| Author |
Message |
    
Jameslarson
Intermediate Member
Username: Jameslarson
Post Number: 183
Registered: 4-2006
| | Posted on Wednesday, June 07, 2006 - 2:25 pm: | 
|
Hi. Does an IMAX need a Balun? What exactly does a balun do? I kind of have an idea of what a balun does, but not 100%. Thanks.
O yeah, how is Balun pronounced (Is it like the word balloon?) |
Tech808
Moderator
Username: Tech808
Post Number: 10211
Registered: 8-2002
| | Posted on Wednesday, June 07, 2006 - 4:31 pm: |
|
Jameslarsen,
All you have to do is LOOK to the LEFT of the Forum here and CLICK on Search which is located under Utilities and TYPE the word BALUN in to get all of the answer's to your Question's.
OR
Just SCROLL on down in THIS Area and READ the Topic's Titled:
Baluns on verticals.
OR
Back with the 11 meter dipole questions
OR
BALUN Discussion
OR
Baluns and chokes
And there are hundred's of other post's you will find on Balun's just by using the Search feature which is located under Utilities located to the LEFT of the FORUM here.
Hope this help's,
Lon
Tech808
CEF808
N9CEF
CVC#2 |
Jameslarson
Intermediate Member
Username: Jameslarson
Post Number: 184
Registered: 4-2006
| | Posted on Wednesday, June 07, 2006 - 5:44 pm: |
|
I pretty much did all that, and while I found many articles regarding balun's, and someone who actually built one, there were not any posts that specifically answer the question if the IMAX needs a balun (At least I could not see any).
Also, I did not find specifically what a balun really is. I was kind of able to figure out maybe what it was for, but nothing was answered directly, so that is why I asked:
1. Does an IMAX need a Balun?
2. What exactly does a balun do?
3. How is Balun pronounced (Is it like the word balloon?)
I will continue to search as well. Maybe I'll stumble upon the answers as well. thanks. |
Marconi
Advanced Member
Username: Marconi
Post Number: 671
Registered: 11-2001
| | Posted on Wednesday, June 07, 2006 - 6:31 pm: |
|
James it is some good reading using the search, but I doubt you will find a direct answer to your question. Balun is pronounced Bal - un, meaning balanced to unbalanced. This refers to a balanced antenna like a dipole to and unbalanced feed line like coax. In my book an end fed antenna is not balance, but they can still benefit from a balun, or choke device that prevent or help prevent Common Mode Currents (CMC) on a coax feed line.
The affects of CMC on a feed line are to disrupt the radiated pattern of an antenna, generate RF problems at the shack and on equipment, and maybe to generate TVI often associated with harmonic type interference. These are complicated issues to grasp and I can't add much more.
What does a balun do, you ask? Basically the 1:1 balun you are inquiring into is supposed to created a high impedance point somewhere on the feed line of the coax usually near the feed point and this helps prevent CMC from passing on into the shack and equipment.
Does an Imax need a balun? Well yes and no. The Imax surely uses CMC in the process of producing RF, but since it is vertically polarized and the feed line is usually vertical as it leaves the antenna, it is MO that it does not hurt anything unless maybe it causes problems or the angel of radiation of the feed line RF is very high and then it does little more than warm the clouds, so-to-speak. This would likely have a strong detrimental affect on any horizontally polarized antenna. |
Tech808
Moderator
Username: Tech808
Post Number: 10213
Registered: 8-2002
| | Posted on Wednesday, June 07, 2006 - 6:32 pm: |
|
From my own personal experience as a user and dealer since the first Antron A-99, then Anttron A-99 and then Solorcon A-99 and the Anttron 305 as well as the Solorcon IMAX 2000, came on the market I personally have never found any reason or needed to add a balun for any of them as I have NEVER had any problem's with any of them that required the use of a Balun.
But if anyone read's the Post's under the Topic's I listed above they will find that several Copper Forum Member's have posted that they have addd a BALUN.
Hope this help's,
Lon
Tech808
CEF808
N9CEF
CVC#2 |
Road_warrior
Senior Member
Username: Road_warrior
Post Number: 1586
Registered: 7-2004
| | Posted on Wednesday, June 07, 2006 - 7:41 pm: |
|
I know what your worried about James. You
only want to install it once in that big
tree and hopefully not have any issues with it.
Right? 
But, the fact is all you can do is install
it and see, then go from there if there's
problems. Put the GPK on it. |
Jameslarson
Intermediate Member
Username: Jameslarson
Post Number: 185
Registered: 4-2006
| | Posted on Wednesday, June 07, 2006 - 10:29 pm: |
|
Yes, I want to install and be done. I do plan on putting the GPK anyway. I was just wondering if adding a Balun would be worth it. Where does 1 buy a balun? I know, I can google it. but with so many results in google, I would not know who is a reputable place, and secondly, what is a good make or model. Any suggestions on brand and model? Thanks. |
Marconi
Advanced Member
Username: Marconi
Post Number: 673
Registered: 11-2001
| | Posted on Thursday, June 08, 2006 - 12:34 am: |
|
James whatever you get you will need to try and see what affect it has before you go into the tree. I have read that they cause SWR problems, but if that is the case with a 1:1 current balun, then it is not doing what it is supposed to do.
I use a field strenght meter to see how the antennas feed line is acting. If I get a lot of FS movement with the meter sitting on my RF meter then I figure I have some work to do if I want to eliminate it. |
Tech833
Moderator
Username: Tech833
Post Number: 1377
Registered: 8-2002
| | Posted on Monday, June 12, 2006 - 11:19 am: |
|
When installing in coax, you do NOT want a balun. If you wish to isolate the antenna from the cable, you would want an un-un. As the name implies, it is an unbalanced to unbalanced transformer. Although, you can do essentially the same thing with some ferrite chokes. |
Drgrant
New member
Username: Drgrant
Post Number: 3
Registered: 6-2007
| | Posted on Thursday, June 07, 2007 - 3:19 pm: |
|
IMO put 3-6 HF rated ferrite snap ons on the
feedline near the input of the antenna before you
put it up. This will help keep any stray RF
currents off the coax. It is cheap insurance,
especially against TVI/RFI problems. I also
stretch-wrap them with some good electrical tape
to keep them from falling off due to sunlight,
temp fluctuations, etc.
-Mike |
