF is present on or between any of the in-shack equipment - if there is that is a serious problem. The RF or any voltage level on the coax and supply should be zero at all times. #2 - the same RF decoupling effect can be had with a suitable choke in place of the balun, which in this case also happens to be decoupling as it is a current balun not a voltage balun. You will not get the same benefit of decoupling with a voltage balun alone, it would need a choke added at the same point.

[@wa9kzy326]

Many hams opt for the choke method to keep the mismatched RF off their feedlines, but it just converts that same RF to heat instead of radiating it into space. Always trade-offs, eh?

[@rickj2913]

You are correct . That is the 1st thing to look for .

[@arconeagain]

Not to mention the run of coax itself. Keeping as much of it possible on the ground or below can be helpful if it is radiating. I know it is best to prevent it from radiating in first place.

[@arconeagain]

@WA9KZY the coaxial chokes that I employ with the amount of ferrite material, I doubt they heat up very little. I would be more concerned with the construction of some of these 1:1 current baluns. The ferrite material and how much there is, the quality of the wire (is it multi stranded and silver plated) and the enclosure it is in. Depending on frequency too of coarse. My chokes are in the air, no enclosure. Imagine a poorly constructed balun in a box on a 40 degree Celsius day.

[@jessgirard]

Very nice demo, Davide! Interesting, we had a talk at our club, "GNARC" (Greater Norwalk Amateur Radio Club in Connecticut) yesterday evening about antennas and we discussed how useful baluns can be. We did not, however, discuss the presence of RF in DC supply leads if not using a balun. The demonstration illustrates their utility. Thanks! I've forwarded a link to this video to a few of our club members. Grazie mille! Jess, ND1L

[@richardallison8745]

With almost 50 years of ham radio, I have never used a balun on any homebrew antennas and it has only been in the last 20 years or so people have been using them like a fad. I don't recall very many of my friends back then using them. This video almost had me convinced but I don't like that switch and not sure what it does to the rf and it is not a switch I would use for rf. I would like to see the experiment redone without the switch.

[@patrickbuick5459]

I already have some on order before the video, but thanks for saving me an experiment! Great information.

[@bassdowg]

GREAT JOB ONE OF THE BEST DEMOS REGARDING RFI AND STRAY NOISE I HAVE EVERN SEEN ON KZbin. THIS PRESENTATIONS SPEAKS A LOT... specially on receive Not just on Transmit..TYVM...73s

[@JarlSeamus]

The term "Balun" is a misuse of the concept. What we are describing is not a Balun at all, but a Choke. The phenomenon IZ2UUF is demonstrating is called "Common Mode Current" where an RF signal is produced on the shield segment of an unbalanced feed line. The choke is inserted to present a high impedance to the RF at that frequency. A 1:1 "Balun" is no more than a reactive transformer that resists the RF attempting to travel on the coax shield. If you want a really good visual demonstration and explanation of Common Mode Current check out Dave Casler's (KE0OG) channel "Ask Og" kzbin.info/www/bejne/fX7IgICtm5d3gLc

[@nonokodog622]

I'm not sure it's even a transformer, there's no flux in the core.

[@ve3dvy]

A 1:1 current balun is a common mode choke, is an isolator. Different names for a device that performs the same thing. What many call a balun is not. Many are just impedence transformers and do not make the BALanced UNbalanced transition. What your saying is not a balun definitely is. What makes a balun a BalUn it transitions the coax to a balanced antenna. This is acheved by forcing equal currents on both the antenna and the center conductor and inner surface of the shield by choking any common mode current. Roy Lewallen and Owen duffy who are some of the most knowlagable on this have written extensivly on this W2DU balun is often called an isolator. Maxwell called it a balun. A guenella 1:1 current balun is often called a common mode choke. Even the So called Ugly Balun is often called a common mode choke. With all respect to Dave Casler who has some fantastic videos seems to not have a great grasp on baluns

[@stargazer7644]

A balun IS a common mode choke. It is a balanced to unbalanced transformer wound in such a way that it has high impedance to common mode signals.

