Thanks for this Justin, you give all the information that is needed and none that isn’t, in a clear and straightforward way, well done! I look forward with great interest to your future videos.
Thank for this impressive demonstration, Justin! 🙂 I am relatively new to the hobby (licensed mid of this year) and I am very interested in that sort of content. What you explained makes it more than clear how a missing balun can reduce the efficiency of a potentially costly Yagi just by "forgetting" to put such a simple balun in place (or in the right place). I myself do not have such a nice antenna, yet your explanation is valuable for me as I was not paying enough attention to putting a balun close to the feed point of a dipole, thinking everything is OK as long as I put a choke on the back of my transceiver. Now I know and understand what the impact of a radiating coax on the radition pattern is. 👍 73 de DL1HNR, Henner
Thanks Henner, this kind of message does make it all worthwhile for me. the biggest difference with a balun on a dipole is getting every horizontally polarised rather than some being vertically polarised. This will reduce noise and unwanted signal pick-up too.
@@hamradioguys My conclusion from what you explained is that having something being polarised in the wrong way is the worst case, but as "the RF does not know where the antenna ends", I assume it makes very much sense to choke the RF at the feedpoint of any (or most?) antenna(s), as the antenna was given a specific shape/ layout for a reason, end whenever we allow part of the RF being radiated by the feedline, it will impact the radiation pattern in a presumably negative way. (Well, these are just my thoughts as a newbie and non-native English speaker.😉)
@@hennero.3826 yes you are correct, antennas can be forced out of balance by real-world nearby structures too, something else I will be discussing soon.
Great explanation of why a correct choke/Balun is needed for a beam.I now know why I’ve been a little disappointed with my 11m yagi performance!! Looking forward to the next 1 regards placement of the Balun.73s Chris
This is why i prefer to use open line feeder on hf wire dipoles, mainly 40/80m, I guess the downside is I use a balanced/symetrical coupler in the shape of a double L, which dont come cheap but i feel it all aids antenna efficiency. Interesting video thou for coaxial fed antennas.
Yes, balanced line feeder is the better option on dipoles but has its own drawback, in particular routing and and keeping it well spaced from any materials (especially metallic surfaces) on the way back to the shack.
Thanks Justin for very interesting and informative video. I did not realise it would make such a difference. Is it possible to share the EZnec file showing how to configured EZNEC for coax to antenna.
it is not something that is easy to replicate. as discussed in the video 'this is a representation of coax cable at the feed point'. Roy Llewellyn, the author of EZNEC shared with me this method of replication some years ago. Basically, the wire representing the coax is either corrected to the dipole to replicate no balun or disconnected to replicate a balun, where not current would directly flow back down the coax.
Thanks, justin for all your guidance. It has been long awaited. Things that you say confirm my beliefs and experience. You say about the testing of common mode after you’ve built the ugly balun. Sometimes this or probably most times will not show itself to be evident so the test is a bit like keeping your fingers crossed. How do you get over that? I always put an ugly ballon on but I have since land they are too far away from The driving element but placed comfortably for the coax to run and ideally I would use messy & paloney 7.
there are clip-on current meters you can use to help show you what is there. Not 100% accurate but I have found the hand- on coax scenario does give good levels of detection.
ladder line is a balanced feed line feeding a balanced antenna so theoretically, no issues. However, Coax is an unbalanced feedline. in such cases, when feeding a balanced antenna, issues such as the discussed can occur.
Thank you I was un shure, but I'm thinking of building a full size guad for 40 meter and using ladder line. Have you ever modaled vhf quad to use 600 ohm before.
Thanks for this Justin, you give all the information that is needed and none that isn’t, in a clear and straightforward way, well done!
I look forward with great interest to your future videos.
Really appreciate your comments Dai, thank you.
