Topband: Disappearing toroid

Lup Schlueter dj7sw at
Fri Sep 11 02:43:08 PDT 2009

The  core loss is caused by a little dyre called in german:

the Stein-Laus (stone louse)

see here for a picture :

You can see one in action here:

Sad to say, but there is no hope, it will surely happen again!
73 de Lup

Jon Zaimes AA1K schrieb:
> 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
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