Feedline Superhero -The Line Isolator

[@WR3ND]

Nice presentation. Thanks. A couple points I would add is that the capacitance of the counterpoise is beneficial to the antenna, a dipole being the prime example, so you don't want that sunk directly to ground on the antenna side before the choke, but after the choke on the tuner/radio side - the choke(s) impede the common mode current and the ground sinks its capacitive charge.

[@OutdoorsOnTheAir]

Thank you for adding this information!

[@thuff3207]

Common mode chokes or line isolators can also reduce RF noise more than most. Thank you for your video.

[@OutdoorsOnTheAir]

Thank you for your comment.

[@2pi628]

A much needed VLOG post👍. Very important but often overlooked.

[@sotachile4224]

Thanks Tracy for your contribution to the amateur radio. I live in the upper part of Santiago de Chile (near to the mountain) and the background noise is very strong and this video can help me to experiment and try to reduce that noise level even if it is a couple of levels. 73.

[@OutdoorsOnTheAir]

Gracias, Mauricio! Good luck with that noise. 73 from VE3TWM.

[@trig6712]

Excellent again Tracy putting up a new multiband vertical soon cheers

[@alandigiovanni5282]

Thank you for the excellent high-level overview of this topic.

[@JnJTrueOutdoorAdventures]

As always Tracy another great video and explanation. I have been bitten before and realized I had a problem and installed a isolator, but never thought about running two of them. Thanks for sharing the information and explaining it so clearly. 73 and Happy New Year. Juddie WD8WV

[@DrHWO]

Excellent presentation Tracy, crystal clear as always. Worth bearing in mind that an end fed random wire antenna might rely on the coax braid to act as a counterpoise to work to its maximum potential, limiting the placement of the choke balun to close to the transceiver ( I learned the hard way!). 73, de 2E0HWO

[@OutdoorsOnTheAir]

Thank you very much for your comment! Your point about the counterpoise is valid. The correct length of counterpoise coax is 0.05 lambda of the lowest band the antenna is designed for. Put the line isolator after the counterpoise cable and your antenna system will be fine.

[@DrHWO]

@@OutdoorsOnTheAir Thank you. I always learn such a lot from you. Most grateful. 73, de 2E0HWO

[@DrHWO]

I'm being a little pedantic here, but does the "standard " formula for the counterpoise coax need to be modified by the velocity factor of the coax used? For an 80m installation using a coax with an 85% velocity factor, this would mean shortening by 0.6m. 73, Howard

[@timg5tm941]

Clearly presented and explained. Thank you Tracy. 73

[@OutdoorsOnTheAir]

Thank you, Tim!

[@tonybutler3502]

**You do a great job of explaining the essentials to "most of us" who are not degree level electronics engineers. I particularly dislike some videos where you are expected to think how clever the person is rather than actually learning what you need to know without the b****t

[@OutdoorsOnTheAir]

Thank you, Tony!

[@erpece]

Nice video and very informative. However, I cannot resist pointing out something that is subject to a lot of confusion: the choke is not a BALUN in this case, but - as the title suggests - a line isolator. The name choke refers to the electrical component, whereas BALUN, UNUN or Line Isolator refer to a specifc application/variation and the job it is doing.

[@2pi628]

Yes. more for the newbs --> a Bal-Un is used as a "transformer" to match impedances between the transmitter and antenna, not as an inductive choke. Bal = Balanced, Un = Unbalanced

[@Coreyztv]

@@2pi628 Where would you put the Balun/Unun? outside with the antenna or inside by the radio? i am confused on this! sorry if this is a dumb question lol

[@g0fvt]

Very clear and concise, I am a firm believer in them, even in installations where open wire feeder is use

[@OutdoorsOnTheAir]

Thank you for your comment!

[@1crazynordlander]

Thanks for sharing. I have an EFHW 8010 and have heard that it is a good idea to have a line isolator at the transceiver end. I still need to do this as I have some interference to my TV and from items in my house.

[@PY2RKC-QRA-MIRO]

Saudações !!! Excelente lição, TKS & 73 !!! 👏👏👏

[@OutdoorsOnTheAir]

Obrigado! 73 from VE3TWM.

