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Author Topic: Type of balun for an aluminium dipole?  (Read 586 times)
MM1APX
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Posts: 17




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« on: February 17, 2005, 06:13:41 PM »

I have a Cushcraft D3 aluminium dipole antenna (20m/15m/10m)....

My intention was to make a simple coax choke balun to use with it (a few turns of coax on say a 6 inch former)... However, in my shack I have a Radioworks 1:1 Current Balun (model: B1-2K Plus) which is just gathering dust at the moment....

Would there be any advantage / dis-advantage to using the Radioworks balun ?
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OBSERVER
Member

Posts: 130




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« Reply #1 on: February 17, 2005, 07:21:10 PM »

Yes, the RW current balun will provide a higher level of choking inductance for impeding outer shield current flow.  Whether or not it will make a difference, who knows.  With your simple coaxial choke, are you seeing a problem that you think that is related to an unbalanced radiator?
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KZ1X
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Posts: 3228




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« Reply #2 on: February 17, 2005, 08:05:51 PM »

Your problem may be the antenna material.  Apparently, the aluminum that Cushcraft sent to the UK has changed en route, possibly due to radiation at the high altitude, if it was shipped by air.  It seems that the material you have now is some similar-looking alloy called "aluminium" with properties unknown here in North America.

Perhaps if you built a dipoule using the aluminium, the addition of the pointless extra letter (kind of like the 'u' in colour) will help balance things out.

;-)
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K0ZN
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Posts: 1553




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« Reply #3 on: February 17, 2005, 08:12:45 PM »


Short version: try it out; that is the only way your will really know... but I have a suspicion that you probably won't be able to tell much, if any, difference between them.

In almost all cases of adding a balun to a coax fed BALANCED antenna you WON'T hear a *noticeable* difference... possibly, you *may* see a little wider SWR bandwidth on the antenna because less energy is going down the shield (which gets worse as you move away from resonance). You *may* notice a little less received noise because man made noise tends to be vertically polarized and the coax shield picks it up more than the horizontal element.

Bottomline: in a properly made and installed horizontal BALANCED antenna, fed with coax, you really won't see or hear much difference, but that doesn't mean the balun is not working and/or is not helping... it is just that the differences are pretty subtle. The "benefits" of adding a balun to a correctly tuned dipole are really pretty minor in most cases.

73,  K0ZN
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N6AJR
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Posts: 9910




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« Reply #4 on: February 17, 2005, 09:21:35 PM »

It may help and certainly won't hurt, and may keep some rf out of the shack, and perhaps kill a bit of RFI.. the balun sort of kills the rf on the outsidde of the coax and helps keep a balanced "load " to the rig. so if you are perfect, there is no difference, but if out of whack, then it will help.

by the way I spell it alunuimunimun... just like it is pronounced,  Smiley
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G4IJE
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Posts: 247




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« Reply #5 on: February 18, 2005, 11:40:48 AM »

I bet KZ1X wrote his reply on a Pentum PC. Personally I find Pentiums much better...
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