[@DavideAchilli]

The common mode choke *is* a balun, also known as "current balun", as it is correctly defined on the ARRL Antenna Book that states "Choke balun model, also known as 1:1 current balun". Differentiating "choke" with "balun" and, even worse, calling "balun" all the impedance transformers, it is a typical misconception present in the ham radio world. For example, the term "un-un" for "impedance transformer" does not exist in engineering world (and it is never cited on the ARRL Antenna Book), but it has created by someone in the ham radio world and it suggests what many OM believe, that baluns and ununs are more or less the same thing with some minor difference, while they are two completely different items with completely different roles in the antenna system.

[@alanb76]

Excellent presentation! Exactly what the theory predicts.

[@wr4i]

Would also be interesting to see signal reports on RBN with/without balun. Also using WSPR. Txs for this great comparison.

[@KX4UL]

Thank you for putting this debate to rest for me...73!

[@n5ifi]

What Debate?

[@rhyoliteaquacade]

Excellent demonstration of practice and theory

[@mikelberrocal5356]

The effect on the SWR value might highly depends on the length of the coaxial cable. As this (without balun) is part of the antenna, half wave even multiples of lambda might cause high SWR values on the transmiter

[@magnusatheos7301]

This answered my question perfectly. Thank you.

[@crazyjd2671]

Fine Business .Excellent demonstration, This and proper earth grounding is of utmost importance to all that broadcast R.F. energy to minimize the occurrence of encounters with other occupants of space deprived dwellings...73's K5JPD

[@Dreamlgider]

Very nice demonstration.

[@julioiphus5650]

Mi hai convinto, prendero il Balun. Grazie!

[@izzzzzz6]

What is the db loss on the signals received? Should it not be an Unbal if it's coax (unbalanced) going into a dipole (balanced) unbalanced to balanced Unbal.

[@theunconventionaldeal3879]

No 1:1 choke s4-s5 noise level and with 1:1 choke s3 noise level on my 9:1 41' not so random wire, Results may vary. A simple choke at the feedpoint and at the radio is usually all that is needed for my simple setups.

[@rihan-haque]

Very excellent video and demonstration. I am wondering if you can share the schematic for the RF power meter using the micro-ampere meter. I have a micro-amp meter which I want to use for this purpose. Thanks

[@meggalavk3ktt]

you answered the great question in ham radio thank you.

[@swicked86]

I'm also curious about transmitted power.

[@g0fvt]

An excellent demonstration

[@johnpeterson7264]

Great video. Well done experiment . Thanks much !

[@stevenbidwell4897]

Thank you for that excellent video!

[@sm3uwzmrportable914]

From now on I wiil always use a Balun (Transformer). Great video.

[@arconeagain]

Don't be blinded just because you saw a single demonstration for a single application from a robot. In other words, keep your mind open.

[@jasonamos3445]

Thank you for putting this together, it is very informative and helpful. I don't have the equipment to do this or I might would myself, I would like to see what the effects of the balun vs no balun when an RF choke is also used on the coax near the antenna feed. Something as simple as 6 turns of the coax in about a 4" diameter, clamp on ferrites could also be used and I have seen that done a good bit and suspect that either of these would eliminate or at least attenuate the RF radiation by the coax and other RF in the shack on the radio, power wires and keyer. Thoughts?

[@DavideAchilli]

Hello Amos. The "1:1 balun" shown in the video *IS* an RF choke. An RF choke is a type of 1:1 balun (the so called "current balun"). See ARRL Antenna Book, 23rd ed., chapter "24.7.1 COILED-COAX CHOKE BALUNS". In my case it was wound on a ferrite core to make it more effective on a larger spectrum, but a correctly calculated ugly balun (wound in air) has the same effect.

[@alaska3333]

*Very* nice and informative video!

[@jtcsrvbi]

Great demo!! 73 John NM2R

[@shaneramos1428]

What is the tester you placed near the coax and power cords?

[@denizyildiz8904]

Goon evening from Turkey Izmir..I need some help about 9:1 unun..I am a shortwave listener..not transmitting, I have only a radio to listen sw..I have 20 meters long wire as anttenna..should I need a balun or it is not necessary? What will be different with unun or without? Thanks

[@RobBob555]

basically folks USE a balun !.. it cannot do any harm and will most likely help.. debate over !