[@thormusique]

Tracy, thank you for this excellent presentation! I only ever had a bit of vague knowledge on the topic but have never really understood it. This clarifies quite a bit for me. Also, being very visual, I found your graphics extremely helpful. I'm about to put up a permanent EFHV wire aerial at my QTH here in the Green Mountains. My location is pretty remote, so I don't have to worry about too much "external" QRM, but being that my coax will be coming into my recording studio (which doubles as a ham shack), I've got lots of computers, modems, routers, and other devices constantly humming along. So I will definitely install at least one of these before the coax feeds my transceiver. I'd thought that with an end-fed aerial I wouldn't need an isolator at the feedpoint, but perhaps that's not true? I'd assumed it was necessary mostly for doublets. 73, k1rsk

[@OutdoorsOnTheAir]

Thank you, Robert! I dream of a shack in such a location 😀 73 from VE3TWM.

[@patrickbuick5459]

Isn't it a unun? You called it a balun in the video. I'm working on / with this now for noise reduction on my antennas.

[@OutdoorsOnTheAir]

My error, thank you for the correction.

[@tonybutler3502]

Brilliant presentation, I find the first thing is to put such an isolator between the two sides of the dipole at the feedpoint and the coax lead, that has done most for me by isolating the outer of the coax at that point however, at least one other isolator, normally near the rig also cuts down the "crud". As per GM3SEK, big big chunks of the correct type of ferrite on the mains power lead from the socket in the shack and/or from the mains distribution unit itself also cuts down the rubbish coming in from domestic electronics. Sadly, I've never been successful with the old style twin feeder into the shack via a fully balanced ATU like the Johnson Matchbox, computer noise always seems to cause problems. It might just me but that's my pennies worth 73 Tony ZRJ

[@OutdoorsOnTheAir]

Thank you for sharing these great points, Tony! 73 from VE3TWM.

[@lesb6542]

Thanks Tracy,I will share with some newly licensed amateurs Les G4JDC

[@OutdoorsOnTheAir]

Thank you, Les!

[@keeper9853]

Tracy. Thanks for another great video. I use a tuner. Would the placement of the isolator be...LOW PASS FILTER>TUNER>LINE ISOLATOR>ANTENNA...? Thank you Jim WX7Q

[@OutdoorsOnTheAir]

Thank you, Jim! Put the line isolator first after the rig...rig > line isolator > low pass filter >...

[@keeper9853]

@@OutdoorsOnTheAir Thank you Tracy!!

[@jfrphoto01]

@@OutdoorsOnTheAir The line isolator should be placed after the tuner (especially an auto-tuner) as common mode currents can cause the tuner give erratic readings and, in the case of an auto-tuner, operate erratically!

[@bigdog911paradio3]

I have a 1.5kw T-4 line isolator , gonna out it behind amp or rig?????? I also have a cde base station filter in line with clip on ferrite on the main coax off the switch box ... Still getting in the kids wired gaming headphones 🎧 pain in the arse🤣🤣🤣🤣

[@ellisc.foleyjr9778]

Great Tutorial Tracy, have I ever been bitten in the shack by stray currents!? let me count the ways!! Thanks for taking the time to do this and bettr yet for sharing it with us. 73 Gud dx.

[@OutdoorsOnTheAir]

Thank you very much! Hopefully you'll never get bit by RF again 👍73 from VE3TWM.

[@gregmihran8616]

New subscriber here - excellent, well-explained video, I'm convinced and will try two isolators. Question, what is that intriguing antenna you show at 1:04 - I think I want one :) Greg KJ6ER

[@OutdoorsOnTheAir]

Hi Greg, thank you! That antenna is a TGM Communications Mini-Quad for 20-15-10 meters. I had one for a few years on a 30 foot tower at my previous home and it worked very well. It did exhibit the issue of non-directionality, but at that time I did not know about the magic of line isolators. I am sure if I had used line isolators that antenna would have worked even better. I'd like to own another Mini-Quad one day.

