Baluns & Chokes - why do you need them?
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- čas přidán 2. 06. 2020
- A short introduction to why operators bother with Baluns/Chokes.
For RF Chokes here’s the Link for the G3TXQ (sk) excellent resource: web.archive.org/web/201804221... - Věda a technologie
Thank you for demystifying this subject. I’ve received so many different conflicting answers over the last few months. Well done, Tim.
Thanks 👍👍
Great summary, after getting some mixed responses, the clarification on the reasoning behind using a balun is very helpful.
Thanks Joe I’m glad it helped 73
Such a clear explanation! I’m putting up my first slim-jim antenna and will be adding the coax choke. Thank you Tim! I have just subscribed to continue my enlightenment. 😁
Thank you for watching and subscribing. Enjoy the antenna!
Great explanation Tim 👏
Thanks Mark! 73
I made a choke back in the late 70s but I just read somewhere that sometimes you needed to put a few turns on the coax, so with a high SWR (it really was not that high, but I wanted it lower) I went about making one. I just played with it, I put 3 turns of coax round a 4" to 6" (old school) and just added another wrap to bring it down, I think I had 4 or 5 turns, just taped another turn on and it turned out to be a good aerial on 11 meters, got into a lot of west Europe, but not into America or south like France. I think that was just due to the location, their signals just went right over the top of me. I am only a few miles down the road now, but I get France and Germany, not heard before in the old home. Italy was far to good, but then it is for everyone! The aerial was just two feet off the top of the house, but it worked well. It was horizontally polarised and if I switched to it half the nearest city vanished, it was great. Shame I can't put one up here!
Nicely Done Tim 👍🇬🇧👍🇬🇧👍
Thanks Paul! 73
Great video - very informative & helpful M7CCQ
Thanks!
Thanks for the information Tim, I have some ferrite rings on my desk waiting for me to turn them into baluns!
Great information for us newbies thanks!.
My pleasure Peter. Thank you for stopping by 73
Very helpful. Thank you. 👍🏻
Thank you Paul 73
We love ya Tim 😊
Ha!
Very interesting Tim, thanks :-)
Thanks Mike. Appreciated. 73
Great videos! I enjoy them! Hope all is well with you and your family!
Kb2rzy lee from the states.
Thank you so much Lee. Hope you and your folks are staying safe and healthy. 73.
Nicely explained Tim maybe you could have mentioned that ladder line feed doesn't need a balun and connects to ATU.
Yes i agree. In fact what you describe for a doublet is the preferred set up. I just wanted to show the use of a Balun in the alternative arrangement for a doublet. Really appreciate you stopping by and commenting 73
Nice one Tim. I tend to roll my own as I'm from Yorkshire, Short arms and Deep pockets ;-) 73 G1AW
Ha! I’ve got a mate from Pontefract ... never his round! 73
Hi Tim I enjoy your videos.
My question is if you have a multiband vertical 80m through 6m could you daisy chain a couple of of chokes of the values to suit thus you don't have to keep changing chokes ?
I need to mull over that one
Great video Tim 👍alot of the balun manufacturers say place the balun at the radio end yet most people on you tube saying put it antenna end????? I use an efhw and getting rf turning my monitor off so what end would work best for me please?? I'd say transformer end??
In your case go transformer end. If you are running 40-10 then about 2m from transformer is good.
You are probably a lifetime seasonal hay fever sufferer and heard all the remedies I find a tea spoon of local honey on my oats for breakfast all year round helps me during my hay fever season. No drugs work for me really don't waste my money on them.
Thanks. Yes it’s a 2 to 3 week window at this time of year which affects me. I’ll check out the honey remedy, thanks.73
Thank you for such a great video, my only aerial option at present is a loft based 11 meter inverted V, we also have a Freeview amplifier box up there too, my main question, in an attempt to stop as much interfere as possible to and from the inverted V, would it be best to have a balun and a wound coax choke, or would it be unnecessary to have both?
I think a good quality 1:1 current balun at the feedpoint in your case is ESSENTIAL. But your biggest issue, given how close the freeview box is you your antenna, is its proximity to your antenna's RF field. I would start with low power and see what higher power does. A lot of commercially acquired freeview boxes and amplifiers are either woefully broad-banded or have poor screening against external RF sources. That may be your biggest issue. 73.
@@timg5tm941 thank you for your reply, is there any kind of box I could put the freeview amplifier into, to help shield it from the 11 meter RF?