[@easyeagle2]

Not exactly, as pointed out below in several below comments, it depends on many different factors in your setup. Also a balun limits the total power that can be fed to your antenna depending on the construction of either one. .

[@Organplayer1947]

I wonder whether ferrite cores added to the feedline would help reduce the rx RF pickup. I didn't read thru the comments...maybe someone already cited this.

[@imken2392]

MFJ makes one PN# MFJ-915 line isolator. There are 50 ferrite cores (not sure of the mix) around a length of coax contained within a 1 1/2 inch PVC pipe with caps with SO239's on each end. Same principal as you mentioned but with 4 points of insertion loss. It works but not as well as the #240-43 ferrite doughnuts I wind with # 16 enamaled magnet wire.

[@caprabi1]

Sorry but this si not a Balun 1:1, this a choke ! Highly recommended to reduce CMC !!!

[@rotaxtwin]

Huh? Balanced : Unbalanced = Balun. It is a 1:1 transformer from unbalanced to balanced, how is this a choke in this configuration?

[@jfrphoto01]

@ caprabi1 ... This is a 1:1 current balun, you are thinking of a 1:1 line isolator (1:1 unun or unbalanced to unbalanced) used on many verticals to reduce Common Mode Currents or CMC's.

[@Capecodham]

cmc?

[@caprabi1]

@@Capecodham common mode current

[@Capecodham]

@@caprabi1 What did you do with the you were not clear saved by not typing ommon ode urrent? REPLY

[@vickykent-hw2bh]

For those concerned re the robotic voice, is it possible this is in order to translate due to the possibility that English is not this amateurs' first language and is from a translation program?

[@cwguy8960]

Great demo!!

[@walteranderson7889]

The one experiment that always seem to be neglected is: How does the radiation pattern from a balanced resonate dipole antenna change with a balun installed vs NO balun installed.

[@KX4UL]

Good demo!

[@kissingbanditt]

if i put the coax coming to my house from a dipole through a lightning arrestor outside,would that affect anything?

[@JarlSeamus]

No. A lightning arrestor is basically a surge protector only. It behaves like a dead short until a critical voltage is reached and then it shunts the current toward ground.

[@kissingbanditt]

@@JarlSeamus so in a normal state it's a short? then how does my signal go out? you mean in a normal state the shield is shorted with the centre conductor?

[@JarlSeamus]

@@kissingbanditt No, A lightning arrestor for Coax behaves just like a barrel connector in the normal state. There is a small air gap (in some higher end unit the gap is in an enclosed capsule filled with an inert dielectric gas). When a large voltage is applied (i.e. a nearby lightning strike) the gas in the gap becomes ionized and allows current to shunt to ground across the gap. Absent of that large surge, the device is electrically just a short piece of coax.

[@MoTown44240]

Interesting. Thank you for video of tests.

[@geokuf9679]

Very interesting video, thanks for posting it. Looks like you are using DIY RF meters. I am having problems with computer locking up during TX and a tool like that I think could help identify source of the problems. Could you please provide info as to how to build one? 73 de SP6CAL

[@you2tooyou2too]

The blog post linked above adds some details, but there are still a lot of variables not described, like grounding, coax routing, etc. Is there theory about the use of the balun that explains the noise resistance other than that of a simple choke?

[@stargazer7644]

The balun stops the outside of the coax shield from becoming a radiating part of the antenna. When it is a radiating part of the antenna, it emits RF on transmit, and receives RF on receive. A balun stops RF flowing on the outside of the coax shield.

[@thuff3207]

I would keep a common mode transformer out of the near field of the antenna to prevent saturation.

[@stargazer7644]

The proper place to put a balun is at the antenna feed point. That's certainly going to be in the near field of the antenna.

[@wayneleake1971]

I got a bit of an RF burn from the microphones hang up loop, that was grounded to the radios ground, hence antenna ground. It was, maybe, before I added the balun to my antenna, One person, before I bought the balun, kept saying I needed pone. Then after I was using it, the same person told me that I did not need it Makes me wonder about him. he held an advanced class license

[@siddharth4662]

I loved your Morse key... Where can I get one??

