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Base 11m dipole symptoms

Wrong. Dipole need balun.
5 turns of coax 7" diameter right under antenna feedpoint.
or 16 turns of coax 4.25" diameter right under antenna feedpoint.
Google for "choke balun", will give you an idea what I mean :)
I suggest to use some ferrite beads at the coax entrance to your house.
Mike
 
sp5it said:
Wrong. Dipole need balun.
5 turns of coax 7" diameter right under antenna feedpoint.
or 16 turns of coax 4.25" diameter right under antenna feedpoint.
Google for "choke balun", will give you an idea what I mean :)
I suggest to use some ferrite beads at the coax entrance to your house.
Mike
Click to expand...

I thought I'd be good to go out of the box, it looks like this .
mCrMjsL2zCBdOnCQQVJ90ng.jpg
 
sp5it said:
Wrong. Dipole need balun.
5 turns of coax 7" diameter right under antenna feedpoint.
or 16 turns of coax 4.25" diameter right under antenna feedpoint.
Google for "choke balun", will give you an idea what I mean :)
I suggest to use some ferrite rings at the coax entrance to your house.
Mike
Click to expand...

Two things.

What you are talking about isn't actually a balun, it is a choke. To be a balun it has to force both sided into balance. The chokes made by winding coax only resist the flow of RF in a certain direction, they do not force balance. Either may work for your needs, but they meet those needs in very different ways.

And the dimensions given are not good for CB use. Here is a chart made from actual testing.

choke_impedances.png


Five turns on a seven inch form would be great for the region between the 17 and 20 meter ham bands. 16 turns on a 4.25 inch form would be great for the frequencies just below the 20 meter ham band. If you are talking about the 20 meter ham band, either of these options would be acceptable, however, if CB is what you where you want the choke to work, 5 turns on a 4.25 inch form works very well.

Limeybastard said:
I thought I'd be good to go out of the box, it looks like this .
View attachment 21467
Click to expand...

That is likely fine. Many of those have a balun inside the PVC covering. Do you happen to have a link to where you got it, or any other such information for verification?


The DB
 
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Reactions: Shadetree Mechanic and Limeybastard
For 10 bucks on ebay i doubt there will be a balun in the white container & it looks too small to contain an effective coaxial choke,
 

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