[TowerTalk] The Balun Blues

[K7LXC@aol.com]

In a message dated 98-02-03 11:37:11 EST, seay@alaska.net writes:

> Your experience mirrors mine. The transformer type of voltage
>  Baluns have caused a lot of trips up the tower.
>  The coiled coax versions are somewhat better, but I've had several
>  problems with interwinding voltage breakdown on these.
>  The ferrite sleeve current balun has never failed me.
>  I've read the efficiency reports, and while I can't verify it,
>  that may be a problem. But, personally, I'd rather loose a few
>  watts from heat than to have to fight the other battles.

Hi, Del --

     One more comment on coaxial wound baluns: Cushcraft recommends them but
cautions the user to only use RG-213. This is because winding the coil with a
foam-dielectric coax may cause the inner conductor to 'cold flow' over time.
This obviously changes the performance and specs of the coax as the
relationship of the inner conductor, dielectric and shield changes over time. 

     Cold flow might explain your voltage breakdown problem.

      If anyone that has the original thread on coaxial wound RF chokes, it
might be a good time to re-post the juicy parts.

73,  Steve  K7LXC

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