[@DavideAchilli]

It a single lever Kent paddle. I bought it at the Friedrichshafen ham radio fair, but I think by searching on the internet you can find a reseller. 73 de Davide IZ2UUF

[@davideisenberger6197]

Thank You for this video! 73's de K8KEM

[@paganphil100]

How about "double bazooka" antennas? I've been told that they don't need a balun because of the way they're constructed.

[@mikelberrocal5356]

If you feed a balanced antenna (as the double bazooka) with coaxial cable (which is unbalanced) you know, you need a balun

[@mrmrlee]

The balun wouldn't have an effect on an SWR that's good, because excessive power is not radiated back down the line. You should test it on a dipole with a poor SWR to see if it improves it.

[@wd8dsb]

Actually the amount of transmitted signal using the outside of the shield as an alternative path is dependent on the length of the feedline, so in some cases you will see a large change when using a choke at the feedpoint, and in some cases you will see little effect regarding transmitted RF on the outside shield of the coax. It has nothing to do with how bad the SWR is, it has to do with the outside of the coax shield impedance as seen by the feedpoint changing based on the length of the feedline. 73, Don (wd8dsb) P.S. this was an excellent video.

[@stargazer7644]

A 1:1 balun does not change the impedance of the antenna. If the SWR is poor without the balun, it will be poor with the balun. An impedance transformer like a 4:1 or 9:1 can change your SWR by bringing the antenna impedance closer to 50 ohms. Note that those transformers are not baluns by themselves, and may or may not also have a 1:1 balun in series inside the case.

[@arconeagain]

Hello robot. I would also like to see a test with a resonant dipole with the specific length of coax (not sure if you are familiar with this theory) without a balun. Just for interest's sake to see if this is true.

[@BarefootBeekeeper]

I HATE ROBOT VOICES!

[@clemensbopp5484]

Thanks for this good vid, 73, DL2GAN

[@DE-iv8if]

Great Video!

[@pauldionne2884]

You did not indicate the balun's effect on RX signal strength. Perhaps other commenters will chime in.

[@eamonegan3955]

One question: is it only a single pole switch, or are you shorting out the balun on both sides? 73, Eamon VE2EGN

[@Iz2uufNet]

Hello Eamon. I'm shorting only the braid. VY73 - Davide IZ2UUF

[@oh1cin]

You just earned one subscriber more with this video and last night by the way I were looking your CW Koch's method app for Android! :-D I can help with Finnish translation if needed. 73 de OH1CIN Op. Mikko

[@randymiller7788]

He should have mentioned a line tuner also, using a line tuner is also misleading as it radiates the antenna lead-in, the entire antenna system (line and antenna) are tuned and therefore can effect overall radiation performance...

[@avrumo]

WELL DONE !

[@MyTube4Utoo]

Very interesting.

[@nickmajor2547]

Excellent Video. Shows it how it is. 73Nick G0HFL

[@RC-Heli835]

What about a very common issue wtith high SWR only with an amplifier on? I just read where a guy solved his high SWR with the amplifier on only? With the amp off SWR was fine but amp on he had high SWR. Amps need an swr of 1.3 or lower. A choke balun solved his issue or so he thought. Others thought he simply masked the issue. www.worldwidedx.com/threads/high-swr-with-linear-amp.148498/

[@stargazer7644]

High SWR with the amp on means the input impedance of the amp is not 50 ohms. A 1:1 balun isn't going to fix that.

[@RC-Heli835]

@@stargazer7644 Thanks for the reply. Oddly that little amp had the SO 239's mounted to the back of the box but not grounded to the board like most amps. I tried grounding it to the board and that made the SWR max out. I removed that ground and tightened the nuts up to where the 239's wouldn't swivel in the box and that got the SWR down to a usable level. I was able to get out 7 miles with the 60 watt amp but was told it didn't sound very good. I"m sure its very old and might possibly need all of its caps replaced. It used one MRF453 Transistor that is no longer available.

[@alphasxsignal]

It might but not always.

