where to put a balun +tuner efficeincy - Page 1
Forum section: electronics / rf-microwave

author: p.larner
author_rank: Frequent Contributor
timestamp: December 13, 2023, 05:58:55 am
content: I have a homebrew t match using a 60mmx 30cm long 60 turn roller inductor and a wide spaced approx4mm 2x300pf dfferential cap,ive just finished the twin needle power/swr calibraton pcb for high and low ranges,its working great but has no balun yet,question 1,where is best to fit the 1-1 or 4-1 balun(undecided what ratio to use), would it be best on the tx side or ant side?,i also have an sem transZmatch ,question 2,what will be most efficient used with a doublet the z match or t match?,cheers +73.

author: p.larner
author_rank: Frequent Contributor
timestamp: December 13, 2023, 06:04:13 am
content: forgot to say i have a ready made homebrew aircored 1-1 balun using 3 wires but guess i cant use that in my atu as it will be near metalwork?.

author: Andy Chee
author_rank: Super Contributor
timestamp: December 13, 2023, 09:56:21 am
content: Here you go:https://www.dj0ip.de/balun-stuff/tuner-baluns/If a 4:1 is necessary, put it at the doublet feed line split, and the 1:1 is at the ATU.

author: p.larner
author_rank: Frequent Contributor
timestamp: December 13, 2023, 08:18:57 pm
content: was thinking of the puting the 4-1 balun made with 2 cores on the atu input(antenna side) pic 1 and the 1-1/choke pic2 balun choke on the tx side of the atu will that work to choke common mode currents and do a 4-1 transformation?.

author: Andy Chee
author_rank: Super Contributor
timestamp: December 13, 2023, 08:23:48 pm
content: Put both the 1:1 and the 4:1 baluns on the antenna side of the ATU. If you don't, you may still have problems with burning up caps in your ATU.

author: A.Z.
author_rank: Super Contributor
timestamp: December 14, 2023, 06:45:52 am
content: Quote from: p.larner on December 13, 2023, 08:18:57 pmhttps://vk6ysf.com/allbandhfdipole_mk3.htm<deep sigh>

author: p.larner
author_rank: Frequent Contributor
timestamp: December 14, 2023, 07:42:58 am
content: forgot to say this is now fitted inside my homebrew t match not the atu-100,i still have to fit the endcaps on the atu-100 case and wire the buttons up,my tmatch is working ok,on the net on 3.775 but its not good as the band is poor,same on hack green web sdr.73.

author: A.Z.
author_rank: Super Contributor
timestamp: December 14, 2023, 09:33:36 am
content: Quote from: p.larner on December 14, 2023, 07:42:58 amYou may still test it on 40m to check how it's working, there's quite some activity there at the moment on that band

author: p.larner
author_rank: Frequent Contributor
timestamp: December 15, 2023, 11:22:48 am
content: the all band dipole on the linked vk6 site is 42m long,mine is 40m,i still cant tune anything higher in frequency than 80m,will adding 1m on each leg of my dipole/doublet help?,i vave trien with a 1-1 balun+ a 4-1 balun.

author: Andy Chee
author_rank: Super Contributor
timestamp: December 15, 2023, 01:57:42 pm
content: I would first try getting rid of the 4:1 balun. Use the 1:1 balun by itself.

author: A.Z.
author_rank: Super Contributor
timestamp: December 15, 2023, 03:27:09 pm
content: Quote from: Andy Chee on December 15, 2023, 01:57:42 pmAs I wrote, it would be a very good idea to plug the 1:1 at the end of the ladder line and then use the VNA he has to check the impedance presented there on the various bands, at that point, knowing the impedance range it will be easier to decide if it's the case of using a transformer and which ratio will offer the better match, for example, let's say the impedance ranges from 200 to 600 Ohm (let aside the R+X for the moment), in such a case a 4:1 or a 6:1 may fit, but if instead we see values ranging from 12 to 600 Ohm, then using a 4:1 would make life difficult for the ATU since the 12 Ohm would then become 3 Ohm and it will be difficult for the ATU (aside other considerations) to match that

author: vk4ffab
author_rank: Frequent Contributor
timestamp: December 15, 2023, 09:45:36 pm
content: Quote from: p.larner on December 15, 2023, 11:22:48 amAn antenna is a system, connect all your bits and bobs in place and then sweep it from 1 to 30mhz and post the plot we need to see something like this to get an understanding of what the antenna is doing. A.Z. has asked you to do this a few times. We cannot give you advice without information, the more information the better.

author: A.Z.
author_rank: Super Contributor
timestamp: December 23, 2023, 08:44:25 pm
content: I sincerely hope he won't come back anytime soon

author: p.larner
author_rank: Frequent Contributor
timestamp: December 24, 2023, 06:35:44 pm
content: extending the windowline by 5ft and removing the 4-1 balun leaving just the 1-1 sorted it.

author: Andy Chee
author_rank: Super Contributor
timestamp: December 25, 2023, 12:10:51 am
content: Well done..... finally!You could probably read back through your 'doublet tuning' thread and maybe understand the advice that others were trying to give you.Because with the benefit of hindsight the challenge now is, to teach your younger self from 1-2 months ago, how to build your antenna with less drama!

author: vk4ffab
author_rank: Frequent Contributor
timestamp: December 25, 2023, 08:03:18 pm
content: Quote from: A.Z. on December 23, 2023, 08:44:25 pmLOL it takes all kinds.