[@Capt_Duffy]

Hi..Tracy.....beautifully explained....definitely going for that...I have S9 + of noise level ON 80 and 40m bands at my QTH...

[@OutdoorsOnTheAir]

Thank you! I hope it works for you.

[@magwhyte]

AP2FLY - Did you get a chance to try the line isolators and if so, did it work? I am curious as your RFI at your QTH mirrors my situation when I visit my in-laws. Thanks.

[@ianparker4720]

same here, did it work?

[@Digital-Sparks]

I count 5 wraps on one side and 6 on the other, am I seeing this correctly? Thanks!

[@budiwaluyo6895]

thank you Mr Tracy, i will learn

[@OutdoorsOnTheAir]

73!

[@ae1tpa92gwtom2]

Hi Tracy, thx for that, once again a clearly explained topic with options,

[@OutdoorsOnTheAir]

Thank you, Tom!

[@SV1RXI]

Great video ,i suffer rfi to my subwoofer and the internet to my home,i will try this and see if my issues resolved .But what about if my neighbors suffer from my antenna ,specefic one neighbor his home is 30meters away from mine and mentioned that is heard me to his pc speakers .I can't put any ground to my equipment because i leave to the thir floor of a building is that is the issue

[@OutdoorsOnTheAir]

You may find that the line isolators fix your neighbour's issue. If not, you can also try using snap on chokes on the power cords to his audio gear.

[@iconoclasticphilosophy5641]

Do you really use 2 line isolators with your hy end fed antenna?

[@OutdoorsOnTheAir]

Yes.

[@ComandoRebelles]

Hi!!! thanks for the video. I have a Bazooka antenna (dipolo) made with coaxial 50ohms to 80m. Can i use this close to the rig? or i need to put close to antenna? thanks again. 73.

[@OutdoorsOnTheAir]

Either at the antenna, at the rig, or both. If I only had the one, I'd put it at the antenna.

[@davidlucas6837]

Great video Tracy, definitely going to try this, many thanks G8XDD

[@OutdoorsOnTheAir]

Thank you, David! Good luck with it, I think you'll be happy with the results.

[@revadan]

Do i still need a balun ? Radio->line isolator->cable ->line isolator ->1:1 balun ->antenna

[@OutdoorsOnTheAir]

Potentially, yes. A balun could be part of the antenna design. If it is, use the balun and a line isolator.

[@subramanianr7206]

A line isolator, common mode current (CMC) choke or 1:1 current BalUn are all one and the same.

[@ronangsr]

Hi very good vid, what if I have linear amp ? I am experiencing my audio comjng out in other speakers in the house, I put a 1:1 balun close to antenna but the problem still here. Will a line isolator in shack help ? Would it go directly after amp or after the power meter?, my set up is radio>amp>power meter>antenna. Thank you

[@OutdoorsOnTheAir]

Putting a line isolator between the rig and the amp should help. But always ask the vendor for advice when purchasing a line isolator, they will be in a better position to advise you.

[@scottdematteo]

Great video and subject. Thanks. W3GTR.

[@OutdoorsOnTheAir]

Thank you, Scott!

[@JasonPullara]

I just came here to say I thought the title card was full of hotdogs.

[@OutdoorsOnTheAir]

Now that you mention it...😆

[@pauld5818]

Hi would a ugly balun achieve the same choking please

[@OutdoorsOnTheAir]

It could. A well-made commercial line isolator (i.e. not a cheap one) will a better job in most cases, though.

[@jeffreypetchharrison4363]

what about a shock from a morse key as i did, lucky my hand did no fall off .. jeff..

[@OutdoorsOnTheAir]

Yikes!

[@hughbassoon]

How do I find the description with the link?

[@OutdoorsOnTheAir]

You need to be browsing on a computer or phone/tablet (most TV's KZbin apps don't show descriptions). Look just below the video for the description box.

[@troy3456789]

It doesn't get any clearer than that

[@JohnTarbox]

Great overview. DE WA1KLI

[@OutdoorsOnTheAir]

Thank you!

[@claudem.p.7969]

yep. va2sob

[@OutdoorsOnTheAir]

Happy New Year, Claude!