Thank for this impressive demonstration, Justin! 🙂
I am relatively new to the hobby (licensed mid of this year) and I am very interested in that sort of content. What you explained makes it more than clear how a missing balun can reduce the efficiency of a potentially costly Yagi just by "forgetting" to put such a simple balun in place (or in the right place). I myself do not have such a nice antenna, yet your explanation is valuable for me as I was not paying enough attention to putting a balun close to the feed point of a dipole, thinking everything is OK as long as I put a choke on the back of my transceiver. Now I know and understand what the impact of a radiating coax on the radition pattern is. 👍
73 de DL1HNR, Henner
Thanks Henner, this kind of message does make it all worthwhile for me. the biggest difference with a balun on a dipole is getting every horizontally polarised rather than some being vertically polarised. This will reduce noise and unwanted signal pick-up too.
@@hamradioguys My conclusion from what you explained is that having something being polarised in the wrong way is the worst case, but as "the RF does not know where the antenna ends", I assume it makes very much sense to choke the RF at the feedpoint of any (or most?) antenna(s), as the antenna was given a specific shape/ layout for a reason, end whenever we allow part of the RF being radiated by the feedline, it will impact the radiation pattern in a presumably negative way.
(Well, these are just my thoughts as a newbie and non-native English speaker.😉)
@@hennero.3826 yes you are correct, antennas can be forced out of balance by real-world nearby structures too, something else I will be discussing soon.
Very educational Justin, thank you! I enjoyed that. Matt
Thanks Matt, that's a nice comment to receive, especially from you! I was watching your experiences of the hexbeam recently..
Great explanation of why a correct choke/Balun is needed for a beam.I now know why I’ve been a little disappointed with my 11m yagi performance!! Looking forward to the next 1 regards placement of the Balun.73s Chris
thank you, really appreciate the comments..
Great explanation video, now I get what happens when there is no balun on a balanced antenna. Looking forward to the balun video. Many thanks Greg
Thanks Greg, it is comments like this that help with the motivation to make this sort of content.
This is why i prefer to use open line feeder on hf wire dipoles, mainly 40/80m, I guess the downside is I use a balanced/symetrical coupler in the shape of a double L, which dont come cheap but i feel it all aids antenna efficiency. Interesting video thou for coaxial fed antennas.
Yes, balanced line feeder is the better option on dipoles but has its own drawback, in particular routing and and keeping it well spaced from any materials (especially metallic surfaces) on the way back to the shack.
Looking forward to your next video!
Thank you
Thanks Justin for very interesting and informative video. I did not realise
it would make such a difference. Is it possible to share the EZnec file showing how to
configured EZNEC for coax to antenna.
it is not something that is easy to replicate. as discussed in the video 'this is a representation of coax cable at the feed point'. Roy Llewellyn, the author of EZNEC shared with me this method of replication some years ago. Basically, the wire representing the coax is either corrected to the dipole to replicate no balun or disconnected to replicate a balun, where not current would directly flow back down the coax.
Thanks, justin for all your guidance. It has been long awaited. Things that you say confirm my beliefs and experience. You say about the testing of common mode after you’ve built the ugly balun. Sometimes this or probably most times will not show itself to be evident so the test is a bit like keeping your fingers crossed. How do you get over that? I always put an ugly ballon on but I have since land they are too far away from The driving element but placed comfortably for the coax to run and ideally I would use messy & paloney 7.
there are clip-on current meters you can use to help show you what is there. Not 100% accurate but I have found the hand- on coax scenario does give good levels of detection.
Hi Justin. What about if it 600 ohm ladder line 80 meter horizontal loop, ladder 40 meter quad all matched with a 1 to 1 and 4 to 1 at the shack
ladder line is a balanced feed line feeding a balanced antenna so theoretically, no issues. However, Coax is an unbalanced feedline. in such cases, when feeding a balanced antenna, issues such as the discussed can occur.
Thank you I was un shure, but I'm thinking of building a full size guad for 40 meter and using ladder line. Have you ever modaled vhf quad to use 600 ohm before.