[@RobBob555]

very poor english at the end " it causes significant radiation from the feedline " implies a balun might CAUSE this.. when in fact you mean NOT having a balun could cause these issues..

[@johndecicco]

I thought the same, then reread the title "not using" a balun.

[@Roddy1965]

excellent

[@joeshmoe7899]

I'd use a 1:1 transformer at the dipole. And a choke at the transmitter.

[@WolfgangS]

Gold :)

[@maverick5117]

Keep away from voltage baluns. Just current baluns.

[@richardwesterman5773]

This is not always true. In many cases, the very best solution is to combine a 4:1 voltage balun with a 1:1 current balun, creating a Hybrid Balun. (DJ0IP)

[@MirlitronOne]

In other words, a 1:1 balun is actually a choke.

[@wa9kzy326]

Most accurately called a 1:1 transformer; no direct coupling between input and output. I put a capacitor across the primary and tune it to resonance. The unbalanced transmitter output is perfectly happy as is the balanced dipole antenna. Although this system is frequency dependent, mine covers the entire 20-meter band.

[@randymiller7788]

you can also use a choke balun, by using a coiled form of the coax (about 10-12 turn on a 6 inch form) at the feed point, this well choke off unwanted radiated power...

[@mikelberrocal5356]

In this case, absolutely. Not in all of them

[@g0fvt]

Randy Miller the “ugly balun” tends to not be very effective, it can also accidentally increase the common mode current due to the inductance behaving like a loading coil in series with the feed line. I have experimented with common mode chokes wound on FT240 series cores, very high impedances over a wide range. Google G3TXQ.

[@SomeRandomPerson163]

Yes but RF-choke isn't true balun. You can perform easy test of balun: if you touch any output of that it should causing amplification of noice in reciever (your body will works as antena). But in RF-choke case touching the grounded output didnt cause any changes on recieving side.

[@DonHavjuan]

This is a choke not a balun

[@washingtonstatepicker3460]

I thought that a balun was supposed to do the opposite! B l ock return rf!

[@cprendon3]

Why the stuttering robotic voice. Surely some human could have narrated this.

[@stargazer7644]

Probably because you would have complained about the person's accent if they had narrated it.

[@АнатолийЧернявский-э2я]

Ок!!

[@joczo97]

I'm on the other side:I have proof now,that for a little VHF/UHF radio,I can put out a dipole temporarily,without any balun. It won't cause any trouble with a 4W handheld for sure

[@rafaela.coutocabral8067]

sorry but that's not a balun. that's a choke.

[@Iz2uufNet]

Sorry, but a "choke" is indeed a balun. See ARRL Antenna Book 20th edition, page 26-21, title of the chapter: "ELIMINATING COMMON-MODE CURRENTS: THE BALUN". Page 26-22: Fig.30 "An RF choke is formed by coiling the coax at the point of connection to the antenna", Fig 31: "Choke balun model, also known as a 1:1 current balun". Please, stop spreading misinformation and feeding myths, we have already too many of them. As you can see from the previous comments, every once in a while some "expert" lands on this video explaining that it is showing a "choke" and not a "balun". Please stop.

[@1redrubberball]

A balun may or may not be needed. Feedline radiation can add "fill" in the radiation pattern of the antenna. I have been an amateur for way over 50 years and have seldom, if ever, experienced problems without a balun. They may or may not create or solve any problems!

[@richardallison8745]

I have been a ham for over 48 years and I completely agree. I have never used a balun on a dipole and don't recall any problems. Back then we usually did not use them. Using baluns is like a fad that has come around in the last 20 years. I had a 3 element yagi from Mosely that had an unbalanced driving element and in the assembly instructions from the manufacturer, they said DO NOT INSTALL A BALUN IN THE FEEDLINE. I never put one in thinking that Mosely engineers advised against them but there were those that installed them anyway. I have used chokes in the feedline and they seemed to work for me. I am using a two band dipole right now with no choke and no balun and have no rf in the shack. I have another high power dipole that does have a choke but it came that way.

[@stargazer7644]

Ah, the old "It hasn't happened to me so it must not be true" fallacy. Feedline radiation is always bad. If you don't like the pattern of your antenna, change the antenna. Don't pretend that RF in your shack is a good thing.

