43ft multiband vertical - balun to unun - Elmers Forum at eHam.net

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eHam.net Forum : Elmers : 43ft multiband vertical - balun to unun

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43ft multiband vertical - balun to unun	Reply
by ES1TU on November 21, 2008	Mail this to a friend!
Hi folks, As you already know I experienced some lousy performance of my 43' vertical and the balun (AT200, which turned out to be voltage balun) combination. Discussion about it is found here http://www.eham.net/forums/Elmers/201882 As w8ji, vk1od and n3ox suggested, I turned my voltage balun from http://www.algonet.se/~adok/aadu/inside.jpg to unun http://www.w8ji.com/images/ES1TU/ES1TUunun.jpg I have slept only 4 hours this night. Why? Because I had SO MUCH fun on 40 and 80 meters! With 100 watts I could work all europe (including EA8) on 40m with solid signal reports. Finally I felt equal to other people ;) On 80m I had to use Palstar-s AT1KP cause my 756p3 internal ATU was not able to tune the antenna. But this time people actually HEARD me on 80meters!! I worked LA1, OZ2, DJ, lots of G and DL. I guess tuner at the base will make things even better on 80m. Anyway - my sincere gratitude to you all. PS! for those who use AT200 with their vertical - you MIGHT want to go through the thread mentioned above and open the cover of your balun. As I said - I also WORKED TA3AX on 40m and got signal report 53. 73, ES1TU

RE: 43ft multiband vertical - balun to unun	Reply
by W8JI on November 21, 2008	Mail this to a friend!
ES1TU, I'm happy to hear of the large the performance difference when changing from a voltage balun to the un-un. There are two things from this everyone should keep in mind: 1.)eHam reviews or other random public opinions aren't as accurate or meaningful as we might think. 2.) Never feed a grossly UNbalanced load with a voltage balanced source system that forces voltage balance. Except in very special situations antennas need current balance in the terminals, not voltage balance. 73 Tom

RE: 43ft multiband vertical - balun to unun	Reply
by VK1OD on November 21, 2008	Mail this to a friend!
Aadu, Pleased to hear of your success. It went pretty much the way I expected. Owen

RE: 43ft multiband vertical - balun to unun	Reply
by WA3SKN on November 21, 2008	Mail this to a friend!
Good to hear its working. Now put it to use! Enjoy, and 73s. -Mike.

RE: 43ft multiband vertical - balun to unun	Reply
by N3JBH on November 21, 2008	Mail this to a friend!
OK i ask this agian... Would the DXE-VFCC-H10-A Feedline Current Choke From DX Engineering be a better device for this antenna? W8JI i think you are very famialer with this unit. Or what would be a Great commercialy built UN-UN for this type antenna Please Jeff

RE: 43ft multiband vertical - balun to unun	Reply
by W8JI on November 21, 2008	Mail this to a friend!
A real current balun is an infinitely better choice than a voltage balun for an application like this. A voltage balun is the way we would NEVER want to feed an unbalanced load like this. It makes no sense at all. Open wire line would be another bad way to feed it, unless the open wire line had a good high impedance 1:1 balun at the antenna. Don't consider this an endorsement of tuners in the house on coaxial lines. It isn't, unless you use a short coax or a very low loss coaxial line and a good tuner. Then it is OK.

RE: 43ft multiband vertical - balun to unun	Reply
by N3OX on November 21, 2008	Mail this to a friend!
"Don't consider this an endorsement of tuners in the house on coaxial lines. It isn't, unless you use a short coax or a very low loss coaxial line and a good tuner. Then it is OK. " I second that! The thing about antennas is that you can only make a particular radiator so good, and there's usually only a couple of paths to getting within an insignificant amount of best performance at a reasonable cost (and for this antenna, that path is to match it at, or very close to the base). But if you try to go the other direction, you can make an antenna AS BAD as you want ;-) Glad you've made yours better though ;-) Dan

RE: 43ft multiband vertical - balun to unun	Reply
by VK1OD on November 21, 2008	Mail this to a friend!
I have updated my article "An unloaded vertical as a multi-band HF antenna" where it deals with the Zero Five / Array Solutions recommended feed arrangement in the light of Aadu's pics of the balun which confirm it as a voltage balun. The article addresses some of the questions about performance, remote ATU, internal ATU, and use of a common mode choke. The article is at http://www.vk1od.net/multibandunloadedvertical/index.htm . Owen

RE: 43ft multiband vertical - balun to unun	Reply
by KZ5R on November 21, 2008	Mail this to a friend!
<<OK i ask this agian... Would the DXE-VFCC-H10-A Feedline Current Choke From DX Engineering be a better device for this antenna?>> I don't believe Tom fully answered this question so I would like to add to it and ask again. In lieu of a tuner at the base of the vertical, what is the consenus for the use of a balun or unun. Should one use the 4:1 current balun and force balanced currents or is a 4:1 Unun more desirable? Also, maybe Owen or Tom could explain why one or the other is more desirable. Brgds, Bob

RE: 43ft multiband vertical - balun to unun	Reply
by VK1OD on November 21, 2008	Mail this to a friend!
Bob, My view is that if the coax shield is bonded to the radial system and you bury the feedline, the common current on the feedline will decay quickly in average or better soil. If you do encounter excessive common mode current entering the shack (short feedline, sandy / rocky soil etc), then a common mode choke deployed outside the radial field would be a good counter measure. I addressed these in the article update I notified in a post above. There are wider issues including line loss, ATU loss, balun loss / power rating at the extreme impedances seen on some (most) bands. Owen

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