I had an R7 matching network have the cores partially disappear because of
water
leakage (these are 2 inch cores) perhaps in conjunction with freezing
weather. Looking
at the interior of the box it was not obvious that water had entered but
pieces of the cores
were gone.
73, Larry W6NWS
----- Original Message -----
From: "Jon Zaimes AA1K" <jz73@verizon.net>
To: "Topband" <Topband@contesting.com>
Sent: Thursday, September 10, 2009 9:24 PM
Subject: Topband: Disappearing toroid
> With the new season starting to get into swing, I discovered a few days
> ago that my phased JA Beverages (each 935 feet long, spaced 175 feet
> broadside) were not functioning. Since a JA was hearing me today, but I
> couldn't hear him, I figured it was time to get things working.
>
> When I walked the wires this morning I discovered that a tree had busted
> one wire about halfway along its length. The feedpoint transformer on
> the one element looked fine (which happened to be the one with the
> busted wire). The terminations on both looked fine.
>
> But the feedpoint on the other was perplexing. The insulated coil wires
> were still in place, looped just as I had wound them on the BN-202
> binocular core several years ago. But the core itself was gone! I
> scoured the ground below but could find no pieces of the ferrite --
> though since this is in a woods they may have been buried by pine
> needles and leaves.
>
> While I thought a lightning strike might have vaporized the core, I
> would have expected there to also be damage to the wires. But there is
> no evidence of this -- the insulation appears undamaged, no blackness or
> other sign of being "cooked." I did have some minor lightning damage in
> the shack a few months ago -- the first in nearly 12 years at this QTH.
>
> So I'm wondering if any others have had this experience with a BN-202?
>
> I have spare cores so will just wind a pair of new transformers to be
> sure -- and check out the terminations with an ohmmeter too.
>
> 73/Jon AA1K
> Felton, Delaware
> www.aa1k.us
>
>
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> Topband@contesting.com
> http://lists.contesting.com/mailman/listinfo/topband
>
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