@@paulwilson1555 I would try the power test first using SSB. It may also be the case that you’ll be getting into other devices either directly or via mains leads etc.
@@timg5tm941 cheers thank you, I shall try that, fantastic advice and very much appreciated. Paul
@@paulwilson1555 you’re very welcome
Hi Tim, thanks for another very useful video...I'm chasing a down a wee issue where transmitting on any band SSB will cause breaking up of my neighbours TV picture...odd....thinking it must be common-mode issue as we are flats and I'm in upstairs flat with coax exiting a window but close to where our electricity (and phone lines) enters the building.
My antenna is not 100% ideally situated at all and my RF does radiate out between his ariel and the TV mast :/
It is receiving and getting out...it's a half size G5RV as I mentioned in our QSO today (5th june) in which you were very encouraging and made me feel very welcome in the hobby, thank you kindly.
Ive stuck a few ferrites on my coax and I no longer knock my own wifi out when TXing on 40m, but Im still causing a break up of his TV picture...oh, FM does not interfere at all.
I now know that the home wound chokes are band specific and will look at the info you've provided in he description.
Thank you again and sorry for waffling :) If you have any suggestions as to what I sould try in my situation I'd be grateful...you gave me a very nice report so my station works other than the issue with neighbours telly :)
Right, diolch yn fawr Tim, 73 MW7GIB
Hi it was great to work you. Just to get a picture in my mind is any part of the antenna itself close to the tv aerial?
@@timg5tm941 The "undriven" leg comes back toward the property and is 5 - 6M away from his aerial at its closest point. Sadly, space requires that the same leg of the antenna have a short length of it dangle down therefore probably compromising and already compromised antenna. It's just too close to his TV aerial isn't it? And it's out of balance isn't it? Thanks for the quick reply Tim.
I agree I think it’s too near the tv aerial. Do you have any loft access at all if you are top floor?
Or a shortened efhw ... 39feet up a 12m spiderpole will get you 40 20 10 as a vertical?
@@timg5tm941 I have got loft space but it is so full of badly-run mains wiring (thanks council contracters) that it's just an interference nightmare up there :( I'm going to move my pole into the middle of the lawn, sod it, and see if I can get some more distance between our antennas...maybe I can get it sorted that way. Otherwise EFHW is worh a shot, as is a G7FEK style antenna that a friend has dropped off for me to try, though Ive not got a pole high enough for that one yet. Appreciate the replies here Tim, thank you sir.
Hi Tim very interesting,if you get time could you do some topics on shortwave listening setups Best Regards Tim
Ok nice idea
Hi there. Thank for sharing. If I make an antenna for monitoring purpose only (connect to receiver), then no balun/choke needed (as there is no common current mode), right?
A choke can help to reduce noise on receive
@@timg5tm941 Thks Tim. '73, de YD1BAF
Hi Tim, another good video and helpful for those on the quest to learn more.
I have an old (4th Ed.) copy of Joe Carr's book, Practical Antenna Handbook which I got at a charity shop a while back. I understand it is something of a bible to US hams in the field of home built antennas. But, it doesn't seem to mention Ununs. Are you aware of another term people may use to describe those?
I know that an Unun is used to match an unbalanced antenna such as a vertical with unbalanced feed lines such as coax. I used a Hamtenna 4:1 Unun to match a vertical wire cut for 40m / 7MHz. It produced a usable SWR but does the Unun also act as a choke?
73 M6EXF
Hi Stephen to match the balanced dipole to an unbalanced feeder such as coax its preferable to use a 1:1 current Balun. The 4:1 you describe is purely an impedance transformer, designed to bring an impedance of around 200-350 ohms to within a useable range for our 50 ohm transceivers. So in essence to ensure you choke off any common mode whilst using a 4:1 you will need some additional form of choking in many cases, including verticals or long wires. With the centre fed dipole with a 1:1 current Balun there should be no need as the Balun itself helps to suppress common mode (provided the dipole remains balanced). 73
@@timg5tm941 Thank you, that is very helpful.
Hi Tim, where can i get the positive/negative binding posts for the top of the balun ?
Are you just missing the binding posts from a Balun you already have?
No I want to make one
Ah ok I’m sorry I’m not sure where to obtain them
OK thanks will do some research
Good work thanks 2e0wsj in Northampton
Thanks!