View Full Version : Build your own 4:1 voltage BALUN for 1kw
W4INF
04-22-2008, 01:50 PM
http://rogertango.com/articleread.aspx?idnumber=34232411
I just finished and posted the article for the BALUN we (daughter and I) built yesterday.
I hope you find it useful.
Andrew
WA6MHZ
04-22-2008, 02:03 PM
Thats a WONDERFUL Article Andrew!!! So very helpful and easy to follow instructions. Much better than we would see in QST or CQ! THANKS!! I will make one!
W4INF
04-22-2008, 02:34 PM
And, the information was free! HA HA!
Thx for the gud words... Hope it serves someone well.
Andrew
A71AN
04-22-2008, 03:07 PM
http://rogertango.com/articleread.aspx?idnumber=34232411
I just finished and posted the article for the BALUN we (daughter and I) built yesterday.
I hope you find it useful.
Andrew
My friend, if I build a dipole for 30 meter is it better to have 4:1 BALUN or 1:1 ?
Thank you and wishing you all of the best
73 my friend
W4INF
04-22-2008, 03:46 PM
If you are running a resonant single band dipole, a 1:1 BALUN is what is suggested sir since the feedpoint will be close to 50ohms.
I hope to have one built soon to show how that is done, very similar but is a straight through connection with no cross over.
The 4:1 BALUN is good for a Marconi, full loop or doublet.
HTH OM,
Andrew
Here you go Click below, very kewl article
Nice job! I'm going to throw one together myself, and see if my doublet loads different than it does with the 1:1 current balun I am currently ( pun not intended ) using !
73, Jim
W4INF
04-22-2008, 08:41 PM
Jim, let me know! I hope to build a 1:1 here in the next few days, Id be interested in your results with the two... and if I should go through the trouble to build one!!
Thx-
Andrew
KI4WCA
04-22-2008, 10:44 PM
Great article!Hope to hear you on 75!
W4INF
04-23-2008, 01:12 AM
I dont have much drive on 75, but... if you drop to the bottom of the band, Ill put my 100w to the most efficient mode I know and work ya! TU sir and GL-
Andrew
W4INF
04-24-2008, 11:48 PM
Ill be trying this on a Zep antenna soon, will post any results I may have.
Andrew
W4INF
06-23-2008, 06:04 AM
Just bringing this back up for more exposure.
Andrew
n4bfd
06-23-2008, 01:04 PM
Great article with excellent pictures! :)
Unless I am missing something, you may want to explain what exactly makes it a 4:1 balun, number of turns ect ect.
k8wpj
06-23-2008, 01:19 PM
dumb question=
why would someone choose to use a 1:1 balun instead of a 4:1?
what would determine whether one was better over another?
TIA 73,
matt
K8WPJ
dumb question=
why would someone choose to use a 1:1 balun instead of a 4:1?
what would determine whether one was better over another?
TIA 73,
matt
K8WPJ
4:1 baluns are usefull when using feed lines such as twin lead and window line since their impedance is usually from 300-450 Ohms. A 4:1 balun will transform that to 75-112.5 Ohms. Or in other words from an SWR of 6:1 or 9:1 to 1.5:1 and 2.25:1, much easier ratios to tune with a tuner, or even use without a tuner (if you're using a tube rig :D).
A 1:1 balun is usefull when using a simple dipole or vertical, since the feed points are usually already quite close to 50 Ohms (flat dipole = 72 Ohms, inverted Vee = 52 Ohms, verticals = 30ish Ohms). 1:1 baluns are less used for converting impedance as they are used to isolate the shield of the coax feedline from the antenna to avoid RF on the line, and in turn coming back to your rig.
Of course, you can make a balun to do any ratio. There's plans in June 2008 QST for a 2.8:1 balun!
n4bfd
06-23-2008, 01:42 PM
Forgot to ask Andrew, are you using this for your end fed zep? Normally you would use a Current balun for that, to keep feedline radiation down. A voltage balun just transforms impedance.
K9MDJ
06-23-2008, 09:31 PM
A 4-1 balun is also useful in building an off center fed half wave antenna. If you have room, 44ft on one side, 88ft on the other with a 4-1 balun in the center makes a nice antenna that works on almost all of the hf bands. Look at the graph below and you'll see that most of the bands are very close to the same point of the impedance curve.
http://users.ameritech.net/mjones004/WindomGraph.jpg
Mike K9MDJ
W4INF
06-24-2008, 04:42 AM
Forgot to ask Andrew, are you using this for your end fed zep? Normally you would use a Current balun for that, to keep feedline radiation down. A voltage balun just transforms impedance.
I just put up a new Zepp... 66ft of wire flat at 25ft AG... fed with abt 35ft of 450ohm ladderline. Yes, I am using that balun with the current setup.
The antenna still seams to tune up fine and good reports thus far.
I am open to all suggestions, including where to find step by step plans for a CURRENT balun. :)
Experimenting with antennas is one of the aspects of the hobby I enjoy, so switching out this for that and trying something different is part of my plan.
Andrew
n4bfd
06-24-2008, 05:52 AM
Actually I guess you could just slip some 61 or 43 mix or ...whatever ferrites right over the coax where it attaches to the balun, that would choke down any feed line radiation.
I used these on a windom I tried that had just a voltage balun, I put ten in a row at the feed point over the coax. You can also use them to make a 1:1 balun to transfer to balance line. Cebik states that if you do that, and use a short peice of high quality low loss coax that it will have less loss than most of the 4:1 baluns built into tuners, but it would probably need to be under 10 feet or so.
http://www.buxcomm.com/catalog/index.php?main_page=product_info&cPath=41&products_id=1032&zenid=504c10cda3e1559fc9300f988a96e597
http://www.buxcomm.com/catalog/index.php?main_page=product_info&cPath=41&products_id=1044
Buxcomm is in Lynchburg, I order odds and ends from them all the time, stuff always gets here the next day.
kc4umo
06-24-2008, 11:29 AM
Andrew,
Good info. Thanks for posting.