Hi Tom: I believe you are correct, the problem is overheating. K9yc has
made many presentations on the topic of wide band baluns and you can read
all about it on his web page. He is right on and I have built and measured
several dozen with similar wide band results. using type 31 ferrite.
I wrote a piece about the type of baluns you describe as well as much
better ones and you can see it on our clubs web page
www.sdxa.org under articals.
73, Dan, N5AR
On Sun, Apr 20, 2014 at 6:34 PM, Tom Hellem <tom.hellem@gmail.com> wrote:
> Fellow TTers:
>
> I built a balun for my triband yagi consisting of 50 type 73 ferrite beads
> slipped over a piece of RG 303
> coax, enclosed inside of a piece of 1-1/2" pvc. Had one of the wires break
> inside and I surmised it must have
> been a result of wind-caused vibration, etc. So after I repaired the broken
> connection, I squirted some of that
> canned foam insulation (the kind that is sold for foaming around windows &
> doors, etc.)into the pvc enclosure,
> encasing the entire piece of coax & ferrite beads in the stuff thereby
> preventing any vibration , etc in the future.
> Upon further thought I am wondering now did I invite the balun to overheat,
> especially while running high power,
> as any heat generated has no way to escape.
> Does anyone have an opinion one way or 'tother?
>
> Tom
> K0SN
> Missoula, MT
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--
Dan Hearn
N5AR
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