[@mrlessismore7352]

good explanation....but if you are dependent on a robot to do your talking, please include the text, the robot was speaking from....robots don't speak well enough yet. Or get a fellow ham to record your text for you. Thanks for your video, you have answered a question I had been asking. 73 KE8DCJ

[@markbruechert9967]

Actually, and somewhat strangely, Aussies understand the voice perfectly. Go figure! VK3PDG

[@DavideAchilli]

Thanks for your comment. It is the first time I experimented with a robotic voice: I thought it could be better understood world wide than my Italian accented one. However the subtitles in English were available since the first publishing. When editing the video, I was about to write subtitles manually using the original text when I discovered that youtube already automatically had produce English subtitles by "listening" the robotic voice. I had to correct a few unusual technical terms like "balun" itself, that youtube understood as "baloon", but almost the entire test was dead-on. The surprising quality of youtube automatic interpretation at that time led me to believe that the robotic voice was quite understandable.

[@collieclone]

I disagree. Yes, the robotic voice is a little unusual at first and occasionally stresses the word wrongly, but is otherwise clear. Any competent radio amateur should be able to understand this perfectly. After all, there is no QSB, QRM, QRN or other disturbance on the audio! Most importantly: this is a really useful demonstration, well thought out and clearly presented. Thank you Davide!

[@BarefootBeekeeper]

Why can't a human speak the words? I will not listen to robots.

[@Capecodham]

sounds like a contester

[@paul.alarner6410]

ok but why use a terrible ai voiceover?,thumbs down for that!.

[@rickj2913]

I see no way this test can be accurate because RF has the Skin Effect and it radiates . The switch may make a better RF path when switched in so my conclusion is that his test doesn't prove anything of value . If the Coax radiates on your antenna you have more problems than needing an RF Choke .

[@mikelberrocal5356]

Read about common mode currents and how to avoid the out side of coaxial to radiate

[@stargazer7644]

If the coax radiates it means you have common mode currents flowing on the outside of your shield and you need a balun. This is exactly what a balun is made for. His test was completely accurate and very valuable.

[@tomrauch5080]

Since the requirement for a balun and the effect of the balun depends very heavily on feedline length to the "ground point" and the layout of the antenna, this video doesn't really teach us anything. The video is pretty much meaningless except for this one particular test. Change one thing in the test, like alter the feedline length to ground, and the results will change

[@stargazer7644]

If you think this video doesn't teach anything, then you're unteachable. This is exactly what a balun is made for and is an excellent demonstration.

[@Jerrythenerdful]

@@stargazer7644 Sorry, you are wrong. The length of the feedline, routing of the feedline, and grounding of the feedline all significantly change the need for a balun and any effects observed. A test in one particular configuration will have an entirely different result in a different configuration. I can add a balun to a specific system and it can: 1.) Decrease common mode 2.) Increase common mode 3.) Not change common mode This is why some people swear by baluns, while other people swear they are meaningless. I have one 75-meter dipole that the addition of any balun of any style will either not change or make common mode worse. I have another dipole that has significant common mode without a balun. The only difference is the feedline length to the shield ground point.

[@stargazer7644]

@@Jerrythenerdful You apparently don't realize if the feedline isn't radiating and the coax shield is acting as a shield as it was designed, you don't have to worry about ANY of that. Then the coax won't interact with anything. Adding common mode impedance by adding a 1:1 balun can ONLY decrease common mode currents. That's how ohms law works. It isn't possible to add impedance and get increased current. Now if you use an improperly designed balun (and a lot of cheap impedance transformers out there say they're baluns when they aren't), or use one designed for the wrong frequency, it is possible that it won't reduce the common mode currents by much. If you have anything other than a 1:1 balun and it only has one wound toroid in it, it isn't a balun. A proper 4:1 balun will have a 4:1 impedance transforming toroid in it, along with a 1:1 balun toroid in it. If it doesn't have that, it isn't a balun, it's just a 4:1 impedance transformer (even though it likely will say it is a balun), and it won't have any common mode suppression.